preventing power loss

Fabian

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Sep 8, 2009
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4,522
Since i've been using the CR Machine Man billet twin spark plug cylinder head, i haven't had a single oil leak from the cylinder head and mating surface; not a single itty-bitty little leak.

I'm telling everyone right now: just hit up the credit card for a CR Machine Manufacturing billet twin spark plug cylinder head, not just because it gives a perfect cylinder head gasket seal, but because it's the dang coolest looking billet cylinder head out there !!!
 
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Fabian

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Sep 8, 2009
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There certainly is, and the head is available in three versions: medium compression and high compression and with the optional provision of a screw-in decompression port, which is the same thread and depth as the other spark plug holes.

I have no idea why his eBay store is no longer on the site but JN Motors has his Twin Spark Plug cylinder head (without decompression port), but no information is given if it's the medium or high compression version.

http://www.jnmotorsbikes.com/product_p/jnm1250.htm


I have purchased both the twin spark plug (medium compression) head (without decomp) and the twin spark plug (medium compression) head with optional decomp port, as well as his modified OEM 80cc pistons with 'machined' exhaust port and transfer port piston ramps.

Do a Google search for "Twin Spark Plug Cylinder Head for 80cc Happy Time Engine" and you'll see detailed photos of the CR Machine Manufacturing cylinder head installed on my bike.
 

Fabian

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Sep 8, 2009
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Yes, it is one of about 12 photos of the pistons and the cylinder head and my setup
 

jaguar

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Nov 25, 2010
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3,476
I finally settled on using a home-made head gasket cut out of gasket material. It can flex with the slight normal head warping to prevent leaks. But the two surfaces have to be planed flat beforehand using sandpaper and glass. Added benefit is that it somewhat insulates the cylinder from the head so that the engine parts are subject to less heat and therefore last longer.
 

mrbg

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Sep 22, 2014
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241
I forgot to mention that I found there was excess resistance in the clutch shaft bearings which was discernable just by turning the shaft by hand (after I removed the chain and clutch) On the sprocket side bearing I had to use my exacto knife to pry the seal off with the sprocket in place since I couldn't remove it. So I couldn't get as much BADFISH GREASE in there as I'd like but it's extra lubricating properties hopefully will make up for that. With both bearings greased the shaft turned much easier. People don't realize that a little turning resistance anywhere from crankshaft to rear wheel robs a big percentage of power when the engine is of small displacement.
 

mrbg

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Joined
Sep 22, 2014
Messages
241
I forgot to mention that I found there was excess resistance in the clutch shaft bearings which was discernable just by turning the shaft by hand (after I removed the chain and clutch) On the sprocket side bearing I had to use my exacto knife to pry the seal off with the sprocket in place since I couldn't remove it. So I couldn't get as much BADFISH GREASE in there as I'd like but it's extra lubricating properties hopefully will make up for that. With both bearings greased the shaft turned much easier. People don't realize that a little turning resistance anywhere from crankshaft to rear wheel robs a big percentage of power when the engine is of small displacement.
I forgot to mention that I found there was excess resistance in the clutch shaft bearings which was discernable just by turning the shaft by hand (after I removed the chain and clutch) On the sprocket side bearing I had to use my exacto knife to pry the seal off with the sprocket in place since I couldn't remove it. So I couldn't get as much BADFISH GREASE in there as I'd like but it's extra lubricating properties hopefully will make up for that. With both bearings greased the shaft turned much easier. People don't realize that a little turning resistance anywhere from crankshaft to rear wheel robs a big percentage of power when the engine is of small displacement.
it's BS that these motors with the crappy bearings are being sold, I was on YouTube and saw a British distributor showing the slop in the bearings and the links for good bearings. They sent a bunch of them back, I guess I'll have to contact the guy I bought from and see what kinda warranty they have I imagine they're not going to be happy take them back ! Here's the. YouTube linkhttps://youtu.be/4sFRAQvAkk4
 
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