Anyone running 850 with pods and 4-1? What carb jetting?

[psyguy]

Cheers Don and Merry Xmas.

As above, I'm running stock Pilot air jets #200.

But I found another suplier = http://www.pjmotorsports.com/
Their website is also not that impressive but I managed to place an order for jets #195 and #190 (4pce each). Awaiting confirmation from them.

[7981GS]

When I made my '79 750 into an 850, I used '81 850 head and 34CV carbs from a 1000 and did not change the pilot jet or the needle at all.
It only took a 122.5 main jet to work flawlessly. I was at Sea level.
Pod's and 4-into-1 exhaust.

Hope that helps!

Daniel

[Suzuki_Don]

Cheers Don and Merry Xmas.

As above, I'm running stock Pilot air jets #200.

But I found another suplier = http://www.pjmotorsports.com/
Their website is also not that impressive but I managed to place an order for jets #195 and #190 (4pce each). Awaiting confirmation from them.

I just checked my air jets and they are #155 x4 and #160 x 4, so would have been too small for you anyway.

Good luck.

[psyguy]

The jets arrived so I'm itching to continue the tuning. Unfortunately, the summer hasn't arrived... it's been raining more or less the whole time last couple of weeks... and the long term forecast isn't too good either. I'll keep you posted.

[nicefighter80]

Not sure if this will help any but i thought id throw it out there

http://www.iwt.com.au/mikunicarb.htm

[psyguy]

That's a good read, thanks.

I've been progressivelly lowering the needle and that kept improving the situation on acceleration. I got down to 2nd notch from top (+washer) but I'll go further down as there is still a slightly rich condition just off idle (sometimes the bike bogs down just a tad bit when accelearting from a stop) and also WOT in 5th gear from low rpms produces a few stumbles til more air starts getting in at aprox 3,5k rpm.

As noted, at this setting there is a massive popping on deceleration. I have now installed two sizes smaller pilot air jets (#190 in place of #200) and that took care of most of the popping but not all. I think I need to go another two sizes smaller (#180).

Pilot screws I re-adjusted (again, just to be sure...) using the highest rpm method and they are sitting at approx 2 to 2,5 turns out.

I also re-ballanced the carbs and while they were already in spec now they're even more ballanced .


So, the next step is to order a few more pilot air jets, pay through the nose for shipping, then wait, and wait for the mail man... and then more tuning.

I'll keep you posted.

[boingk]

Good stuff mate, sound about the same as what I did to my GS850 when I had it. I ended up using proper Mikuni jets and going 18% oversize from the original number on the mains, along with a raising of the jet needle a notch or two. Can't remember the rest but those parts are rock solid in my memory.

You sound like you're pretty much spot on track from what you describe - see how those pilot jets go and get back to us!

CHeers - boingk

[psyguy]

Well, I finally ordered further two sizes down pilot air jets (#180). I should have them in two weeks so, "stay tuned" (pun not intended)

I ended up using proper Mikuni jets and going 18% oversize from the original number on the mains,

18% on stock size #115 would be #145 which is equal to DJ #155. I've been using the bigger #160 which may explain why I needed to lower the (DJ) needle to 2nd notch from top and still have a slightly rich condition...

Would it be better to go smaller on the main jet (#155) and lift the needle a bit or stay with the current main (#160) and further lower the needle? Pros and cons?