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Old 02-05-2015, 08:25 AM
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mapbike mapbike is offline
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Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: Curious about the engine, :question:

Originally Posted by cannonball2 View Post
My conclusions are be careful buying parts. With the turn over of engines/parts inventories you may or may not get whats advertised. I don't think web pages are always change when the inventory does. One supplier just updated his page. What was indicated was not what was received.
My take away on the crank/rod/piston discussion is that the GT5 type engine with the 114mm rod is made to be a true 38mm engine, as the piston reaches the top of the cylinder. What the porting is I cant say as Im not a high-pro guy. The rest of the 38mm cranks with the 110 rod make the 1/2 breed and will require a lot of jug work. And there is the 40mm crank which is what I think that most of the jugs were designed for. My FH engine is 40mm.
So once again as always it sort of a crap shoot as to what you will really wind up with. If you are not able to radically machine a jug, I would say either a GT5 engine or an engine with a verified 40mm stroke is the way to go. Problem is finding folks that really know what they have.

I agree that the GT5 and a confirmed 40mm stroke engine is the way to go if possible for anyone who doesn't have a way to do some machining.

Im seeing that the engines with superior port timing seem to be the 40mm stroke engines, the GT5 seems to be better than the "half breed" geometry.

I do think for the person who just likes putting around in the 25-28 mph range will do just fine with any of the engines discussed here, some a bit better better maybe since one of two exact engines may actually perform better, this is where the "crap shoot factor" comes into play.

I will post some pix here today that I took last night showing the GT5 lower I have with 4 different jugs I have on it, the transfer ports are all I focused on in the pix.
I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!
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