Bike Overheating?

[scott12544]

Hi guys, here is my issue. The bike runs awesome and idels great for the first 10 miniutes of riding it. However after a while when I pull up to a light it does not want to idle. sometimes I pull up to light and it is ideling high then works itself back down to a normal idel then gets slower and slower and eventually dies. I have to keep reving it to keep it running. I have the mix screw out 1 1/4 and I have the clip in the middle position on the needle in the slide. Is it running to lean or rich or is it overheating?

[scott12544]

could the jets be getting bigger from the heat...creating a rich running condition. just trying to figure it out. It is definately do to the heat because it runs great when it initally warms up..I am gonna stop at harbor freight and buy one of those laser thermometers and see what kind of readings I get when it starts idling weird....

[Sam Green]

It could be your coil breaking down.

Sam.

[scott12544]

no way..I just replaced it with a new emgo (i think) 12v coil.

[scott12544]

yeah here is the coil i got..http://www.bikebandit.com/emgo-point...1484958...keep the ideas comming...

Thanks, Scott

[scott12544]

Back in my low rider/ street racing days, I put phenolonic spacers on my intake manifold to reduce heat transfer from the engine block. what I am thinking is cutting one out, if I could find suitable material in order to keep the carb cooler, and replace the stock carb insulator...

[scott12544]

Ok I just got home and I put a meat thermometer in the dip stick hole and I am getting approximately 200 degrees...does that sound right?

[ByTheLake]

I agree, it sounds heat-related.

If the carb is getting too hot, the gasoline will expand, which could provide an overly-rich mixture, especially if the float setting is high. Has the float setting been changed?

Have you pulled the spark plugs for inspection after the symptoms appear? There could be some good clues there. I'm wondering if the plugs have a sooty black surface.

When the engine starts acting up after 10 minutes, are there other symptoms, like blue smoke?

After the symptoms appear and you have to increase the throttle to keep it running, is it running smooth at those higher RPMs or is it coughing or acting up?

[scott12544]

ok checked out the spark plugs and the plugs they were heat range of 5, I ran down to napa and picked up some dh8a's (after checking the forum)....with heat range of 5 versus 8 really cool down the bike as much as 20 degrees. When i was putting the bike together I just replaced the plugs with what was in their, thinking whoever had it would of ran the right plugs... I ran the bike again with new plugs to get it back up to temperature and it appears to be running better, but of course it got cooler out so that may have something to do with it .... The bike always ran well at high rpm, and I have never seen any smoke really at all since having the head rebuilt...also on my way home while at a light I felt the carb and it wasnt really hot just warm...I think now it was the plugs...anybody else had the same situation?

[Jetblackchemist]

Done.

[Sam Green]

It might be an idea to get in touch with a Auto electrition and ask what the implications are of running a 12v coil in a 6v system.
Also, using the wrong plugs coupled to the wrong plug caps can cause all sorts of problems, like the plugs, not all plug caps are compatable. (resistor/none resistor)

Sam.

[scott12544]

Sam I am running a 12v system. 12v battery, silicon rectifier (ohio cycle), and now the 12v coil. I was using the stock coil but the bike idles better with the 12v coil. I think the stock coil was a little tired.

Jetblack, I cant really back the mix screw out much more with out it being too loose. The plugs were a little sooty. I could drop the needle down a notch and see how it runs. I would think a lean mixture would make a the bike run hotter and rich just dirty..

I broke the clutch cable so I could not ride the bike to work today. I will fix when I get home tonight and report back tomorrow on how it runs with the new plugs.

[scott12544]

I appreciate the help guys and ideas. I do love this forum and it has been invaluable resourse through the process of building this bike. The whole process has been a lot of fun. I have two 6v coils, they are currently on ebay, but anybody on the forum can have them free plus shipping.

[Buckets81]

Have you replaced the points and condenser? I thought mine were fine but it turns out that the plastic that the original points were made out of was brittle and causing issues when the bike heated up and replacing the original condenser helped things along as well.

[Jetblackchemist]

Done.