TOPIC:

Hi guys,
I've decided to put pods on, I'm tired of messing w/that d@mn air box. The air pollution nazi's can blow it out their collective ear. I've got the 2 to 1 pipes also. The carbs I have are Mikuni BS34's. Now, as I understand it from reading all the rules of rejetting, you count the # of mods (in my case 2) and subtract 1= going up 1 jet size on my main jets. Standard main jet size is #115, going up 1 brings me to a #117.5. Now, since I am only going up 1 jet size on my main jets and the rule says that if you go up 1 pilot jet size for every 3 main jet sizes you increase. Since I'm only going up 1 jet size on the main, I can keep the standard pilot jet size #40. The pilot needle only has 1 position for the washer. Do I have this correct or have I missed something? I'm not going to be doing any racing and I'm hoping to avoid most stop and go urban traffic also. I also went up 1 tooth size on the front drive sproket. I hope I don't have to consider this an intake/exhaust mod, which requires going up another main jet??? Kinda want a weekend cruser and run around the neighborhood bike.
Thanks

I would try some #140 main jets and #42.5 pilot jets I think. Not sure where your rules came from... good luck!

The carbs I have are Mikuni BS34's.

Are you really sure about that? I believe that all the 750 twins had 38mm carbs, as in BS38's, my GPz750 four cylinder has BS34's.

Good luck finding replacement jets/needles/anything for those carbs, as far as I have been able to determine, the 76-79 carb rebuild kits are still available from Keyster and K&L, but not for 1980 or newer, and the Dynojet kits for 1980 and newer have been discontinued (and are not available for 76-79 either).

I'd be really interested in finding somewhere to get jets/needles/etc for 76-83 750 twins.

Just for info, the standard jet size for 76-80 750 twins is 125, in 82 they started using the smaller jets.

Check with Dennis Kirk for a Stage 3 DynoJet kit, last time I looked they had discontinued it but they still had one available.

Hmmmm, I just checked the manual and it does say the 82 KZ750M1 has BS34's, and I checked buykawasaki.com and it does use the same jets as the 83 GPz750, so jets/needles/etc should still be avaible for your carbs you lucky dog

And in that case I doubt the DynoJet kit I mentioned will work on your carbs

Post edited by: steell, at: 2006/08/28 20:49

Thanks for the replies WG and Steell.
WG, I got the rules I used from motorcyclecarbs.com and rechecked myself at the time I ordered the jets

www.motorcyclecarbs.com/Jetting_Rules_of_Thumb_W43C551.cfm

I also thought I saw similar rules in the knowledge base here at KZR.
According to the parts diagram/numbers at buykawasaki.com my carbs come stock w/either an A112.5 or an A115. They also list 117.5, 120.0 and a 110R for "racing only". Since I couldn't read the sizes from my original jets, I assumed I had the 115s, by going to the 117.5's I figured I had my bases covered. If my originals were 112.5 then I went up 2 sizes, if my originals were 115's then I went up 1 size. The 117.5's were the smallest size listed for "racing only". If I were to go from a 115 to a 140 that would be 10 sizes @2.5/size, that seems a little high for just 2 mods. Remember I have a twin and not a quad. Since buykawa.com didn't list my pilot jet size I called kawasaki.com and they told me that my stock pilot jet was #40.
Steell, I'm positive that I have BS34's. I got that information from 2 sources. It's in my KZ750 twin service manuel, M1 supplement, and before I found it in there I called kawasaki.com and they told me the same thing. If you haven't tried motorcyclecarbs.com you may want to give them a try. It appeared that they had a good stock of jets for these old bikes, don't know about needles, and also seemed very knowlegable. It did take about 2 wks to receive my order.
Ron

Steell, I see you edited your post while I was replying to it and my info to you is old news

Post edited by: ronjones, at: 2006/08/28 20:56

See the last paragraph of my post, I was editting while you were posting

I have checked the site you listed, and they were of no help on parts for the BS38's either, the only places I have found that have anything are the Yamaha XS650 sites, since some models use the BS38's also.

Smithgpz put brand new Mikuni carbs on the 750 twin he built, I don't remember the model of the carbs, but I do remember they cost over $400 and arrived set up for his bike. I guess I should contact him.

My problem is I'm running an exhaust cam on the intake side, .060" oversize pistons, head ported and milled (cut .050" off the first one, that may be to much),K&N pods, and two into one Mac exhaust. I want to get it running and break it in on carbs before I switch to EFI. I'm hoping the DynoJet Stage 3 will be enough.

We'll just keep replying though edits

I have two manuals, one 78 with a 79 supplement, and one 79 with a 80 and 82 supplement, just had to go out to the shop to get the latter one and look.

Post edited by: steell, at: 2006/08/28 21:09

yep, steell, I guess we have been playing "thread reply/edit tag"...I guess you're it!
So what do you think, have I done this correctly?
Ron

Well, you asked and now quote some other source. Good luck!

ronjones wrote:

yep, steell, I guess we have been playing "thread reply/edit tag"...I guess you're it!
So what do you think, have I done this correctly?
Ron

DamnifIknow, I'm obviously no carb expert
And all I know about the M1 carbs is I have a set disassembled in a box.

I have never used pods before, all I have done is 2 into 1 Mac exhaust on the 76-80 models, and they did not require rejetting.

Personally, I hate carbs, that's why my next motor (and eventually all of them) is going to be MegaSquirted.
Forget changing jets, just plug in the laptop and go

George, I am, especially, interested in your opinion,and appriciate your help. I know you are the carb expert around here. I was just replying to your question as to where I got my info and wondering about your recomendation? I hope I didn't, inadvertently, tick you off? Are your "rules of thumb" different? Am I missing something?
I'm having enough trouble getting this beast running...I can use all the help I can get
Ron

Post edited by: ronjones, at: 2006/08/28 21:48

steell wrote:

ronjones wrote:

yep, steell, I guess we have been playing "thread reply/edit tag"...I guess you're it!
So what do you think, have I done this correctly?
Ron

I have never used pods before, all I have done is 2 into 1 Mac exhaust on the 76-80 models, and they did not require rejetting.

This is another reason I only went up 1 jet size as I also have the Mac 2-1 and thought no rejetting was needed for that also.

Personally, I hate carbs, that's why my next motor (and eventually all of them) is going to be MegaSquirted.
Forget changing jets, just plug in the laptop and go

I'd like that also but wife is already upset at the $ I've spent on this project

sorry moto...carbs couldn't help you.
Ron

Thanks for the info guys it was exactly what i was looking for. Did you get your jet kit from that motorcyclecarb.com? I couldn't find it on there site.

Thanks

I didn't get a kit, but bought the individual jets. They ran about $7 each, + shipping. I'm not sure how I found the site, I think I followed a link someone posted, in this or another group. Click the link, I put earlier in the thread and then go to their home.
Ron

Post edited by: ronjones, at: 2006/08/28 22:44