2 stroke will idle but no Full Throttle...

DeeziDennis

Member
Oct 29, 2002
24
0
I recently got my old 2 Stroke yamaha Enduro 100cc out of 15 year storage and did all the specific steps to get it going.

I cleaned the tank. I also drained the tranny and installed new clutches and steels. I bled the Oil Injector and it seems to be working fine. I drained the carb before I put it away for storage.

The bike fired up after 2 kicks and settled into a nice idle after it warmed up and the choke was pushed in.

I can get about 1/4 rpms but thats about it and thats with the throttle pegged. It just levels out and bogs a little it sounds like..
If I let it sit idling for a second I can rev fast and hit high rpms for a second and then it just goes back to what it was doing before. I pulled the carb and disassembled it and cleaned it. It looked fine.

I put the carb back on and it still does the same thing. I adjusted the crap out of the mixture screws even though I set it to factory specs and it didnt help a thing.

Any Ideas
 
Last edited:

snowskater101

Member
Jul 18, 2007
58
0
you might want to look at your head gasket while its idling and see if its cracked or leaking. put your hand all around it to check for leaks and visually look for them too. its a possibility...
 

DeeziDennis

Member
Oct 29, 2002
24
0
I just went and checked it. I dont feel any air movement out of it. I lit a firework Punk and didnt see it moving the smoke around. I dont see any oil or anything coming out from around it. I tourqed it back to spec for the heck of it though.

Still pretty much the same.

Thanks for the heads up though. I may grab a headgasket anyway for it..
 

snowskater101

Member
Jul 18, 2007
58
0
oh yeah i forgot i also wanted to say to replace your fuel filter, it could be clogged from 15 year-old gas and not flowing into the carb fast enough. that would explain why you can idle then hit high rpms for a second. look at your whole fuel line as well, it cant hurt
 

snowskater101

Member
Jul 18, 2007
58
0
have you tried riding it around at all? my yz starts rough and doesnt want to hit high rpms until its been rode and warmed up all the way, yours may run better after a little ride. did you get a new plug since you got it back?
 

OldTimer

Member
Feb 3, 2005
475
0
It sounds like you're the type of guy who would have checked the air filter, right?
And made sure there isn't a dirt dobber nest in the intake boot?
 

DeeziDennis

Member
Oct 29, 2002
24
0
Reeds are stainless ,they look great. I did clean them though just in case. It didnt help.

Oil injector is working. I have bled it and its good to go.

Air fliter is a Uni Sock universial type. I used this same one years ago and it worked well, I bought a new one to try and test it versus the old one its pretty much the same. (Stock Style was discontinued years ago)

As for riding it it just goes 1/4 throttle and thats it. Same as sitting still and trying to rev it.

Dang this little bike :(
 

snowskater101

Member
Jul 18, 2007
58
0
is there any way someone may have ridden it without you knowing and seized it??

how does the compression feel?

how is the power from no throttle to a quarter, does it seem to have normal throttle response or is it weak?
 

DeeziDennis

Member
Oct 29, 2002
24
0
I swapped the entire exhaust today with one I cleaned out a year or so ago. It didnt help.

The bike has power for just a split second. You can have it sitting there idleing and hit the throttle and it'll blast up to the redline. If you hold it there it just goes back to 1/4 or so rpms.

Compression is good.
 
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