mikuni HSR42 pumper on 650r??


3 replies to this topic
  • zrt1

Posted May 06, 2007 - 05:34 PM

#1

Has anyone tried or have had any luck using specificaly a Mikuni HSR42 on a 650r?

  • BWB63

Posted May 06, 2007 - 09:21 PM

#2

Yes, I bought a HSR42 off ebay, used my lathe and PVC fittings making addapters to make it fit just like the TM40 mikuni (they are real close to the same carb). Using the HSR42 helped me in getting a much better jetting setup for the TM40 that I went with afterwards. I think this carb would have worked better on the 680cc engine but, the pump was a little big for a stock setup I had at the time. It ran great, just couldn't burn all the fuel that was being pumped in and I didn't change the pump nossle. 1.2 air jet is a must, 22.5 pilot, 140 main with a 9DJH1-01 needle and a Y-4 needle jet if I remember right. I think the setup would work much better on an engine with a stage two cam, Barnum's or Morawaki type header and maybe a smaller pump nossle. It was very important to have the pump streem hit the needle on both the TM40 and the HSR42 carb.'s. I liked the TM40's power delivery much more then the stock Edelbrock's and the bottom end was better then the 42mm bored Edelbrock I am running now. I sold the HSR42 on ebay, I wish I had it to run more tests now but, I am doing other things on te bike right now and the Edelbrock is working.

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  • DuncanL

Posted May 07, 2007 - 11:04 AM

#3

I've recently fitted one to my xrr. If you're after a roller pumper carb on the cheap, it's well worth looking at.

It's a bit of a tight squeeze and requires tilting towards the frame (without modify the tank). This does result in the corner of the float bowl being close to the exhaust. If you've an FMF power bomb pipe, you may find it won't fit. But otherwise fits with just a little attention to the throttle bracket.

I'm still working out the jetting, after some pointers from Bruce. 140 main, 25 pilot, and leanest pumper. I'm still using the standard needle and jet as I can't find the 9DJH1-01 listed. Perhaps you used the 9DJY01 from the TM40/HS40? :applause:

  • BWB63

Posted May 07, 2007 - 02:24 PM

#4

Yes, that must be it, The needle I took out was a 8Dhj1-01 or something like that. I used the 9DJY01 (bought from a Harley shop) in the TM40 and I am sure I must have used it first in the HSR42. I had to go much leaner then what was in the HRS42 and TM40 with both the needle jet and the needle. Both were setup for Harleys first (that is what most of them are for).





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