More on High Compression Heads...

Treats sells both a 50cc and a 70cc model. The description claims that both can be used with 65cc Metrakit. Someone please explain the difference with advantages and disadvantages.

Thanks.

Re: More on High Compression Heads...

Well....One has a squish zone for the 50cc and one for the 70cc.

With a 65cc kit, you will get higher compression with the 50cc HiComp head--BUT can POSSIBLY have clearance issues. 70cc HiComp head will allow better clearance but slightly lower compression.

If it were me, I'd go 70cc (my Airsal smacked the 50cc HiComp head--now have the 70cc HiComp head).

Re: More on High Compression Heads...

The search button yields awesome results, just for future reference...

https://www.mopedarmy.com/forums/discuss/7/119968/119956/

Re: More on High Compression Heads...

Yeah I used a 70cc high comp. head on my 65 metra , took a comp test before starting and got 210 psi easy . Im sure its higher now since its starting to get broken in . IRE Mike has a simular setup and has 230 psi comp after a few months of use . Does that sound like a lot to anyone else ? I wonder what 50cc head would bring . 250 psi ?

Re: More on High Compression Heads...

250 psi equates to 15.6:1 comp ratio. This is OK on

prem gas and a splash of octane booster but you also have to figure in spark advance

Re: More on High Compression Heads...

When you raise your compression, you have to advance your timing too? I was asking cause i just fixed some airleaks on my ped lately and now i can't get it to take off without dying a second later. Seems to idle ok but when i take off it dies few seconds later. Never got it to warm up though and gonna mess with it today, but have never seen it do that before. I got a 70cc kit with a high compression 70cc head and proma , so with air leaks fixed mostly i think my compression wen't up a little bit too.

Re: More on High Compression Heads...

I ran a 50cc High comp stock puch head on my Airsal Puch 70cc kit with no issues.

I run a 50cc Treats High comp head on my Malossi 62cc Puch kit with no issues.

Using a head gasket on both.

Re: More on High Compression Heads...

This is kind of off topic, but what should I expect to pay for a compression tester? I saw one at harbor freight for like 10 bucks and I was like, how accurate could that thing be?

Re: More on High Compression Heads...

Im sure its pretty close , I bet an acceptable tolerance would be like 10 psi ? Dont you think ?

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