TT 350

[Noely]

[Hodgo1981]

Hi, just a quick one! Has anyone done a conversion on the back brake drum to a disc???? TT350 in mind.

Hey Noely,
I know you have bigger projects to deal with at the moment. But I saw this post from last year and thought I better reply.
About 10 years ago I owned a 97 tt350 that the previous owner had done disk converstion. It was an 88 yz250 set up apparently... most seemed pretty good but could still tell it was a back yard job...it actually had no reservoir, just the hose contimued up tbetween RHS panel and airbox, with a bolt wedged in the end of it. Worked perfect!

[Noely]

Hi Hodgo, that sounds like the go but I have a dilemma. This year has been not a good one financially so I've planned to do the full competition series next year of the South Australian Reliability Trials in the "Pre Class" which means bikes entered in this class must be built from when ever to 1990 to suit the period. So after asking the stewards on what my intentions were on changing the rear brake they said it would not be allowed to be placed in this class so I'm going to leave it alone . So my dream next year is to start with the "Port Rickaby Ride" which the Port Pirie Motorcycle Club put on in Mid February, the reliability trials starts in May and goes to September, the Condo 750 in Easter, the Sunraysia Rally up at Wentworth NSW in early August. In amongst this is the KTM Forrest Rides around SA plus the odd road trip that the bike club I'm in organises.
For the Condo and the Sunraysia I'm planning to find a larger then standard XR fuel tank to do the extra km's. I did think about doing these two on my tenere.

[Hodgo1981]

Wow!!!
Thats awesome that you are so committed to racing old bikes I'm starting to think i might take it up...and get another bike for it of course. It's amazing how well these 350s go in vinduro, great performance and very reliable.
To be honest drum brake rears aren't that bad, since getting my XT600 I've been thinking they actually have better feel, just more fiddly when ever you have to take a wheel off.
I guess a Nomad tank is another alternative to trying to get an XR tank to fit.

[Noely]

Normad Tanks?? I have not heard of them. Thanks Hodgo!
Yeah, drum brakes aren't that bad once you get the feel for them. I spoke to the mechanic a couple of days ago and it looks like it will be a major rebuild. gear box issues due to the rear wheel not being cush drive. So to extend gear box life I'm thinking about putting an XT350 rear wheel/assembly. Not to period but I don't think they'll pick it up in the scrutineering. But I'm not sure if I'll go ahead with just yet. I've got to find the money for the rebuild.

[Noely]

Hi, I just found out that Yamaha do not have 3rd gear cog/wheel for my TT350 Part number is 1LN-17231-01 would anyone have such a thing floating around?? Thanks

[Hodgo1981]

I did a little bit of searching, and it seems that the other gears can be found in various models like more recent ttr250, xt350 and xt250.

So I guess a bit more googling to find what the ratios are on all those bikes, if you are happy with changing the gear ratios the XT350 3rd gear sets are available, and it IS the same motor... so "Should" fit.

[Hodgo1981]

did a bit more digging for you, you can search here for all yamaha model owners manuals...which were quite detailed back in the day https://www.yamahaownershandbook.com.au/index.php
Here is 91 TT350, gearing specs page 91.
https://www.yamahaownershandbook.com.au ... 199-20.pdf

This is the 94 XT350 manual, in Specs on Page 98 there is gear ratios.
http://www.yamahaownershandbook.com.au/ ... 199-22.pdf

Primary and secondary drive combos and 3rd gear is the ONLY gear that is not the same on TT/XT
the XT is 30/22 giving ratio of 1.364.
the TT is 26/19 giving ratio of 1.368.

barely noticeable change... I'm not sure about the mechanics of it all but I "Think" more teeth for same ratio would mean XT might be stronger???

[Noely]

"Shivers Hodgo" What an awesome find. Thank you very much for the info mate. Mmmm. Yes the ratio difference between XT & TT 350's and only in 3rd!!! I have found a wrecker that has one but I haven't had the time to go and see it as yet plus I've got 4 more shops to ring to see what they have. But if all else fails I'll have to go with the XT combo. I was advised to get a XT 350 rear wheel due to the coosh drive which will make the gear box last a lot longer.