yamaha xj750

[bebby]

has anyone worked on one of these bikes before it is a 1983 model and has the YICS engine.Prob is i cant get the carbs set right i have set the fuel levels in the bowls and blanked the air ports in the head which has to be done in the yics system to sync the carbs but every time the engine gets warm the engine races and cant get the revs down under 3000 revs.it has got a ram air system air cone set on it,dont know if i can get an original air box to try that.:bang:

 

[Jaws]

Had this before on one many years ago
Turned out to be air leaks on all the bloody inlet rubbers !!

 

[solorider]

as you have the proper tool (i hope)then as john says an air leak,could be perished carb rubber manifolds or even the carb diaphram

 

[bebby]

tried the inlet rubbers first spraying them with wd when it was running then wrapped them with self amalgamating tape nothing changed.I am starting to lose my temper with it now so ill leave it for a few weeks thanks for the help though.

 

[Jaws]

Before you started fiddling, was it ok ?

 

[solorider]

something i have just remembered,have a look at the carb soindles,i used to have a xj750 which ran loike a bag of shit,i found the spindles has big play in them,i was lucky in that i got a set of carbs cheaply at the time,and they were from a low mileage bike

 

[XXrider]

Air leaks!!!! I had the same problem working on my wife's '83 XJ750, and fussed over everything mechanical forever.... However, 25+ yr old rubber isn't going to seal very well!

Get new stuff - all around - you might fix one, but another is there. Trust me!

Only after you get that stuff replaced can you start looking at mechanical stuff (and making it run right isn't hard at that point).

What you are experiencing is exactly what I saw.

Best to you!

'rider