1983 xj750 k manifold vacuum

Can anyone tell me the average manifold vacuum level I should be seeing on my carbs?

 

Once they are even as idle is 1050rpm 10-12

 

I'm only seeing 7. Might be the crappy gages I bought. The bike idles great

 

you are looking for equal or as close to equal after sync.

it will be different on different gauges.

 

Actually it shouldn't be, unless inexpensive dial gauges are being used.

OP, here's the thing. Yamaha didn't give a spec for manifold vacuum since there are no vacuum accessories other than the petcock. You also can't go by any chart or guide that was made for a different engine type. The only real way to gauge the internal health of the enigne is to perform compression and leakdown tests. As it stands you don't seem to really need to do either.

 

By the way thank you so much for the response

 

Well I am getting ready to colortune. We'll see if that makes any difference at all on the manifold vacuum. The bike performs really well lots of spunk. It only has 7,200 miles on it.