Yamaha RD350LC restoration.

The place to discuss classic motorbikes. Post your latest project or interesting finds.

Moderators: Aladinsaneuk, MartDude, D-Rider, Moderators

Message
Author
User avatar
DavShill
SuperBike Racer
SuperBike Racer
Posts: 1744
Joined: Tue Jan 16, 2007 7:51 pm
Location: Beverley, East Yorkshire

Re: Yamaha RD350LC restoration.

#46 Post by DavShill » Tue Jun 09, 2020 7:08 am

Great work Graham. I wish I had your skill and knowledge.....and a Yam RD350lc !!!

fatboy
World Champion
Posts: 3744
Joined: Thu Nov 03, 2011 7:48 pm
Location: BATH

Re: Yamaha RD350LC restoration.

#47 Post by fatboy » Tue Jun 09, 2020 4:15 pm

If I was in your shoes Graham I would be feeling ' a fair bit chuffed! '
And really nice to see Ginger Dave passing his skills onto his daughter, there is a small shop in Bristol called Piston Broke, he deals with a lot of obsolete stuff, knows what modern piston fits old barrels, knows if valve cut aways need enlarging on piston and/or head, same with valves and guides, he even machines up pistons from blanks.
He should have retired years ago but can't find anyone willing to learn the 'trade'
Cleverly disguised as an adult !

fatboy
World Champion
Posts: 3744
Joined: Thu Nov 03, 2011 7:48 pm
Location: BATH

Re: Yamaha RD350LC restoration.

#48 Post by fatboy » Tue Jun 09, 2020 4:55 pm

Before I forget and chuck the invoice away,
Villiers Services 01384 265797 , they sell a fair old range of tank internal treatments, they deal with old Brit bikes so corrosion ect., is nothing new or scary for them.
Cleverly disguised as an adult !

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#49 Post by mangocrazy » Tue Jun 09, 2020 6:47 pm

DavShill wrote:
Tue Jun 09, 2020 7:08 am
Great work Graham. I wish I had your skill and knowledge.....and a Yam RD350lc !!!
It's more a case of who I know, to be honest. Having ace welders and good machinists just round the corner is a major advantage. I don't need to travel much more than a couple of miles to call upon all the trades I need to get this stuff done. The only exception was the vapour blasting of the crankcases. That guy is in Shropshire.

I think the Yam's survival is partly down to me almost forgetting about it... :smt003

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#50 Post by mangocrazy » Tue Jun 09, 2020 6:49 pm

fatboy wrote:
Tue Jun 09, 2020 4:15 pm
If I was in your shoes Graham I would be feeling ' a fair bit chuffed! '
And really nice to see Ginger Dave passing his skills onto his daughter, there is a small shop in Bristol called Piston Broke, he deals with a lot of obsolete stuff, knows what modern piston fits old barrels, knows if valve cut aways need enlarging on piston and/or head, same with valves and guides, he even machines up pistons from blanks.
He should have retired years ago but can't find anyone willing to learn the 'trade'
Those people are a (literally) dying breed. When they go I can't see anyone replacing them. It's much the same with all the old-school two-stroke tuners.

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#51 Post by mangocrazy » Tue Jun 09, 2020 6:50 pm

fatboy wrote:
Tue Jun 09, 2020 4:55 pm
Before I forget and chuck the invoice away,
Villiers Services 01384 265797 , they sell a fair old range of tank internal treatments, they deal with old Brit bikes so corrosion ect., is nothing new or scary for them.
Nice one, Paul! I'll give them a ring and pick their brains. I've heard of quite a few brands of tank sealants. Which one did you go for?

Ben
Clubman Racer
Clubman Racer
Posts: 238
Joined: Thu Sep 12, 2019 9:35 pm
Main bike: Kawasaki ZX-10R

Re: Yamaha RD350LC restoration.

#52 Post by Ben » Wed Jun 10, 2020 7:36 am

Bravo! What a top job.

fatboy
World Champion
Posts: 3744
Joined: Thu Nov 03, 2011 7:48 pm
Location: BATH

Re: Yamaha RD350LC restoration.

#53 Post by fatboy » Wed Jun 10, 2020 2:53 pm

Graham, I went for Tapox supplied by that company, I was influenced by specifications and price and it's made in Germany.
Give those guys a ring and they can best advise you in regard to the condition of the tank and which product suits your needs,
Then see if you can find it cheaper!
I couldn't
Cleverly disguised as an adult !

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#54 Post by mangocrazy » Wed Jun 10, 2020 9:58 pm

Will do, Paul. I'm going back to Stafford tomorrow (where the bike is) and will be giving the tank a good inspection, as well as seeing what state the fuel tap is in (solid, I'd guess). Once I know what I'm dealing with I'll give them a ring. :smt023

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#55 Post by mangocrazy » Wed Jun 10, 2020 11:13 pm

For a few days the focus has shifted from the motor to the suspension, and particularly the forks. I'm waiting for some dry weather so I can convert the shed into a spray booth without re-spraying the Falco and the Duke a fetching shade of satin black...

A few weeks back I had a very illuminating back and forth conversation with Jon Slenzak of S1 Suspension in Brackley and he supplied me with a set of replacement YSS fork springs (the OE LC ones are very soft and 40 years of use haven't helped) and a set of YSS cartridge emulators for the forks. The LC forks are actually pretty terrible, to be honest - it's just that a) we didn't really notice back in the day and b) the rest of the bike was just as wibbly-wobbly so it was all much of a muchness. But viewed from a 21st century standpoint you can only ask WTF where the designers thinking?

The LC forks have incredibly tiny 32mm stanchions. That wouldn't even pass muster on a mountain bike these days. The fork spindle is only 10mm diameter. The forks do not have replaceable bushes. The only bushing is part of the fork leg. If the bushing wears , you replace the fork leg! Thankfully the bushings are OK on mine and there is no obvious wear on the stanchions or sliders. The forks are also crude in operation - they're damper rod forks and as such are always going to be a major compromise. In normal use and under braking they're very soft and dive like a Premiership footballer. Hit a sharp square-edged bump and they lock up. It's just how damper rod forks are.

The cartridge emulators attempt to try and fix some of the worst failings of damper rod forks. Damper rod forks rely on a couple of holes drilled in the damper rod for their compression damping. The YSS valves provide a system that works in the same fashion as cartridge forks. The little silver thingy with a bolt and spring sticking out in the pics below now takes over compression damping duties. I drilled two more holes of the same size as the existing holes in the damper rods, thereby doubling the effective area for oil passage. The cross sectional area of all the drilled holes exceeds that of the damper rod's internal area and so they no longer offer any meaningful damping - that's now all taken care of by the YSS valves/emulators.

Here are some pics to illustrate:

DSC_4222.JPG
DSC_4222.JPG (936.53 KiB) Viewed 510 times

The little silver thing on the right is the YSS valve. The end with the spring and bolt sits inside the fork spring and the stepped end sits inside the flared end of the damper rod. The bottom of the damper rod is shown in this photo, along with the original drillings - two holes, spaced apart at 180 degrees. The degree of damping is controlled by how much the bolt is screwed in, which in turn changes the spring resistance to the oil trying to get through the valve.

DSC_4224.JPG
DSC_4224.JPG (854.83 KiB) Viewed 510 times

This shows the business end of the valve; the side of the valve that faces oil being forced through the valve on the compression stroke. This pic also show the secondary holes that I drilled in the damper rod, around 15-20mm further up the rod and offset to the original ones by 90 degrees. The aluminium sleeve sits between the bottom of the stanchion and the fork outer. This next photo shows the components as they would be mounted inside the fork stanchion.

DSC_4217.JPG
DSC_4217.JPG (1.15 MiB) Viewed 510 times

The bottom of the fork spring sits on top of the valve/emulator with all those components held in place inside the stanchion. The springs from YSS are intended to be direct drop-in replacements for OE Yamaha, so as I was adding at least 20mm extra preload in the shape of the valves, I had to shorten the springs by that amount to bring them back in spec. Thankfully I have a horizontal bandsaw and didn't need to resort to the angle grinder...

DSC_4205.JPG
DSC_4205.JPG (782.71 KiB) Viewed 510 times

It may all sound rather complicated, but damper rod forks are really very simple to dismantle compared to cartridge forks (especially upside down cartridge forks). All the internal gubbins (springs excepted) can fit inside a medium size freezer ziplock bag...

DSC_4228.JPG
DSC_4228.JPG (1.02 MiB) Viewed 510 times

Tomorrow (all being well) the forks can get reunited with the rest of the bike and the rolling chassis will be mobile again, instead of being propped up on beer crates..

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#56 Post by mangocrazy » Sat Jun 20, 2020 11:34 am

Today has been a 350LC petrol tank kind of day ...

As part of preparing the soon to be 40 year old LC for the rigours of modern life, I decided that it would need to have the (steel) petrol tank internally coated with an ethanol resistant film, and I knew the petrol tap would also need attention. It was the orange-brown treacle that dripped from the fuel hoses that alerted me...

So the tank came back to Sheffield with me, was divested of its fuel tap and filler cap and was taken to RTT Moto in Hoyland (south of Barnsley, north of Sheffield/Rotherham). This place is what motorcycle shops looked like when I were a lad. They don't sell bikes, they just sell bike bits and provide services (like tank sealing). It really was like stepping back 40 or 50 years in time. The tank will get all the old gummy petrol residue removed, be treated for any rust that's present and then sealed internally. Should take about a week.

I did seriously think about sending the tank off to the guys Paul (fatboy) mentioned, but agonised about sending the tank by courier or post, and the possibility for damage or loss involved. Then when speaking to a guy I know who lives in Sheffield and has rebuilt literally hundreds of LCs, he recommended RTT Moto. As soon as I stepped in the shop I knew it was the right choice. No flash, no high pressure sales, just someone who knew his stuff and could do what he said he would. He's only been doing it for 40 years...

When I got home I set about the fuel tap. This was set permanently in the on position. There was no way on earth that you could turn it to any other position. So it clearly needed some high frequency vibration while immersed in fluid to make it straighten up and fly right. I dumped it in the ultrasonic tank for about an hour and then had another look.

When I came back to it I could now unscrew the plastic bowl and the fuel lever would now move. After some persuasion the tap lever parted company with the body, revealing a world of gummy nastiness underneath. The tap then got doused with brake cleaner and had its teeth brushed vigorously until eventually, with a bit of persuasion from the airline, the nylon valve and spring popped out. More scrubbing with brake cleaner and toothbrush and then everything went back in the ultrasonic tank. After another 30 minutes or so, this is what all the parts looked like...

DSC_4295.JPG
DSC_4295.JPG (694.37 KiB) Viewed 410 times

And shortly after, with new o-rings from the repair kit fitted, it was all back together in one piece.

Sorted.

DSC_4298.JPG
DSC_4298.JPG (638.56 KiB) Viewed 410 times

fatboy
World Champion
Posts: 3744
Joined: Thu Nov 03, 2011 7:48 pm
Location: BATH

Re: Yamaha RD350LC restoration.

#57 Post by fatboy » Sat Jun 20, 2020 5:02 pm

Graham, I also would have had grave reservations about trusting a fuel tank that rare to a courier service.
You do seem to have landed on your feet in terms getting in with ' the old Giffer Network '
Good work that man !
Cleverly disguised as an adult !

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#58 Post by mangocrazy » Sat Jun 20, 2020 8:42 pm

Haha, yes. It''s almost a case of 'six degrees of separation'. Earlier this year I decided that I would sell a brand new, in the box, LC wheel. I advertised it on FB marketplace and within 10 minutes a guy was wanting to buy it.

I'd clearly underpriced it (£200).

The guy was as good as his word, came round later in the day and handed over 200 notes, after which we got talking. He lived about 7 or 8 miles away from me and was/is a complete 250/350LC nutjob (in the nicest possible way). A few weeks later I went round to his house, and he showed me not one, not two, but three absolutely as new, factory fresh, (but restored) 350 LCs.

In his living room. He has a very understanding wife... The only one he's missing is the 'Mars Bar' colour variation (and he's working on that). He has the white/blue/blue one (like mine). He has the white/red/red version (released at the same time). And he has the blue/silver version (released a year or so later). And his garage always has anywhere between 3 or 5 LCs that he's working on for various people.

He's already pointed me towards Tony Dawson when I was having problems with the crankshaft. He has a source for the olive-green passivate finish that Yamaha employed widely on these bikes. And he's fairly sure he can sort me out with the LC engine plates and mounting bolts that have somehow gone missing between 1989 and now. And, of course, he's pointed me in the direction of RTT Moto for the tank sealing.

So the moral is that if you sell something for less than its real value, you may come to realise that it's one of the best bits of business you've ever done...

User avatar
mangocrazy
Admin
Admin
Posts: 3713
Joined: Thu Jul 17, 2008 3:24 pm
Location: Sheffield, UK

Re: Yamaha RD350LC restoration.

#59 Post by mangocrazy » Sun Jul 12, 2020 4:35 pm

Not too much has happened on the resto front recently. The tank came back from having all the old gummy petrol removed, rust treated and neutralised and being internally coated with epoxy. It looks great but externally exactly the same as before. Which is as it should be, of course.

The dire state of the postal service delayed the return of my oil pump by a couple of weeks, but earlier this week it finally arrived back from Gary Jones, worker of miracles and king of the oil pump refurbishers. It didn't just look new, it looked better than new. I'd already ordered up new supply and delivery oil pipes (I mean, would you re-use 40 year old oil pipes?) and it was time to fit them. This photo shows the pump reclining on a passing cork, with all its pipes fitted and clamped up.

DSC_4412.JPG
DSC_4412.JPG (991.36 KiB) Viewed 53 times

Then it was time to re-fit the pump to the motor and also to re-fit the water pump cover plate, complete with shiny new plating and the drain hole that Yamaha should have fitted all those years ago.

DSC_4430.JPG
DSC_4430.JPG (1.08 MiB) Viewed 53 times

After that it all got buttoned up and the oil pipes were routed behind the guides that Yamaha so thoughtfully provided. Not a massive amount of work, but very satisfing to tick another task off the list.

DSC_4436.JPG
DSC_4436.JPG (807.19 KiB) Viewed 53 times

The other big problem I've been made aware of relates to the pistons. I've used a company called Camcoat in the past for various surface treatment processes, and they 'Diamondyzed' a new set of Lancia Beta pistons that I'm using in my Beta engine rebuild. Benefits of this process are (allegedly) resistance to detonation, less pick up on cylinder walls, reduction of rings sticking in the grooves etc. etc.

So I sent my (+0.75mm) Mitaka pistons off to Camcoat for them to apply this process. They maintain that there is almost negligible increase in piston dimensions (measured in microns if anything) so piston to cylinder clearance is not a problem. When I fitted the pistons to the barrels I found this to be the case. So far, so good.

The problems surfaced when I fitted the rings to the pistons. The rings fitted snugly in the grooves, but were able to rotate past the ring pegs. Not good. On closer inspection, the ring pegs were pretty much non-existent, and certainly did nothing to stop the rings moving in the grooves. Very definitely not good.

I rang up Camcoat and they confirmed that as part of the anodising/Diamondyzing process, the pistons are immersed in Sulphuric acid, which of course will eat the steel of the ring pegs away. In some cases there seemed to be virtually nothing of the peg left, in others a little more was visible, but in all cases any part of the peg that protruded into the ring groove was gone. They reckoned that as part of the process they should have applied some 'stopper' that prevents this from happening, but it appears that this wasn't done in my case.

So after asking around, I've located a firm in Norwich (BDK Engineering) who reckon they can remove the remains of the old pegs and fit new ones. I sent the pistons off to them late last week and will be ringing them up on Monday morning hoping for good news.

It's always a case of one step forwards, two steps back...

fatboy
World Champion
Posts: 3744
Joined: Thu Nov 03, 2011 7:48 pm
Location: BATH

Re: Yamaha RD350LC restoration.

#60 Post by fatboy » Wed Jul 15, 2020 6:22 pm

Shit, the unexpected consequences of trying to do the best job you can on a rebuild.
Who would have thunk that ?
Well done mate, you are certainly fighting the fight
Cleverly disguised as an adult !

Post Reply