In your first post you said you didn't do a stator test(done and replaced) but haven't done a compression test also. Have you checked this? If compression is low,as an engine heats up it can lose piston ring seal against the cylinder and cause one to die also. Just trying to keep you from throwing more parts at it.

 

Yes, its 140-150 and that is correct for a brand new piston/cylinder set correct?

 

Actually higher than many new ones I've checked,but sounds plenty good enough...

 

Put the new manual choke carb on last night. It runs enought to ride it, but still pretty poorly. It runs perfect for about the first 10% of throttle then bogs a bit before accelerating. It really seems like the fuel mixture is off or something. I do not think it is a fuel supply problem as once it takes off it goes without issue until you let off the throttle.

Here is my next round of questions / thoughts.
- Oil mixer...what regulates the oil mix? It has more blue smoke than I feel it should. I thought about plugging the oil line and running 40:1 premix.

- Carb adjustments - I see two screws. One large sticking out the middle. This one is for idle correct? There is also a recessed one at an angle near the air filter. What does this control? Are there any others that could be involved?

- Reeds - could they be causing how finicky and power jumpy this thing is?


Thank you for the help. I could not have gotten this far without your advise.

Tim

 

Make sure you don't have too much slack at the thumb throttle. About 1/8" play or so.Oil pump mix on most machines are around 50/1 ratio which normally is plenty enough for the little ones. A lot of people freak out on oil pumps and defeat them. If you do,premix 40/1 ratio. The large screw is the idle adjuster,smaller screw is the air screw.Manual shows should be around 1 3/8 to 1 1/2 turns out from a lightly seated position,but you may have to play around with this setting. Plus check that the jets are the same size as in the old carb if you haven already.Another thing on these older ones are exhausts getting plugged up from oil deposits over the years. Check that it has good exhaust flow from the muffler. A good soaking in kerosene can help if it's restricted.

 

Ill check that stuff. I am not against the oil pump system, but I figured it would be almost free to remove/plug the line temporarly to make sure it is not the issue. it did not occure to me to check the jets. I will do that for sure.

Thank you

 

Here is my latest.... It still starts easy and is ride-able but something is still off.

If I have the air mix screw more than 1/2 turn out it will bog when given throttle and not go anywhere. It is currently almost all the way in and the engine is very high strung with the power coming on hard at the slightest throttle

It seems to idle decent.

I took the old jets out of the original carb and put them in. I also replaced the reeds as I found them on ebay cheap.

I'm pretty sure there are no air leaks at the carb/intake but I am running the cone filter that came with the top end kit.

Also I am just running off the shelf std two stroke oil. It does not require anything special does it?

 

Doesn't require any special oil,but don't premix more than 40/1 ratio (if you're premixing) as too much oil can do the same as having the jetting rich. Ends up with too little octane versus too much oil. A cone filter will be less restrictive on air flow(leans the mixture) than the stock set up,which in itself may require at least the slide needle to be played with up or down or possible a jump in the main jet.If you have to set the air screw only 1/2 turn out,this could be it needs more fuel than air. Jets are available and I'd at least have a couple up and down from the oem stock size to dial it in right.https://jetsrus.com/a_jet_kit_atv/po...n%2005-06.html

 

Thanks, I will try moving the needle up a little bit first. The stock jet appears to be 82.5, What size do you think I should start with? 85 or 87 or?? Also do I need to mess with the slow jet?

 

Just experiment with the needle position first and air screw. Plus check the color of the spark plug.White color on electrode is lean,needs to be a tan to medium brown. If it still doesn't run right,hesitates or bogs then you can determine if you need to jump up or down on the main jet.