Overheating Harley experience?

Question

My son has a Harley sportster w/ a 1200cc upgrade.
It starts & runs OK for a while then , overheats & quits.
Oil pressure & flow look OK.
No smoke.
Is this common with or without the 1200 kit.
Limited funds.
There a good way to diagnose without having engine torn down?

Going to let this Q run for a while.
Right now ,it looks like the "lean" people are out front.
I know nothing about bikes, so keep the wisdom coming.
Thanks to all.

Answer 1

Most common cause for heat is a lean condition, caused by too small of jets or an intake leak.
Look at the spark plugs , there should be a tan residue on the ceramic portion that surrounds the electrode. If that area is white, you are lean.
Another cause of heat is having the timing too far advanced, but that would not create an overheat that would shut you down unless you were off 5+ degrees.

Answer 2

I really don't think is the 1200 kit. My friend got a brand new 2006 Sportster 883L and worked fine for a couple of weeks. Once the breaking period passed then he started having problems with overheating as well. H-D dealer told him its normal and would not do anything about it. He actually had more than the overheating problem, the bike would stall nearly in every stop light. The problem here is that H-D would only test it for about 10 minutes and by then everything seemed ok. Most of his problems started right about 30 minutes when the bike was really hot and I mean hot. He finally sold it and bought a different brand with water cooling system.

Answer 3

Here is the problem, not kidding, it's a Harley! Here is the main problem with Harley's running hot. It's an air-cooled, v-twin that runs with one cylinder in front of the other. The rear cylinder NEVER gets cool, fresh air. So, now that you are runnin high performance parts with your 1200 upgrade, you might want to consider a bigger air filter or a carb adjustment. Breathing will help bring that temp down, and stop the stalling problem. Overheating is a problem every Harley owner will face. You are not any different. If a few small adjustments don't fix the problem, you might need to get your local dealership to take a better look for you.

Answer 4

Do the plugs look white = too hot? You might experiment a bit with the ignition timing, less advance might help. However, if the plugs are hot, then the fuel-air mixture may be too lean. Try bigger carb jets and different needle. Only change one thing at a time, otherwise you won't know what fixed it.

(All this is reason not to have screwed with the engine to start with. Too late now, of course.)

Answer 5

One way to check if the engine is runing lean is to pull the choke out just a little and see if it fixes the problem. I have a 2001 883 that I replaced the cylinders on to convert to a 1200, but I didn't do anything to the carb. 11K miles and it runs good.

Do you have spark when it quits running? Pull the plug and make sure it does. Make sure the fule line isn't sitting on the heads also.

Good Luck!

Answer 6

I agree with everyone here. Something isn't right. It is probably running lean. Never a bad idea to get an oil cooler on an air cooled engine. But that'll cost yeah.

Answer 7

Need more info. Depends on carb mods, brand of 1200 kit, ignition timing, if using oem oil filter (a must with sportsters) and condition of ignition system

Answer 8

Sounds like you might be running to lean, Running lean will cause a hotter running motor.
Look at the plugs if they are very white they you are lean.
You can adjust the carbs by jetting with bigger jets.

Answer 9

Has the exhaust or air filter been recently changed?
A free flowing filter or exhaust will run leaner, to the point that you might have to richen up the jetting of the carb.

Answer 10

I am not an expert on HD, and I know that there are lots of people who have perforance problems due to dirty or clogged air filters. It would be a good place to start
Next time tell him to go Liquid cooled and fuel injected