Garbage Gaskets: Crank Case Too Tight

SEGACDX

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I hate how finicky the quality of the gaskets are so I always opt for gasket makers because they work better and are cheap. I often have to rebuild,replace bearings or just fix leaks but sometimes it's just not easy.

My last engine was a great FM80 I got from gas bike years ago worked a charm until the bottom needle broke after almost 5 years of use. Now I have a newer style engine with a much bigger crank compared to the old one.

I have one problem, the crankcase is to small and crank is to big to turn freely without a stock gasket.
It will still be tight with it, but with only RTV it's super tight and that's no good making a lot of heat very quickly causing loss of power and ware.

I have used this for years on my old engine with great results for much longer over the crappy gaskets, it ran cool and had lots of power on all power bands.

I am wondering if anyone else has run into this problem or knows there to buy a full copper gasket set because I am not getting theses s**tty cheap gaskets anymore they last a few months and fall apart.

Please don't tell me just use the stock replacements I do not want them!
 
Look on ebay for heat and oil resistant gasket material ,i bought a sheet of it for about 5€ and have made gaskets for 4 engines already its pretty good, has kevlar in it i'll try to find link if your interested.
 
Look on ebay for heat and oil resistant gasket material ,i bought a sheet of it for about 5€ and have made gaskets for 4 engines already its pretty good, has kevlar in it i'll try to find link if your interested.

I am very interested, I would be good to make my own gaskets, how do you make yours? as in how do you cut them.
 
there is often extra room, but crank cheeks sometimes rub on bearing housing just because bearing isn't all the way into housing on both sides - look for rub marks and try a thin shim between bearing and crank to move crank cheek away from housing on that side (sometimes where journal is swedged in there is a bit of metal sticking out that can be hammered down flat too
 
I had the opposite problem. Crank flopped back and forth with 1mm play. I shimmed the crank bearing. Pretty hard to cut crankcase gaskets, quite intricate. Well worth the small cost they charge.
 
I am very interested, I would be good to make my own gaskets, how do you make yours? as in how do you cut them.
well first i trace it out then drill biggest hole first ,then smaller ones then cut the outline with a scissors some holes are small enough i use a hole punch but the one i have doesnt go very big, the old link i bought mine from is dead will search around a bit and see i know it was from a company in greece so they probably went bankrupt hahaha
http://www.gpg.gr that is the company i got it from but they are no longer on ebay https://www.google.ie/search?sclien...5.4&ei=_TPNV5COM4GEgAbOu7T4AQ&emsg=NCSR&noj=1
Thats the stuff i got gambit af oil
 
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I had the opposite problem. Crank flopped back and forth with 1mm play. I shimmed the crank bearing. Pretty hard to cut crankcase gaskets, quite intricate. Well worth the small cost they charge.
I've never seen a stock motor that didn't have at least 1mm of slop. I had one motor with about a quarter inch of slop a while back, no idea how they could possibly have that much variation.
 
I've never seen a stock motor that didn't have at least 1mm of slop. I had one motor with about a quarter inch of slop a while back, no idea how they could possibly have that much variation.

You are making me feel better. I have 3 engines, Grubee 48cc, 66cc and a black 66cc. The unknown 66cc is the loose crank. It also has the tall piston. The Grubees have only a few tenths mm play.
 
I would put oil on the case, press it onto the gasket paper, and pull it off leaving the oil on it where you need to cut. Once the outer part is cut then place it onto the crankcase and use an exacto knife to cut out the holes. Then cut off the inner part.

You can take the crank out and beat on the side of the crank wheel at the crank pin area to bring the wheels closer together (until there is minimum side play for the connecting rod) and then retrue the narrower crank.
 
i've been thinking could we adapt a mini moto engine crank to fit in they are far smaller and can rev higher especially the balanced racing ones can reach 12000rpm!
 
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