Author Topic: 5th gear problem???  (Read 1329 times)

Online Johnny4428

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Re: 5th gear problem???
« Reply #15 on: April 29, 2022, 02:46:56 PM »
Thanks guys for diagrams and info, it’s unfortunate that I seem to know a lot more about it now than I did when it was in pieces. But the reality is I tried just to put back together as I found it to the best of my ability, albeit with some new bearings and bushes. Maybe have a go this weekend to take engine out and open up, at least I’m armed with a bit more knowledge goin in this time.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Online Johnny4428

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Re: 5th gear problem???
« Reply #16 on: May 03, 2022, 04:55:20 PM »
Just an update on findings. There seems to be excessive end float on 5th gear which must have added or even been the cause of this problem. (At least 2mm) This because of the low insertion from 2/3 plus a little wear was allowing the gear 2/3 to be thrown out of 5 and jamming between selector fork and gear 5 causing a bit of heat as can be seen from photos. So that has left me now probably having to replace gears 2/3 and 5. Also have to look for shims to pack out 5 from case.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Offline McCabe-Thiele (Ted)

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Re: 5th gear problem???
« Reply #17 on: May 03, 2022, 09:38:56 PM »
I know yours is a different model but on my 400 I had an issue with what felt like excessive end float on the gear shafts. I was worried about adding extra shims in case it led to a locked up gearbox  when the engine was hot.
I ended up changing the outer half clip bearing retainers and fitting some new outer needle  earrings plus the locating pins. When I bolted the Crank case halves together I made sure I put some Hondabond on the outer races to keep the keep the shaft float at a minimum. Remains to be seen if its worked long term.
Honda CB400 four super sport

Online Johnny4428

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Re: 5th gear problem???
« Reply #18 on: May 03, 2022, 09:59:28 PM »
I wouldn’t be frightened to take up most of the end float on this Ted, but I would need to find out how much end float is supposed to be there.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Offline K2-K6

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Re: 5th gear problem???
« Reply #19 on: May 03, 2022, 10:37:47 PM »
At least you've got a diagnosis now and certainly worthwhile taking it apart again.

I can never resist changing gear on boxes after putting them together to see what they feel like before running them, just a fascination in how they work really. You can pick up reluctance at that stage so suppose it helps.

Went to look at a Kawasaki Z1000 (from memory) that a friend's friend had difficulty with as it would only select first gear. He'd had the motor out to paint the frame without working on the engine, put it back in and found this non selection,  then pulled and stripped bottom end but found nothing. When we went through it and found a neutral finder device that was supposed to do this, three ball bearing in arrangement that flung out from centrifuge when the output sprocket shaft rotated.  No road speed and only first or neutral available, nothing wrong at all. Hadn't seen one at that time as Honda didn't use them.

Hopefully you'll get this one back to scratch again without big costs.

Offline Trigger

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Re: 5th gear problem???
« Reply #20 on: May 04, 2022, 08:34:16 AM »
The Bluing is a lack of oil. Are the oil holes lined up on the shaft with the cod hole ?

Online Johnny4428

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Re: 5th gear problem???
« Reply #21 on: May 04, 2022, 08:40:56 AM »
Not sure Trigger I will have a look I never had these apart.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Offline Trigger

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Re: 5th gear problem???
« Reply #22 on: May 04, 2022, 08:45:58 AM »
Not sure Trigger I will have a look I never had these apart.

The early cog did not have holes but later ones did. You need to check that no oil ways are blocked in the gear box.

Online Johnny4428

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Re: 5th gear problem???
« Reply #23 on: May 04, 2022, 08:48:33 AM »
Will do Trigger I will have to strip right down and thoroughly clean after the grinding of the gears, I will check all then.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Online Johnny4428

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Re: 5th gear problem???
« Reply #24 on: May 05, 2022, 02:48:52 PM »
Stripped the main shaft gears this morning, here’s the damage. Don’t know what’s happened with the 4th gear circlip. (this must be man made damage) But I am sooo glad I have stripped the shaft this time. Oil ways were lined and there appeared to be copious amounts of oil about the components.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Online Johnny4428

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Re: 5th gear problem???
« Reply #25 on: May 09, 2022, 01:50:09 PM »

Stripped the countershaft this morning all seems to be fine with all gears orientated correctly and circlips fitted correctly. Incidentally there is very little difference either side of the final gear. The diagram suggests that it is flush on one side, this is not the case of course, probably just to illustrate that there is a difference. I make it about 0.1mm of a difference between the sides.
« Last Edit: May 09, 2022, 04:22:07 PM by Johnny4428 »
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Online MrDavo

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Re: 5th gear problem???
« Reply #26 on: May 09, 2022, 03:30:06 PM »
Quote
Went to look at a Kawasaki Z1000 (from memory) that a friend's friend had difficulty with as it would only select first gear.

Zed forums are full of people, over the years, who can only get first after a rebuild, as you say its a safety feature, to only let you get first or neutral when stationary. Why that makes it safer, I don't know. Some pull the engine apart again, only to get the same result of course. I can't say I'm a fan, I wanted to check my Z1A gearbox worked OK before I put the engine in, not wait until I was on the road again.

When I rebuilt my CB750 K1, I remember being paranoid about whether top gear was in the right way round, and deeply regretting not keeping the cluster together, as I was damned if I could tell which way round it went, although I knew it mattered. I must have guessed right as it worked fine, but I did worry.

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Offline K2-K6

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Re: 5th gear problem???
« Reply #27 on: May 10, 2022, 06:33:00 AM »
Quote
Went to look at a Kawasaki Z1000 (from memory) that a friend's friend had difficulty with as it would only select first gear.

Zed forums are full of people, over the years, who can only get first after a rebuild, as you say its a safety feature, to only let you get first or neutral when stationary. Why that makes it safer, I don't know. Some pull the engine apart again, only to get the same result of course. I can't say I'm a fan, I wanted to check my Z1A gearbox worked OK before I put the engine in, not wait until I was on the road again.

When I rebuilt my CB750 K1, I remember being paranoid about whether top gear was in the right way round, and deeply regretting not keeping the cluster together, as I was damned if I could tell which way round it went, although I knew it mattered. I must have guessed right as it worked fine, but I did worry.

You can usually spin bike gearboxes with the first/mainshaft before putting the clutch on so that you can check the gearbox all works without any reservations before committing to final installation.  Old trick on things like Triumph Dolomite sprint and Rover V8 engine when you could remove the distributor and using ad-hoc quill shaft in electric drill to spin the oil pump and bring oil pressure up prior to running springs to mind.
You may be able to spin the Kawasaki input shaft fast enough by hand to check changing upward, or make a drill adapter to spin that shaft and facilitate it that way.

Offline K2-K6

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Re: 5th gear problem???
« Reply #28 on: May 10, 2022, 06:36:09 AM »
Johnny4428,  was that circlip installed like that with the tang sticking out ?

Online Johnny4428

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Re: 5th gear problem???
« Reply #29 on: May 10, 2022, 05:20:13 PM »
Johnny4428,  was that circlip installed like that with the tang sticking out ?
I’m guessing Nigel that this circlip was a victim when the bike threw the chain and it came through the crankcase. You can see an impact mark on the side of it.
Also centre shifter fork a candidate for replacement.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

 

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