Mid-Suffolk CB500 Update & Parts Enquiry

[Roxy John]

Morning all, it's been a while since I last posted so I thought I would update after the first proper ride out after a lot of tinkering.

Saturday was pretty much the first dry weekend day for ages so I took the CB for a shake-down trip - approx 30 miles around various lanes and a bit of dual carriageway. When I first got the bike in January it wasn't running well and was very reluctant to start. Fearing a blockage in carbs after I cleaned the tank, I stripped the carbs, ran them through the ultrasonic cleaner and re-built with Julie's o-ring kit (thanks Julie - excellent service and very good price!). The floats were all over the place so set them all to 22mm and vacuum balanced when all back together.

I also fitted 4 new plugs, new battery, changed oil & filter and checked & adjusted valve clearances.

The bike still doesn't want to start easily but once fired-up, settles to a nice even idle. However, during the ride on Saturday, when pulling up to junctions and waiting at traffic lights, the idle hung around at 2000 (ish) rpm before settling down and felt like it would die at any moment. I pulled on to petrol station forecourt and it did indeed die. It fired-up again having filled up and while riding, responds well to the throttle, pulling very nicely throughout the rev range with no hesitation well up to 8000 ish - any ideas why it may struggle at idle? I wondered about an air-leak but have sprayed carb-cleaner over all the inlet rubbers and no change in revs. It has the DSS electronic ignition which is set correctly.

Also, rather annoyingly, I lost the generator cover plate during the ride - I can get one from DSS but £90.... anyone have a spare or are they so rare that the price is the price?

Cheers, Phil

[McCabe-Thiele (Ted)]

Sounds like an air leak on the induction side somewhere - check between carbs & head - another member here had a similar issue recently.

As regards changes in idle speed I've read somewhere that it's the nature of the beast on these older design of carbs?

[Sesman]

Hanging idle is nearly always attributable to the pilot jets and/or pilot drillings. I put my carbs through the U.S. cleaner several times without success and eventually had to use aerosol carb cleaner in the pilot jet ways, sequentiality blocking the three points of entry/exit. I used STP carb cleaner, two tins of it. I then heated the pilot jets to ‘ash’ any fuel deposits and then pushed through the #40 jets with #38 probe. It worked, the hanging idle disappeared and the throttle response returned to factory standards.

[Roxy John]

Hanging idle is nearly always attributable to the pilot jets and/or pilot drillings. I put my carbs through the U.S. cleaner several times without success and eventually had to use aerosol carb cleaner in the pilot jet ways, sequentiality blocking the three points of entry/exit. I used STP carb cleaner, two tins of it. I then heated the pilot jets to ‘ash’ any fuel deposits and then pushed through the #40 jets with #38 probe. It worked, the hanging idle disappeared and the throttle response returned to factory standards.

Thank you for that - sounds like that's what I need to do then. I've got plenty of STP carb cleaner so will take it all to bits again. Not a job I relish but has to be done! Thanks for your help 👍👍

[Oddjob]

https://www.ebay.co.uk/itm/354154761826?hash=item527544ce62:g:57gAAOSwt~9iyFMV&amdata=enc%3AAQAHAAAA0Ihxg7lWlgyHaFk4hgMBd%2BjxT5faV3GbWHzg8ElFWifVm%2BUJR8q8q0c4zW5ve9JV2HoLFoPYvsmO%2FSNgG2ikl0KZ0HfWsQFCq9TrifVJYqamNGDQi%2F6lWRrr3FtaohdoBt%2Fzbu9vpo1PLEtSAcxG9JhbsHKNE2rN%2BL9S9%2Faf4S9dlGPmU2wCabTAwQodm4ExuskN%2BQdT4Ov6r4F3CnO1TVTG%2Bzo7xN%2Be3tkU8RsyTOgGC0buzD7GwM%2BaV%2FYMs4ykw09XN%2B9lU6RxksCYyoh2Im8%3D%7Ctkp%3ABk9SR5Tt_rvkYQ

Or

https://www.ebay.co.uk/itm/203778550584?hash=item2f7225eb38:g:eLIAAOSw-ldh0aZV&amdata=enc%3AAQAHAAAAwMRnPMXyr1txyl8SX8U5Fla5zb3k4%2Bt7D75c3CMHMx5JX6tiApmxWi%2BhNyLwb29E46T6vp4k6v9FjkrZA36nplnP4H%2Fyp6IQUEuC%2BJFcJnCy9N28IWC5aiGTYPWxcc0kn2cpiifXyVf2v5ZiRIBSGOG%2FuoY5T8sytXwn7LAjByEvjmV5Fk%2FgbE6LYsj%2FKa1efCUmg5cQbgED7O84knuFO%2FjhGq0BCDiNWala1axa2NozNx8J0bvk9TNW%2F0kOFOdT6g%3D%3D%7Ctkp%3ABk9SR47ijbzkYQ

I bought one from Shire Bikes, the seller above, last year and it was £46 which I thought was dear then.

The cover is held on my 3 small spring clips which grip the pegs as they are inserted, they are only mild steel and tend to rust to bits, that causes them to lose grip and the cover falls off. Buy new ones or you'll lose the new cover as well, cover them in grease before fitting to protect them as well.

The other alternative is to fit the generator over off a 550 which looks the same except the Honda logo is actually part of the cover and you can't lose it. The only downside is you can see the 3 screws holding the field coil in place. Finding one in decent nick is the hard part.

Like this

https://www.ebay.co.uk/itm/354463125979?hash=item5287a611db:g:Mo4AAOSwnw5joE48&amdata=enc%3AAQAHAAAA0JnuH4kpS0aBZfxSPo4YVeHdJzOr9vskzZwSJYOurfuFtU5SDkal6%2BFlpNVquh7iu3wrKIO58ct02GgxkXojng2owRkUYgVgI17hOjl%2FDNnPCSONM5pp6mQcvScLBRASXS%2FcvaLBnS1YVJH7DtRYcgg%2FOP70c9%2BV4T2vQN3u0Qm%2BWGxh%2F5lrxF91OaS5VOLMytF3lFBRRvA9rQVSe3ps9UQGD3stdcML0F8QJnE3UwJqDSA%2BCoCO8XMDRemS8HVQgN5O9lpsA0SBRzuY3uynB5I%3D%7Ctkp%3ABk9SR6KnurzkYQ

[Roxy John]

https://www.ebay.co.uk/itm/354154761826?hash=item527544ce62:g:57gAAOSwt~9iyFMV&amdata=enc%3AAQAHAAAA0Ihxg7lWlgyHaFk4hgMBd%2BjxT5faV3GbWHzg8ElFWifVm%2BUJR8q8q0c4zW5ve9JV2HoLFoPYvsmO%2FSNgG2ikl0KZ0HfWsQFCq9TrifVJYqamNGDQi%2F6lWRrr3FtaohdoBt%2Fzbu9vpo1PLEtSAcxG9JhbsHKNE2rN%2BL9S9%2Faf4S9dlGPmU2wCabTAwQodm4ExuskN%2BQdT4Ov6r4F3CnO1TVTG%2Bzo7xN%2Be3tkU8RsyTOgGC0buzD7GwM%2BaV%2FYMs4ykw09XN%2B9lU6RxksCYyoh2Im8%3D%7Ctkp%3ABk9SR5Tt_rvkYQ

Or

https://www.ebay.co.uk/itm/203778550584?hash=item2f7225eb38:g:eLIAAOSw-ldh0aZV&amdata=enc%3AAQAHAAAAwMRnPMXyr1txyl8SX8U5Fla5zb3k4%2Bt7D75c3CMHMx5JX6tiApmxWi%2BhNyLwb29E46T6vp4k6v9FjkrZA36nplnP4H%2Fyp6IQUEuC%2BJFcJnCy9N28IWC5aiGTYPWxcc0kn2cpiifXyVf2v5ZiRIBSGOG%2FuoY5T8sytXwn7LAjByEvjmV5Fk%2FgbE6LYsj%2FKa1efCUmg5cQbgED7O84knuFO%2FjhGq0BCDiNWala1axa2NozNx8J0bvk9TNW%2F0kOFOdT6g%3D%3D%7Ctkp%3ABk9SR47ijbzkYQ

I bought one from Shire Bikes, the seller above, last year and it was £46 which I thought was dear then.

The cover is held on my 3 small spring clips which grip the pegs as they are inserted, they are only mild steel and tend to rust to bits, that causes them to lose grip and the cover falls off. Buy new ones or you'll lose the new cover as well, cover them in grease before fitting to protect them as well.

The other alternative is to fit the generator over off a 550 which looks the same except the Honda logo is actually part of the cover and you can't lose it. The only downside is you can see the 3 screws holding the field coil in place. Finding one in decent nick is the hard part.

Like this

https://www.ebay.co.uk/itm/354463125979?hash=item5287a611db:g:Mo4AAOSwnw5joE48&amdata=enc%3AAQAHAAAA0JnuH4kpS0aBZfxSPo4YVeHdJzOr9vskzZwSJYOurfuFtU5SDkal6%2BFlpNVquh7iu3wrKIO58ct02GgxkXojng2owRkUYgVgI17hOjl%2FDNnPCSONM5pp6mQcvScLBRASXS%2FcvaLBnS1YVJH7DtRYcgg%2FOP70c9%2BV4T2vQN3u0Qm%2BWGxh%2F5lrxF91OaS5VOLMytF3lFBRRvA9rQVSe3ps9UQGD3stdcML0F8QJnE3UwJqDSA%2BCoCO8XMDRemS8HVQgN5O9lpsA0SBRzuY3uynB5I%3D%7Ctkp%3ABk9SR6KnurzkYQ

Ah, many thanks for that Oddjob, much appreciated. I'll go with the Shire Bikes one 👍👍

[Oddjob]

If you need the clips as well it may be cheaper to buy from DS, work it out first before buying.

Clips are part number 11633-323-000, £3.82 each at DS.

The cover looks new in the pic, whoever fitted it probably didn't know about the clips rotting. Shame, you tried looking for it?

[Oddjob]

BTW, if you take the carbs off replace the orings in the manifolds, they can go flat and stop sealing allowing the joint to suck air in. Same part as the tappet cover orings BTW 91302-001-020

Julie sells them. 

[Nurse Julie]

Here you go, a lot cheaper than Honda.  https://www.ebay.co.uk/itm/165957568364?hash=item26a3d7876c:g:0fsAAOSwvTpZ5j~M&amdata=enc%3AAQAHAAAA0KsHAoy2rSkZ8J3UhtQ%2B2cXkY0tU85bMpiigi3CsagLRUchewMb3z1NmJ0GtL5hMxsbH7Ni0nWcy5ziWS0nA%2Fo4Z2ci02vXXDgNBDlJKWWEvtTSp%2BONX2ImGc8pKw6fH7Mk3wJEd2DXiHhOLS%2BmNQQIOsfHYHRQwvnBIOrBcK4Z1dMgjeYDrgj5ZOp%2BatX7YCDX7oHbNVDggBS5l3qzvqM%2BzT3kUB5EKEuLq2SKltmWMYAtMj%2FtgNWaYILWZpj7nGYs4i9UssK7NWgP8r8fS5Eo%3D%7Ctkp%3ABk9SR_i_k8DkYQ

[Roxy John]

Thank you Oddjob & Julie - at the very real risk of looking like an idiot, when I took the carbs off, I didn't find any o-rings like that.....🤔🤔. I'm guessing that they sit inside the carb to inlet rubber boot jobbies and seal between face of carb stub and cylinder head?

Regarding the generator cover - it was a new one, fitted by previous owner.  Must have shaken loose when I was hurrying along a bit on Saturday. Coincidentally I had to re-trace part of the route in the car later in the day and had a cursory hunt as I drove along but no luck.

[Bryanj]

Those O rings are between the alloy manifold and head.
Those covers roll well and get covered in invisiblum!

[Roxy John]

Ah, thanks Bryan - I didn't take the manifolds off last time. I've ordered the kit from Julie so will have a play this weekend.👍👍

[robvangulik]

Also, rather annoyingly, I lost the generator cover plate during the ride - I can get one from DSS but £90.... anyone have a spare or are they so rare that the price is the price?

Did you try to find it? For £90 you can buy lots of fuel for your search

[Roxy John]

I was out for about an hour covering verge-lined lanes and a bit of dual carriageway - I'll keep my eyes open but reckon the chances of finding it are pretty slim... If it's visible from the car it's likely to be scuffed-up pretty bad and if it's rolled into the verge I've got no hope! Will probably just have to put it down as "one of those things"..... :-(

[robvangulik]

I lost a sidecover once (long ago, last century) and found it some 2 weeks later, other side of the road, with just some little scratches, so it CAN happen!