Really high idle fix

[Yountz]

I've had a problem with my new 80cc motor that I've never had here. The idle was out of control when hot. I read several causes and attempted to fix them all.

I do have an offset intake due to my bike frame. I initially thought it was too long and making an unstoppable vaccum at idle, but that was not the case.

Air leaks- I checked for air leaks all around the engine with carb cleaner. I found that the head gasket was leaking slightly, so I replaced it, but no change in the idle. The carb was leaking where it clamps on to the intake, so I upgraded to a hose clamp and fixed the leak, but still no change.

Grounding- while trying to fix the Idle issue I discovered I had a poor ground. Sparks were jumping from the carb to my screwdriver. I installed a grounding cable from the engine to the frame. It fixed the sparking issue, but no affect to the idle.

I finally adjusted the c clip on the carb needle. Worked right away. I don't know why I didn't check that first, just following the internet advice.

 

[Chainlube]

There is a screw on the side for idle adjustment too.

 

[Yountz]

When I adjusted the idle screw, the motor would either stop running or idle really high. No in between.

 

[Mike Cyanide]

When I adjusted the idle screw, the motor would either stop running or idle really high. No in between.

You were way too lean dingus lol jeeze just to be on the safe side I would consider a jet kit. I've found these motors and carbs to be a total grab bag. Also consider a shorty intake,they're cheap and work very well. Also a g2 reed is a great way too offset the intake

 

[Yountz]

I'll look into the Reed. I also found yesterday that the piston was hitting the spark plug. It messed up the gap. I gapped the spark plug again and put another lower head gasket on.

When I originally put the head on, I think I way over torqued the nuts and it crushed everything down. This time I took out the torque wrench and did it properly, haven't had any issues since.

 

[Mike Cyanide]

I'll look into the Reed. I also found yesterday that the piston was hitting the spark plug. It messed up the gap. I gapped the spark plug again and put another lower head gasket on.

When I originally put the head on, I think I way over torqued the nuts and it crushed everything down. This time I took out the torque wrench and did it properly, haven't had any issues since.

Atta boy! Well there are more options than the extra headgasket! An e3.12 is a shorty plug that will stop that or any plug for a stihl saw or you could add a base gasket! The base gasket could grab you some extra power like you never expected! I added 1mm under my ld10p jug and the difference was crazy. It went from 35mph max to 38mph max. Pretty massive power gain for just 1 gasket.

 

[Mike Cyanide]

I'll look into the Reed. I also found yesterday that the piston was hitting the spark plug. It messed up the gap. I gapped the spark plug again and put another lower head gasket on.

When I originally put the head on, I think I way over torqued the nuts and it crushed everything down. This time I took out the torque wrench and did it properly, haven't had any issues since.

Btw no that's not how this works you would strip everything long before the force to crush anything. These motor again are a grab bag. Some huge squish some to tight,some 60s jets 70s jets,over torqued or loose,too many gaskets and missing gaskets. Best bet is it's not even your fault but yes torque wrench good lol

 

[Mike Cyanide]

I just finished this!

 

[Mike Cyanide]

I recommend you get the biggest solder you can find pull the plug and put a 3in curved length or solder I the hole touching the side of the cyl roughly were your wrist pin is on both sides. Will holding solder in plug hole spin motor by hand or roll bike. It may be alittle tough so try to have piston high atdc. Then remove and check solder with caliper. Optimal for your should be .7 to .8. Generally anything over 1.2mm is deplorable lol

 

[Yountz]

Apologies for the late reply.

Unfortunately the Reed valve didn't have enough clearance to fit. Instead, I chopped off the intake as much as I could.

I put a short plug in from my chainsaw, I'm not sure if it's the same one you said, but it had a .7mm plug gap. About half throttle it would start to 4 stroke. Then I bought an NGK B7HS and it stopped hitting. Turns out the original spark plug was trash. Who knew.

Haven't started messing with the jets yet since all the big issues are delt with, but that will be next on my list!