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Yamaha Chappy LB80 high-low problem.

29 Sep 2020 09:52
ie305mp3
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Yamaha Chappy LB80 high-low problem. #1
Bit of a shot in the dark: I'm thinking about buying a Yamaha Chappy. I had one of the very first back in 1976 - LB80llH, four-speed manual - when I was a kid.

Problem with the one I'm looking at - 1981 with a high-low automatic - is the seller's kid jumped on it and did what was either a low-high or high-low "gearchange" on the move (should be done at a standstill), and the seller now tells me it'll only stay in high if the lever is held in place. Let go, and it jumps into neutral.

Anybody any idea as to just how fixable that is...?

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29 Sep 2020 15:12 29 Sep 2020 15:15 by RT325.
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Yamaha Chappy LB80 high-low problem. #2
We sold & serviced a few of those back in the day & good little scoots they were too. But your problem is unusual But you sure wouldn't want to change on the run or not under power. Low to high is a big movement of the lever & goes through a positive neutral at the halfway point. Can only think maybe something has let go on the rod with the lumpy bit that pushes the balls out to lock into high or low. First port of call is to check behind the left cover incase smacking it through has bent whatever pushes on the rod in that lever. Hope it's that simple!!. Other damn annoying thing they did was wear out one clutch, think it was the second gear clutch so you had to over-rev it in first to get the second gear clutch shoes to touch the drum hard enough to take up the drive. Hope that makes sense. Just looking at the clutches in the link i'm trying to think what i may have done to one but i'm not thinking straight because i'd guess the second spring would need to be weaker to let the shoes rise sooner & doubt i did anything like stretch the spring. Maybe i replaced the clutch, which is what 'should happen' but costs of parts was crazy where we are in NZ. Anyway, nothing to do with your problem right now. Links below are LB50 but same horse & all i could find. what country are you in?. ps, i don't recall a manual LB80 but maybe for other markets. We only had the auto model. The local power company used them for meter reading around town. I recall the brakes getting pretty grabby, front one being dangerous so keep the dust out of there & keep the end of the shoes linings chamfered or rounded so they shouldn't grab. Migh'tve been the re-bonded grey linings we were getting done--too long ago.
Just to add. I'd guess or hope something is bent in Plate 1 in link 1. Or the cover screws are very very loose.


www.babbittsonline.com/oemparts/a/yam/50...shifter-lb50pg-ph-pj
www.babbittsonline.com/oemparts/a/yam/50...mission-lb50pg-ph-pj
www.babbittsonline.com/oemparts/a/yam/50.../clutch-lb50pg-ph-pj

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30 Sep 2020 00:42
ie305mp3
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Yamaha Chappy LB80 high-low problem. #3
I'm in the UK. It looks like most parts are available, until, of course, it comes to the vital part that isn't.

I was a kid when we got our LB80. At the time we had very close ties to Yamaha, and it was given to us. It arrived in 1976, and, so far as I can tell, was a Swiss spec bike. Quite why it was Swiss I don't know, but only very few markets had a 4-speed. Even when I hit road legal age in 1978 the local Yamaha dealer said he'd never seen one.

If I buy it, I suppose the worst that can happen is having to find a replacement motor or bottom end if any vital bits aren't available, but from what I can see there seems to be pretty good availability.

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30 Sep 2020 02:50
ie305mp3
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Yamaha Chappy LB80 high-low problem. #4
Hmmm. Seller says that if he tapes the high-low lever in the high position then it doesn't jump out of gear.

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30 Sep 2020 14:45 30 Sep 2020 14:46 by RT325.
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Yamaha Chappy LB80 high-low problem. #5
Yes does make me think it might be something as simple as damage to whatever holds the arm right forward. Like a detent spring & plunger or a wiggly bent springy flat but that clicks over a pointy thing. No 3 & 4 might be worth looking at although i'd guess low ratio would be affected too if that spring behind the plunger was rusted or stuffed. The rod up the middle has to be moved so it arrives under the 4 balls--has 8 but only 4 shown--must end up central under the balls to expand then & lock the gear to the shaft. But if not moved enough then the balls resist & try to climb down the side of the expander lump & force the rod back out of gear. Very unlikely the damage is internal as that system is pretty bulletproof unless its taken a hunk off the leading edge of that expanding lump. Sorry--too much irrelevant information haha.

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30 Sep 2020 16:23
MarkT
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Yamaha Chappy LB80 high-low problem. #6
From the diagrams it looks like a two-speed version of the old Sachs "ball lock" transmission design Yamaha used in models like the early YG1 four speed trans?

It is a very robust design... hopefully just something with the linkage or maybe even an adjustment? I will see if I have an old manual here someplace.

1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250

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01 Oct 2020 03:29
ie305mp3
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Yamaha Chappy LB80 high-low problem. #7
Brilliant, thank-you gentlemen.

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