81 XV750 won't return to idle .. idles too high

[thewiz]

A really nice Hogley rider approached me yesterday and remarked how nicely he thought my bike, a factory stock XS1100 Standard, ran. After some chit chat, he said his nephew had a Yamaha that wouldn't return to idle. Come to find out that this bike is an 81 750 Virago. I told him what I thought in it might be in terms of transverse 4s but I have no personal knowledge of that motor, carb arrangement etc but I'd like to help if I could. This is rural NC and these boys have no internet or confusers ... so here I am !

What would I look for on this model? Can I synch these carbs with my Morgan Carbtune? Is there a manual online somewhere? Other things to watch out for or look for? Lets try that for starters ... and thx.

[GARTHXS]

gosh

I thought you got a vtwin for a second , you should be able to sync with just two hoses, you know the deal

[thewiz]

Listen here, ...

numbnutz ... if I want crap outa you, I'll just git on out thar and squeez yer head .. ... after I get everyone to sit on ya' so I can reach it.

Cereally though, G, .. not so sure all this works the same .. for ex. I think ya' gotta' synch with something other than a Morgan on a YICS motor ... I just don't know yet. If it is similar to the 4s ... well ... piece of cake ... otherwise maybe I can get a little bit of guidance. Haven't even seen this bike yet either... soo ... I found a Virago forum, joined and posted the q up there too .. just have to wait and see, I guess.

[rpgoerlich]

I'd check the throttle cable as well as the choke/enrichment cable to make sure they are releasing all the way.

Then grab your morgan carbtune and sync them carbs. You'll find it fun trying to get to that sync screw even with the tank off...

[soccer4m]

just sold one

Hey Wiz,,,,,I just fixed up and sold an 82 xj750. The carbs are pretty simple,,,to synch just use two hoses to the vac lines and adjust. The screws are a little hard to reach, in the middle but it can be done. Also, there is a mixture control box under the left side just in front of the gas tank under the small plastic panel. Disconnect it and plug the hoses going into the carbs. It causes numerous headaches on these bikes. Also check the vacuum hoses, as there is a bunch of them, not like the xs1100's, for leaks. The mixture screw in on the bottom of the carbs, you need a small screwdriver to adjust,,,a tight fit. Also, the slides could be sticking, but unless you want to yank the carbs to check, also a minor pain in the arse, sych them first, yank the control valve and plug, check the vac lines and you should be narrowing the problems. It also has known starter problems, like spinning and noisy,,,that is normal on the viragos. Let us know how all that works out. There is a couple of Virago websites with lots of info,,,do a search for virago owners.......hope all is well in your new territory,,,,,,Mike in Sun Diego

[thewiz]

right on ...

rp ... just needed to know that it could be done thataway. Appreciate it. Thanks I'll git 'er done ....

[thewiz]

Why, Mikey ...

Awesome .... that's exactly what I need to know ... missed it when I thanked rp ... how's Tom ... did he use one of those motors??

[chevy45412001]

sticky

i found on a bike one time,that it sat to long and the fuel turned to varnish. got real sticky ,like when u whacked the throttle it stayed open,cleaned and cleaned those carbs but i had no luck. short of replaceing all the lines chemical treating the tank....u see were this is going.just a passing thought.

[MindWebs]

OH CR&*$

WIZ..

did you see that soccer4m is talking about an XJ??

the xj is the same as our XS's it's an inline 4 sometimes with YICS.
(i have 2 of these)

You are talking about an XV 750 which is a V-Twin.. or V-4 (i forget)

There are diferences in the carb set-up, but tuning the carb's is the same procedure as our XS/XJ's but one thing you have to becareful with is the airbox assembly, make sure you don't have leaks when assembled, this will throw the carb's out of sync with each other.

It's ok to tune it with that crap off if it's in your way, as long as both carb's are "free air" and 1 isn't restricted by tubing.

i'm not familier with the brand of tool you refered to but any vacume gauge will work to sync carbs, be sure to take any adapter parts with because i don't think the XV hooks to the gauges the same easy way. all you need to do is look the assembly over and you will find "ports" to hook the gauges to.

good luck

[thewiz]

Hey, MIndweb ... thx for the info ... I just re read Mikey's post and he refers to both the XJ and the XV in there. So you have a point. I'll call him for clarification .. thx again

[chevy45412001]

yics

was on the xj1100,still don't know eXSactly what it is something to do with the cold air starting or some thing like that.if i'm not mistaken tube connects all 4 carbs for enrichment at cold start....???? but someone on this site made a tool to plug for syncing the carbs. Pipe in if i mispoke on this guy's.