New top end with bore running hot. How should I change jetting?

Chris Long

Member
Jan 17, 2005
33
0
I just put my 2000 RM80 back together with a new top end. Due to some scoring, I bored it and now it runs hot. Water pump is new and coolent is WaterWetter. I use BR10ES plug, 32:1 with octane. It has a FMF Rev pipe and FMF shorty silencer. It has a 190 main jet and stock is 220. Pilot, needle and air screw are all at stock settings.

The bike came with the 190 in there becasue thats what the FMF pipe called for. Could this be too lean? I'm thinking I need something over stock like 225 or 230.

Any thoughts. Thank you very much.
 

SHSPVR

Member
Oct 24, 2006
200
0
Possable is that the Water pump is not pump the water check that frist by taking the radiator cap off and watching it is there any flow?.
What dose the plug look like.
How do you bleed a cooling system that eazy as eatting apple take the radiator cap off let warm up add in more when needed.
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
When its cold take the cap off and start it, see the coolant flowing? Begin with stock jetting and jet the carb. You have to look at the plug. Who and to what specs was it bored to?
 

Rotorranch

Member
Feb 10, 2007
436
0
Some bikes won't bleed the air out just by running it with the cap off.

There may be a small screw on top of the cylinder head. Fill the rads about half full, then remove the screw slowly untill you get water out the bleed hole. Tighten the screw, fill the rads, then check for flow with the cap off. And be careful...the coolant can be HOT!

Not sure if the '02 RM80 has a bleeder or not.

Rotor
 
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