Cant get a KT motor to start after it sat for 2 years

(john walsh) #1

Im trying to start my kt100 that I let sit for 2 years. New battery in starter, starter spins engine fast, fresh fuel, plug is getting spark, fuel is getting to the carb, disassembled carb, tried all different position on the high and low needle. It wont fire up… it looks like there is fuel coming out the exhaust when I try I start it?..any help is appreciated. john

(Andy Kutscher) #2

Carb kits are cheap, grab one and make sure all the gaskets are fresh esp the diaphram. Also make sure screen isn’t clogged in carb but I doubt that is the culprit if you are getting gas to the carb.

Double check pop off pressure, racers run 9-10 psi but it causes a rich condition, something in the 12-14 range might help get it started.

Set the high needle fully closed and run about 1 1/4 on the closed for cold start. You will need to richen it up to drive it but on the stand at lower RPM this setting works best

If you are getting fuel out the exhaust it’s likelu flooded at this point, throw a new AR 51 on there.

Best of luck.

(Andy Kutscher) #3

Actually…before doing any of that check the compression. When these sit the rings can rust to the iron liner in the cylinder and cause loss of compression when it breaks fee.

If you don’t have more than. 100 PsI it won’t start no matter what you do.

If you leave it for more than a few days you should put some oil down the spark plug hole and rotate the engine a couple of times to lube everything.

(john walsh) #4

I checked compression. 75psi. So it looks like its internal. Thanks for your help. john

(Andy Kutscher) #5

rings are cheap…if you’re not looking to compete at the national level throw a ring at it and run a dingle ball hone through the bore a few times and have a it. Could be up and running for $50-75 and an hour or so of your time.

Set ring gap between .010 and .012

(James McMahon) #6

You’ll might find that the ring is just gummed a bit with oil. You could clean in/around it with brake cleaner, put a cloth in the crankcase to keep it from going in there. Put it back together and see if the compression comes up some.

Other things you need to be aware of after it’s been sitting.

Hardened or oil/kludged up diaphragms in the carb.
Stuck open or closed inlet needle.
Hardened crank seals causing an air leak.

At 100 psi I should at least give a kick and fire up.

(john walsh) #7

I still have quite a bit of fuel coming out the exhaust when I try & start it…here are some photos of the head & piston. Anything look really wrong?

(James McMahon) #8

Hmm, that ring around the edge of the piston makes me concerned that the main/crank bearings are done. When the play gets excessive the piston can contact the head, removing the carbon.

(Bryan Williams ) #9

Honestly at this point you might as well just spend the 400$ send it to a shop to have them get it running.

(James McMahon) #10

I agree. Having seen inside of it, it’s time for some fresh parts.