Tuning and spark plugs

[Zingzing29]

Why do I have this issue with grayish and white color?

Brand new coil
New spark plug Br6hs
68 main nt carb with jets 55-80
Needle clip in 2nd from top position leanest

I developed a vacuum leak after switching from regular87 to mid89 now premium91.
It runs better and smoother especially at higher speeds but seem to always have a bad 4stroking issue. I put a new coil in and it ran alot better. Still pretty bad with the 4stroke. Still white /gray. Put a hotter spark plug in br7hs to br6hs. Expected no difference. My idle plug runs wet/rich in the cold/OK range on a plug chart but my WoT plug always tells me tells me lean/hot but showing symptoms of cold with the oil and carbon fouling. So i got a hotter plug to try to burn it off a little.

Now that I've have the head off 3 times after switching fuel incase of detonation. The issue though is it gets worse from a 66-67. Unless is cool under 75-70 it runs greats just a bit of faint fourstroking and I have to ride hard. Even on 87octane. Still I have a white grayish plug.

I pull the head to check on everything to see what's going on. And I found the vacuum leak there's a smidgen of crud that indented the head. But that conditions above still persist prior.

So what do I do about it?

 

[Gordy]

Spark plug color

Is this the color it should be or?

motoredbikes.com

Check out this thread. It sounds like you might be having a similar issue

 

[Zingzing29]

I thought that carbon build up is a condition of richness?

 

[Zingzing29]

I'm also looking for a head with a wide squish band that bolt on ready.
Do you know what I can find one with the right cylinder diameter specs

 

[Gordy]

What engine do you have and what cc is it? I know for the 66/80cc heads you can find them on Amazon for a decent price. I think some people have also used Puch 50cc heads before.

 

[Zingzing29]

What engine do you have and what cc is it? I know for the 66/80cc heads you can find them on Amazon for a decent price. I think some people have also used Puch 50cc heads before.

66cc zeda triple 40
47.7 is what the cylinder Dia. Is supposed to be I think

 

[Gordy]

66cc zeda triple 40
47.7 is what the cylinder Dia. Is supposed to be I think

Any 66cc head will fit on it

 

[Chainlube]

I'm also looking for a head with a wide squish band that bolt on ready.
Do you know what I can find one with the right cylinder diameter specs

The head you have is great. If you have a bench grinder with a wire wheel on it, then use that to clean it up. Did you ever get a squish measurement on that engine? Is the piston at TDC in your picture? If so, then you have over 1mm of squish and might have to sand down the head.

The whole combustion chamber looks like you idle around most of the time.

If that is a Zeda triple 40 then the cylinder should have a ceramic coating. It will run cooler than a nickel coated cylinder.

For the carb, put you stock jet back in and put the C clip at one position above center.

 

[Zingzing29]

The head you have is great. If you have a bench grinder with a wire wheel on it, then use that to clean it up. Did you ever get a squish measurement on that engine? Is the piston at TDC in your picture? If so, then you have over 1mm of squish and might have to sand down the head.

The whole combustion chamber looks like you idle around most of the time.

If that is a Zeda triple 40 then the cylinder should have a ceramic coating. It will run cooler than a nickel coated cylinder.

For the carb, put you stock jet back in and put the C clip at one position above center.

I do alot of low speed travel and idle at stop lights. I also keep it richer on the low circuit. When I decked the jug it was .1 with a weird taper that was .8 toward the inner part of the squish. I don't have. Dremel anymore or a battery charger for my drill to re machine a proper squish.

I agree it's a great head but the squish promotes top speed not low power like wider squish.

 

[Zingzing29]

CDHPOWER Racing Head for 2 Stroke 66cc/80cc https://a.co/d/0tZ3wHA

Something like this I've had one of these heads and it was great but got damaged. I don't remember where I bought it though.