350 downshift blues...

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stratos23
Posts: 12
Joined: 08 Dec 2015 19:29
Location: New Zealand

350 downshift blues...

Post by stratos23 »

Hello from NZ!

I’ve recently rebuilt an '81 350 Kanguro engine and just fitted into the bike. Everything seems to work beautifully as it should EXCEPT for the gearbox.

Whilst it shifts up through the gears nicely, when chopping down, it becomes incredibly vague and often requires several prods to get it to change with lots of false neutrals in between.

The linkages are all adjusted up correctly and the clutch is behaving as it should.

Having to pull the engine out and apart again is such a pain, but before I do, I thought I’d put it to the forum. Ideally, I’d order any parts needed before I start disassembly, since ethane I can hopefully do it all in one go!

I suspect it might be a weak return spring? But any thoughts would be hugely appreciated!

Thanks!
'It must be a .....'
Posts: 365
Joined: 12 Sep 2010 12:25

Re: 350 downshift blues...

Post by 'It must be a .....' »

Hi, I would double check that the linkage/lever isn't the problem because of play/adjustment; touching footrest, frame etc or even the rose joint twisting and limiting movement when changing down

Good luck
MickeyMoto
Posts: 2415
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: 350 downshift blues...

Post by MickeyMoto »

Was the 'stop' removed from the gearbox? This needs to be setup.
morini_tom
Posts: 920
Joined: 05 May 2006 13:47
Location: Northampton

Re: 350 downshift blues...

Post by morini_tom »

As mentioned above, linkage adjustment can cause these sort of symptoms, but assuming all is ok here, as Mike says, the stop plate in the gearbox needs setting when the cases are apart, as described in the blue book.

The spring can jump out of its groove when mating the crankcases too so sometimes it is just unfortunately a case of splitting the cases and putting it back again.

Finally, you don’t say whether this issue is when riding or statically on the bench. I once had issues checking for good gear engagement after a rebuild and pulled the engine from the frame only to find no assembly issue and the same happening once I’d put it back together again. Eventually I decided just to see how bad it would be when ridden and it was a lovely gearbox with never a missed gear. I think the dogs were hitting eachother face on and without the engine turning just didn’t want to go home. Now when I check gear selection on the bench I rotate the input shaft whilst providing some drag on the output shaft- but it’s a bit of a 3 handed job!
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72degrees
Posts: 1549
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: 350 downshift blues...

Post by 72degrees »

morini_tom wrote: 23 Jan 2023 18:09 Finally, you don’t say whether this issue is when riding or statically on the bench. I once had issues checking for good gear engagement after a rebuild and pulled the engine from the frame only to find no assembly issue and the same happening once I’d put it back together again. Eventually I decided just to see how bad it would be when ridden and it was a lovely gearbox with never a missed gear. I think the dogs were hitting eachother face on and without the engine turning just didn’t want to go home. Now when I check gear selection on the bench I rotate the input shaft whilst providing some drag on the output shaft- but it’s a bit of a 3 handed job!
THIS.

The rebuilt Forgotten Error 350 engine was so hard to change gear 'on the bench', on a trial assembly, that I wondered if the stop plate was not positioned correctly. Decided to go for it and it was fine.

If you put a 350 in to a 2C 250 with standard 250 exhaust system one gotcha can be the linkage hitting a pipe.
3potjohn
Posts: 1243
Joined: 02 Jun 2007 13:58
Location: Devon

Re: 350 downshift blues...

Post by 3potjohn »

I had a touch of gear selection issues once but after living with it for a short while discovered my linkage was just contacting the cover. Rectified by adjustment. I should have known better.
John
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