Yamaha RD350LC restoration.

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mangocrazy
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Yamaha RD350LC restoration.

#1 Post by mangocrazy » Fri Jan 03, 2020 10:30 am

As I've mentioned elsewhere, I paid my £100 deposit on a 350LC in late 1979 and patiently waited. And waited. Then waited some more. I finally got my hands on it in August 1980 and it was the only bike I owned for the next 9 years (times wuz hard). Being a two-stroke (and being owned by me) it suffered a number of mechanicals along the way, holing a piston in Spain in 1981 being the lowest point. I only found out many years later that there had been a recall to completely replace the carbs on the very first batch in the country, but inexplicably my dealer hadn't told me about it. Probably because he was a robbing sod who ripped everybody off until he finally got caught bang to rights. No names, no law suits...

Anyway, in 1989 a couple of things happened. In June of that year I bought a brand new VFR750-FK (times had improved). Around the same time, and doubtless in a fit of jealousy, the LC spat its dummy. The LH cylinder barrel exhaust flange parted company with the rest of the barrel, as I found out when I stripped it. Being the dutiful, conscientious type that I am, I promptly left the half-stripped engine to fester on the floor of the lockup garage for the next 20-odd years. Yes, I know...

It would probably still be there now if the garage owner hadn't sold the block of garages and told everyone they needed to vacate. As a result the motor (and lots of other tat) got relocated to my cellar (the motor), hallway (the LC rolling chassis) and various other locations in the house. The wife was understandably elated at these developments...

So - long story short, it's time to fix the motor. As you can see, this will not be a trivial matter. What you can't see here are the cylinder barrels (that's a topic for another day). It's the bottom end strip down that starts here. I'll update this as and when, but don't expect meteoric progress. Or in fact, much progress at all. Here are the pictures. First up, RH (clutch) side of motor:
DSC_3788.JPG
DSC_3788.JPG (890.2 KiB) Viewed 661 times
Next up LH (alternator) side of motor.
DSC_3796.JPG
DSC_3796.JPG (1.36 MiB) Viewed 661 times
Close-ups of the general decrepitude:
DSC_3791.JPG
DSC_3791.JPG (1.33 MiB) Viewed 661 times
DSC_3793.JPG
DSC_3793.JPG (1.07 MiB) Viewed 661 times
And lastly, a glimmer of hope. The internals ain't that bad:
DSC_3807.JPG
DSC_3807.JPG (1.15 MiB) Viewed 661 times

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Re: Yamaha RD350LC restoration.

#2 Post by Ben » Fri Jan 03, 2020 1:14 pm

Do we introduce the tumbleweed to this now or 6 months from now? :smt003

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Re: Yamaha RD350LC restoration.

#3 Post by mangocrazy » Fri Jan 03, 2020 1:47 pm

You obviously recognise the timescales I work within, Ben... :smt003

Progress is liable to be erratic, is all I can say...

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Re: Yamaha RD350LC restoration.

#4 Post by RiceBurner » Tue Jan 07, 2020 9:16 am

mangocrazy wrote:
Fri Jan 03, 2020 10:30 am
As I've mentioned elsewhere, I paid my £100 deposit on a 350LC in late 1979 and patiently waited. And waited. Then waited some more. I finally got my hands on it in August 1980 and it was the only bike I owned for the next 9 years (times wuz hard). Being a two-stroke (and being owned by me) it suffered a number of mechanicals along the way, holing a piston in Spain in 1981 being the lowest point. I only found out many years later that there had been a recall to completely replace the carbs on the very first batch in the country, but inexplicably my dealer hadn't told me about it. Probably because he was a robbing sod who ripped everybody off until he finally got caught bang to rights. No names, no law suits...

Anyway, in 1989 a couple of things happened. In June of that year I bought a brand new VFR750-FK (times had improved). Around the same time, and doubtless in a fit of jealousy, the LC spat its dummy. The LH cylinder barrel exhaust flange parted company with the rest of the barrel, as I found out when I stripped it. Being the dutiful, conscientious type that I am, I promptly left the half-stripped engine to fester on the floor of the lockup garage for the next 20-odd years. Yes, I know...

It would probably still be there now if the garage owner hadn't sold the block of garages and told everyone they needed to vacate. As a result the motor (and lots of other tat) got relocated to my cellar (the motor), hallway (the LC rolling chassis) and various other locations in the house. The wife was understandably elated at these developments...

So - long story short, it's time to fix the motor. As you can see, this will not be a trivial matter. What you can't see here are the cylinder barrels (that's a topic for another day). It's the bottom end strip down that starts here. I'll update this as and when, but don't expect meteoric progress. Or in fact, much progress at all. Here are the pictures. First up, RH (clutch) side of motor:

DSC_3788.JPG

Next up LH (alternator) side of motor.

DSC_3796.JPG

Close-ups of the general decrepitude:

DSC_3791.JPG

DSC_3793.JPG

And lastly, a glimmer of hope. The internals ain't that bad:

DSC_3807.JPG
Well... I've seen worse....

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Re: Yamaha RD350LC restoration.

#5 Post by mangocrazy » Sun Jan 12, 2020 7:35 pm

And just to prove that I have been making (slow) progress on the dismantling, here's the LH (alternator/drive) side of the motor, minus alternator stator/rotor, minus gearbox sprocket and minus cylinder studs.

DSC_3852.JPG
DSC_3852.JPG (924 KiB) Viewed 475 times
For every one of those components I needed my trusty electric windy gun to shock the offending item free. Without it (and with the engine out of the frame) I would have stood no chance with the sprocket nut and similarly with the rotor. It's worth its weight in gold in situations like these. This is the tool:

https://www.machinemart.co.uk/p/clarke- ... ct-wrench/

The next phase of the strip-down is waiting on some Vessel cross head impact bits to arrive all the way from Japan. You only get one chance with these cross-head screws (made as they are from cheese) and they're coming out first time...

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Re: Yamaha RD350LC restoration.

#6 Post by mangocrazy » Tue Jan 14, 2020 9:40 pm

Well, the Vessel impact bits arrived today and they worked like a charm. Those cross head screws never stood a chance. Once thet and the parts they retained were off and bagged, it was time for the crankcase bolts. The M8 fastenings on the underside of the crankcase around the crank had been in place for around 35 years and they didn't give up without a fight, but they had to give best. With those and the M6 bolts on the top crankcase undone, it was time for some strategic blows with a rubber mallet and bits of wood. It wasn't long before a unit separated into two halves, as you can see below:

DSC_3857.JPG
DSC_3857.JPG (921.84 KiB) Viewed 443 times
Now the real work starts and the piggy-bank gets raided. This will not be cheap or quick. But it will be messy.

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Re: Yamaha RD350LC restoration.

#7 Post by fatboy » Fri Feb 07, 2020 7:55 pm

Well done Graham, that deserves a tipple or two
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Re: Yamaha RD350LC restoration.

#8 Post by mangocrazy » Mon Feb 10, 2020 10:41 pm

Cheers Paul. I'd be lying if I tried to make out I hadn't awarded myself a well-earned libation or three... :smt003

Anyway, to everyone's surprise (not least of all me) things are actually movng along. The crankcases and crankcase covers went off to Shropshire Powder Coating (they feature quite heavily in episode 29 of Project Binky) for vapour blasting and powder coat and came back almost unrecognisable from their former state. The insides of the crankcase halves:
DSC_3951.JPG
DSC_3951.JPG (1.21 MiB) Viewed 246 times
And the outsides. These were in a disgusting state...
DSC_3958.JPG
DSC_3958.JPG (949 KiB) Viewed 246 times
The side covers (outer) restored to as new condition:
DSC_3965.JPG
DSC_3965.JPG (909.8 KiB) Viewed 246 times
And the inners of the side covers:
DSC_3967.JPG
DSC_3967.JPG (816.63 KiB) Viewed 246 times
At roughly the same time the barrels and crank went off to Gerry Pell for him to get the barrels rebored (now + 0.75mm) and supply new (quality Japanese) pistons. Gerry also worked his way through the crank, replacing the big ends with YPVS items, replacing main bearings and fitting rod kits and balancing the crank (something of a dying art). There's not a great deal that's original about the crank now.

Next step is to tap all threads and blow them out with an air line (vapour blasting residue is not stuff you wish to leave in threads), clean up the powder coating flash where holes were plugged and clean up bits of overspray. I'm also getting the original bolts and studs de-rusted, cleaned and re-plated. I'm toying with having the new pistons coated with some hi-tech wizardry that doesn't actually increase the dimensions of the pistons; the coating sinks into the surface...

And then I can start to think about the rebuild. Oo-er, missus...

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Re: Yamaha RD350LC restoration.

#9 Post by fatboy » Tue Feb 18, 2020 7:21 pm

Almost unbelievable transformation, what a bloody good start !
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Re: Yamaha RD350LC restoration.

#10 Post by Gio » Thu Feb 20, 2020 6:30 pm

That engine looks fantastic hat is off to you Sir, :D
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Re: Yamaha RD350LC restoration.

#11 Post by mangocrazy » Fri Feb 21, 2020 12:06 am

Thanks chaps, I have to stress that I just farmed the work out, I didn't do it myself. But most things are a case of who you know, rather than what you know...

Having said that, I did clear off all the chain-lube related gunge and gave the crankcases and covers a good soaking in Jizer, hot soapy water and Shiny Sauce. I know that blasting companies really don't like massive amounts of grease contaminating their blast media. But the real transformation was due to the vapour blasting and powder coat.

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Re: Yamaha RD350LC restoration.

#12 Post by fatboy » Sat Feb 22, 2020 5:21 pm

Stop being so modest Graham. Media blasting and the type of engineering work are not the sort of thing the average bod does in his shed, working out what needs to be done then getting it done is the major part.
I'm more than sure you deserve to pull the cork on another one!
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