How does a motorcycle petcock work?

[@aalennn1]

no proper lights no special equipped tools no graphical representation but still one of the best #1video that explained about motorcycle petcock perfectly. thank you sir.

[@jimcurtis8410]

Took me a while to think of your name but finally found you I’ve watched your repair videos numerous of times haven’t found someone who can explain it so easily

[@mrmaxstorey]

glad to help

[@agentblaque1971]

Mrmaxstorey, thank you so much for taking the time to make this video. It was very informative. I have an '81 Maxim, there is no way I'd still be riding it if it were not for your help and the other KZbin University professors.

[@gagerose3820]

hey, I got a 82 maxim also

[@rickburrington408]

Thanks for the GREAT Video! Very descriptive explained everything for me. I've had my first bike for 2 weeks now so didn't know anything about the petcock. I was out in middle nowhere and my bike stopped running I couldn't figure out why, finally I turned the petcock back and forth and then it started. I got to a town and it died again, so I turned the petcock again and it started up again. This happened all the way home and now I know what was wrong. The gas in my tank was lower than the on position and I was moving the petcock and letting fuel in but I didn't know enough to leave it in the res position. You saved me from an embarrassing visit to the cycle shop. A BIG THANK YOU!!!!!

[@basimfara]

as long you understand the principal of the part you can solve most of the problem by your self but still need the experience of such guy like you explaining the theory. thanks this video help me a lot.

[@mrmaxstorey]

Glad to help

[@iangodbehere19]

Most useful video I've found for ages. Got symptoms of a broken diaphragm on my tap. Only works on prime. Just gonna check the air line isn't broke then I'm getting a tap. Thanks again

[@keving52002]

This is the only video on youtube that thoroughly explains this subject on petcocks. thank you for posting this....

[@spelunkerd]

Max, you are my hero tonight. A few months ago I took my gas tank off, and I wondered why gas didn't flow out when I removed the tank and petcock together, with the petcock set to 'on'. Then I thought, maybe Max can explain it to me. Before I got around to asking, you posted a video that answered my question. Bravo.

[@jurplaa]

Thanks mate! I'm new in motorcycles and thanks to you I'm not keeping my bike on prime anymore! :)

[@m.h.3214]

Finally someone who can explain it simply and perfectly

[@1BrownElCamino]

Thank you so much for taking the time to make these videos. I just bought a 1969 Honda CA77 from my uncle, and I really know nothing about vintage motorcycles (or newer motorcycles for that matter) and your videos help me out tremendously.

[@mrmaxstorey]

Brown ElCamino Glad to help

[@bobvansand6346]

Bob Belgium🇧🇪👌nice visual setup of what happens in tank. Thats what u tubers need, elementary clear calm insight. You are the best!

[@beam887]

This is a very helpful video to understand how this type of petcock works. Thanks a lot for it. Now I can dry my carburetor just by pulling off the vacuum line and run the motor until it die for winterization.

[@digitalfun59]

Thank you for this description, just what I needed to know. My cycle worked fine with a test tank on but not with the stock tank. Now I know to check and clean the petcock valve.

[@GeorgeBohnisch]

Thank you so much for this video. I was having issues diagnosing the frame mounted petcock on my 2000 GS500e and your explanation and demonstration was so clear and thorough. I tried this out myself and found that the diaphragm was leaking due to a bad gasket. Thanks!

[@bobvansand6346]

Hey mate the primesetting is new to me...that explains my initial doubt, cause i put it exactly there, not knowing it existed, suspecting my vacuumsystem was shot. Thx a lot man!

[@freerunnerJ]

Thanks a heap, there is not a lot of info on petcock's on the internet. I did not know whether small leakage out of the fuel feed side was normal or not. Now that mine is slowly dripping, I know to repair it.

[@1Man1Band34]

Thank you for directing me to this video! I have just bought my first bike and knew nothing about it. So my leakage was most likely caused by the petcock being on PRI? I switched the setting to ON earlier today and when I came back there was no leak; and yes there was gas in the tank. So just to clarify, I should keep my petcock switched to the ON position most of time unless I'm running low on gas (RES) or if I need to drain the tank (PRI)? Thanks again for the videos! Really helping me out!

[@chnapz]

Exactly what I was looking for ! Thanks for your video :-) just found an 82' SR400 and wasn't sure about PRI. Greetings from France !

[@mrmaxstorey]

It depend son whether they are vacuum actuated or not. If they are not, then there is no difference between PRI and RES, so they add an OFF function so you can manually turn it off if you want

[@mrmaxstorey]

Yeah you got it, altho as I mentioned in my first petcock video, when you get leaks like this it is mainly a failure of your float needles in your carburetors. Check out my video called Carbs Leaking? Heres how to repair it for more info on that

[@bahenbihen]

Nice video! Mine doesnt have the vacuum hose, so I guess it creates pressure directly from the fuel line going to the carb. My question is whether adding an external fuel filter would significantly lower the pressure as I start running out of gas (due to lower weight of fuel)? I really wanna add the plastic filter, but dont want to end up dealing with a low pressure fuel system.

[@mrmaxstorey]

Its not under any pressure, it just comes down by pressure. I havent had any problems with inline fuel filters

[@bahenbihen]

mrmaxstorey thanks

[@paultappenden4337]

Awesome explanation. Knowing the basics help diagnose problem...I will look tonight!

[@adamcolbertmusic]

Ahhhh....okay....see, my petcock (from a Chinese 48cc engine kit" has "Fuel -->" written on the switch, and you can turn it 180°, and at the 0°, °90 and 180° points there are 3 tiny diagrams (respectively for each degree point), which are a half tan, closed/solid circle (in the °90 degree point), and a half tank. I believe you just solved my mystery ;) the "half tank" means you are reserving the reserve tank, so to speak. I'm so glad I found your video!!!

[@mmisayah]

Hi! wow i feel so stupid. I did just check as you said and saw the O and the RES marking. I see, so do I also leave it ON when the bike is parked and not running?

[@Tacbi0325]

Hey bro .... so at night time I have to turn it OFF or just leave it in position ON ?????

[@Bw-210]

Did you find out

[@mrmaxstorey]

Its not an overflow hole, its a vacuum line. They can leak if the diaphragm is punctured, but then the petcock would not function so its less likely. Get down there again and see if its actually leaking from the faceplate or from the fuel nipple. Then, consult my channel for my other petcock video, and watch how to repair and restore them. Thanks

[@mrmaxstorey]

Take another look, it really should say on pri and res. Like the video demonstrates, you want the petcock on ON or RES when it is running depending on how much gas is in the tank

[@Errorcode_X]

Hey! My petcock is from a 1982 xj550, I cleaned out the gas tank/ petcock thoroughly but when I allow the petcock to be on any setting fuel keeps flowing out! Very informative video btw!

[@mrmaxstorey]

Sounds like something is messed up inside the petcock

[@Errorcode_X]

Is there anyway to repair it?:(

[@mrmaxstorey]

***** Yeah check out my other petcock video

[@TheFoolintherainn]

Finally, a solid video that demonstrates the part. A 1980 Suzuki 550gs will be running soon. Bike mechanics must resent you -this $aved me a few $. Thanks much.

[@gallum55]

May I make a suggestion, put a link in the description to your rebuild a petcock video other then great as always

[@genevickers1702]

Thank you for the helpful information the lecture was described in perfect detail.

[@spelunkerd]

This video made my understanding much more clear about how the petcock works. So much so that I put a link to it within a video I did on replacing my motorcycle cable. Cheers!

[@wsaunders64]

Thanks for the info i have a 1995 GSXR and could not remember the settings RES ON PRI also the video was very helpful.....refreshing my memory Thanks Whitney

[@mmisayah]

Hi, I also am new to motorcycles and just got a new bike today. Might sound like a dumb question but how do I know if my petcock is on, res, or pri if there are no visible markings on it? Also, do I need to petcock on, res, or pri when the bike is running?

[@hunclemike]

I am trying to get an old 2001 Yamaha 125 back in running order. In an attempt to empty the old gas (I did put Stabil in the tank periodically) I removed the fuel line, thinking fuel would run out and into my container. The petcock is vacuum actuated....is that why no gas came out? Would I have to suck or blow into the vacuum line to see if the petcock works and gas comes out? I took the squirt gun off of a spray bottle and connected it to the vacuum line (it fit perfectly) so I will have a vacuum when I squeeze the trigger. The battery is shot and I have to grab a new one today. I was afraid to run it until all gas was cleaned out. I took the petcock apart and it looked clean as can and the diaphragm seemed to be fine as well. I think you just answered my question but suggestions would be great. Super video, very informative.

[@mrmaxstorey]

Does your petcock have a prime setting? If so just turn it to that. If not, consider taking the petcock off the tank and letting it all gush out that way

[@sivucit]

hi, if the petcokc is leaking the gas into carbs, what sort of problem i will face, will it be rich when i start up..

[@ecirlos4902]

Is it ok to run the petcock on reserve always or will that affect the performance? Thank you,, great video

[@mrmaxstorey]

It's fine if that's what you want to do just watch your gas consumption. By running it on reserve all the time you are removing the safeguard in place to alert you when you are low on gas

[@pinballpoolshark]

I've watched a few of your videos and appreciate you not only putting them up, but also the guidance in the comments. I've been trying to get my late Father's 1979 GS850 back on the road. I've got it finally to the point of running smoothly again, but have a steady drip from the petcock. Only when the bike is running tho. It stops immediatly when I power down, am pretty sure it's coming from the (overflow?) hole in the bottom of the petcock, much like in this video.Your thoughts on my next step?

[@AlvaroGarcia-kf3ih]

I just replace the seals on my petcock n still having problems when is in on with vacuum on have nothing no gas went I switch to reserve it will leak small droops help. 94 Suzuki katana

[@rivermetal]

Thanks for the video, I have an1985 GS550 that is a crank but no start, it has spark from both coils & and I can spray fuel in carbs and it will run so I thought it could be a petcock problem so I hooked up a remote fuel source and still wont run, cant smell fuel & plugs are dry, former owner changed float valves any idea?

[@mrmaxstorey]

Rivermetal Clean those carbs man

[@kennethkrajewski9443]

Great video!! Question. Just picked up a 1982 cb900f. Jetting spot on. And it runs super strong. Going down highway after only a couple tank fulls on this bike and it started to bog and I hit reserve but still stalled. Pulled over still had about half gallon in It! Do you think the reserve hose is clogged??? Put 2 gallons back in it and it started right up again

[@mrmaxstorey]

Maybe, this video shows how to test

[@j.ramone4116]

was wondering about that.all my other bikes were on,off and reserve.my xj got the prime,i used to switch it to that for a couple of seconds before starting from cold.it always started so i carried on.

[@mrmaxstorey]

Probably you are just fine. Take a look at the oil level, if it is high, smell it. If it smells gassy, change it before you ride the bike again. No worries

[@juan8777]

my petcock leaks from a small hole on the plastic piece that sandwiches the vacuum connector plate to the back of the petcock. It was clearly put there by design. Just wondering what the purpose of this hole is and why it leaks when i have pet set to on or reserve but there is no continuous flow. Any thoughts?

[@mrmaxstorey]

+Zillacus Your petcock leaks because that diaphragm has a hole in it and will need to be repaired. The purpose of that tiny hole is to allow air to go n and out on the other side of the diaphragm, so trapped air isn't providing pressure for the vacuum to work against. Otherwise it would be a closed system and wouldnt be as effective. Hope that makes sense.

[@morgan-richardmurphey7797]

How come some petcocks have the option of "on" "res" or "off" and others have "on" "res" or "pri". Becuase "pri" and "off" seem to be polar opposites. Thanks, Morgan

[@raulgonzalez4776]

Great video!!! I have a Dyna 2001 and is leaking gas so I bought a petcock from Golan Inc, However, it does not have the out for the air hose, only for the gas.... Any ideas?? Thanks.

[@mrmaxstorey]

Yeah so its a manual petcock instead of a vacuum actuated petcock. Thats fine, you just gotta plug up that old vacuum line. Tie it in a knot and shove it up out of the way

[@jadinwemette8251]

Exactly what I was going to ask 6 years later lol, I have a 1986 yamaha radian yx600 and the petcock has on/prime/res. And it was leaking in all 3 positions, I just bought a replacement but its almost impossible to find an original petcock replacement. The new petcock on its way has on/off/res. So I was wondering what to do with the vacuum line. Makes perfect sense that it wouldn't any longer be needed but I wasn't sure if it was going to be a problem.

[@gazbugz8745]

so u probly guessed im new to bikes.have learnt hell of alot since i got bike and all from start and many an hour browsin vids on utube and very helpfull and keen to learn more & work on them so thanx for all ur info..i see the vacuum actuated petcock must be what i need for my new carb but why would u have a need for this when u can have free flowing into carb bowl? what am i missing ,whats the advantage of vacuum? or does the vacuum pipe pull fuel through itself to feed carb also secondary o.O

[@karllatraverse6772]

Where does the vaccuum attach?? Is it possible that it attaches to the carburator joint

[@mrmaxstorey]

yes it attaches to a same sized nipple pointing up, either on the carburetor or on the intake boot

[@ro31369]

Properly functioning floats should keep the 'Reserve' setting on the petcock from allowing more that the necessary amount of fuel through to fill the bowl.... correct?

[@mrmaxstorey]

No. When the bike is running, the petcock is open like an open faucet, ad it is up to the floats and float needle inside the carburetors to regulate the amount of gas in the bowls. When the bike is shut off, the petcock stops the fuel flow

[@RuffianTux]

Excellent description and demonstration.

[@donjorgerosebushes4886]

My petcock was liking and I used a plastic steel adhesive and it worked out just fine

[@joshburr1549]

I have a 1983 Yamaha Maxim 550. I am new to riding. I have the on, res, pri settings. When I am not riding, what should I turn it too?

[@mrmaxstorey]

on

[@joshburr1549]

Awesome, thank you.

[@raffyl2112]

Hello this is from the future and I have a quick question. I have a scooter with a petcock and carburetor that doesn't require a vacuum feature. Now my carburetor have a problem and I have a reserve carburetor but it has a vacuum hose attached on it. My problem is can I still use this carburetor and just plug its vacuum port since I don't have a vacuum port to attached it on my petcock? Thank you very much in advance for answering my question.

[@mrmaxstorey]

Yeah thats fine

[@raffyl2112]

@@mrmaxstorey do i need to plug the end of the hose or leave it as it is?

[@mrmaxstorey]

Plug it up

[@DK-il7ql]

Does all petrol drains out of tank if accidentially petcok remain on for like 2-3days? And where does it flow? On floor?

[@mrmaxstorey]

+Dark Prince Im not sure I understand the question

[@Spinneh122]

i think he means "if the petcock remained in the prime position for an extended period of time, would the gasoline continue to run out even with the bike off? and if so, where would it go?"

[@jasonstorm7402]

So on my 1980 Kawasaki 440 I have two plugs on my petcock. One is a line that goes to the fuel filter and the other is a vacuum... but how can I tell which is which?

[@mrmaxstorey]

The vacuum is smaller and on the back

[@jasonstorm7402]

mrmaxstorey thank you sir. I finally found the manual as well... the carbs are leaking fuel now. Any suggestions?

[@mrmaxstorey]

Check out my video on leaking carbs

[@MunkeyDumps]

What do you think might be the problem if I have a bike that if I put the petcock on the ON position it starts all good and runs good but then about 20 min later the throttle response will weaken until it sputters and dies. However, if I turn the petcock just a little bit to be in between the ON and PRI positions it works completely fine the entire time. Any ideas?

[@mrmaxstorey]

Take your petcock apart and see what is damaged in there

[@raulgonzalez4776]

Thanks for the tip!! I was able to replace the petcock but after a couple of days the choke is acting funny and is actually leaking gas from the carburator any suggestions?

[@mrmaxstorey]

Check out my video on leaking carbs. It is a separate problem which is often found together with petcock problems

[@straightsixgarage2178]

Quick question, when I disconnect the vacuum line from the engine block and suck on it, gas flows through the petcock but when I connect it again to the engine block and crank the bike, fuel doesn't flow at all. what does this mean?

[@mrmaxstorey]

Maybe the line is leaking? Or that cylinder doesnt have compression?

[@lipab94]

Thank you. What happens if I always drive my motorcycle always in reserve mode? Is there any possibility to suddenly lose some power the engine, or something like that?

[@mrmaxstorey]

If the petcock is functioning well then you shouldnt see any difference, unless you run out of gas of course

[@MultiKoolcatz]

I just bought a 1988 bmw r100gs and when I was on the freeway about 60 mph it sputters out. It was not a full tank so perhaps that was the issue? Or petcock? Also I may have cycled through prime to get to on. May I have flooded my carbs? Or would that cause this problem? May also be the suction line? This is my first car bed bike. I would appreciate your help. Thanks

[@mrmaxstorey]

Its not helpful for me to guess at your problem, you need to do some investigation and see what you can find. Put the bike on prime and see if it starts. Take a look and see if there are vacuum lines disconnected. Take the petcock off and see if it is clogged. That type of stuff

[@jadinwemette8251]

Once getting around that speed its probably due to a clogged carb jet im guessing

[@NJ-ds4ft]

yo, thanks a lot! I've got a '96 Kawasaki Ke100 and this helped much. I'm new to bikes and got this bike from a dear friend. However, the hose that runs from the vacuum to the engine I presume will not fit? am I missing a part which attaches to the hose as an intermediary?

[@mrmaxstorey]

Usually its just the hose. See if you can squeeze it on there, sometimes the rubber shrinks and its tight

[@NJ-ds4ft]

It's shrunken for sure. I may just try to expand it if not then replace it. I did an inspection and I've gotta grab a new petcock. That delicate tube that you spoke of eroded with the old gas. The bike had been sitting for a few years. I've got work lol. Dude, I appreciate your patient video, you've inspired me in many ways

[@mrmaxstorey]

Glad to help

[@carrizalesbm5]

could you do a video on how to run vacuum lines from the carbs to the petcock and motor? i have an 1983 Kz550 F1 Spectre and i cant find how to run my vacuum lines. Thanks

[@mrmaxstorey]

You should only have 1 vacuum line, which runs from the small nipple on the petcock to a carb boot.

[@carrizalesbm5]

Do I just cap the other 3 or leave them open?

[@carrizalesbm5]

Do you know what size mm line it is?

[@mrmaxstorey]

Brandon Carrizales No i dont know what size it is but bring the old line to the auto parts store and they will be able to match it for you. Yes you cap the other three nipples coming off the boots, but dont confuse them with the carb overflow hoses, as they are supposed to hang free to the air

[@carrizalesbm5]

Ya I don't have any vacuum lines on the bike at all, when I bought it they were all missing. Thanks for the help though!

[@heinricheugenkarlvonhelmbr9645]

Excellent demonstration! Thank you!

[@annamckinney6622]

Questions....1) could this be the root cause of mine flooding and pouring gas all over the floor? I always thought it was the float valve sticking. Was it acting as if on "prime" and constantly flowing fuel, even though on "run"? 2) Would this cause problems if tank was not vented or vent was somehow blocked? Any useful comments are greatly appreciated.

[@mrmaxstorey]

Yes when your carburetor is overflowing while sitting then 2 things have gone wrong, both the float valves are sticking open and the petcock is leaking. If the tank is not venting then you would have fuel restriction after running for a short period, and that is an unrelated problem.

[@timothytime4176]

Does it matter what size petcock as long as it's vacuum assist to replace the bad one? My 1981 Suzuki GS1000G. I am trying to adapt from a different bike, rather than be out a bunch of money.

[@mrmaxstorey]

Well I wouldnt replace it with a GS400, but if you find one that offers similar fuel flow you should be good

[@timothytime4176]

mrmaxstorey Would a Gsf600s Gsf1200s size petcock work?

[@mrmaxstorey]

Timothy Time If you can get it to fit on your tank, it would probably be fine

[@HickeyX]

If you have a a vacuum petcock on your bike , can you put a gravity petcock on it ? Or does it have to have vacuum

[@mrmaxstorey]

yes you just need to block off the old vacuum line

[@HickeyX]

@@mrmaxstorey the one on the carb?

[@mrmaxstorey]

@@HickeyX Coming out of your petcock are two hoses, a big one and a little one. The big one brings gas to your carbs, and it must be hooked up to your new petcock. The little one was the old vacuum line which used to open the petcock. You don't need it now, however it must be blocked off so the motor does not suck in extra air. Leave it connected to either the intake manifold or the carb depending on your bikes setup, and on the other end which used to connect to the petcock, put a little bolt in or tie it in a knot so it is blocked off

[@HickeyX]

@@mrmaxstorey oh okay yes that answers it all , thank you Sir , mad respect 🙌

[@raymondlopez4035]

How important is the screen/filter? I recently had my tank painted and misplaced the filter.

[@mrmaxstorey]

Just put in an inline fuel filter youll be fine

[@willmcmasters4012]

Outstanding video! Thanks for that, now I know what the hell that prime setting is for

[@jasondesousa2440]

I'm checking if my petcock needs replacing...I put it on prime (same exact petcock you have) and nothing at all came out... you think I should just replace it all together

[@mrmaxstorey]

Try to clean it out first. Look at my other petcock video, I take it apart and you can clean it out while you are in there

[@gazbugz8745]

hey bro question for ya,just bought new carb..no diaphram for original on net.for en 125.has extra pipe intake yet suppossed to be for that bike.guessing its for vacuum fuel intake as its on engine side straight to airflow and into engine. i guess to add extra fuel at higher revs but this would make mix rich right? im stuck ,cant find petcocks like yours for en 125 and could i get one that freeflows AND has vacuum fuel line ..my real question is whats the extra intake on carb for and can i block

[@RykerLife]

I was just given a 1985 Honda shadow V. T 500 C, and there's the one line that goes from the petcock. Straight to the cylinder head. Then there's a big line with the Spring on it. That goes to the big nipple on the back. Then there's a little nipple on the back. Also, that when you turn the petcock on the fuel shoots out of. And I can't for the life of me, find out where to hook that 1 up to.

[@Taika_talvi]

Nice visualization with the little experiment.

[@udaya160]

I Own Pulsar 150. Reserve supply in petcock is not working when my fuel is in reserve state. I filled up fuel more than reserve level. Now fuel is flowing from both on main and reserve. What is the problem here??

[@mrmaxstorey]

Udaya Kumar Sounds like the petcock is malfunctioning

[@lazy_panda1380]

hey i was wondering is that how a petcock suppose to pour the gas out ? like when you turn it to "on", does the gas suppose to drip out lil by lil to the carberurator or does it pours ?

[@mrmaxstorey]

Watch the whole video

[@lazy_panda1380]

i did, i mean so you say "prime" itll run so when its turn to "on" is it also suppose to pour out like that ?

[@mrmaxstorey]

Lazy_Panda13 If you have a vacuum petcock, then gas is only supposed to pour on ON when vacuum is applied. Again, these questions are the reason I made this video, and the answers are the central point to the video

[@lazy_panda1380]

oh ok, but like i mean when vacuum isnt applied, does it still suppose to pour ?

[@mrmaxstorey]

Lazy_Panda13 no

[@Biker_Space]

Simple but truly informational. Thanks for sharing it bro.

[@1a2b3cdude]

Oh my god i had it on prime for four days. Am i ok or did i mess up my bike? Pls someone with knowledge reply

[@weiky79]

Great video. Short, sweet, to the point on Petcock 101! I’ve heard constant turning petcock slowly wears the diaphragm eventually causing failure. Any truth to this and what are your thoughts??

[@1800grantallen]

Is it okay to ride my motorcycle without the petcock filter on it? Will it harm anything without it? When the gas tank was repainted the petcock filter was left out at the body shop and has not been replaced.

[@mrmaxstorey]

If the inside of your tank is spotlessly clean and stays that way, you wont have any problems. However if you develop any rust, dirt, corrosion, or sediment in there, there is no filtration to prevent it from going into your carbs. It is cheap insurance against a carb cleaning

[@1800grantallen]

mrmaxstorey gotcha. Insurance is a good way to look at it. Thanks for the reply!

[@bombaya85]

This was such a great help! Thank you!

[@EvilTwin123]

Great explanation and demonstration. I learned that petcock is one word and not a two-worded sexual reference!

[@manuelseniceros9550]

I juwt bought a 1981 kawasaki 440 and my petcock has like 3 places it looks like you can plug stuff into. But only one place is pluged in. The bike wont stay running if its switched to on it will eventually stall when i slow the bike down. Is this an issue with my carbs or the petcock

[@manuelseniceros9550]

Also the petcock does not have an off mode just. ON PRIM AND RES

[@coriwhitesell2849]

Manuel Seniceros I have a 95 Suzuki Savage 650LS. My bike was running just like the way you described in your comment. I just changed my factory petcock to a Yamaha Raptor 660 gravity pulled petcock. My factory petcock only had a RESERVE, ON, and PRIME also. The new one I'm running allows you to turn off the fuel all together while sitting. Also I knew my bike was having issues once it started to only run in the PRI and RES postions. The part cost me 30 bucks for a brand new genuine Yamaha petcock instead of 110 for a new Suzuki factory one. It took me about 15 minutes by myself to fix the issue.

[@nitsujecirp6354]

Please help! My bike starts to sputter and die at about just under half tank of fuel. Only thing that fixes it is to fill the tank back up to full. Any ideas? Petcock issue? Other than that it runs fine. It's a 2006 virago 250

[@mrmaxstorey]

Nitsuj Ecirp Yes take it out and blow it clean

[@tonybryan473]

if you turn the petcock to the off position , and fuel still poor's out of the tank when i remove the tank on a Kawasaki e13, is my petcock faulty or is this normal ?

[@mrmaxstorey]

+Tony Bryan When the petcock is off gas should not come out

[@_junney]

2019 and this video helped me out a lot. Thanks!

[@z32323232]

Ive had 10 bikes and never given the vacumm a thought never knew looking at my 02 fxdl it has this diaphram thanks.

[@gazbugz8745]

new phones givin me s*@! cant do vid sry.what is pipe 4 on carb and if it is for vacuum fuel inlet then wouldnt it effect richness at high revs? what should be my next move to go about installing it with this new pipe hose difference compaired to other one on as im lost for parts on net as its a mexican 2004 model otherwise known as suzuki yes..its the fact i havent found anything related to this hose connector on any carb vids urs closest with the 2 fuel connector on P/C. PS good vids tnx alot

[@SnuggleBear1970]

I have a 93 Kawasaki Vulcan 750. My petcock does not move as easily as it should. Should I be concerned?

[@mrmaxstorey]

Oscar Cruz You can take it apart and clean it

[@jbsbayareajbsbayarea]

Thanks for information, was stressing about my quad leaking fuel, now going to give it a try to fix it.

[@SaiasAdventures]

I had a question hope you can help. Trying to get a 1977 Suzuki GS550 going. It’s my first project bike. 😬 So when my tank and petcock all hooked up looks like no fuel is going through but when I disconnect the petcock to test it it seems fine. Is it a vacuum issue or carb issue? Total rookie at bikes but trying to pick up a new hobby. Your videos rock!

[@mrmaxstorey]

Im not sur eI understand your question. Are you saying that with gas in the tank, and your petcock on the gas tank, you turn the petcock to PRI and you do or dont have gas coming out?

[@SaiasAdventures]

When I have it on prime gas does come out when it’s not hooked up to the carburetor. But when it’s all connected to the carburetor it looks like no gas flows through the fuel line. I also realized that what I assume is the vacuum line isn’t connected to anything and just has a screw blocking it. So maybe it’s that? Or am I wrong?

[@mrmaxstorey]

@@SaiasAdventures OK so either the carbs are already filled up and dont need gas, or the floats are stuck not letting gas through. At some point the vacuum feature of your petcock failed and the previous owner plugged it up, so now it operates as a manual petcock where PRI is on, and any other setting is off. Thats fine for the temporary until you fix or replace the petcock, so long as the vacuum line going to your intake manifold is also plugged up.

[@SaiasAdventures]

Thank you so much! I will check those next

[@SaiasAdventures]

So I removed my carburetor and notice little to no gas in them. Taking apart the carbs all the float needle inlet valves have a groove in them. Which I believe is causing the floats to stick. But I also noticed the carburetor isn’t the original set. The service manual has a Mikuni BSW30SS and I currently have Mikuni KOGYO. Would this be an issue as well?

[@jerterh2]

So the Vacuum line leads the the carbs, and the fuel drain( where all the water was escaping from) leads to where? the engine or a fuel filter?? If anyone cold answer than for me it would greatly help! Btw i have a xr100r.

[@mrmaxstorey]

That goes to the carburetors. Sometimes there is an inline fuel filter, its a good idea to have one

[@jerterh2]

Thanks! Ill check it out, trying to get this dirt bike rebuilt for the summer haha

[@cesarvargas8943]

if u aplied suction and gas does not come out what would be the issue

[@mrmaxstorey]

+Cesar Vargas Clogged petcock, or damaged vacuum diaphragm

[@perfektrepairs7934]

I've got a GS500 1999 model starts great on idle but dies soon as I try and rev it I've cleaned carbs and checked for air leaks all good there could my Petcock be at fault ??

[@mrmaxstorey]

If gas is getting to your carbs to allow the bike to idle, then the petcock is probably not at fault

[@perfektrepairs7934]

mrmaxstorey yes true I though maybe the flow may be very slow but would rather leave it alone incase I cause a split in a seal or something. Bike had previously sat for 3 years ran perfect before storing I'm baffled carbs are clean no air leaks and tank is clean with fresh fuel

[@mrmaxstorey]

How is your compression?

[@perfektrepairs7934]

mrmaxstorey 150 on each cylinder first thing I checked even though a mechanic told me if it's starting straight away compression will be fine however I checked anyway and got just shy of 150 on left and 150 on right

[@mrmaxstorey]

Plugs not fouled? Good air filter? Float heights checked? Emulsion tubes cleaned? Valves adjusted? Clean carbs again...

[@mrmaxstorey]

What type of bike is it?

[@eananstrain6817]

Great vid, thanks for taking the time to make it!

[@robertojaimes9503]

Should i set the petcock to off when storing it in my garage every night after a ride?

[@mrmaxstorey]

Its a good idea

[@robertojaimes9503]

mrmaxstorey ok thank you

[@urbanedtheturbaned7247]

Which way is on/off on a pitbike?

[@michelmaltais9204]

Wonderful explanation. Thank you for taking the time to do these it helps understand how things works.

[@shanec4441]

The vacuum valve is a safety mechanism to stop fuel flow when the bike is not running. Correct? That is its purpose

[@mrmaxstorey]

Yes

[@reasoncyko]

Hi all,the petcock on my xv500 is now dead, and it has a double diaphragm at the back. Could I replace it with a single diaphragm petcock???

[@s7vnexes336]

Michaël Barthelemy wouldn't recommend

[@CheapGuitarsAndMore]

What do you do when no gas comes out at all, even on prime?

[@mrmaxstorey]

Take apart the petcock and clean it. I have a video up for that as well

[@CheapGuitarsAndMore]

mrmaxstorey thanks im gonna go watch it