HUGE PROBLEM after Rebuild. $1100 Big-Bore Yamaha YFZ450 Needs Help

[@fire_node2416]

Its crazy how much I've learned watching your videos, I easily rebuilt my friends dirtbike and knew what to check and things like that.

[@dylanj9072]

Moat quads need to be moving for the pipes to get some air flow to cool them down, if it doesn't get red hot while riding it your good. For the overheating problem, leave the radiator cap off it needs to get the air out to the water jackets and the thermostat.

[@jlunks3680]

While you had it apart there are 3 things you should have done. 1. A common mod with these carbureted yfz is called the zip tie mod. If I recall correctly there is almost like an accelerator pump lever that lags behind the throttle linkage in the carb, if you zip tie them together it gets rid of the bog when you snap the throttle. 2. You should have done the cam mod when re assembling it. I forget it it’s advancing or retarding the timing on the exhaust cam by 1 tooth. 3. The oil mod. Pre 2007 yfz had oiling issues. I had a 2008 years ago and did the zip tie and cam mod, made a big difference. Been out of the game for a while so I forget the exact details about everything. The glowing header is completely normal. If your still a little nervous just up the main to 175, also depends on your altitude. If you take the air box lid off it will run more lean if it’s leaning out now keep that in mind.

[@Davido50]

YAMAHA YFZ450R #1

[@MK-qv7bq]

This needs more upvotes

[@danebowen729]

Header glow is extremely common on the YFZ. Look it up. Bump up the pilot jet a size or two, and possibly the main as well. Who knows if they ever dialed it in correctly, especially with the built engine.

[@quadbrothers5801]

if it’s dark my trx header has visible glow in like a minute and a half

[@daveswarbrick5576]

If it's a full aftermarket system, they tend to be thinner wall tubing, which can account for them to glow red, a lot of stock headers are double skinned , so you wouldn't see them glow. I'd get a temp gun and check the cylinder head, see how hot it's getting.

[@nigelmielke4706]

My ltr had a stock header years ago and it glowed, mapping was correct, called a dealer they said it was normal. Rode it like that for a years and never had a problem.

[@Davido50]

Truth

[@TripR32]

It’s normal for bone stock yfz 450 on the showroom floor right now to have the pipe glow at idle , on the older carb models like mine no matter how big you go on the pilot it will still glow. Even normal riding it glows after just a few minutes. Pipes are made thin on race bikes for weight so that’s the main reason they glow so easily. It’s also the reason i have exhaust wrap on my pipe so i don’t keep melting my riding boots lol.

[@maverick1airsoft988]

@@TripR32 my 2004 yfz has never glowed and it runs absolutely perfect, I have a couple buddies, one with an 08 and one with an 05 and both of them don’t glow either

[@maverick1airsoft988]

Stock exhaust systems by the way

[@codyswilley]

35:53 watch closely by the header. You can see a little spark fall down

[@2vintage]

I saw that

[@Brandonp95]

“We’ll torque this guy down” proceeds with impact to precisely 4 ugga duggas 😂

[@mmaaddict78]

Using those German torque specs, good’n tight.

[@makoman67]

Lol

[@staygold902]

@@mmaaddict78 🤣🤣🤣

[@corbingray9330]

All the Sally's that are always in the comments whining about him always using a impact just disliked this comment😂

[@darrynruzicka2883]

crank it down till it's just ready to snap then back it off a notch.

[@darrinwoodward14]

Good job.a little helpful hint,use an ultra thin layer of grease on your gaskets.that will hold them in place for you,plus they won't stick if you have to take it back apart.makes for much easier gasket clean up.

[@MrStatic101]

Would you recommend that over permatex?

[@david676adghj]

Mr Static101 yes

[@YFZ450DOUBLEJUMPER]

Very known problem for the yfz, it's just running lean. Go bigger on the pilot but the yfz glow will never go away. Especially at idle, these aren't meant to idle, meant to be ridden hard and fast to keep it cool. The air pushing through the radiator will help tremendously.

[@albertchavez2693]

Please get lrg shop fan for cooling it down before it overheats :( :)

[@Tennessee_Jon]

On mine the stator has oblong bolt holes. Took it in when it was new and got a big bore put on. They advanced the timing with the stator and it was causing the same issue. Took it back and they put it back in it’s original position and hasn’t been red hot since

[@hamood1234fool]

Maybe this is the issue. hope he reads this

[@lukecombs5242]

My experience in buying timing chains only buy d.I.d they are as close to oem as you can get if not better than oem don’t ever cheap out on a timing chain it’s a vital part of seen the cheap ones break and you know what happens when the chain breaks catastrophic damage.

[@mikehudg2209]

I have raced a yzf250 , 400 , and 450 , all my bikes experienced " header glow " not uncommon, jumping up 2 or 3 sizes on both pilot and main will help considerably, these are highly tunable engines and designed to work better the faster you go , great 👍 video, nice work Joe

[@yetti4life974]

great job! I always heard not to use permatex with gaskets. I use thin layer of grease or some oil to hold gasket in place.

[@rockman49er]

I think he does this method nowadays 😮

[@briantripod3826]

I love your videos when I see that there over 30 minutes that makes me happy you're very informative and keep doing what you're doing brother

[@thomasquaka2301]

Late ignition timing can make exhaust temps soar

[@mmaaddict78]

Good job. Those modern four strokes aren’t the easiest things to work on.

[@Davido50]

Not that hard either. Forget the 2-stroke an get a modern 4-stroke! U won't go bk to mixing gasoline.

[@kevinAuman1]

Check the fuse for the fan, sometimes they're not very easy to find because they're under a rubber protective cover but if you follow the wires from the fan you should eventually find one because I had same issue with my Z400 I never heard the fan kick on and I rode the quad it never got hot but pipe would get cherry red if I sat still idling like this then one day a buddy broke down miles from anything so I had to pull him back and mine overheated so I stopped and let it cool down and we limped it back luckily I didn't hurt anything but I never once heard my fan kick on so it got me curious and then I found a blown fuse changed it and she has been working perfectly ever since...

[@Davido50]

Those Yamaha YFZ450Rs are gold!

[@jimnorcross2515]

My 06 raptor 700 which is fuel injection, the head pipe always glowed red. I had power commander fuel injection module on it, with a pro design billet stage 2 intake and an HMF full exhaust and the computer was mapped for all the mods. Did all the work myself and the dealer double checked everything. Ran better than any quad I ever had and the head pipe ALWAYS glowed red. I never once had an issue with it. BTW, love your channel. Keep it up bud. My friends that all had yfz 450s, some with big bores n they glowed red too so I think you're good.

[@nathanialdavis7706]

Dude youve came a long way, like the content alot!

[@charliepapa5835]

I didnt see an oil sprayer mod when u had the head off....make sure it has that or the motor will burn down....04-05 yfz450s had an oil supply problem from the factory and needs the oil mods to function properly

[@James-sir]

Since you have a chimney you can get a little wood stove for fairly cheap I agreed with you on the last one and started looking at em there’s some deals I am now probably going to get one they really give off some heat

[@localenterprisebroadcastin5971]

Sounds lean. Go one size larger on both jets in the winter…the jetting you’re running is great for the summer, header pipe shouldn’t be glowing.

[@allan1353]

I'm thinking the same

[@user-uz5nv4hs8d]

I agree with you.You also know it because it bogs and bakcfires when givin it throttle

[@TripR32]

It’s normal, even a brand new EFI yfz 450 glows after a short time, just thin pipes on race bikes even stock pipes. Several videos of shops with stock bikes showing them glow just because it surprises everyone.

[@mattintime5152]

Most 450s come with a Keihin FCR carb, and when the choke is on it allows more fuel AND AIR into the mix, causing a high idle, but also warming up the engine way more efficiently without hurting it. They also bog a lot when the water temp is below 100. Bike is definitely running lean, from experience with bikes lean as can be from the factory and generally run hot, I've never experienced a glowing pipe, only discoloration.

[@arturomedina5746]

Minute 35:54 there's a spark that comes out maybe around water pump area.. check it out.. maybe there could be a problem... on another note I am currently fixing my first 07 yfz 450 can't wait just waiting on oil drain plug and a few others to get it started.. I've never owned anything bigger than a blaster..

[@greenhornet41y]

I would try to turn the fuel screw out and if the idle gets higher as you go out keep turning out until it’s highest idle then adjust idle to where you want it

[@shawncave8339]

When you reassemble the engine one of the cams looked higher than the other. The lobes on one was down further than the intake.

[@timjohnson9230]

The yoshi on my LTR glows red. Kinda freaked me out when I first saw it in the night time, but never had any issues.

[@davebarrowcliffe1289]

With jetting on engines that have been monkeyed around with, I like to start high and work down in size 'til it stops bogging out. Always go high and work down, not the other way round... But that's just me ... Love your work, kid! 😃👍

[@Dm-cr5lk]

When u torqued the head to 14lbs then u said another 180 degrees it looked like u didn’t even do 90. 180 is half a circle inst it

[@ndasigerry]

Hahha, said to myself ' maybe he'll do another 90 degree again, but seems he didn't.

[@Dm-cr5lk]

Wasn’t even 90 my guess is 45/60 . That last 100 degree he missed was probably 75% of the torque value..

[@charlesmurphy1510]

180 seems excessive, maybe 80 degrees.

[@itsbroster21channel]

@@charlesmurphy1510nope I rebuilt my 04 yz450f they r right

[@nigelmielke4706]

Trx's,ltr's,yfz's they all have head pipe glow. Certain pipes are thin wall and made with certain metals that cause that effect even if the jetting/mapping is correct.

[@briancrull8678]

Way to hot . Thermal gun would blow up Lean or oil starved ? Ignition timing can do it too

[@codyswilley]

Great video. I would go up a size in the jets(both pilot and main) I would try that. Your running a pretty good setup for the summer in my opinion. Winter not so much.

[@corbingray9330]

Every yfz I've been around has had a glowing exhaust. The 2013 I had with a full exhaust and tuner would always be glowing bright red when just sitting there idling/revving but once it got moving it wasnt horrible. Yfz450s always seem to run on the hot side imo

[@sergiosandoval2167]

I agree I’ve got a 2010 450x Bill Ballance w the Power Commander V and auto tune w the o2 sensor and it glows while idling, seems normal

[@inductionsymphonytrd]

Hey man , great video . I want to say , I notice you use quite a bit of expensive oil in your machines . I would look into Rotella t6 5w40 , it is rated for wet clutches and comes in 5 gallon pale for much cheaper $/quarts . Thanks for being an influencer , I have been buying and selling quads and dirt bikes as a side hobby , I bought a 04 trx450r with a KTM 520 swap $1000 , and I'm going to look at a 07 Thursday for another $1000 "cranks, shifts but won't start , I don't know", should be easy !

[@project4stroke876]

been waiting for another vid! keep up the great videos man.

[@MAD450r2]

find out if your exhaust is ceramic coatted. My sparks exhaust was on on 04 trx 450r and it did glow too when not movig fast, but as yours does it cools fast as well. The ceramic coating pulls the heat from the valves better.

[@Thumper68]

I had a really nasty 450 with big bore kit and much much more if I wasn’t driving it would get to hot. It’s not surprising you get a little glow with big bore kit. There’s also a reason the heat shield is right there lol. Your fine.

[@hrsey71]

on the 450 honda motor with a titanium exhaust it is common for the pipe to glow red. get yourself some pro circuit cylinder head temp stickers so you can see where the temp is at at all times

[@nightowl5959]

I got an 09 yz450f dirtbike and it does the same thing. Pipe started glowing really fast after starting it. I also have an aftermarket pipe. And my jetting is about the same as yours

[@corycurtis6315]

very normal after a rebuilt on a yfz. fyi big bores normally need a smaller main. cc does not effect the air fuel ratio needed to run. in a nut shell the big bore creates more vacuum and pulls more fuel through a smaller jet. yfz always glow and it will get a little less as it breaks in. if you want more info on big bore jetting let me know

[@gmc4x4s]

I'd run a 48 pilot 180 main get a ncvq needle and put the c clip on the 3rd or 4th notch going down towards the point. Also u don't have to take the carb off to change the pilot or main or the needle. Just losen it on the boot on the intake and rotate it so the 17mm plug on the bowl is accessible, remove it and u can access the pilot and main very easy and make quick getting changes. As for the needle just remove the seat and take the top of the carb off and access the needle that way.

[@JoshX9]

My Old Raptor 686 (Which was recently stolen from me..) did the same thing with the headers pretty common on aftermarket pipes to get red hot especially with big bore engines.

[@aidenlambert8554]

Love your videos keep up the good content. I have seen this before many times. Exhaust valves are not staying closed long enough. Probably as simple as a valve adjustment.

[@trose7620]

I like the copper gasket spray on stuff for holding gaskets, it al works OK though.

[@bananabrooks3836]

1st thoughts are was the engine turned over on the bench and all the gears working, then was that done when in the frame with it all timed up with the head on? (Oh l thought it sounded clanky but maybe the audio) Was the oil pump pumping? Coolant circulating? If so maybe its a lean mixture causing premature heat build up so check for air leaks.

[@2vintage]

Yep all gears and turning over great on the bench! Yep oil pump is pumping!

[@danielrita9663]

Stock yfz450 header pipe there known for turning cherry red wile siting and running

[@painistemporary4855]

The kfx 450 does the same, and i think its because the header is made from titanium. And the 450's are made to race, it's normal to glow and once you start riding they will cool down

[@zerxyy3872]

Lettsss goo, a new day a new upload

[@KentRoads]

Your first problem is reassembling with an impact...

[@darrinwoodward14]

Don't waste your time bud.the little kids that watch his channel will bitch you out.

[@miller2167]

I was thinking the same thing

[@robertdavis4184]

Just out of curiosity how come you don't use assembly lube like engine builders use when assembling a new engine?

[@2vintage]

I use oil for the parts. I just bought some assembly lube though. I will start using it.

[@jessemurray1757]

@@2vintage oil is just fine if it doesn't sit for a long period before starting. I personally use assembly lube though.

[@chrisbec3313]

I have a CRF450R with a Yoshimura exhaust that I recently installed and it glows exactly like yours does and I have a JD Jetting Kit also. It doesn't display any of the lean running symptoms and actually runs really good, but at idle after sitting and running for a couple minutes it is glowing red, looks pretty cool at night. Maybe turn the idle screw out some to richen it up at idle until it almost dies then in the other way lean till it almost dies then split the difference. May also read the plug too to know for sure.

[@baldtireproductions1281]

my dad had a 440 ex i just remembered that when its a big bore you need more air drill holes in air box or test with lid off ik it helps for honda almost same proble sputtering and overheating

[@NyMadePookie]

That’s how that yoshi pipe is I had the same one on my 08’ special edition and all you need is a exhaust wrap I promise you

[@abe1199]

Header turning red is common on most yfz happens to mine to

[@brianstroud6306]

I had 2 raltor 700's both dis the exhaust pipe turning red ! Made me really uncomfortable. Lol. I like d my 400ex more! Keep up the great work

[@countryboyvlogs776]

Great job on the rebuild I been waiting for this video can’t wait for the next

[@2vintage]

Thanks, it was a lot of work. Hopefully it will be worth it!

[@jmendo2546]

What's the spark plug say? Jet's goes by elevation also per size change. Does it have a neddle setting with e clip, Im not fimilar with this carb. I have a 2005 Trx450r with big cam and 14:1 piston my pipe glow's

[@aaronchapman6092]

I also have 450r and my header glows to couldn’t find the problem

[@aaronchapman6092]

What jets you running

[@redrider533]

Realize this is an old video and I’m not reading all the comments. First this when you see a non stock pipe is to understand stock jetting it out the door. You needed to check the Yoshimura site for their recommended jetting for what looks to be a full system. Then is the air box and filter stock or modified. That will change things. Third, is the air boot between the carb tight and sealed. Any air leak is a big problem and will lean out the fuel mixture too. Last is the compression stock even with the big bore or high compression. Many factors dictate correct jetting. Something else on the YFZ Big Bores is that the water jacket in the cylinder is known to crack because it’s so thin.

[@timpence825]

Header glow is normal.. make sure you bleed the coolant system when putting coolant back in. I had an 06 50th anniversary addition. Header glowed at idle.. My Raptor 700 does the same thing at idle and it's been dynoed.

[@erhodes8745]

Love when this guy posts

[@sandmanbub]

What's the plug telling you about the air/fuel mixture? If good, I'd want to know if it holds compression, then I'd check ignition timing followed by the valve timing. Some times the valve timing's off a bit after rebuilding. I've seen it happen to more than one mechanic.

[@krotchlickmeugh627]

Make sure the oring and washer are in the air fuel screw needle. Make sure the air fuel screw is backed out 2 1/2 turns

[@peteraitken6494]

Good job joe sounding great hope you find out why the pipe gets so hot take care mate nice video 🔧🔧🔧👌👌

[@connorbryan1663]

Pull the plug and check it it’s common for the pipe to turn red on a warmer day with riding never seen one get that hot that fast just idling sound lean as well pull the plug and it’ll give you a good idea where is at

[@kennypettit7894]

Hey bud what happened to the side by side that the Pistons was wrapped around the crank that you worked on at the old people blew up you know the one that had no piston left in the hole it was right there on the crank did you ever fix it I never seen anything further

[@kyleglenn4893]

My yfz get the header the a bit hot as well granted I can't see it glow like that due to it being a stock header but you can't try to jetting to help bring Temps down

[@makoman67]

Why break out a torque wrench on the head bolts, just hit it with the impact like you do everything else..... 😂

[@Abyss955]

Prolly so some people didn’t get mad 🤷🏿‍♂️

[@dylanmathis6605]

@@thamenace9985 WRONG

[@heathwak3030]

@@thamenace9985 don’t see you making any videos fixing bikes…

[@makoman67]

All joking aside, my nephew used to work for a BMW dealership as a mechanic. They were paid piece rate and thought it was perfectly normal to install heads with the impact gun, I shit you not. A BMW dealership.... smfh

[@jeffthejinjer]

It's assembled using an impact from the factory. It's set to a certain torque.

[@aaronlinder7157]

My 14’ z 400 with the exact same system on it glows in low light. It’s Dyno tuned so I know afs are good. I don’t think you should worry about it so long as your properly jetted..that might be the whole problem if you ask me. Float heigh also comes to mind…nvm. After watching the rest of the way through, I think it runs fine

[@15brucet]

Can also check the throttle arm they get play in them which it won't return to idle

[@upperroomtoo]

How come we never heard the fan kick on? That and the little lean pop on throttle release tells me you're lean.

[@francismorel]

idle screw as a washer n oring on the tip of it....yours probably stayed stuck in the carb,just be carefull not to loose it !! and what is the reason for putting the engine in the frame when the head isnt installed?

[@jcaptnnitro1]

Does your fan ever turn on? I had an 06 YFZ450f and from the factory one of the pins in the fan connector was bent just enough that the plug clicked together but one of the pins didn’t make connection with the female side of the plug. Luckily I found it within the first 20 minutes of owning it.

[@chathamguy1able]

i had a snowmobile it made the header pipe glow found out it was out of time just a bit to far advanced so i put it back a bit and never did it again ----good luck

[@nalyd6386]

2 vintage, you are my favorite on here by far. Love the race bike and quad videos you do, awesome stuff.

[@lovelover3769]

just make sure the fan is working glowing red is normal when sting still

[@RCgarageTexas]

if you take the lid off the airbox it will more than likely lean out more if it is already a little lean on the main

[@MaxsGarajMahal]

Sounds like a vacuum leak between carb and head causing the fast idle and that can also cause the glowing exhaust due to lean condition. Idle usually will NOT cause a glow unless the jetting is extremely off and even then not likely.

[@kylemurray8840]

I had an 06 an the only thing that got the glowing to go away was to put the stock exhaust and stock jetting

[@miketherider]

I owned several early model YZ400Fs (98/99) and 426s (02) which are similar. The headers used to glow as well, one so bad it melted a radiator guard and caught fire (after market big gun “dual” header). That’s kind of the norm for those, something to do with limited air flow and the material for the header itself. The farting and popping is a concern, probably need to ride it, check the plug and evaluate as needed.

[@luixzzzz]

My raptor 700 Dosnt flame but it back fires nothing like this jsut like a pop after Iv r been high rpms it sounds sick but is it a bad thing ?

[@Nathan-oe1bt]

Take the airfilter top off and put a k&n filter on… night and day. The exhaust always glows… heat wrap at autozone is like 20$.

[@MM_in_Havasu]

Adjust your idle mixture with engine running. Aftermarket pipes will do stuff like that as well. My turbo CBX will turn the exhaust system cherry red clear down to the feed tube into the turbo if you run it at high idle while stationary(thank God for Jet-Hot ceramic coating).

[@andronikhanson2785]

Need to ride it w/o! Keep that cool air on it, should be fine.

[@vadimkargin3200]

When u tighten the flywheel. Big Gear in the back was just free spinning. Not sure if that suppose to happen.

[@2vintage]

Yeah it can turn one way, but not the other way. It's connected to the one way bearing for the starter.

[@Ash1978E]

The header pipe is stock titanium. Its thin so it heats/cools quickly while maintaining its strength. 100% normal

[@maxball7497]

Let’s go very happy to see a new vid

[@shaunmeadows2998]

JUST SEND IT! Love your videos bro keep em coming!

[@andgweedle]

Did you bleed the radiator after filling it up to the top you never had it running with the radiator cap off ? If you didnt bleed the radiator there is probably air in the system causing it to get hot faster

[@petershute3580]

Replace the radiator cap,it’s like the thermostat,it opens and closes to let coolant and out of the expansion tank read the cap it will tell you

[@wvatvrider2353]

All carb model yfz pipe glows red right there at idle I have 3 and they all do that and I’ve had one professional jetted and it still glows red

[@lawerncemiller6557]

The head pipe are thin titanium they get red but I'm pretty sure it's idling rich turn the idle mixture screw in to 1 turnout see if it idles smoother , I've never had to go more than two sizes bigger on a pilot jet size on any bike engine build

[@mattoaida]

I just bought a 2004 yfz450 and it was popping a lot on deceleration. I checked the jets and it had a 45 pilot with 168 main. I called big gun exhaust and told them my mods. K&N air filter without lid and full exhaust. Everyone saying to run 48 pilot and 175 main

[@morrow49]

Lmaooooo I love how the thumbnail says NOT NORMAL.. when in fact.. this is completely normal for the yfz’s

[@yt_nickgage1542]

I have the same quad, all yfz 450 run very lean its normal for the pipe to get red at some point

[@NewLife-qj9mx]

Hits my soul every time

[@kevinAuman1]

You weren't at all concerned with how discolored that crankshaft bearing was from overheating?

[@allensnook7760]

I saw the same and was concerned at those current temps again to cause glowing exhaust its only matter of time it siezes again.snooky pa.

[@trose7620]

Low altitude, low 02 more fuel. Air/ fuel mixture settings should fix. Fuel screw at 3 turns, air at 1.5 to 2 turns.

[@reitzy69]

Better to be too rich then to lean...unless you dont like valves...everything I own is jetted rich....with NO issues...go up two jets on both pilot n main...im above 3 times the jets on my engines and runs great...spark plugs are cheaper then tearing down and engine to rebuild...ya just gotta burn the carbon out any chance ya get :)

[@jasonmoritz6574]

My trx 450r header pipe does that too especially in the cold

[@jesusmylordsaviorking3726]

should have checked the spark plug to see what the color was. if to lean it will be nearly white.