Author Topic: YZ 100 with IT 125 motor  (Read 1034 times)

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Offline Helmet_Hair

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YZ 100 with IT 125 motor
« on: March 13, 2011, 04:03:18 PM »
I just kind of hung stuff on the YZ today.  The motor fits, but there's some niggles:  I moved the motor off to the right as far as I could to line up the CS sprocket with the swinger.  I haven 't yet fit the IT rear wheel.  Just wanted to see how far to the right I could possibly move this thing.  Expansion chamber is fouling the tank, and REALLY hangs off to the right.  The kick start shaft is right on the right peg too.  Not entirely sure this will be totally possible any more without really hacking on the frame or the motor.  Here's some pics for you Frankensteins out there.















So, stuff I know I can use on the YZ 100 include the carb joint from the IT 125 (but I'd lose the YEIS capability) and also the spark arrestor bolts right up.

What do you gents think about making this project still work, or just build out the 100 motor with the option of adding the IT 175J cylinder and piston?
'79 IT 250 F x 2
'83 PW 80
'93 DR 350 S
'90 600 Katana

Offline WIXEE

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Re: YZ 100 with IT 125 motor
« Reply #1 on: March 13, 2011, 04:18:36 PM »
What do you gents think about making this project still work, or just build out the 100 motor with the option of adding the IT 175J cylinder and piston?

I would do the 100/175 combo... a lot more easier than modifing the exhaust and engine mounting not to mention the braking setup.

Cheers,

Wixee.
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Offline 4V5

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Re: YZ 100 with IT 125 motor
« Reply #2 on: March 13, 2011, 05:23:41 PM »
yep 100/175... or would a YZ125G top end work?

or leave it a 100 ;)

Cheers!
Leslie
IT465x4 IT400C IT175F YZ465G YZ250C YZ250WR XJ650G RD350LC RD250LCx5 DT175Nx3 TW200x2 DT200L DT200R RT3 RX100G GT80F YZ80L PW50J KH250B1 KZ250D1 PE175C TS250ER TS185ER AG175B AG100

Offline Martin I Henry

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Re: YZ 100 with IT 125 motor
« Reply #3 on: March 13, 2011, 07:45:56 PM »

After looking at those photos, I would be tempted to go with the IT175 J/ K top end, assuming that the exhaust will fit.

My other alternative would be to leave it at 100cc and fit the heavier flywheel and ignition from the IT175J. This would give the little 100cc motor some more grunt at the bottom end of the rev range, and smoothing the transition through the powerband.

Dave R

Offline Helmet_Hair

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Re: YZ 100 with IT 125 motor
« Reply #4 on: March 14, 2011, 03:04:41 AM »
Those were my thoughts too, gents.  I need to move the motor even further to the right to get the counter shaft sprocket to line up.  I'd end up with a very off center motor, some VERY elaborate and likely expensive motor mounts, pipe mods, moving the pegs around, and only a 125 motor to show for it.

So, new plan.  Sell the 125 motor.  I'll keep the IT CDI box and I'll take Dave's advice about the heavier flywheel.  I think I'd try one or the other (CDI or flywheel), but not both.  It'd probably ruin the characteristics of the motor.
'79 IT 250 F x 2
'83 PW 80
'93 DR 350 S
'90 600 Katana