Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: SteveD CB500K0 on February 23, 2011, 05:33:07 PM
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From .net:
As of this writing, CB500 clutch push rods are pretty much impossible to find anywhere. They come up on Ebay every now and then but sell for $50+. That's just stupid for something that may well break again...
So, between Shifter19 and Number13 (seeing a theme here?):
Measurements for a Honda OEM pushrod are:
10 1/8 inches or 257 mm long
3/8 inch in diameter or 9.5 mm
You can easily fashion a push rod from
3/8" steel rod found at any hardware store.
The shifter side end should be ground flat and square,
and the brake side end should be neatly rounded in a semi-sphere
to mate with the clutch basket. If you err, err on the side of a bit too
long since this will allow you to keep the lifter mechanism low and avoid cracking.
May also be a good idea to quench harden the ends.
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But surely these parts cannot be rare, I've got a few kicking around in my workshop.
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...also, at a push (no pun intended), does the CB250/350K one work?, It is the same diameter but 255mm long.
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But surely these parts cannot be rare, I've got a few kicking around in my workshop.
Get 'em on eBay. That's $100!
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crikey Florence you are minted ;)
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Crazy
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Steve, how about stainless?? thoughts..........
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The last genuine one i had in a Honda bag was one pice steel so i think thats the way as long as you aint racing as the extra weight will slow down the clutch operation.
To be pedantic one realy ought to use the correct diameter silver steel rod and harden the ends!
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Some of the cluch pushrods I have (my first 4 stroke bike was a 500cc engined chop project with 3 engines in bits so engine wise I've a few) had 2 shorter pushrods with a ball bearing inbetween them - why are some a one piece steel rod and others 2 parts with a balll bearing sat in the join? Was it a American markett thing or a later mod in hondas production? or previous owner modification / bodge?
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The only 500 bottom end I ever took apart had a two-piece with ball bearing too. That's the bike in the avatar.
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So someone with a dead long type could in theory just modify it to short pushrod speck and add a ball bearing and short bit............
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Honda NEVER supplied a two piece pushrod but what happened in service was this:-
Original pushrod is alloy middle with steel end(s)
Chain not adjusted whips off front sprocket on overrun and hits pushrod breaking the end off.
Oil leak starts as pushrod now does not move linearly also operation deteriorates
Owner pulls out the broken piece, assumes cos he dont have a manual, that he has lost the centre ball bearing that a lot of britsh bikes had so puts one in (probably at the same time losing the ball in the operating mechanism)
Clutch operation gets even worse as the shorter piece wobbles even more
owner gets fed up, wont pay dealer prices to sort it properly and sells the bike
Further owners think this is the way its supposed to be and live with it
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Ah, very enlightening, always wondered why the difference, Will use the one piece assemblies then. Must have been some very poorly adjusted chains out there as I've never had the chain jump off on these bikes and I consider myself to be about the worst offender for neglect of the bike. Come to think of it I've had a couple of engines that were really bad on the gearchanges so got shelved, I'll have to make a note of which ones have the 2 part pushrod as it may well save me a coupla rebuilds, just leaves me the mystery of the 500/4 engine that ate camchain tensioners to investigate..................
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Canchain tensioners got et when either
was not adjusted correctly
or
idiotic numbnuts put a screwdriver in the slot and forced the toothed wheel resulting in a crodged (technical term) tensioner
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This bugger ate 2 tensioners in a year (10 000) miles, Adjusted them as per manual which is the same way as for all the other 500 /550 motors I've owned, I'm convinced the problem may lie deep within the bowels of the engine, say a crank sprockett thats cream crackered in some way but possibly a chain that was too short? Enigine was a USA inport and looked near mint but nothing to say some PO had been in there for somit..............
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crikey Florence you are minted ;)
Good incentive to tidy the workshop!
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..just found some CB350 ones which is much shorter and makes me realise the other one is a CB500 one. It is in three sections, steel at either end with alloy in the middle. The outside part is threaded into the middle section.
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From .net:
As of this writing, CB500 clutch push rods are pretty much impossible to find anywhere. They come up on Ebay every now and then but sell for $50+. That's just stupid for something that may well break again...
So, between Shifter19 and Number13 (seeing a theme here?):
Measurements for a Honda OEM pushrod are:
10 1/8 inches or 257 mm long
3/8 inch in diameter or 9.5 mm
You can easily fashion a push rod from
3/8" steel rod found at any hardware store.
The shifter side end should be ground flat and square,
and the brake side end should be neatly rounded in a semi-sphere
to mate with the clutch basket. If you err, err on the side of a bit too
long since this will allow you to keep the lifter mechanism low and avoid cracking.
May also be a good idea to quench harden the ends.
thanks for this info,just found my pushrod is snapped,so ordered a length of 3/8 silver steel,
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John, i have had a batch of pushrods made by a tool firm. I found a NOS one to take the blueprint from and had them made to the measurements in silver steel with hardened ends. If anyone require one i will sell at cost price to members.
John, the CB500 push rod is not 9.5mm. when i bought the NOS one i was still not sure that i had the right rod, so i got Oddjob to send me one to confirm the right size.
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Trig
You are a gentleman best of luck mate
Cheers
Bitsa
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Bitsa, Had to have them made in the end because i could not find them anymore and the last one from the states cost me $75 + customs+++
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John, i have had a batch of pushrods made by a tool firm. I found a NOS one to take the blueprint from and had them made to the measurements in silver steel with hardened ends. If anyone require one i will sell at cost price to members.
John, the CB500 push rod is not 9.5mm. when i bought the NOS one i was still not sure that i had the right rod, so i got Oddjob to send me one to confirm the right size.
Hi Trigger,so the details from .net site are wrong,and a 3/8 steel bar will not fit?
obviously it will be easier to buy a ready made piece,
please let me know the cost,-))) Thanks
OOOPS !!!! just seen you message,will be in touch
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The last genuine one i had in a Honda bag was one pice steel so i think thats the way as long as you aint racing as the extra weight will slow down the clutch operation.
To be pedantic one realy ought to use the correct diameter silver steel rod and harden the ends!
John, if you read the quote. Bryan is right. PM sent.
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Do people still need these, I might have one from a rusty old bottom end I recently bought on ebay? Need to check the workshop carefully.
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So before i go looking for my last NOS one what was the diameter of the ones you had made Trig? I know the seal has an 8mm hole
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I had cause to replace mine recently. The push rod oil seal is 8 mm and and the domed end on the clutch side which fits snugly into the mushroom lifter ( clutch rifter joint ) is stepped down to 7.8mm and domed. The rod length should measure 257 mm which allows a little play to be adjusted by the adjuster clutch, any longer and there is a risk of engaging the clutch when you replace the left crankcase cover. I ordered silver steel 8 mm rod from an engineering company advertd on eBay. I had a mate lathe/ turn the dome and I wet and dried the bar finely to a micro under 8 mm so it didn't grab the needle bearing beyond the oil seal. I then heated hardened both ends. The bar with delivery cost 4.85 delivered then half an hour to fashion and I'm a novice at this game.
Sent from my iPhone using Tapatalk
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So before i go looking for my last NOS one what was the diameter of the ones you had made Trig? I know the seal has an 8mm hole
It worked out at 8.05 giving it a nice fit in the seal. Had them cut by a wire eroder machine.