I'm thinking about getting this black CNC head

[Member 30571]

Since summer is just around the corner. I'm thinking it would keep it a lot cooler ? plus I think it would look great also.
https://www.ebay.com/itm/Racing-CNC-Cylinder-Head-For-66cc-80cc-Gas-Motorized-Bicycle-Square-Silver/263237289036?_trkparms=aid=555021&algo=PL.SIMRVI&ao=1&asc=20190711100440&meid=8cb5dfd0619142889111d9a08280f424&pid=100752&rk=1&rkt=3&mehot=co&sd=192925644949&itm=263237289036&pmt=1&noa=0&pg=2047675&algv=SimplRVIAMLv5WebWithPLRVIOnTopCombiner&_trksid=p2047675.c100752.m1982

 

[Tyler6357]

There are better heads out there but it would be better than stock.

 

[Member 30571]

What head would you use ? . My ears are open to all good advice

 

[Tyler6357]

In my opinion the best heads for these engines are made by Fred at CRMachine known as "the Fredhead", He was one of the first to design heads for these engines and then everyone copied his design. Generally speaking the larger the head is the better it will dissipate heat and the cooler the engine will run and having large fins helps it air cool. The only problem with getting a Fredhead is they are expensive! Take a look at the fredheads here and attempt to find an imitation that closely resembles it. Notice how large it is at the base, 3 layers of metal before the fins even start, this kinda acts like a heat sink to cool the engine-----> https://crmachine.com/shop?olsPage=t/cylinder-heads&page=2
Also, the volume makes a difference. Most heads are 6cc volume and that's what I got on mine.

These are pretty nice, but again, you are looking at $60, might as well get a fredhead. https://www.gasbike.net/collections...c-cylinder-head-2-for-66cc-80cc-free-shipping

 

[Member 30571]

Ok thanks, It looks like most of them are out of stock.

What about this one ?. It looks beefy ... https://www.ebay.com/itm/CNC-Cylinder-Head-Shark-Racing-For-66cc-80cc-2-Stroke-Motorized-Bicycle-Engine/353037586857?_trkparms=aid=1110001&algo=SPLICE.SIM&ao=1&asc=20131231084308&meid=8f67b870e83347938f956ee045f4e230&pid=100010&rk=5&rkt=12&sd=264280654556&itm=353037586857&pmt=0&noa=1&pg=2047675&_trksid=p2047675.c100010.m2109

 

[Tyler6357]

Ok thanks, It looks like most of them are out of stock.

What about this one ?. It looks beefy ... https://www.ebay.com/itm/CNC-Cylinder-Head-Shark-Racing-For-66cc-80cc-2-Stroke-Motorized-Bicycle-Engine/353037586857?_trkparms=aid=1110001&algo=SPLICE.SIM&ao=1&asc=20131231084308&meid=8f67b870e83347938f956ee045f4e230&pid=100010&rk=5&rkt=12&sd=264280654556&itm=353037586857&pmt=0&noa=1&pg=2047675&_trksid=p2047675.c100010.m2109

I would say that looks much better, however I've never tried that one before. I figure any of them are better than stock. A good head is one of the most expensive upgrades you can get besides an expansion pipe but running cooler will extend the life of the engine.

 

[Member 30571]

I was looking at the expansion pipes.. WOW they don't give the away very cheaply. Are they made out of gold.

 

[Tyler6357]

Ok thanks, It looks like most of them are out of stock.

What about this one ?. It looks beefy ... https://www.ebay.com/itm/CNC-Cylinder-Head-Shark-Racing-For-66cc-80cc-2-Stroke-Motorized-Bicycle-Engine/353037586857?_trkparms=aid=1110001&algo=SPLICE.SIM&ao=1&asc=20131231084308&meid=8f67b870e83347938f956ee045f4e230&pid=100010&rk=5&rkt=12&sd=264280654556&itm=353037586857&pmt=0&noa=1&pg=2047675&_trksid=p2047675.c100010.m2109

Fred is not usually out of stock, I bet he will get some more soon. It might be worth it to wait if you don't mind spending $65. I found an exact replica of the Fred head a few years ago on e-bay for $40 but I haven't seen anymore of those in a long time.

 

[Member 30571]

I can wait. My motor isn't here yet.

 

[Tyler6357]

I was looking at the expansion pipes.. WOW they don't give the away very cheaply. Are they made out of gold.

Ha! Yeah, you will spend $80+ on a good pipe. I got an MZ65 pipe for $80 back in 2018 and I was glad to get it, they can be hard to find but there are other similar pipes out there that are probably just as good. Or, it's possible to go to a junk yard and find a nice motorcycle pipe, like off a dirt bike or something and adapt it to fit the exhaust port. Generally with pipes, the bigger the expansion chamber is the better it will be but it is good to have a bit of a header.