One cylinder running lean and hot.

[sweatybetty89]

Got my bike to sit and idle couple times today but, the left side cylinder was running very hot to the point there was some smoke that seemed to come off the head and headers. Would sit and idle okay. Eventually would die. Checked plugs side that's hot has lil ashyness and carbon build up. Bought new plugs cleaned out carbs again real well. The bike was seized up when I got it have not inspected the top end what so ever. Wondering whats my next move? Drop engine work on top end? I figure it will be easier if the motor came out or maybe that's the only option for the top end. Thanks guys

 

[nj1639]

Check compression and compare both sides.

 

[5twins]

Yes, the motor has to come out to get into the topend.

 

[gggGary]

what ignition? check timing?
Genuine mikuni jets?
low compression won't run hot.

 

[arcticXS]

what ignition? check timing?
Genuine mikuni jets?
low compression won't run hot.

And neither will lean or rich condition. A perfect fuel/air ratio (stochiometric) will give the highest combustion temperature. Pre-ignition, poor timing etc may be the culprit here, as already pointed out by Gary.

 

[sweatybetty89]

what ignition? check timing?
Genuine mikuni jets?
low compression won't run hot.

Did a static timing check and its braker points gary. Could need to do it again seeing as it was my first time doing it. Yes genuin mikuni jets.

 

[gggGary]

I'd want to get both sides checked and set at idle AND at full advance with a timing light. Quite a bit of timing variation side to side is often found. As is too much, sticking advance, lots of threads on causes and cures for advance issues. Air cooled motor, don't run it very long in the garage. Get a big fan pointed at it. Since it was stuck you really want to see what the compression is.

 

[sweatybetty89]

I'd want to get both sides checked and set at idle AND at full advance with a timing light. Quite a bit of timing variation side to side is often found. As is too much, sticking advance, lots of threads on causes and cures for advance issues. Air cooled motor, don't run it very long in the garage. Get a big fan pointed at it. Since it was stuck you really want to see what the compression is.

so when did last static timing adjustment the problem cylinder has now shifted to the opposite side from before. had to move back a step and get my valve clearances correct but even so why did it go from one cylinder to the other any idea garry?

 

[sweatybetty89]

I'd want to get both sides checked and set at idle AND at full advance with a timing light. Quite a bit of timing variation side to side is often found. As is too much, sticking advance, lots of threads on causes and cures for advance issues. Air cooled motor, don't run it very long in the garage. Get a big fan pointed at it. Since it was stuck you really want to see what the compression is.

did compression check btw 140 psi

 

[5twins]

You can't trust a static timing set to be 100% accurate and right. Check it dynamically (running) with a timing light. It can be a chore to exactly dial in this dual points set-up. Basically, it's like setting and dealing with two separate little ignition systems. Not only do you need to gap the points and set the timing on each one but then you want to match them to each other. You want both points sets gapped the same and both cylinder timings set in the same spot.

 

[gggGary]

Check and double check, wire connectors, grounds, ground wire from engine to frame and condensers, test the condensers. New CORRECT spark plugs? the correct plugs are NLA so you typically need to change plug caps to non resistor type to use
If you have resistor caps= Bp7es
If you don't have resistor caps=bpr7es
SWITCHES both ignition and kill switch are prone to current robbing corrosion inside.

 

[sweatybetty89]

FUCK YEAH! went through again today gave it another go and she quite over heating. Just followed steps to set cam chain, valve clearance, then gave the brakes points one more go and no more over heating(well a lil still but no smoking heat) now to go by a strobe and do dynamic set for timing and on to the next step. Appreciate all the fucking help guys feels good to have got it done.