Might be of interest

[z1100r]

Some stuff I tested once upon a time...
  The 4into1 and 4into4 exhaust stuff ....I had 3 types of 4-1, a brand new set of std 500-4 pipes, and a good set of std 550K3 pipes....The 4into4 550K3 pipes were by far the best..that was on a 500 a 550 and my 610 motors. No 4into1 got near them, they just made a better noise... ...

 Another thing I have tested is carbs...I have tried the stock 500 carbs...the stock 550 carbs and a set of 750 F2 carbs..modified.....again the best were the 550 carbs....the screw in jet type...not the push in. I have obviously religiously jetted them all. The 550 carbs on my bike at the moment with a 610 motor do 55mpg..super smooth right through with no glitches/flatspots..and I thrash the turdy out of the bike all the time...its always around the 100mph mark. With the 500four carbs - although performance doesn't suffer - it never does more than 33mpg...? The larger 750 carbs just weren't worth the effort....performed exactly as the 500four originals....I did all this when I raced the bike in 85-86. 

 Camshafts... I have 3 extra camshafts for it...a Yoshimura road and track (crap)...A yoshi IOM race (OK)...and one I had made by Joy cams...which was welded and reground to XL125 motocrosser profiles...(awesome 8,000-10500rpm)...she used to rev her tits off...great for racing but not too good on the road.

I did all this when I raced the bike in 85-86. My 500four bored to 610 was exactly the same speed as a GPZ600 on snetterton straight.

[matthewmosse]

I seem to have a few gearboxes with dodgy 1st + 2nd gears ie they keep jumping out of gear. Worn selector forks. Did you have these problems? I recon the stress of tugging a loaded chair for 10 years could have contributed to this wear on the original motor. Who knows what/where how the other engine was used for? However I don't recall the 500's carbs being that thirsty (with k&n filter and the 4 into 1 with triumph raygun 'silencer' You must really have been kaning it!

[SteveD CB500K0]

My 500 jumps out of third gear, worn selector forks I suspect.

[z1100r]

I cant remember which gear it was now maybe (5th)....but one is very weak in the 500 engine. It wears the dogs and slots very badly and can snap the slotted larger gear into 3 pieces. It was a well known problem at the time and the gear was superceded by a solid backed one. My 610 motor has the replacement an so do my 550 motors....my 500four original motor still has the std gear. Racing I snapped 2 2nd hand gears with serious teriffying lock ups before going to Honda agent and buying a new one. The new one was obviuosly the solid backed replacement. You can get a neutral somewhere around third..I used to shim mine up to avoid this.

[matthewmosse]

Hmm, I've not yet tried using mixed gearbox bits from 500/550. When I get round to fixing up the original 500 engine I'll look into whether I can save on cost by replacing some of the worn parts from a 550 motor. I think I'll still have to fork out for a new selector fork though Seem to recall they are rather different..............

[z1100r]

oooops...I got that wrong...I remember now...its the 550 thats the weaker gearbox. Its my 550's and 610 that have new superceded gears....the 500 is original and strong enough. I did swap some gearbox parts...using 500 parts in the 550..because they are stronger.....but they use different ratios and hence the gears themselves are different. Oh dear, 1984 seems so long ago.. My brains going...