Basket Cases

[Bully fanatic]

I always get my Barnett plates from Barnett itself. These are made in the US and they have a website. They don`t make driven plates though. They do make clutch springs which are very stiff so if you are using your Sherpa T as a drag bike would be very good! If you took a good driven clutch plate into a lazer cutting place they could just make some for you David! Only using 4 of the Barnett plates also means that after 4 Barnett clutch plate kits you then get a free set of driven plates which works very well for us tightarse Trials Riders!

[David Lahey]

I always get my Barnett plates from Barnett itself. These are made in the US and they have a website. They don`t make driven plates though. They do make clutch springs which are very stiff so if you are using your Sherpa T as a drag bike would be very good! If you took a good driven clutch plate into a lazer cutting place they could just make some for you David! Only using 4 of the Barnett plates also means that after 4 Barnett clutch plate kits you then get a free set of driven plates which works very well for us tightarse Trials Riders! :Bultaco: :Bultaco: :Bultaco:

Thanks Graham. I hadn't thought of getting driven plates custom made.
Pretty sure I also bought my Barnett plates from Barnett but it was too many years ago to be sure. I also bought a set of Barnett friction plates for my SP370 and later found out they are the same friction plates as go in the RL250 motor!

[David Lahey]

In the early 1970s, my Dad spied a very weathered 1937 Norton 16H in the bush near the road to Adder Rock beach near Point Lookout. Being a Norton person, next trip to Stradbroke Island he took a trailer and brought it home. This is what it looked like in a back yard at Point Lookout.
Yes it was returned to a running condition by my Dad. Amazing

[David Lahey]

There's this place in Brisbane who could cut some clutch driven plates for me using abrasive water jet. Sounds pretty cool
http://www.kilner.com.au/index.php/serv ... uQQAvD_BwE

[Bully fanatic]

They sound as if they would be worth a phone call David. I don`t need any at the moment. The ones in my Sherpas are all fine. Happy New Year!

[David Lahey]

I'm awaiting a part for the 360cc TY250 I'm rebuilding before I can progress it so today I made a start on the reassembly of my KT250 motor.
I pulled it apart about a year ago to get a rebore done and decided to replace the conrod at the same time. It still had the original 45 years old conrod and I didn't want to have to pull the motor apart again any time soon hence the new conrod kit.
George McKenzie sourced and fitted the conrod kit to the crankshaft. It's a high quality aftermarket conrod kit made for a KX and as such is a few mm longer than the original KT rod so a cylinder spacer is needed to get the piston at the right height. I bought a spacer kit from Robert Cochrane in NZ for this.
The cylinder studs end up a bit short with the spacer there and I'm in the process of deciding how to deal with that.
Anyway today I test-fitted the crank in one side of the crankcase to check that the new conrod will clear the crankcase mouth. There are important differences to the geometry of the clearance for the rod: The new rod has a bigger cross-section near the bottom, the spacer and the longer rod changes the angle of the rod at that point of closest approach to the crankcase.
George lightened the new rod to get it close to the mass of the old rod, to help with crank balance. Where he removed metal is where you can see shiny areas on the rod.
The Wiseco piston going in is one made for the CR/MT 250 Elsinore and they do sterling service in the KT250 motor. The piston that came out was also a Wiseco CR/MT250 piston that I fitted about 20 years ago when the bike had its first rebore.
To make it easy to do the test-fitting today, I loosened the fits for the old LH main bearing that I had taken out for the rebuild. For the OD of the outer race, I ground it down slightly using a bench grinder, holding it by the inner race. For the ID of the inner race, I gripped the outer race in a soft jaws vice, ground it with a small mounted stone in a high speed hand drill and applied some drag to the inner race.

[JC1]

Dave, please tell us more about the 360 TY

[David Lahey]

Dave, please tell us more about the 360 TY

It's Peter Paice's comp bike from 1977. It is a TY250D which was used for solo and sidecar trials in 1977. He had it modified to 360cc at a Yamaha shop in Newcastle in 1977 where a well renowned engine person worked, using info from Mick Andrews which had been gleaned from their trials bike development work. After Peter went to Montesa sponsorship in 1977 or 1978, he had to give this bike back to Yamaha. Yamaha loaned it to Steven Gall as a cross-trainer and it was later sold off to a private owner. In around 1985, Peter came across it somehow and bought it back. It had been well hammered. Peter had the motor overhauled in the 1980s and rode it as a solo and also with sidecar at his and friend's places until it started making a funny engine noise sometime around 2010/2013?
Peter wanted a bike to ride and look at but it was in a fairly poor visual and mechanical condition. He had intentions of restoring it but didn't. A couple of years ago he asked me if I wanted to do it and he brought it up to Conondale Twinshock Masters for me to collect and bring here to restore. I've almost finished it.
I know you'll want the technical stuff John. It would have been less work than my hot rod TY175 to build because there are no mods needed to the RT3 cylinder and head they used. The crankcase mouth was enlarged to fit the RT3 sleeve base. The transfer ports in the cases were enlarged to match the RT3 cylinder. The TY250 rear cylinder stud locations were moved about 8 mm closer together and long studs fitted a la standard RT3. RT3 has long steel head nuts like a TY175 that hold the cylinder on as well as the head.
The crankshaft is DT400B/C and rod is DT400B/C/RT3. No mods needed for the crankshaft. DT400 crank used so that the TY250D drive pinion will fit. RT3 crank has spline drive like TY250A. Later TY250 is key drive like DT400 BC. The balance holes in the DT400 crank wheels are different to the TY250 crankshaft and it has a slot in the RH end for the oil pump drive but all the important dimensions are the same. A huge weight band replaces the original weight band on the magneto cup. It is actually the flywheel from Peter's fuel-injected 1975? TY250. The exhaust connection is in a slightly different spot to the TY250 cylinder so the pipe had to be tweaked a bit. Peter couldn't put this motor in his "best-ever TY250" with the raised motor frame because the cylinder is to tall for the raised-motor frame.
I've posted photos of the insides of the motor somewhere, possibly here on Trials Australia. The cylinder is still off it so if you are coming up soon you could have a look inside.

[JC1]

Thanks Dave, that's quite fascinating. I knew Andrews tried a 360 engine but didn't know Peter Paice had too, still less that you had his old bike. I often wondered why anyone would want such a large capacity trials bike tho I know Martin Lampkin had a 370 Sherpa and loved it.

I had a DT360 engine at one stage and I measured up the crank to see if it would go straight in a TY engine and it seemed like it would, but I was only thinking of a long-stroke 250 engine (70x70 which would have brought capacity to 270cc). I still wonder sometimes how good/bad an engine that could turn out to be.

[David Lahey]

A DT360 engine (and a DT400 engine) is longer and heavier than a TY250 engine.
However an RT3 360 motor would be a bolt-up in a TY250 but would have too little room to fit a decent-sized flywheel and would have trailbike gear ratios.
An interesting motor similar to what you mentioned is a (360cc) DT1 250 that has an RT1/2/3 crankshaft and a big-bore/long stroke DT2 cylinder (and used in pre-70 MX).
Yes, why someone would want a 360cc TY250 is a good question but don't forget that is exactly what Christian Rayer did in the early 1970s before Yamaha enlisted Mick Andrews.