#1 cylinder running colder than others?

[ChadXJ821100]

I just finished sycronizing the carbs and the engine seems to run pretty good in the shop. I am a little concerned with the #1 cylinder since the exhaust is colder than the rest.

History: I have did some work with the electrical but all cylinders spark very well! I have throughly cleaned carbs (4-5 times) and replaced the most important jets with new. I have put on new 4 into 1 exhaust since the original was full of holes and leaked everywhere. I adjusted the timing chain. I feel like I am getting closer to the test ride one of these days.

I haven't checked valve clearence yet. It is on my to do list and I realize I should have done that early on. Could this be part to the problem? I could only hope.... I am told it ran good prior to being parked 10 years ago.


Thanks,

Chad

[egsols]

If the bike is running good then it must be firing on all four but may be getting a weak spark to 1. Check the plug wire? Wouldn't hurt to check the plugs as well to see how no.1 is running compared to the other 3.

[randy]

I haven't checked valve clearence yet. It is on my to do list and I realize I should have done that early on. Could this be part to the problem?

YES!

Proper tune up starts with valve clearance, then carb synch.

[boyat68]

ChadXJ821100:

If you have redone your carbs and #1 float height is not correct, then there may not be enough fuel in the bowl to allow your pilot jets to pull fuel. I think that your pilot jets are fed through a drilled hole from your main jet tower a few mm up in the tower, with a stopper on the bottom of your pilots. If there is not enough fuel height, then the pilot cannot pick up and that pipe would be colder than the others. If you run the bike above 4000 rpms, then the mains kick in and the pipe would get hot. Also if the air pilots (idle) are not balanced, then the one pipe could be colder. You may have to pull the carbs and check your fuel height.

[ChadXJ821100]

Thanks for all the suggestions! I will work on it again tonight and double check a few things. I have those nipples on the carb float bodies so I could easily check fuel hieght with clear tubing.

I had set the pilots or Idle mixture screws back to what I found them after removing factory caps. I did play with them a little to try tuning by ear but it didn't jump out at me so I went back to what they were.

Thanks again, this Association has made this process alot more enjoyable working on my bike.

Thanks again,

Chad

[planedick]

What

boyat68 said sounds like the problem. Reading the plugs should comfirm it. Float setting is important.