turret toolng aka Fred Head questions

M

mountain80

Member
Hi all, considering buying a freds head as My Puch head coupled with 175 pound cranking psi tends to get hot pulling the long hills and hits about 375 degrees farenheit. I custom machined the combustion chamber for more cc's as it would have too high of a compression ratio. I have emailed fred twice but cannot seem to get the following answer: how deep from the top of the cylinder head is the counterbore where the cylinder head nuts go? I have a pretty tight frame and want an answer to see if I can sneak it it without machining. The fred head looks like it has a heck of a lot more aluminum than the puch so as to be a better heatsink coupled with a lot of surface area. also if anyone has a definitive answer what cc head are you running and what sort of temps are you running. I use my motorized bicycle a lot and did a 70 mile afternoon trip a couple of weeks ago so I built my engine with performance and reliability in mind.
Thanks for any help given.
 
Best way to improve cooling on a marginal setup is richer jetting.
Two stroke engines benefit from more oil/fuel mixture which cools things off quite a bit.
I've been riding and working on ring-dingers over 35 years and I have NEVER seen overheating problems on an air cooled engine that was PROPERLY jetted.
Trying for every last bit of power by leaning the mixture is usually the cause of overheating problems.
Try a bigger jet and I'll bet your problem goes away.
 
A little four-stroking is almost impossible to stop without a reed kit and cylinder mods to take advantage of the reeds.
Simply the nature of piston port two-strokes.
Tune for smooth acceleration and just a touch of four-stroking at cruise is about all you can ask without serious mods.
Sorry I can't help with Fred specs as I run stock heads on all my builds.
Nice as the hi-po heads look, I'm not spending double (or more!) the cost of the entire kit on a hop-up part.
You might have better luck pm'ing some of the race guys in the forum. They would have more experience with the part you describe.
Good luck!
 
Hey M-80, long time no hear bro.
I'm running his head.
It's a stage II with 6.0 cc Combustion chamber.
I run AMSOIL 32:1/premium fuel in 93 octane plus AMSOIL octane boost Yur brings me up to 98 octane and JAG cdi / NGK Iradium 8
On the hottest day this summer (105 degrees) with my TTO temp gauge
My hottest going up a fairly good inclined stretch that lasted about a mile and a half
My temperature only climbed up to 360 degrees
bear in mind goes extreme condition but normally like today it was 80 degrees out I remember a really hard runner really hard about 345 and that running hard.
But just cruising lightly around town 28O-315 degrees.
If you buy the head he's got that got 5.3cc Combustion chamber,
it's recommended did you run racing fuel or fuel it carries least 100 plus octane .
Go his site to buy : crmachine .com
brnot
 
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Hey Huffy, it's been a busy summer but my machine is all sorted out for the most part. thx for the temperature info. Do me a favor: measure from the top of the head where they machined the "pocket" or counterbore where the head nuts go in, I need that depth measurement to determine if I can sneak the head in without slightly machining it or not.

Cheers.
 
The prices I saw were $200 plus for the crmachine head. Fred Chelminski right?
Show me a link to a $85 dollar hi compression head please.
 
Much better prices than the post I saw in the fb forum....
It was $285 there and I did not know they had lower priced heads.
 
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