Shifting problems

[jcknapp]

Hey all
So I've always had issues in the shifting of the cb500 I ride. It's a 1971 cb500 four and sometimes when I shift it's hard or not smooth. I also sometimes can't get it into gear unless I let off the clutch a bit or hit that sweet spot. Any others had problems? I heard this model was notorious for having this problem. I rebuilt the clutch ( new plates, new basket, new lifter rod, new mechanisms in the left side crankcase too) but still have problems sometimes. Is this a matter of fine tuning the clutch on the clutch lever, left side crank case screw or anywhere else?? It's been happening for some time and drives me crazy. My buddy said it may be due to "hard drum gears" internally but I really don't want to tear this open to replace those. Any advice would be welcomed. Thanks

J

[K2-K6]

Your comment about releasing the clutch slightly (if I read that correctly) to help get it into gear suggests that the clutch is operating as it should, i.e. with the engine running and lever pulled in the gearbox is then stationary and needs to be rotated to assist you in moving the gear lever into 1st gear. If that is the case, I would say that part of it is OK.

A question, how easy is the thottle to operate? if this is stiff/ difficult to get fine adjustment then it will screw your timing by having a missmatch as you shift and make it hard for you to syncronise a smooth change.

The gears should shift the same with or without using the clutch when on the move, it's just thottle and timing that gets it to match well.

Hope this helps, post again with any questions.

[matthewmosse]

On my '74 500/4 I used to be able to go 90 miles with no cluch usage with a sidecar attatched. However that was following on from bmw ownership where I got well practiced at slick gearchanges at spot on rpm's

[steve j]

Gearchange problems can be oil thickness related. Have you changed the engine oil recently?Maybe to a thicker viscocity, my 550k was running perfectly ok last year and as usual I changed oil and filter for new year and im now struggling to get neutral and the gearchange seems harder ive gone from 10/40 to 15/40 oil coincidence?seems I could be changing it again soon.

[K2-K6]

Isn't it the 40 grade that is held when up to temp? so should be the same when warm as I understand it.

Thought the 10/15 is the cold rating so should not have a big impact possibly.

[deltarider]

Actually 15W40 is the better oil, unless you live in the north of Canada and ride at temperatures below zero a lot. Mine shifts better with 15w40.

[kifer]

I have read with great interest and am definitely no expert with regards to oil, But through the years have owned many 750,s,
As I remember I used Morriis oil 20/50 changed every 1000 miles, I don't even think it was bike specific, I used bikes every day in all weathers even snow and never had any gear box troubles.
Now moving on 30 years we have all these fancy oils but seem to have more problems with clutches and gear boxes.
That said I have as in a previous post just put 5/40 fully synth in an old DR and seriously its a better bike smooth changes etc.
I think keep it clean keep it changed cheaper oil more often.
Good luck with your 550,

[Tomb]

Its more to do with the API (American Petroleum Institute) standards of modern oils rather than the grades, our old bikes are best suited to SE or SF oils, they have less friction inhibitors. Friction inhibitors of modern (SJ, SL, SM) oils are obviously a huge leap forward, until you put an old style clutch or starter motor clutch in the mix, then the problems can start. I always used 20/50 grade oil in my old bikes whilst they were readily available, they ain't any more coz modern cars use 15/40 now.

I always had better shifting with the heavier oils as they're nearer to proper EP (Extreme Pressure) gear oils.

I now use Morris Ring Free 15W/40 APISL which still gives me clutch slip but its the best I can get at none silly prices.

For our old bikes the cheaper/nastier the oil you can get, the better it is, that is as long as it does have an API of around SE or above.

[toucheturtle]

I had the gearbox rebuilt and new clutch on my CB500 but once it was warm I still found it difficult to change up from 1st-2nd or to find neutral. I was using 10/40 mineral oil but am now using 15/40 Shell Helix. It has made a noticeable improvement, the change is very smooth when the engine is cold to warm but is still a bit reluctant to shift in to second when really hot.