Topic: new Member cb500 f

[epicracer]

first off this is my 3rd bike .

i have a 1966 CB450 Black bomber
1975 CB200

and recently aquired a great CB500 four

great bike runs as it should,but 4th gear is shot. all other gears shift fine.

question is what would cause such an issue, and what are everybodys recommendations to repair it. would love to take this thing out before it gets too cold, but would feel loads better once i know eveything is in tip top shape.

Thanks.

[calj737]

Upshifting to 4th? If so, broken or worn gears. Check the oil pan for remnants before damaging the trans.

Depending upon how badly mangled, undercutting the gears for the up-shift side works well. 500s are notorious for fragile trannys.

Welcome and cheers-

[epicracer]

Yeah when shifting up or down gear rattles and does not engage.

No metal in pan , won't know more until I tear her down. Real shame too, everything is pristine on this bike

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[epicracer]

what is everybodys recommendation when replacing the transmission. I have been looking around and some say do a full rebuild where as others say just split the cases . from what i have read so far this should be able to be accomplished by simply splitting the cranks cases and accessing the transmission from the bottom. ( i know easier said than done)


recommendations are appreciated.

thanks

[Tews19]

Maybe buy a complete running 650 engine. Drop it in and call it a day. That is a direct swap option on a 550.. Should be the same for the 500.

[calj737]

Pull the motor, install on engine stand that rotates 180, split the cases, and install the trans. Put the motor back and ride. I'd attempt to buy a replacement and send it out for undercutting before removing the motor. When in your hand, remove and repair. This wI'll significantly shorten your window of "in the garage".

Besides, most transmissions you buy used for a 500 are probably a bit buggered up anyway.

You could buy a 550 motor and swap it in. Easier to tend to than a 650 with greater abundance of parts.

[Stev-o]

+1 drop a 550 motor in it.  I had a '71 500, was disappointed in the performance compared to my 550. 

PS. Can you post pics of the Bomber? I'd like to get one.

[epicracer]

I already purchased a transmission, so I am going to repair for now. It's hard to find motors here anyway.

[epicracer]

My beauty's

[Stev-o]

Very nice!

[epicracer]

Whats the best way to pull this motor out. The manual says raise slightly and remove from the right side. But It getting hung up on the oil pan and top of the motor between the frame

[dave500]

i pull the breather cover and pan off along with the oil filter housing.

[epicracer]

@dave500 thank you sir. i was able to get it off. so now to the transmission rebuild, just first looks all the gears look fine, no broken bits anywhere. just looks like 4th gear is not engaging.

could this just be a bent fork?

if  so can i simply bend it back a little or do i have to replace it?

[DaveBarbier]

@dave500 thank you sir. i was able to get it off. so now to the transmission rebuild, just first looks all the gears look fine, no broken bits anywhere. just looks like 4th gear is not engaging.

could this just be a bent fork?

if  so can i simply bend it back a little or do i have to replace it?

I'm no expert but I'd think bending it back would not be a great idea. I guess it depends on how bent it is...I'm thinking of work hardening the metal by multiple bends could make it a little more brittle. I am about halfway done with an almost full rebuild of my '78 550. (I found bits of gear in my oil pan) I found a full used transmission on eBay, delivered, for about $60 that looks to be in good shape.


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1978 Honda CB550K

[Tews19]

Post pics of the tranny. I recently thought I finished my 550/605 build and having a hell of a time with the gears. Everything looks great but I'm thinking I installed incorrectly.

[epicracer]

Here is what I have discovered the middle fork and gear have ground each other down .



I have a replacement transmission but now I also need new forks.

The second picture is the orientation of the forks do they look correct? I wonder why there ground each other down. 4th gear was not engaging all of the way on the old tranny probably due to the forks not pushing all of the way. Give me your thoughts

[dave500]

the 500 can be prone to rounding over the engagement dogs,then it jumps out of gear loading the fork excessively,the shifter drum can also float left and right making the situation worse,the 550 had a few improvements over the 500 transmission in the clutch release and drum locating being the main ones,also the three forks on 500s are all hung off the drum,in 550s only one is on the drum and the other two ride on their own shaft.

[epicracer]

Well I am aware of the rounding, but the dogs pretty decent it's The middle fork and adjoins gear that look chewed up. If you look closely at my picture you can see the middle gear is black, this looks due to heat where as the other two gears look fine. Hence my question regarding orientation. 

[dave500]

got a good shot of the dogs and slots?also if the hub of the spinning gears can wobble on the shaft excessively the dogs dont run square and can jump,once a 500 has jumped two or three times its starting to wear.