My Latest LC Project

[jools58]

Having put the LC250 engine in the Spondon Roller I was left looking at the LC Rolling Chassis thinking it was a waste just sat there.
I was originally going to restore it to a road special 250LC, but seeing how much the missing parts was going to be got me thinking (Always Dangerous)
I'd just sold the TZ350 so I was thinking another 350 from the spare 250 motor might be in order, for the 350 Forgotten era Class.
Looking through my parts I must have lent someone my 350LC race top end (I wouldn't have flogged it)
Advancing years means I'm buggered if I remember who (i have a faint idea so will have to tap him up) BUT on the shelf sat a useable TZ700 cylinder and TZ350G head. Offering up a spare set of TZ350 pistons I could see these would go in with some work on the inlet side. So I set to with resurrecting the rolling chassis.
The forks received some Racetech 0.75kg springs and 15W oil. The paln is to fit a pair of 18" Astralite wheels - 2.15 front and 2.75 rear rim width.
These will be shod with Avon AM26 front and a Dunlop KR145A rear.

[JonW]

heehee, we just cant leave em alone cane we...

[jools58]

Its an illness I reckon, with no cure - a bit like leprosy - only the inflicted will have anything to do with us !

[jools58]

Just had a brain wave on the wheel front -
My TZR 250F3 bike has wider 17" wheels and slicks which I will have to change for next season as the proddy class is being tightened up.

If I stick a TZ750 cylinder on the bike, it will be 375cc and I can run it in the 500 class which then allows me to use 17" wheels. The wheels from the TZR will do nicely !! and I have a set of wets on rims to go with them.

[jools58]

No, it doesn't allow me to use 17" wheels - only the 750 & unlimited classes - DOH!

Since my last visit i had a few bits for the engine arrive to play with

First up was a pair of straight cut primaries off a mate sale or return, depending how i found them. In reality it willbe a while beofre I get around to that.........

The second was the trial assembly of the 700 top end. The cylinder fits pefectly onto the casing which just needs a bit of fettling to match up the transfer passages. dropping in the crankshaft, I slapped on a pair of TZ350G pistons to see how it went together. Perfect fit on the cylinder but I needed to mark the back faces to cut them away.
I didn't have any 750D pistons as a pattern so I used a modified RD350 pistons to transcribe the cut away height, then Dremelled the backs off and radiused the edges away to suit.

Going well so far, I dug out the TZ350G head and here is where it all went base over apex as the dowel sizes on the cylinder are 8mm while the head is about 13mm. No probs I just turned up some stepped adaptors. That is when the penny should have dropped as no matter how i tried the cylinder head was offset front or back to the block by about 2.5mm, so they are obviously not compatible, which is probably why the dowel sizes are different!

A quick phone call found me a 700 head plus the reed valves and intakes I also needed.

Now, just remodelling the garage/workshop to move the partition wall by one stud space to increase the machine shop side. Not too hard other than moving crap around all the time to work around it !

[jools58]

After a bit of a workshop revamp I got around to assembling the TZ700 top end on the LC Special.



It has TZ350G pistons with the backs cut away as per the TZ750D style. The TZ350G head didn't fit so I managed to find a 700 head and some reeds and intakes at the same time. The Lectron Carbs fit nicely but are yet to be set up.

Next on the list is a set of Swarbrick kit pipes.

[BRG1200]

What overall look are you aiming for?

[jools58]

I don't really go for looks as such - it will end up what it finishes as

It will have a used Patina finish, keeping the stock LC tank with a race seat, if I can find one I'm comfortable with. That's always been a problem for a tall inarticulate bugger like me, as the joints ain't as bike friendly as they used to be.

I remember going bike to the std seat and it felt like I was sitting on a fence !! Comfy though

Ordered the pipes fro Swarbricks last night, He has a design that will work well with the early 700 cylinders.

[jools58]

Finally found a bit of time to do a bit more to this project in between jobs.

Having seen what Pludmugger did with his LC special on the RDLCCRAZY forum I tried a few seats that I had knocking around for inspiration.

I liked his use of the TZ250 4TW seat has its swoopy lines work well with the std LC tank.







What do ya reckon ?

[jools58]

Back in manufacturing mode..........................

The rear wheel needed to be centred and an assortment of spacers for using the R6 rear calliper mount.

First off the wheel was fitted with new bearings, one in the brake side hub and two in the drive side hub.
The wheel was offered up with a pair of basic spacers which are captive in the wheel bearings - makes handling the wheel removal process a lot simpler.

Before I could do this I had to fit the rear disc, which was a cheap TZR style one from China. Being a 3 hole mount it required an adaptor plate spinning up.
Using some 12mm flat alloy plate I roughed out a blank, drilled and tapped an M8 hole near the centre, fitted an M8 bolt and nut and using this as the mount in the chuck of the lathe, slowly turned the dodecahedron into a 115mm round blank.
Swapping the chuck jaws to grip the blank on the outer edges, an increasing larger hole was drilled and bored out to fit the hub centre of 64mm. The new disc needed a 100mm flange and would be held to the adaptor by three csk M10 screws. The mounting holes of the disk itself had to be countersunk to allow clearance to the calliper mount. The adaptor was held to the hub with three 10mm holes on 80mm crs. A 6mm step in the adaptor allowed the disc to sit nicely on the 100mm flange.

The calliper mount could then be offered up to measure how wide the inner spacer needed to be to centralise the disc.

With the wheel in and measured, the sprocket side spacer needed to lose 5mm, which had to be added on the brake side spacer. I made the brake side spacers in two parts. The inner part mentioned above sits captive between the bearing and the calliper bracket. 25mm dia for the captive bearing part, 32mm dia for the bearing race face and then turned down to 28mm to fit inside the R6 calliper, but only by 9mm. The outer spacer was a top hat with outer dimension of 38mm by 1.5mm wide and a 28mm dia step that fit into the other side of the calliper bracket. This all bolted up nice and snug.

[jools58]

Second attempt at this post............

Continuing in manufacturing mode while the momentum was up.

I had originally planned to fit the complete R6 rear set assembly , which ahs the lever, peg and master cylinder mounts on the same frame mtgt bracket.

This would have meant a fiddly bracket to adapt to the awkward frame mounts on the LC and the first attempt was time consuming and unsatisfactory.

The original LC rear sets I used had a convoluted lever spring operated by a rose jointed adjuster with a snail cam lever locator and a part for the original drum brake rod.

The lever extension was the same width as the master cylinder clevis so all I needed was a longer bolt to replace the clevis pin. This would allow the spring rod to be mounted inboard of the master cylinder clevis.

The top frame mount of the rearset has a 6mm spacer and this would be replaced by a master cylinder mounting plate of the same width.

The single bolt mount for the plate will be supplemented by a 6mm screw on the inside that will prevent rotation of the plate.
Here the finished bracket has been lightened.


Next up are the Brembo adaptor brackets for the front end.