Jetting Question

Friday evening picked my bike up from the shop and they told me the bike was running great but it seemed to be running really hot. So they said that it was running really lean.

There is also the infamous bog in 1/4 throttle range. One of the guys we were riding with said to lean it out.

Too hot cause its lean and the bog is because its rich somethings wrong here, any thoughts?

It could be rich or lean in different areas of the throttle range. Running hot MIGHT mean lean on the main jet. You could try going up one or two steps on the main to see how it acts. As long as you don't muddy up the power, you're not too rich.

Conversely it may be bogging because you are too rich in the needle position or pilot jet. You could try raising the clip one or two positions to compare. Here is a link for some jetting basics. http://www.motocross.com/motoprof/moto/mcycle/carb101/carb101.html

To cure the bog your jetting must be pretty much spot on at each throttle position. Once you get the rest of the jetting lined out, if it still bogs then you can attack the AP squirt by tuning the leak jets. See www.thumperfaq.com/ap.htm

Alright thanks barton...

I will try those suggestions as soon as a get a chance :cry:

How do you know it was running hot?

4 strokes generate lots of heat, alot more than a 2 stroke.

How do you know it was running hot?

Exactly. Is there antifreeze coming out of the rad overflow? :cry:

We brought into a shop to get the brakes master cylinder rebuilt. They finished it and rode it around to make sure the brakes were working. When we went to pick it up they said the brakes were working fine but the engine was running hotter than normal...

How they would know this i dont know.

I'd suggest ride it and keep an eye on it. When the bike is cold, check the radiator for antifreeze level. Make sure it is right up. When you ride the bike, avoid the engine running without the bike moving (except for initial warm up). Keep an eye on the rad overflow hose. Is antifreeze escaping? If so either your bike is overheating or the rad cap is defective. After the bike cools down, check the rad again. If the rad is full you do not have a heat issue.

The bike runs very hot. You can find many posts here asking if it is normal for the header pipe to glow red.

You may not have any heat issue, just a bog issue. Once you understand the heat issue you can work on the bog issue. :cry:

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