any Yamaha TY riders out there?

[David Lahey]

The A model is the odd one out for gaps between the gears. I notice it most when trail riding and there is a huge gap I think from third to fourth. The gap is right where you want a gear to be for flowing stuff amongst trees.
I have a B and a D too and they don't seem to have such a big gap as the A. I'll have a look in the parts books later tonight when I've put the kids to bed and see what I can find.

[David Lahey]

I couldn't resist looking at the TY250 books.
The books reckon that as far as internal ratios go, the A and B are the same and the C and D are the same, and the only difference is in 4th gear, in that the C and D are a bit faster in 4th. The ratios are:
A and B: 2.714, 2.058, 1.523, 1.000, 0.656
C and D same as A and B apart from 4th which is 1.038

There is a bit of disagreement between the books too. I'm looking at the Yamaha TY250A parts book, the Yamaha TY250A/TY250B parts book, the Yamaha TY250C parts book, the cycleserv TY250B service manual and photocopies of service data sheets for the TY250A and 434 model (our B model) and the TY250C model from what is probably a US multi-bike tune-up data book.

[JC]

Dave,

My TY bottom end is #493. I always tho't that made it a B model, but from what yr saying maybe its a C.

Should it have 1.00 4th gear or 1.038?

[David Lahey]

493 prefix on the motor means C or D model.
493 prefix on the frame means B, C or D model. The B frame is different to the C and D but they retained the prefix.
434 motor prefix means A or B model.
434 frame prefix means A model.
a 493 prefix motor should have a 1.038 4th gear ratio

The porting on the first of the A models is like the DT3/DT250A. These barrels are visually distinctive in that they have a boss above the exhaust port where a decompressor could be fitted. The later A model barrels and the B model barrel have no boss there. Here is a link to some photos I took a while ago trying to illustrate the differences.
http://www.trials.com.au/phpBB3/viewtopic.php?f=16&t=3938

[JC]

Thanks D,

Whats the good oil on the footpeg relocation? Is it worth moving them rearward a little when then moved down?

[David Lahey]

Yes they can go back a little bit without upsetting the riding position. Suitable front/rear location of footpegs seems to be in a range from an imaginary line that touches the OD of the rear tyre at the front of the tyre, to about 75mm forward of that point. The further forwards you go the more comfortable it is to ride sitting down and the worse it is standing up for very steep uphills. I'm only 5' 10" so I don't know for sure but I suspect that moving the pegs back even more than that range might benefit a very tall person.
I have a tall riding buddy (maybe 6' 4") who moved the pegs on his Montesa Cota 348 which is a bike with similar high pegs to the TY250 and he lowered the pegs 65mm pretty much vertically and it transformed the ergos for him and the bike almost balances itself. The trade off with pegs that low is that they hit rocks where other bikes cruise over the top. The bottom of his are slightly below the lower frame tubes.
Theres another string in that twinshock trials forum that shows where I put my TY250B footpegs and it made the bike better for balancing stationary and much more comfortable for my feet. The bottom of those pegs is the same height as the bottom of the bashplate.
David

[JC]

Thanks D,

I was thinking straight down, but above bot of bash plate.

I scaled off the distance from front axle to pegs on SherpaT, TY & Cota & they all scale at close enough to 950mm, even tho wheelbases are a little diff.

[firko]

Firko, it sounds like you have a rare bike. Resto it and bring it out for a couple of rides.

That's the gradual intention but I've got about five projects in front of it on the assembly line and I'll sort my Maico trials bike first. It's a unique piece of Aussie trials history in itself.
I'm a bit exited by the possible Mick Andrews connection and the mention of Dave Pinkerton and Peter Pace. I remember seeing both of those blokes riding over VWs and 44 gallon drums at various country shows back in the seventies. I can't remember what either was riding except for a slight memory of Pinkerton hosting a trials school at Menai with a TY, but I may be wrong on that. I have a sneaky suspicion that the bike is something special so tracing its history is equally as important to the project as is getting it going. I really want to restore it with the green/white paint scheme so if any of you have any photos of early trials showground performers, even if they're in black and white I may be able to tell if it's the bike or not.
I won't be getting down to the farm until New Years Eve (for our annual New Years Eve party). When I'm there I'll drag it out and snap off a couple of shots of it. It's been locked in the shed (an old shipping container) for so long I can't remember what other goodies are in there with it. Possibly  TL 125 and SL 125 Hondas and a DT400B. It's got my curiosity up now.

[HuskyPete]

Firko, Kevin Brown knows a guy called Howard who rode a lot of trials back in the 70s, he might be able to help you with the  TY. Howard was the guy that rode a Honda wheelstanding down the aisle of a office between the desks in a Honda advert.

[firko]

I remember that ad! I'd like to have a chat with Brownie but I won't do anything until I get some photos of the TY. Ta Pete.

[HuskyPete]

I just remembered the guy's last name it was Howard Chapman. Must have had to many Kozels last night

[JC]

D,

Despite several searches I can't find the thread on the trials forum about the relocation of TY footpegs. Any chance you can point me in the right direction pls?

[David Lahey]

It was quite a few topics down from the top

Here it is

http://www.trials.com.au/phpBB3/viewtopic.php?f=16&t=2678

David

[Oldbiker]

David,
Is there any advantage to lowering the pegs on the TY250? I am after as much ground clearance as I can get. I've see it done to the ty175. Would it be better to locate them further back, not lower? As I'm trying to get my bike ready for the '09 season, any help is needed.

[JC]

Thanks David (for the site reference)

Did you make yr own footpeg holders/brackets, or adapt something off another bike?