Yamaha Virago XV 535 Carb Issues and Float Height Adjustment

[@richiewood]

I've recently been working on a virago xv535 that I bought to get me to work, it seems to have been completely neglected by previous owners. That also had both of the Fuel Air screws stripped. I managed to drill them and hammer an old torx screw driver into the hole and wind them out.

[@OldBiker]

Yeah Rich I tried the same but whoever owned the carbs before had drilled the heads of the screws off center ruining any chance of repair, have another set now but still having running issues

[@richiewood]

@@OldBiker ah ok, that's not good. had mine running ok for a few weeks, now its stopped running on the rear cylinder, I only changed the plugs, boots and coils a couple of weeks ago... at a loose end.

[@OldBiker]

​@@richiewood Where did you get the coils? I read in the Haynes manual it states the plugs should be BP7ES and not BPR7ES , but somewhere else I read the plug caps should be 10k ohms, so I'm guessing the 5k ohm caps and the plugs with resistance adds up to the 10k mighty confusing these modern ignition systems!

[@richiewood]

@@OldBiker the coils were just form eBay. Not too sure on the quality. Time will tell. I am using Bpr7es with the 5k boots. Didn't even realise that was a thing. I will read up on it and may even swap to bp7es to get a stronger spark then.

[@jackmack973]

Super helpful. Watched another vid to get the carb out and wish I saw this one first. Never pushed the intake up so that was a fun wrestling match.

[@BugsWisely]

Putting those Mikunis back in is a royal pain; emission control pipes in the way on top of that. Not to mention the washer that gets stuck at the bottom of the Idle mixture screws. A suggestion on those air mixture screws - leave the spring, washer and o-ring out. Push in a piece of fuel line the same size as the hole in the hole til it butts the screw, and cut it off flush with the outer end. Then put a screw in the end of the fuel line as a wedge to secure. A dab of Loctite LB 8023 on the air mixture screw thread, and never a problem again. Also keeps wasps and spiders from getting in there and bunging up the hole. I would ahv liked to see you remove the float valve seats. I replaced the brass plug in top - after tapping - with a 7/16" 20 3/8" set screw. Worked like a charm and i can replace the seats now without removing the carbs...

[@OldBiker]

That's a good idea about blocking up the holes, as for the float seat I never removed that, it's a terrible design and didn't want to chance breaking it.

[@UPTHETOWN]

I've used a left handed drill bit to get pilots out, about 50/50 chance of knackering the carb body but sometimes you get lucky

[@OldBiker]

Cheers Andy I'm looking into this left handed drill idea, thanks to you and "The Dadtato" who both mentioned it.

[@johncooper7242]

good to see you've still got some time to work on bikes, even if it is someone else's bike lol. Every used carb I buy has usually been damaged by some heavy handed owner who thinks everything should be tightened up with a breaker bar. groan... That pilot jet problem looks like it might be an non viable repair . I wish I listened to my own advice at times and stop wasting hours trying to salvage things by bodging when it would be a lot cheaper in the long run to just buy a good used replacement.

[@OldBiker]

alight John, I'll probably have a go at drilling the jets out using a reverse drill as mentioned by a couple of chaps in the comments, I never thought about doing that before, only using a normal drill and a easy out tool, come to think of it my last smallest easy out tool snapped off in the XS650 jet I eventually got out haha Today is a day to remember, its the day my channel reached 1000 subscribers! Oh as for the carbs, the one that has the jet screwed all the way in is the one I'll try to drill out, I may just leave the other one, well that will depend on if I can get the first one out.

[@johncooper7242]

@@OldBiker good luck with that Cliff. My only attempt to use a Easy out tool resulted in it breaking in the stud of an iron cylinder I was trying to remove it from which made the situation worse, brass and aluminium should be a lot more successful I imagine Took my 79er out for a quick blast the other day and I'd forgotten what a beast it is and how much I'd missed it. I tore up the village high street like a complete hooligan and the exhaust roar was something else. The camper van is nearly finished so we are going on a snagging break for a few days on the Jurassic coast . When I get back I'm going to concentrate on the XS and see if I can get to the bottom of the worrying noise from the crankcase.

[@karlh4313]

Got another question for my 95 Yamaha Virago 535SG. For the main jet sizes the manuals say 137.5 front cylinder 135 rear cylinder. But online Yamaha diagrams it shows the 135 in the front carb and 137.5 in rear carb where throttle lever is. So why do the manuals say front cylinder 137.5, rear cylinder 135? Isn't the front cylinder behind the front tire and the rear by the back seat? I have someone telling me the rear is the front and the front is the rear, I know (from rear to front of bike) cylinder numbering is 1-2 which I thought was firing order idk. But I also see that in the book it says to take the "front carb" enrichment diaphragm off and that's before you split carb. So I'd think that the front carb goes to front cylinder and rear carb (where gas goes in first) is going to rear cylinder, right?? I'm just so confused 🤔

[@MrChris4366]

Very helpful m8. Cheers.

[@karlh4313]

How come your needle valves don't have the clips on them? Do you need them? Mine is like a c clip with a L coming off it. Ive got the L behind the tang on float I'm wondering if it should be in front so float doesn't slide off

[@karlh4313]

I'm having a real issue with getting this fuel level measurement right ughhh! My carbs are already installed on bike so I have to keep taking covers off. I'm at 30 mm below the center mark on the cover and I can only get it to about 18 and then it seems to keep the pump running and no gas comes out till I bend the tang down on the float to let the valve down some.. what am I doing wrong? I have a 3 mm hose attached to the drain fitting with a adapter for a hose and then the Yamaha glass part for this with the mm's on it.. I'm confused!!!!! Ive spent 3 days trying to get it right and I can't I've even tried doing just the front carb to get it to 14mm below the mark on cover and can't get it.. I feel stupid

[@karlh4313]

f I bend float tang up with them on bike it brings float up more and puts valve up more and let's less gas out and makes the pump continually run. If I bend tang down it's let's more gas out and the valve lowers more but the float is lower and has to raise higher to close valve. I feel like I've screwed up smh it's all rebuilt but one float it was good other had gas in it and showed air bubbles when dunked in water...

[@OldBiker]

Hi Karl with them on the bike its a lot harder to set the heights, I just looked at a set I have laying around and with them sitting as if they were on the bike the floats sat level, set yours to look level and work from there, also if you see bubbles coming from the float when it is submerged, its had it I'm afraid. Are you from the UK?

[@karlh4313]

@@OldBiker no live in America

[@karlh4313]

@@OldBiker thanks!

[@karlh4313]

@@OldBiker yeah I got rid of the old float that was bad..

[@Virago_XV]

Would it be possible to make these adjustments while the carb is still on the bike?

[@norwichscott]

Im going to check my float heights on my vmax 1200 very soon... do you know if these are the same carbs?

[@محمدشاكر-ق7ف]

The need for a Yamaha Virago 400cc motorcycle

[@rc2634]

Is it the mixture air fuel screw that we can see at 16:11 ? The one we should set at 2 1/4 turns out? Thank you

[@OldBiker]

Yeah Rui thats the one, if it is hard to turn it maybe seized in there so be careful when adjusting it, make sure you have a screwdriver that fits perfect

[@rc2634]

@@OldBiker thank you so much for your answer and advice

[@BrianSPC]

What is the std. position of the needle i the carbs ?

[@OldBiker]

Hi Brian the centre slot is normally the standard setup, don't forget on the Virago you have different needles and jets for the front and rear carbs.

[@thedadtato9738]

Maybe a reverse drill bit to grab that jet and back it out?

[@OldBiker]

I was thinking about trying a Vix bit which is a self centering drill bit that the body of it fits snug down the hole to drill a small hole in the screw, then using a easy out to get it out, I might have to make one just for the job

[@tightbro]

Did this work? I just bought an xv535 with the same issue.. Don’t want to mess up the carbs

[@OldBiker]

@@tightbro No matey, but I did get one out the other day by cutting a bolt down so it would drop into the hole where the air screw goes, but before I drilled a very small pilot hole down the center of the cut off bolt, this gave me a perfect center to drill into the stuck jet, by using the bolt as a drill guide I had no issues with the drill moving off to one side. Once I drilled the small hole, I then went in with a larger drill and used a EasyOut bit to remove the screw. Hope that helps. If you get the easyout bit locked in and the screw still wont budge, you probably wont be able to get it out unless you cut the tube down to the top of the screw itself, I'll do a video sometime to show what I mean by this.

[@tightbro]

Thanks a lot for the explanation and instruction. I’m gonna borrow an easy out from a friend who builds motorcycles. He has all the gear. If it works I’ll let you know here!

[@محمدشاكر-ق7ف]

A used Yamaha Virago 400cc is in electronic condition

[@digga1667]

Security torx screws.....

[@GreatEgret]

Exactly! T-25 security torx I believe.

[@rc2634]

Is it from factory?

[@markielarkie445]

Wasting your time.