Anyone interested in helping some with a strange conversion?


10 replies to this topic
  • tzr426james

Posted November 25, 2005 - 03:20 PM

#1

I am in the middle of stuffing a yz426 motor into a Japanese road TZR250 chassis. I am about half way through and found I need to possible go in a different direction depending on the answers to the following.<br>
Questions: <br>
Does the YZ/wr400 have the same basket as the 426? Does the 426 have the same as the 450. I am looking to use a slipper clutch and the motor has YZ400F tranny right now. I am not sure what basket. <br>
Does the 450 clutch cover fit the 426? <br>
CanI convert the 426 to starter or do i need a totally different bottom? <br>
Can I run a 450 CDI in order to use a Rev box, which I can't find for the 426? <br>
If I use a different bottom end ie. 450, can I use the 426 cylinder and head?
Which Yamaha models have starters? YZF/WR? <br>
Do the 450 cams fit the 426? I was told by the builder to use 450 stock ex. If so, I have a set of good conditon Hot cams for the 426 for sale. <br>
Thanks for the help. <br>
James <br>
massie_james@yahoo.com

  • badassdad

Posted November 25, 2005 - 05:36 PM

#2

how much for the hot cams?

  • Hick

Posted November 25, 2005 - 06:27 PM

#3

Does the YZ/wr400 have the same basket as the 426? Does the 426 have the same as the 450. I am looking to use a slipper clutch and the motor has YZ400F tranny right now. I am not sure what basket.Can I run a 450 CDI in order to use a Rev box, which I can't find for the 426? If I use a different bottom end ie. 450, can I use the 426 cylinder and head?
Which Yamaha models have starters? YZF/WR?
massie_james@yahoo.com


Only the WR450 has an e-start.



I believe the 426 has an extra clutch plate, and beginning in '01 has an inner circular spring inside the first plate. Upshot is I wouldn't be surprised at all if a 400 basket works fine (w/ 400 plates and 400 pushrod), but I'm not sure if a 426 basket will fit in a 400.

I know of no way to put e-start on the 426, I seem to recall somebody offering a kit to fit an e-start, but can't recall who it was and who knows if this is still available.

The 450 motor has a host of changes to the head and tranny etc., I doubt many, if any, internal parts will swap, although the camshafts will indeed swap into a 426.


I don't know about the CDI, if the connectors are compatible it would probably work, but the ignition curves are likely different...

Hope this helps.

  • bmeador

Posted November 26, 2005 - 07:21 AM

#4

Why don't u just buy my Yz450f and you will have all u need accept the e-button! :applause:

  • henrysdad

Posted November 26, 2005 - 07:34 AM

#5

Better yet get a WR450 and convert the cams to YZ spec. This way you will get button start. ,you can get a slipper clutch,you will have a 5 speed and power for some lights.

Viola! I make it sound easy.

Sounds like a cool project you have . Will you post a few pictures?

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  • tzr426james

Posted November 26, 2005 - 12:52 PM

#6

Yeah, pics are coming soon. I have been making the Carbon Fiber tank and do some odd jobs on the side to fund the project. It should be a mean and nasty little toy when done. I would opt for the 450 engine. Anyone got one for sale? The motor I have is pumped up for racing with fresh rebuild. I bought it off someone parting out a Lonestar rolling chassis. The motor has new .60 over, with fresh chromed cylinder and Chapman performance port job.

  • tzr426james

Posted November 26, 2005 - 12:54 PM

#7

As for the cams. I have no idea how much they are worth. I've been racing two strokes for four years. Make an offer. Or dig me up a stock 450 ex cam for trade.

  • schuon

Posted November 26, 2005 - 01:42 PM

#8

Just keep the HOTCAMS, if you are going to buy a 450 cam when you already have a 426 hotcam with autodecomp you are just wasting money IMO. I think hotcams should give you more power too over the 450 cam, the only reason people put 450 cams in 426's is for autodecompression release, hotcams have autodecomp.

  • tzr426james

Posted November 26, 2005 - 04:37 PM

#9

The guy I bought the motor from said since I was going to road race the bike, the milder cams would cause less "valve float" since the bike will be pinned alot and the autodecomp was good for kicking it over as a street bike. Looks like I have my work cut out for me. I am a little concerned with power loss, but could use a recommendation based on this being a road race bike.THX

  • tzr426james

Posted November 26, 2005 - 05:30 PM

#10

'nother question...what does the .60 overbore make for CCs now?

  • tzr426james

Posted November 26, 2005 - 06:13 PM

#11

Nevermind on that last one...it was a 1.5mm over bore





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