No top end power

[DieselTech]

Here is a pic of a new cylinder than has not been ported, but that's how my piston looks in my engine in relation to the exhaust port. Could you get me some pics of your engine with 1 base gasket installed. I want a picture of the piston in relation to the top of your cylinder/ jug

I found some regular bolts. Check pic. The piston clears the whole exhaust port once at the bottom. Should i just take off one gasket while my head is off?

 

[DieselTech]

Basically I want pictures that look like this, so I & others can get a idea where you are at with squish with 1 base gasket installed.

 

[Jaycee604]

Here is a pic of a new cylinder than has not been ported, but that's how my piston looks in my engine in relation to the exhaust port. Could you get me some pics of your engine with 1 base gasket installed. I want a picture of the piston in relation to the top of your cylinder/ jug


View attachment 164158

As i thought. Your jug is a different style. Its the older one with the transfer ports not cut out. The ports on mine are square, bigger and prob a different height. Comes like that stock. Also i put it all back together to try it with two gaskets. I ll let you know tmrw and take one off if needed

 

[noah9988]

Have you checked your spark plug? I've had my engine not rev up like it's supposed to as well, but I knew that it was due to carb tuning and not anything else. You said you have a pz20 carb but don't know what jet size, so I would start there instead. Sometimes the simplest answer is the correct one.

 

[Jaycee604]

Have you checked your spark plug? I've had my engine not rev up like it's supposed to as well, but I knew that it was due to carb tuning and not anything else. You said you have a pz20 carb but don't know what jet size, so I would start there instead. Sometimes the simplest answer is the correct one.

I dont know if i stated, but i allready had it running fine when i installed the pz20 and my plugs are good. All tan color

 

[Karl Snarl]

Hey guys, me again. Just came across this problem and need some input. My engine (with the clutch pulled in) revs really crappy. Doesnt rev like my other two. Normally the bikes will shake a bit more and its very loud. But this has a boggy sound. Happens when i ride too. 1 to 25kmh seems to be fine but then sounds like it four strokes after and runs like ass. Im waiting for my new jug (because i think i ported this one wrong) and my expansion chamber (mz65 clone) but there was a point that it ran better. Its worse now. I just changed the exhaust, base and intake gaskets yeaterday. I used a rubber cork material. Im thinking i shouldnt have done that.

66 cc
Hc cdh power head
Pz20 carb (jet size unknown) played with the needle, made no difference
Ngk plug
44 tooth
Stock mag and cdi
Poo poo exhaust ( yes i know this is crap, was working fine with it before, this isnt the cause of my recent power loss)

Did you ever tune the carb between mods?

 

[Jaycee604]

Did you ever tune the carb between mods?

No. Update. I took it for a spin after replaces the cork gaskets and had two base gaskets, runs great and doesnt four stroke as much. Although i have a new problem. My 420h chain had the master link fall off halfway throttle. Im putting a new link on at home. Also when out of gear there is an occasional consistant knock coming from the drive sprocket or clutch side, or the driveshaft. Hoping its not messed up. Will update once i go for a ride

 

[Jaycee604]

Did you ever tune the carb between mods?

Update. Okay so i went for a ride ( it is raining ) and the knocking sound seems to be gone, chain is good now and the engine performs better. But still four strokes at higher speed still. Its weird, it four strokes alot then you can hear a couple of 2 strokes ( that proper 2 stroke putter) then back to more four stroking. My guess is air and or fuel problems. It performs a bit better on hills but the top speed on flat and downhill are just not good. I stated before that i am getting a new jug because i think i messed the ports up and still waiting for my mz65 pipe. If it still runs like that after those then i will buy a jet kit. If that doesnt work then i ll walk off a bridge lol

 

[Karl Snarl]

Update. Okay so i went for a ride ( it is raining ) and the knocking sound seems to be gone, chain is good now and the engine performs better. But still four strokes at higher speed still. Its weird, it four strokes alot then you can hear a couple of 2 strokes ( that proper 2 stroke putter) then back to more four stroking. My guess is air and or fuel problems. It performs a bit better on hills but the top speed on flat and downhill are just not good. I stated before that i am getting a new jug because i think i messed the ports up and still waiting for my mz65 pipe. If it still runs like that after those then i will buy a jet kit. If that doesnt work then i ll walk off a bridge lol

Go up a hill, if it four strokes, it's rich. If it gets up and goes, it's good. 2 strokes 4 stroke when the load is not large enough. It's just what they do. They also should 4 stroke a little at cruise. If you get no 4 stroking at all regardless, you are to lean. They should be a little here and there, it's just the way these beasts work.

 

[Jaycee604]

Go up a hill, if it four strokes, it's rich. If it gets up and goes, it's good. 2 strokes 4 stroke when the load is not large enough. It's just what they do. They also should 4 stroke a little at cruise. If you get no 4 stroking at all regardless, you are to lean. They should be a little here and there, it's just the way these beasts work.

Doesnt four stroke up hills. But it really rides like crap on flat or down hill. Sounds like it really wants to run normally