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Old Yesterday, 03:12 AM   #1
tHEtREV OP
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Location: Middle Park, Brisbane, Australia
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Question Wr426 mods for desert racing?

Picked up some WR/YZ426f parts the other day with the plan of fitting a DT/IT400 engine in it after reading a bit about a guy doing it with a 426 and an it490 engine, but after collecting the parts and finding I had a complete WR bottom end I began to reconsider.

I though I was just getting a WR rolling chassis and YZ frame, triple clamps, wheel, swing arm and shock.

My other long term plan was do a couple of races I had always wanted to do, namely the Hattah Desert race (4 hour race around a circuit that is 30 or so Klms from memory) and the Finke desert race (high speed (for some) 230 Klm run one day, and then 230K back the next).

I have an 07 Gas Gas EC250 that I was going to use (simply because I have it and didn't want to add unnecessary cost to doing two events that I will be lucky to afford to get to anyway), but was thinking the WR built specifically for the occasions might be better.

In reality it probably wouldn't make any difference which bike I ran because I'm just going to be one of the slow guys trying to finish the races that they have dreamed about riding in since they were a kid and I doubt I would be riding either of these bikes close to there limit, but I really like the idea of building a bike specifically for the events.

And so here is my question, what mods should I do to the 426 to give me a better chance of finishing?

Other than a fully sick sticker kit.

The engine has a bend con rod, and I will be replacing all the bearings while I have the crank out and inspecting the gearbox.

It is missing the cylinder and head, I was going to get a reco cylinder or a second had one and get it plated, head I was going to get a good second hand one, fit stainless steel valves and YZ cams.

The CDI and all the wiring is also missing, I was toying with the idea of getting a Vortex ignition, but second hand ones don't look to expensive, and is there a difference between the YZ and WR CDI?

And all chassis bearings will be replaced.

What other things do you guys suggest or should I just scrap the idea and get the Gasser set up for it?

Oh and I have about 10 months before the Hattah, and the Finke assault will be another 12 months after that, so I'm not really in a hurry yet.
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Old Yesterday, 09:22 AM   #2
Kawidad
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The transmissions on these bikes can be the weak points. Go through the tranny with a fine toothed comb. The transmissions aren't all that bad, but guys who do clutch-less shifting tear them apart. Also since there is no cush hub on the rear wheel, tarmac puts a lot of strain on the parts.

Stay with the WR parts, because the gear ratios sound like they'd be better for what you have in mind. The YZ transmission is better for closed course tracks, unless I misinterpret your type of racing, then reverse what I wrote.

Overall, they are really tough bikes that are really well made and should well for what you have in mind.
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Old Today, 03:21 AM   #3
tHEtREV OP
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I originally chose it because I thought the only way I could get to race the Finke was ride there and back, and I thought that would involve crossing the Simpson (500+K of sand track through the desert), and I thought is was one of the bikes that could handle it and still be decent of road (and I found it cheap), but once I started looking into it properly, the shortest way is actually accessible by 2wd car so it would be a lot easier to cart the bike.

Otherwise I would have only had my 640 or my KLX to choose from, and I don't think either would be great fun in the race.

But taking the car brings my Gas Gas back into the equation...

I'll be rebuilding the WR regardless, but weather it is worth it for two races I don't know (sounds like fun though).

So anyway, as I said, the gearbox will get a good inspection and bearings replaced.

Is a Vortex CDI worth it, or should I just stick to a standard WR (I can pick a standard up for around $100, but Vortexs are around $300 second hand.

And should I bother with a full exhaust, just go the slip on, or pick up a cheap stock one?
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Old Today, 08:25 AM   #4
Kawidad
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I don't have any experience with the Vortex, which is why I didn't say anything about it. Personally, I'd just go stock and spend the money on ss valves, forget about Ti, too fiddley. You can get oversized valves with springs and maybe a cam and get more bang for the buck than the ignition.

As to the exhaust. If you stay stock on the engine components, then a good slip on will help. Keeping the stock head pipe will give you a little more off of the bottom, but take away from the WOT performance. For what you have in mind, it go with full monte. Since the bike has been around forever, some good used ones should be easy to find. I personally like FMF stuff, but other companies make good stuff too.
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