Engine Mods revisited

In light of gavinfdavies' current obsession to seriously bend, if not break, the UK Land Speed Record on his Silverwing I thought I'd resurrect some of this thread from 2011 wherein bobhrc1 documents his engine build.

The second post (from 2016) is a Facebook link. If you scroll down --way down-- there is a brief video showing the results of that engine build where bobhrc1's Silverwing soundly beats the pants off a Harley while doing a very dramatic wheelie. "...and Lo!, there was weeping and the gnashing of teeth..."

bobhrc1

Subject: Engine Mods...    Sun Oct 30, 2011 3:54 pm
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I have searched the internet for engine mods, but have found none.
Having done all the common mods - J Costa – Power Commander - Leo Vince exhaust - Dr. Pulley HiT clutch - Malossi spring - and air box mods I want more. Has anyone ever played with their engine? I purchased a totaled wing to get the engine and disassembled to see what there was to work with. The cams went to Web Camshafts (very helpful people) in Ca. to be rewelded and reground. The stock pistons are a 72mm bore at 10-1 compression. Honda CBR954 pistons are 74mm bore with a 11.3-1 compression and with luck the piston pin diameter and location are exactly the same. The cylinders were bored 2mm over, that is about as much as you can go as the cast in liners are fairly thin. Next, the crank was sent to Pittsburgh Crank in PA. to be stroked a 1/4 inch. Now with the longer stroke the connecting rods had to be shortened 1/8 inch, so off to Powroll Performance in Or. they went. They are big in single cylinder dirt bike strokers and have been shortening rods for years, but were willing to shorten the wing rods. With these mods the engine displacement will go from 582cc to 670cc. Anyway, all the parts have been attained and the assembly has begun. The worst part of the job is swapping the engines as it almost entails tearing the wing down completely. I'll report the results when finished if there is any interest. I am hoping for a real sleeper.

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Subject: Re: Engine Mods...    Sun Sep 11, 2016 12:57 am
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Got the Silverwing out of mothballs. Video of wing drag racing a Harley. Check Facebook. Scroll down on right - check the hammer out.

https://www.facebook.com/McChesney-Motors-121940804599560/


You can Search "Engine Mods..." on this forum to find the link to that complete topic conversation.

Tim

hehehehhe

I think a big bore / long stroke motor is a bit beyond me at present. I have done it before with my MSX/Grom that went from 125cc to 215cc and almost tripled the power, but that had already lunched the stock crank, and an off-the-shelf kit from an expert was cheaper than OEM parts.

At present I'm probably not going further than a new header for now. I think tinkering with internals is going to be a bit too much for a daily commuter.

Oh, and maybe a proper Racetech front suspension setup with linear spring and cartridge emulators. I've done it on my other bike, and that now feels tauter than a similar vintage Fireblade. I'm a tad sick of riding pogo sticks!

Reading around also taught me a few things about the HiT clutch, on which you apparently are one of the experts! I'm thinking that it is now on my list of bits too, once I've finished tinkering with the motor.

The biggest problem I'm finding is that I'm USING all this extra umph I've got now. It's that old 'speed' drug again.