how do I establish a baseline?

[yotaman423]

i have read everything on this site and bass cliff page and a whole bunch of other stuff. i bought this 80 GS850GLT with aftermarket no name pipes. how much will this effect my baseline for tuning? i plan on cleaning my carbs this winter and wondering if i will have any problems setting the carbs back up per suzuki spec. with the aftermarket exhaust. or will i be ok? thanks

[tkent02]

With the stock air box, probably not much change, maybe a size or two on the main jet, maybe tweak the needle height a tad. The airbox makes a bigger difference than pipes.
4-1 pipes?

[Big T]

You'll just have to take the carbs apart and see if the stock jets and needles are in there

They all have really tiny numbers on them, so you can tell what size they are

Old guys like me prefer the Helping Hands (down the page), but any magnifying glass will do

http://www.harborfreight.com/catalogsearch/result?category=&q=magnifying

Once you know what you have, then you can proceed

Your stock specs are in the sticky at the top of the page, or check your service manual. You will need larger than stock jets, or a jet kit, to make the bike run properly with a 4-1. This may have been done already

You can get a service manual from BassCliff

[yotaman423]

they are not 4-1 they are some slip-on 4-2 with leaks at the slips. there are no clamps to tighten them either weird. im waitin on parts to dissasemble and clean carbs ill let you know what i find

[Steve]

Just for reference, the stock main jets on an 850 are 115.

Of the three 850s at my house, only one, my #2 son's '81, has an aftermarket pipe on it. (you can see it in my sig, just click on the link) It has a nice, quiet baffle and runs nicely with 120 mains. Depending on how quiet your pipes are (quiet is somewhat related to flow characteristics), you might be in the same area.

.

[tkent02]

they are not 4-1 they are some slip-on 4-2 with leaks at the slips. there are no clamps to tighten them either weird. im waitin on parts to dissasemble and clean carbs ill let you know what i find

No way of knowing, they could flow more or less than stock exhausts, or maybe even the same.

[yotaman423]

thanks for the input i think there are no baffels just straight pipes

[yotaman423]

so im in the process of cleaning my carbs. so far all jets pilot and mains and evertthing else is all stock. so my question is this- with the stock airbox and filter and aftermarket free flowing exhaust do i need to run bigger jets to compensate for the exhaust. i will say the bike seemed to run good before. i rode a 900 mile trip with no problems. any help would be appreciated thanks

[Steve]

... with the stock airbox and filter and aftermarket free flowing exhaust do i need to run bigger jets to compensate for the exhaust.

Reading your spark plugs will be the ultimate determination, but generally speaking, yes, you need to run bigger jets.

I have 120s in my son's bike with a Jardine header (quiet baffle) and it does well. With your "free flowing" exhaust, you might need bigger ones.

Again, only your spark plugs will know for sure.

.

[yotaman423]

ok so where do i order the bigger main jets? i found the jets do i order 117.5 or120 or both

[chef1366]

I'd order 122.5s and 125s
Try Denniskirk.com

[yotaman423]

are the 122.5 and 125 a smaller step up than i think?

[chef1366]

are the 122.5 and 125 a smaller step up than i think?

I'm not a mind reader

[yotaman423]

Touche lol