Chain question

[ChrisACT]

Has anyone ever done a 428 chain conversion on a DT2 or similar bike?

I'm trying to find a 428 sprocket that will fit my DT2.  The standard is 520.

Any ideas?

Thanks,
Chris

[Tim754]

Chris stay with the 520, we did just what you are thinking to a XL250 motosport racer in earlier times , saved some weight, but fiddly costly and lovingly stretched the small chains quite quickly till one came of rear sprocket and into cases.................. Hey hang on  just at present I am converting the sidecar "back" from 630 to tiny little 620 pitch.

[ChrisACT]

Fair enough.  It is a pain to find something so I guess I can stick with the 520.

Thanks,
Chris

[LWC82PE]

you can get good o-ring 428 chains for bikes. The CT110's come out with 428 std chains but the postys dont like them because they stretch and wear out quick and need freaquent adjustment which is a pain beacuse they are not allowed to do any maintenance on the bikes and have to bring it to me. The local PO has just got a new fleet of bikes (2) and what i do is put o-ring chains on them when they are new and take off the std chain, which i will be doing next week probably. Its no point getting the post office to order them because they get supplied std issue non o-ring chains so i will get some for the bikes. When fitted with o-ring chains they stay set at adjustment much longer and can stay at set adjustment till each service and dont need the chain to be adjusted between services. They dont stretch and they last a lot longer.

whats the reason for going to 428? do you just want lighter weight? i can see if a 428 front sprocket is available if you like

[ChrisACT]

Well, it's sort of a long story but the crux of it is that I'm running an FZR250 rear wheel on a DT2 frame.  Weight saving is one thing but you also lose a bit of horsepower through the bigger chains compared with the smaller ones.

I know guys that are running 415 chains on their RS125 race bikes.  So that's 40+ HP and 200 kph.  They're not having problems but then they're not generally riding through the dirt, nor are they doing big kms on them before they get relubed.

The FZR250 runs a 428 chain so it's easy to get 428 sprockets for it.  Just a matter of whether or not I can get a 428 sprocket for the DT2 engine.

Here's a pic of the bike with some photoshopped extras so you get what I'm working on.  Essentially it's a DT2 cafe racer.



Yes, I know it needs a clean, polish and paint (not to mention a zillion parts).   

[mx250]

That's a DT frame . I wouldn't have pick it, not in the photo anyway.

Is the rear wheel 17 or 18"? It looks slightly bigger than the front.

I can't recall exactly where I've seen it but I know I've seen ads for companies that do all sorts of tricky things with sprocket including cutting from blanks. They pretty much guarantee
that they can replace any sprocket. Enjoy the search, sorry I'm litle more than a cheer squad .

I'll be interested in your outcome. I can't see why you can't run the smaller/lighter chain. As you say, relative low speeds with close attention and high maintenance it should survive. Make up a chain guard over the front sprocket protecting the cases is always a worthwhile and prudent mod .

The other issue is the quality of the chain. As you probably appreciate there is a wide variety in the quality of chain. Seek out the best and be prepared to pay (expensive ).

I'll be interested in the outcome of your project and the rideability of the bike on the road. It should be quite pleasant; good power, lightweight - good acceleration and braking - and reliable. A Yamaha Metrella (that will upset the Bully Boys ). Probably something Yammy should have done in the day .

My interest stems from a germ of an idea that is rattling around in the back of my head. It would like to make up a Street Dirt Tracker is this fashion (below) based on the bits I have left over.

 

[ChrisACT]

Yes, it's a 1972 DT2 frame and engine.
1990 FZR250 front end and rear wheel and brake (both wheels are 17's.  Front tyre is lower profile, but I'm not going to use those tyres anyway.  The previous owner of the FZR over tyred it, big time.)
CB400 super four rear shocks.
TZ250 tank and seat.

There's a long way to go but it presses my buttons so I'll get there eventually.

MOTA has it running around 45HP at 9,000RPM on pump fuel.  The barrel has been bored out to 71.25 so it's 255.2cc.

I'm expecting it to weigh about 110kgs dry.  With the frame, wheels, brakes, forks, shocks all mounted, I can lift it without much trouble and I'm no muscle man.  I mean, it's heavy, but I can lift it off the ground to get it on and off the work stand.

Only minor engine parts, lights, electrics, exhaust, seat and tank to go, so it'll be reasonably light.

I think it's fair to say that it's not likely a DT2 has ever had such big brakes.   

Rake is 27 degrees, trail is 100mm, wheelbase is 1350mm, so it's not going to be super twitchy.  It's really a matter of what the frame is capable of. 

[mboddy]

What does the current one look like Chris?
One of these?



Have you had a look at the JT sprockets online catalog to find one?
http://www.jtsprockets.com/52.0.html

[mx250]

It's really a matter of what the frame is capable of. 

Ah, nothing a steering damper and a big heart can't fix .

[mboddy]

Can you use one from an xt350?

[LWC82PE]

looks like mboddy has already gone to the JT book which is what i was going to do. if you find one thas 428 with the right center but not the teeth you want, let me know and i will try another larger listing with more teeth to choose from. another option is custom made or re-banding. there is a place in Adelaide i use to make custom sprockets or reband the centers of original ones to different spitch or teeth quanities. they are called Chains And Accessories. i will try find their details.

OK this is the place i use

http://www.completedrives.com.au/

[ChrisACT]

My sprocket is the top one, with more splines.

As far as the JT catalog goes, I can't find any 428 sprockets that would bolt straight on.

However I was toying with the idea of running an MX250 transmission in my cases which would enable me to run the XT350 front sprocket.

So a closer ratio box (which I want anyway) and I can run the 428 chain too.  A win, win.

Sweet.

Thanks guys.

[Rossvickicampbell]

I can only help just a little more than MX but I think the company he is referring to is either Chain Guys or chain gang and they reside in SA - basically can/will make anything for anything out of anything - but if I remember also weren't cheap.

Hope that helps ?

Rossco

[matcho mick]

hey Chris,you sent the tank cap up yet?

[LWC82PE]

is this the place your thinking of? they are not in SA though

http://www.chaingang.com.au/sprockets.php

P.O. Box: 627
KENMORE 4069
Brisbane, QLD Ph:     (07) 3715 8990 Freecall:    1800 806 857 (9am-5pm Monday - Friday)   
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5 /617 Seventeen Mile Rocks Road,
SEVENTEEN MILE ROCKS, 4073, QLD Fax:    (07) 3715 8991 Em@il:        [email protected]