Author Topic: 500 ride again project  (Read 4091 times)

Offline Safo

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500 ride again project
« on: December 28, 2018, 06:14:26 PM »
Hi everyone
Some of will have seen my intro in newbie section.
The motor is now fully striped and I'm looking at the 3rd gear issue, which I now to be a problem the thing is there is signs of wear but not execesive, the forks look straight
Does anyone know how long the 3rd gear dogs should be should be
Thanks

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: 500 ride again project
« Reply #1 on: December 28, 2018, 07:32:14 PM »
We have a customers CB500/4 engine in for overhaul at present. If you can wait until tomorrow either I will measure it or get Trig to and let you know but it's usually the width of the dog end which is measured and the service limit is in the service manual.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

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Offline Bryanj

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Re: 500 ride again project
« Reply #2 on: December 28, 2018, 08:01:00 PM »
If you assemble everything into the top case with selectors engaged you should be able to turn the shafts(both need to turn) and select all the gears to visually check of engagement.

Offline Safo

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Re: 500 ride again project
« Reply #3 on: December 28, 2018, 08:30:12 PM »
Yes I Already tried this, looks OK, also tried to Separate the gears by taking up all slack in selector mech but they still seemed to have purchess, just found 0.9mm end float in selector drum, selector fork measures 4.9 Grove in gear is 5.15 I think is OK what do you think? Tried to post pics but to big

Offline Bryanj

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Re: 500 ride again project
« Reply #4 on: December 28, 2018, 09:54:16 PM »
Sorry no can diagnose without pics i am afraid.

Offline matthewmosse

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Re: 500 ride again project
« Reply #5 on: December 28, 2018, 11:15:33 PM »
If theres wear in the actual dogs on the gears they can jump out of engagement under load I think. Selector forks seem to be a common culprit for wear.
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline Bryanj

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Re: 500 ride again project
« Reply #6 on: December 29, 2018, 12:23:26 AM »
Lets start from scratch.

(1) What was the 3rd gear issue in the first place

(2) You dont move 3rd to engage 3rd

(3) It really is impossible to diagnose by mystical guesswork

Online Laverda Dave

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Re: 500 ride again project
« Reply #7 on: December 29, 2018, 07:26:02 AM »
Safo, it sounds as though you are trying to post full size photos (as in Meg size) and not jpeg which are smaller and don't exceed the size limit you can post.
When I take a photo with my phone I send it to myself via a message. When I recieve the message I save the photo to my phone as this is automatically reduced in size to a jpeg. You can then attach this saved photo to any forum reply using the attachments and other options located below the message box.
Hope this helps.
Dave
1976 Honda 400/4
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
1982 Laverda 120 Jota

Offline Safo

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Re: 500 ride again project
« Reply #8 on: December 29, 2018, 12:51:57 PM »
Thanks everyone will try again

Offline Safo

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Re: 500 ride again project
« Reply #9 on: December 29, 2018, 02:28:45 PM »
OK, if this has worked there should be 2 pics

Online Laverda Dave

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Re: 500 ride again project
« Reply #10 on: December 29, 2018, 02:33:45 PM »
Yep that's worked👍
1976 Honda 400/4
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
1982 Laverda 120 Jota

Offline Safo

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Re: 500 ride again project
« Reply #11 on: December 29, 2018, 02:55:22 PM »
And yes it has, top one is 2nd gear selected by turning drum by hand below is 3rd selected, it seems to be fully engaged but when the bike was last running it used to try jumping out of 3rd but never actually did so it was a case of short shift to 4th but it spoilt the ride, as I said before there is signs wear and evidence of the gears trying to separate but I still don't think it's excessive, should I turn my attention to the claw that pulls the drum around, is this a part that wears?
Thanks in advance

Online Laverda Dave

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Re: 500 ride again project
« Reply #12 on: December 29, 2018, 11:19:21 PM »
It may be the light of the flash but the countershaft pinion (second photo) appears to be worn to me? I've never had a CB500/550 and maybe this is normal? I'm sure someone with better knowledge of these bikes can confirm and offer some insight though.
1976 Honda 400/4
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
1982 Laverda 120 Jota

Offline Bryanj

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Re: 500 ride again project
« Reply #13 on: December 29, 2018, 11:43:13 PM »
The selector has overheated and probably worn to excess or is bent. If it is the centre one you are going to have trouble getting a new one, last one i saw advertised on ebay was over £100 delivered. I think it is the same as the 350 twin but will have to check numbers again and if so there are lots about used in the US and for some reason they dont wear as much in the 350.

Offline Trigger

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Re: 500 ride again project
« Reply #14 on: December 30, 2018, 09:13:03 AM »
I am not understanding "it tried to jump out of 3rd" ? Was it going in to a false neutral between 3rd to 4th ? 

 

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