Yamaha RD350LC restoration.

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Tipper2
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Re: Yamaha RD350LC restoration.

#76 Post by Tipper2 » Sun Sep 27, 2020 3:07 am

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That's mine finished, always wanted a "Mars Bar" LC.

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mangocrazy
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Re: Yamaha RD350LC restoration.

#77 Post by mangocrazy » Sat Oct 10, 2020 6:33 pm

That looks lovely, Tipper. I really like the Mars Bar colour scheme as well. Had it been an option when they first came out, I'd probably have gone for that, but in August 1980 it was a case of take what you're allocated.

The white wheels work quite well I think, but they are actually a bit scabby and need a refresh, but that can wait for winter. I'm still not sure whether to return the wheels to standard (like yours) or re-do them in white. The white wheels really do give the bike a 'lift', but they're a bugger to keep clean. Mind you, so are standard wheels. The reason I had the wheels coated white was because road salt had got at the alloy and made a right mess of them. No chance of that happening now...

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Re: Yamaha RD350LC restoration.

#78 Post by mangocrazy » Wed Jan 20, 2021 12:59 pm

It's been quite a while since I posted up any updates. In September, with the bike just having got its MoT, we gallivanted off to the moneypit in France for a much-delayed (by Covid) break, and stayed for a whole 5 weeks. Lovely. This meant that by the time I got back autumn was well advanced in the UK (mid October). However I did manage to get about 300 running in miles racked up and the bike now feels pretty good. It's been running in so far on premix using basic mineral two stroke oil so that rings etc. bed in quickly. When it next turns a wheel it will use the injector pump with fully synth Silkolene Comp2.

Then I can start giving it some beans... :smt003

My last ride was to Buxton and back (from Sheffield) and it brought back memories of when it was my sole transport and it got used in all weathers. Even 10 degrees is a bit on the cold side for me these days, so it got washed down, returned to the shed and had its wheels taken off and all bearings, seals, circlips, discs, brake shoes etc removed. Then the bare wheels were taken first to a local firm to have them dipped and vapour blasted and then taken over to the most excellent C J Ward in Burton on Trent to be powder coated back to as close to original as possible (I'd decided that originality was the way to go). This was just before Christmas.

A few days ago (just before the snow arrived) so did these little beauties. I'm delighted with the way they've turned out.

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Now it's down to fitting tyres, inner tubes (I hate those fuckers), bearings, oil seals etc, then put the wheels back on the bike.

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Viking
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Re: Yamaha RD350LC restoration.

#79 Post by Viking » Sat Feb 06, 2021 8:41 am

Hot damn....
Those wheels look amazing.
It's the V-twin thing. There's just something about it that inline-4s don't have at all, and V-4s don't have enough of.

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Re: Yamaha RD350LC restoration.

#80 Post by mangocrazy » Thu Jun 16, 2022 11:15 pm

I've only just realised that it's been nearly 18 months since I updated this thread. Mea maxima culpa...

The next step after the wheels was to get the exhausts refurbed, and for them I decided to go with ceramic coating. It's pricey but the finish is about as close as you can get to factory original.

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The running in miles had clicked over to the point where I was ready to switch over to the autolube pump and high quality Silkolene Comp2 oil, and so the switch over was made and me and Mrs Mango set out on a celebratory ride into the Derbyshire Peak District. So off we went, cleared the urban sprawl and were just about to start on the twisty bits of the A621 on the way to Bakewell when - guess what?

The bloody thing seized solid halfway round a bend - that's what.

Fortunately some vestige of muscle memory had kept my left hand hovering over the clutch lever, and we managed to avoid a painful, expensive and unpleasant meeting with the tarmac (or a car coming in the opposite direction.) It's hard to put in words just how pissed off I was, after spending most of 2020 restoring and rebuilding the bike, only to have the bike's first outing of 2021 end so unceremoniously.

After another look at the bike I fairly quickly spotted what had caused the seizure. Basically the LH cylinder (why is it always the LH cylinder?) was starved of oil because the oil delivery pipe for that cylinder had come into contact with the hot exhaust and had been cut in two. The photo below shows it more eloquently than I can explain.

All this was because I have always been annoyed by how little slack Yamaha provided on their delivery pipe. It only ever JUST fitted. Now I know why. By providing a lot more slack in the oil pipe I became the unwitting architect of my own downfall.

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As it turned out, the damage to the cylinder was not as bad as I feared and the aluminium smears were cleaned up with a light hone. The piston was toast, of course, so a new pair of Mitaka's finest were needed. And when it was all reassembled I made very sure that there was no slack in the supply pipes. And just to go full belt and braces, I bound all oil delivery and supply oil pipes in spiral wrap. Once bitten...

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The next issue I encountered was one I'd been peripherally aware of for a while. Oil on the shed floor, by the LH side of the centre stand. After consulting various forums, it appears that there are 3 possible causes of Elsie's incontinence:

1. The gear shift rod wears against the oil seal and over time the seal lip gouges a groove in the shaft allowing gearbox oil past.

2. The neutral indicator switch either gets cracked or the inner oil seal decays and falls to pieces allowing gearbox oil past.

3. There are two aluminium bungs that are punched into gear shaft drillings in the crankcase and over time these unseat themselves allowing gearbox oil past.

As it happened, I had all 3 issues to a greater or lesser degree and had to fix all of them. #1 is a well-known issue with LCs of a certain age; in some cases the steel shaft actually wears the alloy crankcases giving rise to iffy gear changes. Mine hasn't gone that far but the solution is the same; hoick out the old oil seal and replace it with a niftily machined alloy part incorporating an o-ring, phosphor bronze insert and new oil seal housing which moves its position outwards by 10-15mm and on to an unmolested part of the shaft (see picture).

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The machined alloy part is an interference fit and is drifted in to the former oil seal housing using a suitable length of steel tube. Once the alloy part is fully home, the oil seal is then drifted into position in the same manner. By far the hardest part of the whole operation was removing the old oil seal. Once that was out, cleaning up the seal housing and fitting the new parts was the work of a couple of minutes. The kit even provides a replacement for the manky 40 year old nylon sleeve that protects the gear change shaft from flappy chains.

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However close examination of the above picture shows an oil droplet poised to descend from the neutral indicator switch housing. So I'd only partially cured the problem. Next step was to unscrew the 3 fasteners holding the switch cover in place and check out the state of the cover and o-ring behind it. The cover was fine and undamaged, but the 40 year old o-ring was brittle and flaky. Thankfully a replacement part was available and inexpensive and a few days later that was fitted. Would that cure Elsie's incontinence?

No it wouldn't. It was still bloody leaking oil...

After further investigation (and consultation with the LC nutters on the RDLC forum) it appears that oil was weeping past the little alloy bungs that blank off the holes for the shift fork spindles. Apparently they work loose over time and start weeping oil. The cure (allegedly) is to give them a little tap (nothing too violent) to re-seat them and allow them to seal again. There are two such bungs, one by the neutral switch plate, and the other just behind the gearbox sprocket.

Just to be sure I ordered a pair of new ones from Fowlers as backup if the weeping continued. If so I'd remove the ones in there and seat the new ones on a bed of silicone sealant. But I gave the tap treatment a go first, as it was cheapest and easiest and I do have a strong lazy streak.

When I came to inspect the gearbox sprocket area I was quite surprised by the amount of oil that seeped out since I last had a butchers. You can clearly see that the forward bung (circled in red) is wet with oil and there is a fair old pool of it in the crankcase web.

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I cleaned up all the oil using paper towels and brake cleaner and then gave the bungs a restrained (but still manly) tap with a drift and hammer. Would this work?

As you've probably guessed - no it didn't. So I headed out into the shed armed with a cordless drill and a selection of drill bits. After a few minutes, this was the scene:

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Being ali the little plug didn't put up too much resistance. It's only 4mm deep and there is an air gap before you hit the end of the selector shaft. I drilled a pilot, then a 5mm hole as 5mm is the tapping clearance for an M6 x 1.0 thread. The plan was to tap an M6 thread then use some kind of slide hammer type arrangement to get the plug out. I was secretly hoping that the action of tapping an M6 thread would cause the plug to loosen its grip and come free; and believe it or not that was exactly what happened. Not just for one but both. That made life a whole lot easier.

I then cleaned up the holes with a mixture of paper towels, brake cleaner, vacuum cleaner and compressed air. But not at the same time. That would have been silly. Then I dug out the tube of Threebond I've been using for years and painted TB1215 over plugs and holes and tapped the plugs into the holes using a drift. One went in dead easy - the other put up a bit of a fight. Guess which is which...

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The new plugs were left for a day or two (or three or four) for the TB to cure, and then the gearbox was re-filled. And having had a look at the grooves on the clutch pushrod where it encounters the oil seal, that also got renewed. And the result?

A totally oil-free shed floor and engine. Top banana.

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Re: Yamaha RD350LC restoration.

#81 Post by mangocrazy » Thu Jun 23, 2022 2:59 pm

A couple of weeks ago I had to go in for a hernia op and I'm still in recovery mode and getting mighty bored endlessly watching Youtube vids and scouring forums, so I've been looking around for something to do that doesn't involve too much (preferably very little) exertion. And I've found something - buying stuff.

The stuff in question is a set of brake caliper adaptors. all the way from Webike in Japan. It all started when I was browsing a thread on the RDLC nutters forum regarding alternative calipers for LCs. I upgraded the brakes on the VFR earlier in the year to 4 pad 4 pot Brembos off the Factory RSV Mille, so that left the old calipers surplus to requirements. These are old (mid-1990s) Goldline Brembo 4 pot jobs, as fitted to early 916s. Not shabby, by any means.

I asked some questions on the forum and one of the peeps gave me a link to a set of adaptors. They looked absolutely bang on - made to fit 1980-82 350LC (well, OK RZ350 in the blurb) with 42.5 mm mounting centres and 4 pot Brembo Goldlines with 40mm mounting centres and single pad pin. Check. These are the calipers:

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Price including 3 day courier shipping was a very reasonable £83.40 so I hit the buy button and a few days later these little puppies turned up:

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Mmmmm, Shiny, shiny...

I can't actually fit the calipers and brackets to the bike yet, as I decided that I wanted stealth rather than gold bling and sent the dismantled calipers off to Powerhouse in Chesterfield for them to clean, refurbish and repaint in satin black (same as OE). The Brembo name and logo will have the paint removed in similar fashion to OE. Just in case you'd forgotten what an LC caliper looks like, here 'tis:

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They're pretty rubbish by today's standards, being a sliding caliper design, and I always leave more room than usual to the vehicle in front, simply because I don't trust them to pull me up quickly in an emergency stop situation. And having taken a look at that photo, I think I've found something else I can do with my enforced leisure - give the LC a good wash.

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Re: Yamaha RD350LC restoration.

#82 Post by mangocrazy » Mon Aug 08, 2022 9:17 pm

So today at 9 a.m. saw me rocking up to Dave Whattam's place in West Yorkshire with my LC in the van. Half an hour or so later it was strapped down onto the dyno and Dave was doing some initial checks. First thing was to check the state (and presence!) of the air filter and make sure it wasn't over-oiled. Then he checked the setting of the oil pump, and was pleased to see it had been recently overhauled by 'Arrow' on the RDLC Crazy forum. Then it was time to have a look at the plugs and after that time to warm the engine up and do some exploratory runs.

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The first dyno runs confirmed what I knew to be true - that there was a black hole in the powerband at 5000 revs that didn't clear until gone 5500 rpm. Even before he'd checked the Air-Fuel ratio, Dave could tell it was running very rich, partly due to me running a very conservative (i.e. big) main jet size. Each run Dave did, the top end improved as it burnt off carbon deposits brought about by running in mileage. So now it was time to pull the carbs off for inspection and jetting changes.

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I couldn't believe how quickly Dave had the carb broken down to its component parts. On both carbs there was loads of crap in the emulsion tube chambers, and also behind the brass balls, The float needles and seats were badly worn on both carbs, allowing the fuel level to be too high and contributing to the over-rich mixture. To fix this, Dave fitted a service repair kit to each carb and also went down two sizes on the main jets (220 down to 200), but left the needles at the mid position and verified that the needles were correct and undamaged (which they were). I couldn't believe the amount of crud Dave removed from the carbs, and likewise just how quickly he could remove, disassemble, refurbish, rebuild and replace the carbs on the bike. It would have taken me all day, even if I had known what to do. It took Dave about 30 minutes .Then it was time for the 'after' dyno run. To say I was pleased with the results was an understatement...

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