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Post by midlifecrisisrd on Jun 19, 2020 18:35:12 GMT 1
Right now Building an LC motor for a mate, buttoned up the cases today then went to fit the clutch and primary gear The story is that it's built with the best parts out of 2 engine (New crank and bores mind 😉) and I struggled to find the number on the driven gear but degreasing and a close up pic with flash reveals 67B The primary I have is 86 so I have 153 My first thought was it's not the matching primary (other basket was scrap) but on checking the other one was 79 so further out Normally 1 out while not the "ideal" I'd have been ok with on a near 40 year old engine but a few things make me worry Firstly there are 2 marked teeth but nothing looks proud of the marks and secondly what's going on with these rivets? Opinions please Steve      |
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Post by hoist1 on Jun 19, 2020 18:46:51 GMT 1
Someone already had it apart and rerivetted it?
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Post by headcoats on Jun 19, 2020 19:03:14 GMT 1
Been apart for sure
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Post by dusty350 on Jun 19, 2020 19:10:01 GMT 1
+1 on that Hoist. Aftermarket rivets are available for the baskets and I wonder if that's a DIY rivet job ? Certainly never seen originals flattened like that before. No evidence of the red gasket either - you can normally see it if it's there, but on strip down often prove to be torn and split so not always put back on reassembly. As for the teeth - maybe picked some debris up from a failure in the past ? And 153 = good enough I reckon. Both my 400's are about 10 out !! Dusty  |
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Post by marrcel on Jun 19, 2020 19:43:40 GMT 1
+1 on that Hoist. Aftermarket rivets are available for the baskets and I wonder if that's a DIY rivet job ? Certainly never seen originals flattened like that before. No evidence of the red gasket either - you can normally see it if it's there, but on strip down often prove to be torn and split so not always put back on reassembly. As for the teeth - maybe picked some debris up from a failure in the past ? And 153 = good enough I reckon. Both my 400's are about 10 out !! Dusty I have a set 147 in my spares. It is used. From what I understand the number 156 is the ideal combination when it is new. But they wear and eventually the play gets more. So used set of gears of 147 will become 156 eventually? I know whishfull thinking. Can anybody shine a light on this? |
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Post by dusty350 on Jun 19, 2020 20:09:39 GMT 1
It gets talked about regularly Marcel. The ideal is to build with the Yamaha spec of 155+/-1. 40 odd years of wear must make a difference you would think, but mileage and use would have a part to play in how much wear of course. At the moment, it's not too difficult to achieve the correct numbers for an Lc or a Pv, but it will get harder in the future I expect. I know Tobyjugs has done some measuring, but info on the specs is not readily available it seems.
Dusty
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Post by midlifecrisisrd on Jun 19, 2020 20:12:55 GMT 1
Not worried about the 1 out
More the rivets and chipped gears
Think I've found a replacement in the right range
Maybe this is better suited to a "runner" build and not an "all new" build
Steve
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Post by Tobyjugs on Jun 19, 2020 20:26:08 GMT 1
They have been riveted by hand, good enough in my opinion, but last year was talking to and ex Mitsui technician at the Gedinne classic TT and he explained to me the correct way to rivet the basket. Ideally each rivet should be done in one stroke using a hydraulic press.
As for the gear wheel on the basket, it will probably be ok judging from the feed back i see about average milage per year, but if you are going to use it for what it was made for (high milage and ragging) don't take the chance.
And now time for a moan.
Why do people on this forum always go on about the primary gears wearing away like they are made from old cheese??? Nobody ever talks about the rest of the transmission gears.
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Post by dusty350 on Jun 19, 2020 20:35:21 GMT 1
I guess the reason why primaries get talked about is they are numbered, and meant to be within a given range. If the numbers weren't engraved then nobody would even know probably  Dusty |
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Post by midlifecrisisrd on Jun 19, 2020 21:13:16 GMT 1
They have been riveted by hand, good enough in my opinion, but last year was talking to and ex Mitsui technician at the Gedinne classic TT and he explained to me the correct way to rivet the basket. Ideally each rivet should be done in one stroke using a hydraulic press. As for the gear wheel on the basket, it will probably be ok judging from the feed back i see about average milage per year, but if you are going to use it for what it was made for (high milage and ragging) don't take the chance. And now time for a moan. Why do people on this forum always go on about the primary gears wearing away like they are made from old cheese??? Nobody ever talks about the rest of the transmission gears. If I remember tomorrow I'll post up a pic of some strange gears Steve |
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Post by Tobyjugs on Jun 19, 2020 21:16:51 GMT 1
I think your one of the only people that has mentioned transmission mishaps such as worn bushes.
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Post by dusty350 on Jun 19, 2020 21:22:19 GMT 1
I had rusty gear clusters in my 400 build. Does that count ?  |
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Post by stusco on Jun 19, 2020 21:27:32 GMT 1
 Better than mine ,its not a single handed job |
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Post by midlifecrisisrd on Jun 19, 2020 21:52:15 GMT 1
The thing is the engine has been lying for many many years like that
Steve
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Post by mak595 on Jun 22, 2020 15:12:11 GMT 1
jumping on the thread, ive got a basket that needs riveting up, see yambits sell the rivets, so i assume it really needs to go to an engineering spot to get em riveted properly?
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Post by stusco on Jun 22, 2020 16:17:48 GMT 1
You can do it yourself if your handy with hammers but you really need two people, i did mine with a half pound hammer its not a job for a mash hammer
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stevvo
L plate rider.
Posts: 45
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Post by stevvo on Jun 24, 2020 21:59:39 GMT 1
Could do with a 95 if there are any knocking about? Mine is corroded around the face and Im worried that it will knock the seal out quickly.
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Post by midlifecrisisrd on Jun 25, 2020 19:48:50 GMT 1
I think your one of the only people that has mentioned transmission mishaps such as worn bushes. Right here you go This was out an engine I was hoping to use the internals from. Everything seemed ok till I took the gears out and looked at them The stripes on the teeth are one thing but I cat explain the pitting on 2 of the gears 🤔 Steve        |
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Post by Tobyjugs on Jul 1, 2020 11:49:05 GMT 1
Looks like cavitation. I might be caused by all the tiny rust pits which will encourage cavitation.
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Post by marrcel on Jul 1, 2020 11:57:08 GMT 1
Or did someone used a file?
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Post by midlifecrisisrd on Jul 1, 2020 14:34:09 GMT 1
Whatever it was it p1ssed me right off
I paid £100 for the complete engine 😆
Steve
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Post by arrow on Jul 1, 2020 19:50:47 GMT 1
I'm guessing but, it looks to me like those gears have stood for a long time, picked up some corrosion, then been used again with out the knowledge of the corrosion.
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