grubee big bore kit?

jatgm1

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has anyone ever seen a big bore kit for the grubee model 2 stroke engines? something to bump it up to a larger displacement? they seem like common engines, seems simple enough to do but i couldnt find anything.
 
What motor and size do you have now? Keep in mind the Gurbee motors like one other use a longer rod. This is how you can tell by the piston.
 

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not possible because of lack of metal between the stud holes and the cylinder bore.
that is the 69cc

the 48cc accepted 55cc and 60cc cylinders though. (I don't think they're available anymore)
 
not possible because of lack of metal between the stud holes and the cylinder bore.
that is the 69cc

the 48cc accepted 55cc and 60cc cylinders though. (I don't think they're available anymore)
what about if you were to get longer rods and just make it larger vertically? is that done somewhere? or has any person on the forum ever done it by machining it themselves?
 
what about if you were to get longer rods and just make it larger vertically? is that done somewhere? or has any person on the forum ever done it by machining it themselves?

I need to know what size your engine is now! If it has 6mm cylinder studs then no way to do it as Jaguar said there is not enough spacing between the studs and the studs are too small. Yes a long rod can be put in if you have the equipment and the knowledge to rebuild a crank but you might be getting into more money then you can by a bigger motor.
 
its currently a 66cc, i was wondering if it could be done somewhat easily but i guess it would be much easier to just get a cruzzer motor and find a way to mount that.
 
a longer rod won't increase the piston stroke, only a different crank with a longer radius from crankshaft center to center of the crank pin that the conrod spins on.
 
If it is all ready a 66cc you all ready have a 47mm cylinder. So the only way you could get more is got to a 40mm stroke which will only give you a little over 69cc not really worth the cost to gain such a little bit unless the motor is messed up.

Yes longer rods only slow down the piston speed and give a better rod angle.
 
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