Topic: CB500 Hp with factory rod

[Matt.h]

Hi all I'm looking for advice on the reliability of the factory CB500 rods in a performances motor.

I have a CB500 that has not been on a  dyno so hp is not known but I will list the mods.
I'm worried I should of putt rods in it ?

572cc big bore 11.5:1
Dp335 cam
Ported head  bigger intake valves , springs ect
Dyna 2000 ignition
Cr 29 carbs

[turboguzzi]

my 500/4 racer did 5 seasons on stock rods, no issues and i think other had similar experience. unlike the 750 which had known issues and has kits, I doubt that youll find any aftermarket rod kits for the 500.
the only 500 rod swap that we've seen here in hipo was by rene who transplanted gsxr1000 rods into one but it requires quite a bit of work

[Matt.h]

Ok thanks that makes me feel better about it . What sort of hp were you getting from your 500?
Carrillo make a Rod for the 500 but at $1600 us    And I’m in New Zealand so was closer to $2400

[turboguzzi]

last dyno i did was 62hp. but it's a 500cc, mind you.
bwaller's 600 was around 70, check out his thread
nice to know about carillo, but out of my $$$ range too
now i recall that also davies motorsport in uk was doing a kit, might be cheaper

[Matt.h]

Ok thanks I will check out his thread . Yip I have seen the ones that Davies motorsports sell I have some gearbox parts and oil cooler adapter  from there .

[bwaller]

It's the rod bolts that are the weakest point, but with the later 750F3 bolts & nuts 572's have been (safe) to 70? I went with Carrillo's early on for peace of mind, what's that worth?  Mine is also 572cc and HP is over 70, but is actively raced so better rods over time is easier to justify.

Has the bike run? That DP cam has been known to cause valve to valve issues.

[MRieck]

That cam...the 335 is poison with an OS intake valve.

[Matt.h]

motor Has just recently been assembled but I have not run it yet . Seams to turn over with out interference but now I’m worried hahah .   Has this been happening if you get valve float? Or is it a interference issue from day one ?  The intake valve is 28.5mm   Factory exhaust valve.

[bwaller]

Perhaps MRieck can better answer. Seeing as how you're using a stock 23mm exhaust valve maybe will be ok, I just can't say with certainty.

[MRieck]

 Did you check valve to valve clearance @ overlap? That's the only way to really know. I have seen valve damage with that cam. The engine ran but the margins were all beat up....not good.
 My personal opinion is there is to much duration in the cam. I prefer some more lift with quicker closing ( with an efficient port)to build compression and cut down on the valve to valve issues