Tuning help

Chrisj796

Member
Hello I have a 72 CT70 with a #60 main jet an #35 pilot, bike was getting hot pretty quick so I adjusted clip on metering rod to lowest level. Rode around block today an bike started to cut out going up small hill. Cylinder head was 168F and front of exhaust was 278F after about 5 min of run time. I thought lowering clip would give it more fuel in return motor running richer an cooling down but I have seem to have an opposite outcome. Any suggestion would be appreciated.
 

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lukelaw1

Active Member
I don't know for sure but I don't think those temps seem out of line. I don't have a temp gun and have never temped a motor. I would be more worried about oil temp. Lower the clip should richen the air fuel mix. The bike probably started to cut out because it was too rich.

Is this a fresh rebuild and are you in the process of breaking in the motor? Can you take a picture of the carb and carb flange? A #60 main jet for a 72 K1 doesn't feel right to me.
 

Chrisj796

Member
I don't know for sure but I don't think those temps seem out of line. I don't have a temp gun and have never temped a motor. I would be more worried about oil temp. Lower the clip should richen the air fuel mix. The bike probably started to cut out because it was too rich.

Is this a fresh rebuild and are you in the process of breaking in the motor? Can you take a picture of the carb and carb flange? A #60 main jet for a 72 K1 doesn't feel right to me.
It’s got got around 10 hours on rebuild. the jet sizes are what’s in stock carb also. I
 

Deoodles

Well-Known Member
Those temps are not too high but they got there pretty quick. Have you thought about checking the oil screen. If it’s clogging up with lint from the rebuild that will heat up the motor very quickly. I know this because it has happened to me in the past. I make it a point to check it a few hours after a build. Lean the bike next oil change and use a phone to snap a picture in the oil bolt hole. It can give you a pretty good visual if you carefully do it. Another source could be if the A/F screw is closed too much. I have that T-shirt also.
 
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