500 gearbox woes part 2 ...

[mr stainless]

ok here goes ....
I have a 86 CR 500 bottom end with an 84 barrel on it with 5 speed box . Now I lost 3rd gear last Sept so after taking it apart I was supposed to go to the Telford show and see Andy at HVA but for one thing an another I couldn't go but I did pick up another gearbox off ebay with casings .
All good I hear you say ....yes to a fashion ....all the gears are definitely in better nick than mine and so are the casings but ...the new casing doesn't have the extra hole at the top and according to the number on the case its an 86 ..... why would that be !!
Now I also have a problem with that the gear on the back of the clutch unit is ....lets just say not very good ..... but Andy doesn't have one and its liable to be bloody expensive if I find one ...
So enter a 1993 te350 motor..... now this started as a hunch that the case would fit so I would have a better way of servicing clutch and bingo it fits a treat ...so then I have this idea of fitting the whole clutch unit !! no that wont work but the 350 motor does have an immaculate 6 speed gearbox in it ....will it fit me thinks ...well blow me it does .....

So what I want to know is .... why has the 86 casing missing the extra lug !!
and secondly is there any reason why the 350 gearbox and all its other bits will not work properly... it would solve a big problem and has cost me very little to get this far ...
many thanks
graham

 

[dukkman]

Early 86 was probably old 85 stock stamped 86.
Fit a deco and you have no problem with these

 

[fran...k.]

ok here goes ....
I have a 86 CR 500 bottom end with an 84 barrel on it with 5 speed box ......

So what I want to know is .... why has the 86 casing missing the extra lug !


and secondly is there any reason why the 350 gearbox and all its other bits will not work properly... it would solve a big problem and has cost me very little to get this far ...
many thanks
graham

Some of the bikes that get identified as 1986 seem to have that extra lug and some don't. You get more arguments and disagreements in the 85-88 era with owners and sellers than is worth worrying about. The plastic and the linkage and the removable plate over by the chain sprocket to me seem to mark a line between 85-86 and 87-88 and perhaps 89 in other parts of the world. Maybe there are 85-86 plastic without the plate by the sprocket just don't have a large enough sample. Case half's halves? can get switched also but usually are numbered (or the numbers aren't rubbed off)so one can figure out if they are still a matched set.

The 87-88 also differ from an 1986 in the 500 and others in that the clutch attaches with a nut and fold over washer instead of a snap ring. I would expect the 350 four stroke you have for parts does not have a clutch held on by a snap ring. So could you be more precise about the "gearbox and all of it's bits" as at least you would have to use the input shaft with the first gear built into it the way I see things. The ratios for the big bike wr and xc stayed on in the four stroke section for at least another 10 years and I do know the third gear on the input shaft shared the same part number. Putting the cases together without a crankshaft is pretty easy to make sure an error isn't made in getting the pieces figured out. What if you change all the gears primary drive and starting included behind that clutch cover any chance that will work? My guess would be a 610 (577 really) primary drive would be more appropriate if they differ.

As to adding that extra bolt on the left case. A blob of magnsium can be welded on which I did on one, the cover is flexible enough to accomidate what mimimal flexing occurs. About the time I joined here someone was offering a bolt on extra piece. Or just making a bolb out of epoxy that kind of wraps around the back is the last tactic I tried. You end up with about an inch threaded which is way more that the one and a half times diameter rule of thumb I have heard of, perhaps for steel/Iron. The stresses are going to be a pull and those clutch covers tend to crack at the rear locating pin. It isn't uncommon to buy a bike from someone that changed the clutch cover. I think you really need attach the blob and then create the tapped hole. Magnesium solder might also be possible to attach a piece of a junk casting shaped properly. Or other low temp repair tactics.

Fran

 

[ruwfo]

"As to adding that extra bolt on the left case"
Just make a peice & bolt it to the main case like wildebeest90210 did , it's so simple , most wouldn't have thought of it.

http://www.cafehusky.com/threads/83-cr500-here-begineth-the-lesson.22344/page-11

Husky John

 

[86 400 XC]

HVA Factory sells that part to add to the case..

 

[mr stainless]

thanks for the reply's guys , keeps the ideas coming .
Right I have put the 350 6 speed gearbox into 86 engine casings and so far everything seems fine ....the only problem I have so far is the output shaft (front sprocket) has a different bearing set up but I think I can get round that .
The clutch on 86 unit is snap ring but the 350 is bolt on hence the reason why I've gone down the road of transferring the whole gearbox .
My only concern is ....will this 6 speed box be up to the job !!!