Please help diagnose

[jtcrespo]

1983 GS750ES 8000 miles

I synched my carbs today, and still have the #2 cylinder running signifcantly cooler than the other three.
Here's the temps from digital gun after warm-up:
#1,3,4 @ 209 F
#2 @ 106 F

The electrics check out, new NGK plugs getting spark, no smoke in exhaust.
I called a mechanic and he said it's probably a tight exhaust valve. Get this: He quoted 4 hours of labor! Questions are as follows:

a) Does this sound like a correct diagnosis?
b) I should be able to do this on my own in less than 4 hours, right?
c) If it is possible that it is something else, what can it be?

Thanks in advance for any help, It's much appreciated

[earlfor]

Re: Please help diagnose

The first thing I would do is check compression on all four cylinders. If #2 is the same value as the rest, then the problem is not a valve. If #2 is low, then its most likely going to be an exhaust valve. If compression is low, the #2 plug will likely be very black. If its a lack of fuel flow problem, the plug will be clean. It shouldnt take 4 hours to remove the gas tank, valve cover and checkt one valve.

Earl

1983 GS750ES 8000 miles

I synched my carbs today, and still have the #2 cylinder running signifcantly cooler than the other three.
Here's the temps from digital gun after warm-up:
#1,3,4 @ 209 F
#2 @ 106 F

The electrics check out, new NGK plugs getting spark, no smoke in exhaust.
I called a mechanic and he said it's probably a tight exhaust valve. Get this: He quoted 4 hours of labor! Questions are as follows:

a) Does this sound like a correct diagnosis?
b) I should be able to do this on my own in less than 4 hours, right?
c) If it is possible that it is something else, what can it be?

Thanks in advance for any help, It's much appreciated

[Anonymous]

hrlp

the dealer is giving you the time for a complete valve service and is using the supplied flat rate book he can more than likely do it faster but your going to pay what the book says, what earl says is right on target

[SqDancerLynn1]

Problems with the #2 cylinder can also be cause by a bad petcock

[moto_dan]

Problems with the #2 cylinder can also be cause by a bad petcock

I agree. Check this first since its the easiest! Just pull the vacuum line off either from the petcock or the #2 intake and it should be dry. You can also clamp off the vacuum line and turn the petcock to P(rime) postion and see if #2 heats up. Good luck.