Jet size help.

[nisom512]

Ok so I got around to taking apart the carbs on my 850 today and the guy I had bought the bike from told me that he rejetted it but couldnt remember what he put in.

So like I said I was taking them apart today and found out that he didnt put in a jet kit all he did was put in bigger mains and pilots and possibly air.

So the stock size is
Main:115
pilot:40
Air(the one on the battery side):?

What he put in:
Main:122.5
Pilot:42.5
Air: 180

Questions:
1.So I dont know what this means?

2.How does this compare to getting any certain stage of jet kits?

3.It has an aftermarket exhaust on it with stock air box. I would like to put pods on it so would this set up work or should I go for bigger?

Any help is great
Jake

[nisom512]

what no body knows any thing about this?

[Steve]

Working on a similar problem myself, but it's the other way around. The bike I am dealing with has pods and a stock pipe.

My son's bike is similar to yours, with stock airbox and a pipe. We got it with 120 main jets, all others stock. By the way, your 180 air jets are stock, too. We have not done a lot of extensive testing yet, but his bike seems to be working well, so it's probably close. Your bike with mains one size larger and pilots one size larger will likely run just a bit rich, unless the header has a minimal ( or no) baffle. My son's bike has a decent baffle and fresh packing, so it's comfortably quiet with a good sound.

If you want to go with pods, you will probably want to go with 125 or 127.5 mains, your pilots should be fine.

How does it compare to a kit? What you have might be considered Stage 1. With the pods, you would want a Stage 3.
Why have we never heard of a Stage 2?

.

[nisom512]

Working on a similar problem myself, but it's the other way around. The bike I am dealing with has pods and a stock pipe.

My son's bike is similar to yours, with stock airbox and a pipe. We got it with 120 main jets, all others stock. By the way, your 180 air jets are stock, too. We have not done a lot of extensive testing yet, but his bike seems to be working well, so it's probably close. Your bike with mains one size larger and pilots one size larger will likely run just a bit rich, unless the header has a minimal ( or no) baffle. My son's bike has a decent baffle and fresh packing, so it's comfortably quiet with a good sound.

If you want to go with pods, you will probably want to go with 125 or 127.5 mains, your pilots should be fine.

How does it compare to a kit? What you have might be considered Stage 1. With the pods, you would want a Stage 3.
Why have we never heard of a Stage 2?

.

Thank you very much Steve I guess I will get it goin and if I need to I will move up to bigger mains once I get the pods on there what size are the pods on the bike you are down grading? if they are 54mm and in good shape I could buy them off you?

[gearhead13]

If you really want to go with pods, do yourself a favour and get the dynojet stage 3 kit.
BTW what year is it, does it have cv carbs?

[nisom512]

If you really want to go with pods, do yourself a favour and get the dynojet stage 3 kit.
BTW what year is it, does it have cv carbs?

it's a 81 so yeah cv. but why would it not run with the right mixtures if I just put 125's in there?

[almarconi]

The stage 3 kit also gives you adjustable needles.

[Steve]

Thank you very much Steve I guess I will get it goin and if I need to I will move up to bigger mains once I get the pods on there what size are the pods on the bike you are down grading? if they are 54mm and in good shape I could buy them off you?

Must be a little confusion here. Two separate bikes involved.
Bike #1 - my son's bike, has the stock airbox and a pipe, 120 main jets, everything else is stock. Seems to run well, no changes anticipated.
Bike #2 - actually just a rack of carbs I am working on that will be mailed back to the owner. This one has the pods and a stock pipe. I don't have the pods here, so I don't know what size they are, but they would fit the BS32 carbs that come on the 850. Not sure if any changes are anticipated for this bike, so I am going to install larger jets than stock and hope it works well, because I will not be there to fine-tune it.

.

[BassCliff]

Research

Hi,

Here's a PDF file with Stage 3 Jetkit info:

http://www.dynojet.com/pdf/3306.pdf

Here's the poop on the stock carb settings:

http://members.dslextreme.com/users/bikecliff/images/carbspec_float_height.html

Want to learn about plug chops? I've collected some information here:

http://members.dslextreme.com/users/bikecliff/images/highest_rpm_plug_chop.html

Here's a pretty good write-up about jetting from Factory Pro:

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

Is there anything else I can do for you?

Thank you for your indulgence,

BassCliff

[mbake99]

help with jetting

Guy's I am have the same problems I have a 80' Gs 850 that I have turned into a cafe racer. Got the pod filters cause they look cool but Jetting is always an issue with pods. I just finished rebuilding the carbs with K&L kits changed o-rings on fuel tubes the hole works. started the bike to get it to idle Im at least 2.5 turns out on my fuel micture screws. 1/4 turn of the throttle and on it progressivly got worse until it would shut off..... I think I need to go down in my pilot and up in my main??? and stage three jet kit the answer come on sell me........ I also have a four into 1 kerker header with a yoshimira slip on from an 01 r-1 lots of air movement here tried it again with the mixture screws 4 turns out idles awesome touch the throttle and it dies please help.........................................

[gearhead13]

it's a 81 so yeah cv. but why would it not run with the right mixtures if I just put 125's in there?

I tried it with my '82 750 and my adjustable canadian needles, couldn't get it to run right.
The stage 3 kit has the air correctors and slide drillbit that allow the cv carb to work with pods properly.

[nisom512]

I tried it with my '82 750 and my adjustable canadian needles, couldn't get it to run right.
The stage 3 kit has the air correctors and slide drillbit that allow the cv carb to work with pods properly.

dang I was hopin it would be real easy for me but I never seem to get a break with bikes..... oh well. I guess I can try it tho.
what was the set up you had if you remember?

[nisom512]

Hi,

Here's a PDF file with Stage 3 Jetkit info:

http://www.dynojet.com/pdf/3306.pdf

Here's the poop on the stock carb settings:

http://members.dslextreme.com/users/bikecliff/images/carbspec_float_height.html

Want to learn about plug chops? I've collected some information here:

http://members.dslextreme.com/users/bikecliff/images/highest_rpm_plug_chop.html

Here's a pretty good write-up about jetting from Factory Pro:

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

Is there anything else I can do for you?

Thank you for your indulgence,

BassCliff

I was reading this earlyer but cant seem to understand what "plug chopping" does for your bike or power wise? is it just a way of tuning to what range RPM you want? cause I get it then but is there something im missing?

[BassCliff]

I was reading this earlyer but cant seem to understand what "plug chopping" does for your bike or power wise? is it just a way of tuning to what range RPM you want? cause I get it then but is there something im missing?

Reading the plugs, via "plug chops", at different RPMs helps you determine what jet sizes to use with your bike's configuration (pods, pipes, etc). You tune each carb circuit, adjusting jet sizes, to get the most efficient fuel/air mixture at each throttle position. This gives you smooth performance through the entire throttle range without flat spots or surges. It's an art and can take some time to get everything just right. I'm no expert. This is why I leave my bike all stock.


Thank you for your indulgence,

BassCliff

[nisom512]

Reading the plugs, via "plug chops", at different RPMs helps you determine what jet sizes to use with your bike's configuration (pods, pipes, etc). You tune each carb circuit, adjusting jet sizes, to get the most efficient fuel/air mixture at each throttle position. This gives you smooth performance through the entire throttle range without flat spots or surges. It's an art and can take some time to get everything just right. I'm no expert. This is why I leave my bike all stock.


Thank you for your indulgence,

BassCliff

First of all Cool thank you for the info I dont know if I have the patients to try it this winter but maybe next.

Second what are you doing up at this hour you should be in bed.