02 ktm 125 mod

[dirtbikr99]

Hi, I picked up a 2002 ktm 125 as a project. Buy and sell. Got it for 350 bucks. Had a bad top end.

Tore into it, needed full rebuild bottom and top. I put new main bearings and seals and rebuild the crank. Top end has 2mm over bore, sleeve. There was no chamfering on the ports haha. I chamfered the ports, honed it and did a little porting to the exhuast. Put new wiesco 56 mm piston in it. Cleaned the carb. Cleaned the power valves and made sure the timing marks were correct.

Starts up good. Does not rev out fully.

I am careless and did not check too see the main for pilot jet sizes. I am thinking its not getting enough fuel.

What do you guys think? What would be good jets for this bike?

Thanks a ton.

 

[helio lucas]

by pro circuit web site: main 192, pilot 45, needle 1469H 3rd groove and air screw 2 turns out from fully closed position.
those will be fine for starting fine tune.

check the powervalve connection since it may not fully open.
a good clean to the carb seems to be in order. check the reeds while you´re at it and clean the air filter.
repack the silencer with new sound absorving material.

 

[dirtbikr99]

Thanks mate!

I will pull the carb apart and see what I have in there now.
The reeds are worn, but in my opinion still usable for now. The silencer could use repacking but i'll let the new owner do that.

The power valve got me thinking now. When i took it apart it was tight. One of the side powervalve cylinder rotating things was tight. I polished the cylinder and honed the actual cylinder hole for it. Put it together and it moved very nice. I lined all the marks up. But when you put the cylinder onto the cases its hard too see if it goes onto the powervalve arm correctly.

If jetting doesnt fix this I may need to pull the top end off to check it out.

 

[helio lucas]

you can take the inspection cover, or something like that on your model, with the engine running and see if it moves at all.

 

[dirtbikr99]

I checked the jetting and float level. Then I checked the magnito. I had lined the marks up on the trigger and the cases, to top dead center or whatever. So I figured what the hell, and advanced it a bit. Rode it and my problem was fixed. The bike rips! Very powerful, low mid and top. Rode it for like 30 minutes and I notice some antifreeze dripping. I think maybe its just from the over flow hose. Its the head gasket. I tighted the bolts and it does not leak from the out side. However I believe its leaking into the cylinder. I go to ride it and it will run then cut out. I topped off the coolant then rechecked it and it was low. I think the coolant is fouling the plug out.

I need to pull the head off and put new gaskets on it. I had reused the old ones when i rebuild the engine. Whats the torque spec for the head gaskets?

Very Very happy with the power from the engine though.

 

[dirtbikr99]

New head o ring fixed the problem