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Discussion Starter · #1 ·
Any info on these would be helpfull, like HP #s or potential problems.

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[This message has been edited by TSAVO5150 (edited 03-16-2001).]

[This message has been edited by TSAVO5150 (edited 03-16-2001).]
 

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I have an '86 with a 907 kit and it's alot faster than my friend's stock '86. I really don't know too much about the kit because it was already done when I got the bike. However, it fouls plugs so often that every time I start it up, I let it run for about 2 minutes then i tap each header with my bare fingers to see if it will burn my skin (if you do it fast enough you skin will just get really smooth and the heat won't even make it through the first layer of skin... in other words it doesn't hurt) so i know that all 4 cylinders are running correctly. After that, I take it out and ride the piss out of it, because my motors does NOT like loping around. It wants to be ridden hard ALL THE TIME. Also, don't be fooled by displacement sizes, I have a '96 750 that dyno'ed at 123 HP and the '86 will never even dream of being as fast as the '96. Good luck and don't take my word, 'cause it's all the experience I have with those kits.

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If one of the kits allows you to keep your stock liners, go for that. It'll save you the cost of having them professionally done, or not pro done and totally fucked up by some moron. Having the liners moving while the engine is running is a common occurence when poorly redone.

Otherwise, spend the smart money and phone/email APE and see what they'll ding you to do it. I believe they throw in the rebore if you buy the pistons from them. At any rate, you can at least rest easy that your engine won't be a pile of shit like so many overbored ones wind up being.

All the best with your future killer machine!

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I also live in Gilbert, and coincidentally have a '91 GSXR750 with a big bore kit in it. I have a 955cc kit from Rohm Performance Machine in Yuba City, CA (530) 674-9123. I did all the disassembly and reassembly myself, so saved a lot of labor cost, but the process is remarkably simple and there is absolutely no need for your bike to end up running like the second guy's bike does.
After removal, the cylinder block gets slow heated to about 250 degrees or so, the sleeves are pushed out, the deck is re-bored by a machinist who really understands the difference between tolerances that are "close enough" for a car engine and those required for motorcycles. The new sleeves (L.A. Sleeves) are pressed into the reheated block with a hydraulic press using a custom-built jig to apply even pressure. After cooling, they're pressed again just to make sure they're not going to move. The motor is then "dummy assembled" to check piston to head height. The block is then "decked" to the proper height to optimize compression as well as to make the deck perfectly square for sealing to the head. Reassembly was fairly straightforward with the exception of trying to wrestle the block down over the pistons without breaking a ring - that part is no fun. As for the rest of the motor, I retained the stock CV carbs, just adding a Dynojet Stage III kit. Billy Rohm did a mild cleanup of my ports and a 5-angle valve job. I retained the stock valves and cams. I found a Yoshimura Duplex exhaust system on the internet (Motorcycle Online's classifieds, I think). I'm running JE forged pistons on stock rods. All told, the whole thing set me back about 1200 buckos, as I recall. The bike runs like a scalded dog. It made 124.3 horsepower on Billy's Dynojet dyno, but the best part is that it makes over 60 ft-lbs of torque from 4000 rpm on, which is about the same as an R1, but the peak number isn't as high - but it can be now that I have the displacement.

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Have to add my agreement about Mr. Rohm. A real gentleman and a true motor expert.

The way Beeno describes it is THE way. I don't know what some of these so-called machine shops do, but the only oval cylinders I ever heard of were done by Honda.



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Discussion Starter · #6 ·
Thank's for the info BEENO my bike is a work in progress that's pretty much just getting started.It would be cool if we could get togther so I could check out yor bike since we live in the same neiboirhood.E mail me and see what we can do.
Thanks, Mike [email protected]

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damn, Beeno! I'm pissed off at the guy that sold me my 907! If i had known all that, I'd never have bought the bike. oh well, you live, you learn!

Derick K



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Handikraft,
No worries, Bud! Billy told me when I did the kit that the 907 was plenty good, plus it allows for one or two more overbores in the event of some sort of engine damage. I don't have that option, so as always, there are tradeoffs in life!

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