Topic: Dr. Tom Marquardt's 550 Hybred AHMRA Racer

[cafe75-550]

The 64mm Kawi pistons wouldn't happen to be an overbore kit for a KZ650 would they? I'm in research/mock up of a similar engine (550 with 750 liners and 650 head) and had planned to use 836 pistons, but the 750's have offset valves so I may have a problem. The KZ650's don't seem to have offset valves, but I wonder about wrist pin size etc...Any information would be much appreciated...otherwise I jsut may have to try to get my hands on some used kawi pistons...

[crash]

Novice Historic Production - Heavyweight would be a fine class for a basically stock CB750.

Novice Production Heavyweight - basically stock, no engine or carb mods allowed I don't believe.  Front rotor drilled, baffles removed, aluminum rims, reduce as much weight as possible. I just bought this one from a fellow named Steve Bem, who has raced past couple of years.  I don't think he will mind me posting a pic (apologies for temp hijack of a thread).



And now it sits in my garage, unsure of whether to restore it, or as Steve said "just race that thing".


I think the competition gets a little hot and heavy with the Vintage Superbike classes as you start competing against CB900's, Kawi Z1's, 1100 cc bikes, etc.  For racing the 550 and 350 Hondas would be the ideal way to go I think.

[mlinder]

Crash, I don't think Id race a 750 with stock exhaust. If you go down, you've ruined unobtanium. That would be my worry.

[crash]

Yeah, but it's okay, they are 341s not 300s so I have to replace them anyway 

[Chris Liston]

Crash,

Curious, did the previous owner drill and tap the swingarm with spools for that rear stand?  Sorry for the off topic.  I just want do do the same to my 550 so I can remove the center stand.

[crazypj]

I remeber seeing an old CB550 factory Honda at Pembray circuit some years ago (around 1985/86)
The Yamaha FZR1000 was new and  running in production class.
 '550'??? works bike  accelerated passed Yam into the hairpin off back straight. It sorta kinda looked like a stock frame, (for an earlier Norton .)
The rear loop at swing arm was completely different to stock one.(it really looked like a 'Featherbed' frame in miniature)
 Had a couple of HRC parts on it.(it wasa a lot more laid back those days, you could wander around paddock)
 Dont know if it was originally built for endurance racing? that was very popular in Europe in the mid/late 70's early 80's
PJ

[cafe75-550]

PJ-
Any thoughts on using 836 pistons with 650 head as far as valve clearance (offset 750 valves vs opposed 650 valves)? Been trying to figure out if I need custom pistons, or figure out which Kawi pistons Dr. Tom is using...

[Tim2005]

I remeber seeing an old CB550 factory Honda at Pembray circuit some years ago (around 1985/86)
The Yamaha FZR1000 was new and  running in production class.
 '550'??? works bike  accelerated passed Yam into the hairpin off back straight. It sorta kinda looked like a stock frame, (for an earlier Norton .)
The rear loop at swing arm was completely different to stock one.(it really looked like a 'Featherbed' frame in miniature)
 Had a couple of HRC parts on it.(it wasa a lot more laid back those days, you could wander around paddock)
 Dont know if it was originally built for endurance racing? that was very popular in Europe in the mid/late 70's early 80's
PJ

I wonder if that was the bike that Alan Jackson won the 1977 F2 TT on, which was a Seeley 750 frame fitted with a works 550 engine. Last heard of it being in John Kenworthy's loft, without an engine, about a decade ago. Apparently the works 550 engines were something very special, with no stock parts whatsoever. Perhaps someone here knows more or can validate that this is correct.

[fastbroshi]

Moderators:  I ran across this thread in a random search.  Maybe this should be put in the HiPerformance section?