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needshelp

Beginer Questions PLEASE READ

8 posts in this topic

Ok, I'll thank you in advance for any advice...

First, is there any difference in an 01 WR426 or YZ426 motor? Does one make more power? Are the blocks the same?

Next, I need to put an electric start on either of the two. I've seen kits from france for the WR426, will the same one work on the YZ? Has anyone ever heard of an electric start being placed on these motors?

Finally, after I do decide on an engine, what are the standard upgraded you guys do to get more power out of them

As you can tell, the motor isn't going in a bike.

Thanks again for your help

John

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First, is there any difference in an 01 WR426 or YZ426 motor? Does one make more power? Are the blocks the same?

Yes. yz more powerful by about 2-3 HP (by yamaha specs), different gear ratios, different flyweel weight (yz revs faster), yz do not have lights stator.

Next, I need to put an electric start on either of the two. I've seen kits from france for the WR426, will the same one work on the YZ? Has anyone ever heard of an electric start being placed on these motors?

I havn't heard anyone done this...

Finally, after I do decide on an engine, what are the standard upgraded you guys do to get more power out of them

Race cams, Big bore kit, high compresion piston...

BTW I do not know what do you want to put this engine in, but keep in mind that this engines week point are gears.

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from the sounds of it you are putting this in a go kart, just the compressions to high to bump start it, if this is what you're doing then try getting a yz250 engine, they'll get you going at what seems like 600 mph because your butt is 1 inch off the ground, and they weigh a lot less, but if you already have the 426 motor, try the 450 camshaft, adjust the valves, take some juice off the flywheel, raise the idle, and if you still want more get the 450 big bore kit :D:)

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Thanks for the info guys...let me explain further

Its going in a SAE formula car (college kids+ hp+ light weight= good times)

We usually use a 600cc bike engine, sometimes turboed)with around 80 hp (restrictor in place, has to be electric start 4 stroke))in a 500 lbs car. We run 11's in the 1/4. We are building a lighter car this year and hence, need a lighter engine.

I guess I have some other probably obvious questions. First a 250 will require a turbo, and they take time to tune. We can't get a 450 electric start from yamaha for a decent price, but we can get a new (but outdated) 426. The car needs an electric start by rules. We've found kits for around a grand for the 426. Here are the questions...

First, do these motors run alternators from the factory? (we fuel inject so we need power) and if so does the YZ have one?

Does anyone know where to get a hold of a 450? Fat chance I guess.

Do you guys clutch all your shifts on your bikes? just downshifts?

Anyway, thanks for the info, keep the opinions coming, this is your area.

John

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Drag racing upshifts will need clutch. Normal up and down shifts do not (on dirt...) If you are on pavement, then I dunno, but I raced shifter carts with a dirt bike motor and tranny, and you only used the clutch to start and stop.

Gearboxes lasted way longer than motors...

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I thought the engines were the same except for the timing? YZ time a WR engine and it should produce the same HP at the crank.

What college are you at? CSU's engineering dept. here in Fort Colins used to do small Indy cars. When I was there we did a solar powered vehicle in the GM Sunrace. They've also done a GM alcohol conversion vehicle.

Sounds like fun but if the other schools put a newer 600cc sport bike engine in their cars, you're toast. They're pushing way over 100 hp stock. They have so much more breath in each gear even with the lower weight, I don't think you'll hang. Have you considered going to a junk yard and finding a wrecked CBR, R6, ZX6 or GSXR600?

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Yeah, these things look like little indy cars, we're from Lehigh University in Pa.

We ran a yamaha R6 bike motor in the last car (100hp+ stock) but we have to run an air restrictor, so you'll be lucky to make 70. Those engines way 120+ pounds. Our last car, weighted in at 490 lbs. total. This year, we're building a 290 lbs car so the 426 will keep up with a 600cc no problem, its all relative. Plus, we all know why we like the thumpers so much....TORQUE!!! On a small tight track, a motor with torque is faster than a high hp motor any day. Besides, this thing will probably wind up with a turbo. When the speeds are low, we'll keep up. Thanks for the input keep it coming

John

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