Stop backfiring carbs on decel on 1981 Virago XV750 - Vintage Yamaha Backyard Restoration Quick Tip

[@vintageyamahabackyardresto4995]

Help prevent this channel from backfiring by clicking LIKE and SUBSCRIBE for more vids :)

[@agaba5500]

hey man. im restoring an 82 virago 750 and your video helped me alot. thanks

[@vintageyamahabackyardresto4995]

Great to hear. I am glad you are keeping one of these awesome vintage bikes on the road!!!

[@agaba5500]

its mostly in the garage lol. after im done messin with the carb i got a buncha electrical problems.@@vintageyamahabackyardresto4995

[@padraigfitzgerald4524]

What a niche channel but thank god. Getting an 82 virago and looking for how much work I’ll be putting into it. Thank you!

[@vintageyamahabackyardresto4995]

Anytime. Im glad you like the content. Stay tuned :)

[@peterbiltroy]

Thanks for this, I scored on an 85 Virago 1000 that was in storage for 16 years and am getting it dialed in!

[@vintageyamahabackyardresto4995]

Great to hear!!! Get 'er dialed in and back on the road! :)

[@NickyD626]

Aye I just got a 85 750 last month, how’s she goin buddy?

[@hfcrocks]

Your a legend. Thx for sharing your knowledge.. l'm looking forward to giving it a go with my my 1994 750 Virago..qaa

[@vintageyamahabackyardresto4995]

Thanks for the kind words and good luck with your project :)

[@BanTexHardstyle]

Have the same problem! Just bought this motorcycle, thank you! I will try this.

[@vintageyamahabackyardresto4995]

Great! I hope it helps!!!

[@mcrand7887]

Good trick for air screw setting. OR maybe backfiring is an issue with mixture control valve (pressure release)? I also noticed there is no Breather pipe given on your 81' model's front cylinder head but on rear, I have it on my front cylinder. Never understood why Breather pipe and mixture control valve both are given on front cylinder of my 82' XV750.🤔

[@jerrypeal653]

Mine was popping because the carburetors were out of sync, do that first then adjust pilot jets .

[@vintageyamahabackyardresto4995]

Yes, syncing the carbs are important. If synced and they are still popping, then try this. Thanks for the comment!

[@KMRB951]

I will try this trick! Thanks 👍

[@forestexplorateur]

Very helpful on my Virago '82. Regards.

[@billred3820]

Awesome channel dude. Thanks for the help

[@vintageyamahabackyardresto4995]

Anytime. Thanks for the watch. We are all learning together!

[@bystander_1]

Thank you for your knowledge. Please do more diy maintenance/mod videos on the Virago. Have you thought about turning it into a bobber or a cafe racer? Much love from Georgia.

[@vintageyamahabackyardresto4995]

I have a bobber project planned for this upcoming season hopefully. Thanks for the kind words.

[@anthonyarmstrong9508]

You've got a subscriber. Also I have a 1984 xv750. Good sir my bike spits pop fires when acceleration, what causes that? Thank u in advance.

[@vintageyamahabackyardresto4995]

Sounds to me like a carb issue. Maybe it is time to clean your carbs out(check the jets for restrictions) and reset/sync?

[@strider5453]

Let's try somwthing a bit easier. Pull your plugs and inspect them for color. If the plug is burning a light chocolate brown it's fine, reinstall it. If it's burning black with carbon it's running too rich or If it's burning white it's too lean. Reinstall the plugs. If black with carbon give the corresponding screw a 1/8 turn to the lean side. Take the bike out for a ride and see if that helped. If it is improved but not perfect stop the bike and give the screw another 1/8 turn and ride it some more. Do this until the popping stops. Do this in reverse to enrich the mixture if your plug is burning white or too lean. You can do 1/4 turns but I find the 1/8 to be more accurate. Which way you turn your screw is different with different carbs depending on if the mixture screw is on the engine side of the carb or on the intake side of the carb. Your screw is on the engine side so cw will lean out the mixture, ccw will enrich the mixture. Run a tank of fuel through the carbs, pull the plugs and check to ssee how they are burning. I hope this helps.

[@grahambyett8134]

Thank you very good video 🙂

[@vintageyamahabackyardresto4995]

Thanks so much for the comment. I do what I can. We are all learning together!

[@auggierobinson7278]

Thank you for the info. And wou like to know how to adjust my floats on my 85 virago 1000

[@vintageyamahabackyardresto4995]

Here is a great resource for float leveling Viragos. I should make a video soon on this topic. viragotech.com/newtech/Float%20level%20adjusting%20-%20simplified.htm

[@hologrosk]

Great videos! Keep it up. Where can I find a back rest like that?

[@juanpachecopardo8952]

Sr. Great video, I have a 87 xv750, but I have problems with backfire even when a leave it in 1000 rpm (idle) my spark plug is carbonized, might be to much gas, I wonder if this wideo could fix the problem?

[@vintageyamahabackyardresto4995]

Typically, when you have backfiring happening at idle it is usually because the carburetors are out of synchronization. In one of my other videos, I end up setting and synchronizing carburetors on a red xs850. Check it out and see if it helps. You can buy the gauges off of Amazon for about $35 USD

[@pb6972]

Ive got the same bike..i took off the exhaust middle muffler with the end pipes..leaving the main pipes still on conected to the cylinder..i wrapped the pipes in cloth put to small 50mm end pipes..went out for a drive sounds loud but ok but coming back fk me it backfired all the way home...so do i put the stock back pipes back on with the under bit muffler....or would i cure it another way....hmm thanks for your video appreciation 👍☕️😉

[@robertswift4791]

Hi Thankyou for your video yes my xv 750 1994 us custom has had a backfire in rear cylinder carbureter .so I shall try your advice .thou I also have a persistent problem with front cylinder NOT firing eg plug is wet when removed I have removed carbs cleaned and refuted also today replaced both ignition coils and fitted iridium plugs ...but when I gun the bike for any distance front cylinder stops firing and eventually engine cuts out ...any advice be much appreciated many thanks from over hear in UK CHEERS BOB ...

[@vintageyamahabackyardresto4995]

It sounds to me as if the front cylinder may be running to rich so when you are going WOT it is dumping too much gas into the cylinder. I would check to see if factory jets are in the carbs (or if someone has put oversized jets in it) and check the air/fuel mixture as well. I hope this helps and thanks for watching!

[@BIGGZ46]

I just finished my rebuild and I’m running to rich. The plugs are fouled and covered in black soot, similar to yours. Is it simply a matter of turning those screws to lean out my mixture? My bike will not start or idle.

[@vintageyamahabackyardresto4995]

I would say yes. If they are Mikuni carbs on a Yamaha Virago XV750 you are looking at running in the pilot screw all the way in and start at about 2 full turns (many other bikes start out with a stock setting similar). I have had some carbs even go as much as 3 full turns. Try to pop the plug wire off of the other cylinder so you are only dealing with 1 cylinder at a time while setting the pilot screw. Once you get less pops and it smooths out, then do the same to the other side. Finally send lightning to both spark plugs and see how she runs. :) I hope this helps. Thanks for watching!

[@TheCrabCoreKing]

What tool arr you using to screw/unscrew? Im having a hard time with what i have om hand. The placement is not super friendly lol

[@vintageyamahabackyardresto4995]

Hi.. I am using a Philips screw bit and a 1/4" boxed end wrench. The bit should fit right in the boxed in side and you can twist that way (some bits are 3/16", so you may need a 3/16" wrench if yours is bigger) Thanks for writing!

[@HHG_BREEDINGGROUND1]

Ahhh I see now. You remove the spark plug from the cylinder you are not setting the mixture screw for, right ?

[@paulgrossman2034]

Hello from Brooklyn - Thanks for the great video. I got a 'barn find' '82 XV750 that hadn't run in many years but only 6K on the odo - wasn't starting so it was almost free. I have been tinkering for a few months (cleaning the whole tank and fuel system and rebuilding the carbs so I can clean the bowls and jets, etc.) and she is now at least starting! Thank you so much for the idea for pilot screw adjustment with the carbs on because they are a ***** to take off and put back. One question if you have a second: the bike starts great but when its warm and I back off the choke she dies after a few seconds - is this a pilot screw adjustment fix? I am new to these Hitachi carbs, any ideas would be amazing. I am grabbing some of your merch BTW - that swag looks good!

[@vintageyamahabackyardresto4995]

Thanks for the comment, yes it could be the pilot screw adjustment. I would also check the jet orifices just to make sure that there is no obstruction. A trick is to use a High E (smallest) guitar string. It will fit in both jets and you don't have to worry about a piece breaking off inside. I use them all the time for reaming out jets to make sure that they are nice and clean. Feel free to pick up some merch. I have been slacking on the videos as of late, but don't worry.... more rebuilds are coming :)

[@islandercafe54]

From Befair, WA recently acquired 1982 920J Virago. Needle for main jet has no slots of e clip do you know if it needs some shims or what?

[@vintageyamahabackyardresto4995]

Check out www.motorcycleid.com/1982-yamaha-xv920-virago-carburetor-jets-needles/ as they are a good resource to see what is in a complete jet/needle kit for those bikes.

[@187infrared]

I have the same bike when I get into high rpms it jumps looses power I don't know if it's air fuel or filter

[@vintageyamahabackyardresto4995]

Maybe check your diaphragms for gunk/tears. Just be careful when trying to get them out that you don't rip the rubber. I put a thin layer of vaseline on mine and wiped it clean to try and soften up then rubber. I hope this helps. Good luck!

[@jongraf1714]

Had a similar problem and literally just needed new spark plugs on my 97 750. Try new plugs and wires before anything more expensive!

[@cjm8373]

Question. I just bought an 81 virago. Where there is supposed to be a flathead insert, it is just a flat piece of metal

[@vintageyamahabackyardresto4995]

Can you be more specific? I am not sure where you are talking about.

[@gefrinjim6803]

Sounds like you can't find the screw head ? It is probably blanked off (at the factory ) with a cap to prevent tampering. It's called a Welsh plug. There are vids how to remove it. Good luck 😃😃

[@jongraf1714]

Same here; friends at the bar say insert a drywall screw and try to remove? Terrified since it's on the bottom of the floats but I think I'll try after work tonight!

[@tidwellrdarc]

Air filter change. Could use some knowledge on that.

[@vintageyamahabackyardresto4995]

Thanks for the episode idea. I may just get on that :)

[@Mihaitza4ev3r]

do you have a 500 virago that you have a backfire and misfire and have a rough idle to show us how to ajust the carbs

[@vintageyamahabackyardresto4995]

Unfortunately, I do not. Just 750s and a 920 but the process should be very similar on a 500

[@jewelsatan7856]

I have a virago xv750 of 1982.la I turn on and does not last on then it turns off and that I just put the new spare parts to the carburetors. some advice that you can help me solve that failure greetings from mexico

[@vintageyamahabackyardresto4995]

Verifique que los chorros dentro del carburador no estén obstruidos. Puede usar una cuerda de guitarra E alta para eliminarlos. Parece que definitivamente es un problema de suministro de combustible.

[@EldonBeix]

UMM - I think you should be working on the carb that is firing instead of the one that has the plug pulled. You can turn the Idle air screw until hell won't have it on the dead Cylinder and it will not make one iota of difference to engine speed.

[@vintageyamahabackyardresto4995]

"Dead Cylinder Method" has been used by several people. Some people use a dummy plug. You can read more about it here: (Yes, I realize it is on an XS forum, I also have an Xs850 3 cylinder that I am restoring) www.xs650.com/threads/dead-cylinder-method-for-carb-setting.49892/

[@reneguay1347]

My 750 is backfiring and as soon ss take the off the bike dies also the bike has not run for a few years any ideas?????

[@reneguay1347]

Sorry i missed a few words when i take the choke off it dies

[@vintageyamahabackyardresto4995]

@@reneguay1347 Check to see that the jets in the carbs aren't plugged/gummed up. This happens with a lot of bikes that sit. You can use a high E (smallest guitar string on a 6 string guitar) and poke it through the jets to clear out any obstruction. Good luck and thanks!

[@nickharnish]

My 82’ virago feels liek it’s not getting fuel when I pin it, if I give it a little gas the rpm’s will build and such but when I pin it it doesn’t jump or have any more power just the same steady build in rpm’s, what the hell is going on with my bike any idea? Last season it pulled hard now it does not

[@vintageyamahabackyardresto4995]

Check for possible jet orifice partial blockage. Ream it with a high E guitar string. It may be starving for full at WOT. Thanks for the reply and the watch. We are learning together!

[@longdong3889]

From a bike mechanic: Pops don't come from s carburetor, its unburned gas in the exhaust system. It's a rich condition.

[@vintageyamahabackyardresto4995]

Yes, and how do you typically rectify a rich condition? Air/jet screw, right? That is located on the carb, so you have me confused with that one.

[@longdong3889]

@@vintageyamahabackyardresto4995 a "backfire" is a timing issue, popping in the exhaust is rich mixture. Two entirely different problems.

[@vintageyamahabackyardresto4995]

@@longdong3889 All I can do/show you is what has worked many times for me. "*Results may vary" if you need a disclaimer. Thanks!