I just installed a grubee skyhawk gt5 - interesting

KTOKTO

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I have been messing with a cheapo 66cc ebay engine on a friends bike. It was around $59 on ebay so I figured why not take a chance. I put about 200 miles on it and it functioned quite nicely. No problems or complaints really.

A few weeks back I bought a grubee skyhawk gt5 to see how it compared to the ebay generic motor.

I just got everything swapped out and took it for a little spin. It fired right up so I idled along for a couple blocks and took it up to mid throttle. Torque, sound, vibration seemed pretty much identical to the ebay motor.

Now here is the interesting part. I was a few blocks down the road and noticed a bit of smoke rolling off the motor so I went back home to check everything out. I let it idle in the garage for a couple minutes and smoke really started rolling off the thing. So I shut it off and the entire bike is covered in oil and gas and the garage floor is an oil slick.

I let it cool down and checked everything externally and didn't find anything wrong so I pulled the head off and think I found the culprit. There is no head gasket on this thing! Is that right? this should have one right? It idles and revs and runs fine, it just throws more gas on the bike than in to the motor I think.

I guess I am going to need to run in to town and get something to make a gasket. Any suggestions? Would copper RTV work?

I'm not worked up or anything. I just think it's funny that this motor was advertized to be a cut above the rest of the ones out there. I'm not seeing it thusfar, I will have to take another assessment once I get the leak fixed and get it broken in to see if it has any more power or is smoother than the $59 ebay motor.
 
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I would (will) get a roll of P.T.F.E. Teflon tape to twist up and use as the head gasket.
I have read it's a good gasket and it's certainly cheaper and easier to carry for spares on long rides.
I think we have headsmess to thank for that one if I remember correctly.

Search: Teflon. :)
 
white plumbers tape.
i use it for exhaust and head gaskets. I take about 6 feet of it then triple that in folds and twist all together to form a rope like thing which i then place around the jugs head or exhaust port.
 
I figured I'd do it right and just bought a gasket kit for it.
 
The China girl once again shows that even the best kit can have faults right out the box. I'm equally surprised you get anything worth while from it without the gasket, they must have a pretty good machining process to be flat enough to actually do something. Certainly that motor will have some serious power once you can keep all the fuel in the engine until its actually ready to leave.
 
The China girl once again shows that even the best kit can have faults right out the box. I'm equally surprised you get anything worth while from it without the gasket, they must have a pretty good machining process to be flat enough to actually do something. Certainly that motor will have some serious power once you can keep all the fuel in the engine until its actually ready to leave.

I pretty much just idled down the block and back before I noticed it was smoking like mad. I let it idle for a bit but after it warmed up it wouldn't stay running unless I gave it some gas.

After it cooled down I started it again and it stayed idling until it warmed up again and started smoking and again wouldn't stay running unless I gave it some throttle.

I'll dig back in to it when the gasket comes in.
 
I pretty much just idled down the block and back before I noticed it was smoking like mad. I let it idle for a bit but after it warmed up it wouldn't stay running unless I gave it some gas.

After it cooled down I started it again and it stayed idling until it warmed up again and started smoking and again wouldn't stay running unless I gave it some throttle.

I'll dig back in to it when the gasket comes in.
That's kind of unique, you'd think that after warming up it could hold an idle, not the other way around. I wonder why that is.
 
It will probably clear up once the head is sealed. If not I would raise the needle clip one notch. It might just be a bit rich, and becoming a bit too rich once it warms up. hopefully it isn't like the ones I was shipped that only had 1 notch on the needle.
 
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