Kawi2strokes.com Forum

Thanks Graham for that description and enlightening us. An interesting set up for sure!

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1972 Kawasaki H2 Mach IV (Candytone Blue),1984 Yamaha RZ350 (KRR- Yellow/Black), 2004 Honda Helix (Clipper Yellow).

“Jeff and Chris are THE MEN!”
RIP John E. Evans

Good stuff indeed. I can see how this would still be useful even today.

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There are 3 kinds of people in this world. The kind that can count and the kind that can't.

The powerjet carbs for the TZ/TZR type Yamaha's look like these below and are electronically controlled...


I picked up a 92 3XVR model project a few months ago. Have it about all sorted and road worthy. Can't wait to go ripping around with it!

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71 A7SS, 73 H1D, 75 H2C, 85 RG400
92 NSR250 MC21, 93 TZR250 3XV
03 ZRX 1200R

In regards to the Left side big end failures, I can add to this.
Yamaha liked helical cut primary drive gears because they are quieter and smoother operating than the str-8 cut variants. The issue with a helical cut primary drive set-up is that they create a lateral push, or "thrust" on the crank. I've taken many of RZ apart and found .080" rod side to side movement on the RT. side rod and NONE on the left, as in turning colors but not yet failed.
WELD All yamaha twin cranks, especially RZ's and LC's because the center press is a smooth press fit, while the old RD's use a pressed spline in the middle.

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1975 H1
1974 S1
Yamaha RZ350
...and a smelly Honda CB350-Four

As mentioned in a previous post, Yamaha started using power jet carbs in the early 70's on race machinery. I had a 1978 Yamaha SR-X 440 snowmobile that came with powerjet 34mm Mikuni's. There were 2 jets in the bottoms of each bowl, one main jet and one power jet. cool ! I also had a 1991 Yamaha WR200 enduro dirt bike-- factory Kehin flatslide power jet carb also. Hmm, all this reminds me that my 85 Yamaha RZ500-V4 Has stock power jet carbs, kinda,(26mm Mik's) but the fuel exit holes are not drilled. No, I'm not gonna do it !!!-lol
This dambed bike is complex enough.

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1975 H1
1974 S1
Yamaha RZ350
...and a smelly Honda CB350-Four