Topic: CB500 1975 Gearbox problem replacement parts compatibility

[Jawadjb]

Dear forum members,
I hope you're all well. I own a CB500 1975 model in Pakistan. Unfortunately there aren't many CB500s left in the country and sourcing any parts are nearly impossible.

My motorcycle when running misses the gear or jumps out of the 1st, and 3rd gear. I've searched this forum extensively and I'm aware that his could be caused by bent shifter forks, worn out dogs and that sourcing the replacement parts are impossible or are very expensive even from UK where I reside currently.

I've found some gearboxes on internet auction sites which are for Honda CB400 or CB350 which are at an affordable prices but I can't tell if those gearboxes or their parts such as shifter forks etc can be replaced with the ones in my CB500. Could anyone with experience help with this.

Alternatively, any procedure or guide that may be available to fix the known gearbox issues in the CB500s if can be shared will be very helpful. Please help if you can.
 
One of the example parts are listed below for your consideration.

https://www.ebay.co.uk/itm/305921976663?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=aXf4hUOqRE6&sssrc=4429486&ssuid=h9_BT1NtSC-&var=&widget_ver=artemis&media=WHATS_APP

Kind regards

Jawad

[bryanj]

No they wont fit and if its a 75 it must be a uk model but need to know frame and engine numbers to be certain.
The "normal" 500 gear problem is the centre selector which is the same as 350 twin BUT  only that and selector drum are same.
You need to be very careful with replacement gears as there was a change to tooth profile during the years of production so some gears MUST be replaced as pairs, safest is a complete gearbox but they are getting scarce and expensive.
You can fit a 550 engine as long as you have the 550 RH rear engine mount plate for the clutch cable mounting

[Jawadjb]

Thank you for the reply BryanJ.

I've explored the option of finding a cb550 engine which is easier to source from the UK but unfortunately as far as I'm aware Pakistan import policy doesn't allow used engines to be imported into the country.

And finding a CB550 engine in Pakistan is impossible because I've searched the local scrapyard there. So it looks like I'm stuck with the cb500 engine that I have.

I don't have access to the motorcycle but the registration book picture shows the below

Chassis number: 2073687
Engine number: CB500E-2162274
Model Year: 1975

I'm not an expert. Could you please tell from this information which model is the one I have and what compatible parts could be used to fix the gearbox problem explained in the original post.

Many thanks

[Deltarider]

Welcome Jawad! The year is irrelevant in determining what exact model you have. Go here where you find all CB500 parts lists, that is: in western alfabet. In the first 4 pages of each parts list you'll find the frame- and enginenumbers listed, indicating which models that particular parts list is about. https://www.honda4fun.com/materiale/documentazione-tecnica Compare your numbers with those listed.
Look up the page in the appropiate parts list that deals with the transmisson and check if there have been modifications during the production of your particular model. In that case Honda has indicated from which number on, a part was a modified one.

[RAFster122s]

Sounds like you need to load the bike in the back of a truck and drive across the border to where you can pull and replace the motor...then reenter the country with none the wiser any changes were made... Only inspection of the engine number would reveal the discrepancy...

[bryanj]

A quick look on ebay gives me item number 126788906342 where the selectors look good, not the cheapest but looks good and less than just 3 selectors.
BEWARE he has another listing saying 500 550 which is a 550 and will not fit, the 500 has all 3 selectors on the selector drum whilst the 550 has 2 of them on a seperate shaft

[Jawadjb]

Thank you BryanJ. Just had a look at the item you specified and have added in my watchlist.

Please kindly comment on the item below. This appears to be for th cb350twin. Three selectors. Only asking because the price is within my budget.

ebay.co.uk/itm/316023707794?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=8O8R5KZARse&sssrc=4429486&ssuid=h9_BT1NtSC-&var=&widget_ver=artemis&media=WHATS_APP

[Jawadjb]

Sounds like you need to load the bike in the back of a truck and drive across the border to where you can pull and replace the motor...then reenter the country with none the wiser any changes were made... Only inspection of the engine number would reveal the discrepancy...

Too much of hassle, paperwork and redtape involved plus the costs. Easiest option would have been to source a 550 engine if I could find one locally.

[Jawadjb]

Welcome Jawad! The year is irrelevant in determining what exact model you have. Go here where you find all CB500 parts lists, that is: in western alfabet. In the first 4 pages of each parts list you'll find the frame- and enginenumbers listed, indicating which models that particular parts list is about. https://www.honda4fun.com/materiale/documentazione-tecnica Compare your numbers with those listed.
Look up the page in the appropiate parts list that deals with the transmisson and check if there have been modifications during the production of your particular model. In that case Honda has indicated from which number on, a part was a modified one.

Thank you Deltarider for sharing the information. I'll study this in detail and see what I can find re the parts I need. Kind regards

[Deltarider]

To find out what Honda models shared the same part, go to https://www.cmsnl.com/honda_model8286/. Provided you log in, CMSNL can list you all Honda models, that had that same part, you were looking for. Very convenient as it's not unusual that parts have been used also on older models.

[bryanj]

Not worth the 350 ones as only 1 selector is the same the others dont fit

[Jawadjb]

Not worth the 350 ones as only 1 selector is the same the others dont fit

Noted. Thank you.

[Jawadjb]

To find out what Honda models shared the same part, go to https://www.cmsnl.com/honda_model8286/. Provided you log in, CMSNL can list you all Honda models, that had that same part, you were looking for. Very convenient as it's not unusual that parts have been used also on older models.

This website is very helpful.Thank you for sharing.

[bryanj]

A lot of 500 transmission parts are nla and those you can get are expensive, that german set whist sounding expensive is not really for a complete gearbox

[Jawadjb]

Makes sense.