Why did my top end go?
- Thread starter Upbasher
- Start date
Well the fact that you say you have an fmf with stock jets might be causing a little overheating problem.
A dripping carb is a sign of incorrect float level or dirt in the needle and seat assembly!
The FMF header will call for a #260 jet on its own, any other mods including pre mix will need larger jetting to be confirmed by a plug chop!
The FMF header will call for a #260 jet on its own, any other mods including pre mix will need larger jetting to be confirmed by a plug chop!
I can tell you with that wash on the dome, you are lean!
2 things cause a air cooled 2 stroke to overheat.
1 no air flow over the engine
2 too lean, fuel cools even in a 4stroke!
My question is who/what told you it overheated??
Even if you hone it, the ports should be inspected and chamfered if needed
Do it right to do it once.
Im sure everything you asked has been answered in this thread and you ignored most of the advice
Do it right to do it once.
Im sure everything you asked has been answered in this thread and you ignored most of the advice
Things to think about,
1 check chamfer, I don't care who did it!!
2 no engine has ever blown up because of too rich!
3 fuel leaks of any kind, stop and fix, NOW!
4 no 2 engines are alike, as in jetting. You could have to 2 blasters with them both stock and the jetting will not neccesarlly be identical! I've seen this many times.
5 all parts made for engines need to gone over closely, never just throw them in. Mock up and make sure all is well. It's reasons like this that sometimes it's better to have a professional assemble you're engine if you don't know how to check things.
I have had parts wrong right out of the box! Not very many company's make parts that fit right in, as in the automotive race part world.
1 check chamfer, I don't care who did it!!
2 no engine has ever blown up because of too rich!
3 fuel leaks of any kind, stop and fix, NOW!
4 no 2 engines are alike, as in jetting. You could have to 2 blasters with them both stock and the jetting will not neccesarlly be identical! I've seen this many times.
5 all parts made for engines need to gone over closely, never just throw them in. Mock up and make sure all is well. It's reasons like this that sometimes it's better to have a professional assemble you're engine if you don't know how to check things.
I have had parts wrong right out of the box! Not very many company's make parts that fit right in, as in the automotive race part world.
A plug chop is a sure fire way to ensure that the air fuel mixture is correct, so that the engine performs correctly.
Before you make the plug chop run it is important that the float level is correct, the idle is set correctly and there are no air leaks in the system, otherwise the smoke ring may lie about the AFR.
WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.
Warm up motor to operating temp.
Fit new B8ES plug, ride WOT through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.
Switch off the motor and pull in the clutch, apply brakes to come to a stop quickly.
Take the plug out and replace the old one for the ride home.
Carefully cut the threaded end off the plug to expose the insulator.
There should be a smoke ring of a cardboard or biscuit colour around the insulator.
If it is non existant or a very light colour, you are lean and require a larger main jet.
If it is a lot darker you are rich and may go down a size in main.
I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
You have to get up a reasonable speed so that you can get the motor to pull strongly.
Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
The idea is not to get speed but to make it pull strong at full throttle to get onto the main jet circuit.
I find I can safely do it on a short run by applying the brakes some.
If you have not enough room you can use 4th or 5th gear with good results.
Let me get this straight you seized your motor got on here for advice, ignored what every one told you and seized another? HAHAHA. You are awesome man! Send to KOR or anyone that deals with ATVs have a bore and hone done for the piston they sell you as well, assemble the engine, do a leakdown, jet accordingly to mods, re torque after break in and re-do leakdown test...
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