Suzuki GS 850 mukuni bs34ss cv carbs..help!

[webragg]

hey folks i am new to this forum and internet communication so if i do things wrong please bear with me. i have several old suzukis 1982 gs 1100 gkz [winter resto project ] , 1972 t 500 [found buried in a shed w/full tank of c*@p & rust ] , and 1980 gs 850 gn . my questions concern the mikuni bs 34 ss cv carbs and inlet pipes on the 850 . i purchased this bike from the original owner [14000 mi ] pacifico fairing [8 trk plyr ! !] vetter tourpak super clean unmolested ride . never quite idled correctly , sometimes was hard starting . my business interests forced me to park it for about 1 yr but before i stopped riding it i put stabil in fuel and ran it thru . now upon pulling it out again wouldn t run without keeping choke pulled out so i tore carbs apart completely, soaked all metal parts in new carb cleaner , got kits and o rings , set float heights according to clymer specs , blew thru all passages ,i am pretty sure they are clear [carb rebuild tutorial from your website extremely clear & concise , my compliments & thanks to that gentlemen ! ! ] . my intake pipes are prettyhard and distorted , center 2 had shrunk so bad they came off of carbs and were loose in airbox [ air filter foam had disintegrated totally also ] . resealed carb adapters also [ o rings hard & cracked ] . now without air filter box installed bike idles perfect , off idle is great [ 2500 3000 ] but as you roll into throttle it bogs & stutters terribly until it gets into upper rpm s briefly . have checked diaphrams ,no holes . your charging system flow chart was excellent also , anything like that for this carb system many thank s for any help

 

[Rat44]

Welcome aboard.
Sounds like you are on the right track.
I am in the process of resurrecting a 850 myself.
Good luck.

 

[Steve]

With the airbox off, it seems to be operating exactly as expected.

Key point here is "airbox OFF". The airbox imparts a restriction in the intake that is necessary to raise the slides. Without that restriction, it won't run well at all. If you would like to do a 'quick and dirty' test just to see if it's running OK, fold a shop rag in half, drape it over the carb inlets. Use a zip-tie to hold it to the outer carbs, making sure it's reasonably snug over the inner carbs. It should work well enough to ride like this, but it's not accurate enough to do jetting checks.

.

 

[webragg]

thanks very much, will try shortly , any recommendations for jetting tips & directions on which way to go when installing pods or different airfilter system [ i.e. my original intake pipes , internal air box foam seal & air filter element have not aged as gracefully as the rest of the bike ] existing setup is as follows ; needle jet 318 ex-5 , main jet r 115 , pilot jet 40 , air jet 180 , float level in all 4 carbs is between .85 in & .86 , idle air screw out between 1.25 & 1.5 also good reputable supplier source for jets i am in maryland thanks for your assistance in these matters

 

[Guest]

Your carbs are 34's?

 

[webragg]

from everything i can find they are numbers on right hand of each carb near diaphram are 45110 over top of c9z15 if that is any help

 

[Guest]

from everything i can find they are numbers on right hand of each carb near diaphram are 45110 over top of c9z15 if that is any help

I'm not familiar with those numbers but the bike had 32's when it was new and I don't think 34's would fit without a great deal of modification. (Your 1100's have 34's.)

 

[webragg]

thanks for info , how can i tell for sure, measure inside throttle bores ?

 

[Guest]

Measure the throat on the filter side.

 

[Steve]

Measure the throat on the filter side.

Filter side? I always thought it was engine side.

If it has 34s on it, that might explain why the boots are not in good shape.

Personally, I would go with restoring the intake system to stock. The engine-side boots are about $20 each, the filter-side boots are considerably cheaper. Not sure how much a filter costs, as both of my 850s have K&N inserts. For about the same money, you can get a set of pod filters, but then you will have to go through all the 'fun' of rejetting. Not saying it won't be worth it in the end, but that seems like too much work for me. For all those that say that it's so much easier to remove the carbs with pods vs stock airbox, I say 'true', but then ask 'how many times do you need to remove the airbox after the carbs are clean and properly jetted?' It has been three years in the case of my wife's 850, and I have had the carbs off once, and that was to check the cam chain tensioner.

.

 

[Guest]

Measure the throat on the filter side.

Are you sure about that? I believe it's the I.D. on the other side; the side facing forward towards the engine. (The I.D. on the side facing the filter would be closer to 50mm.)

 

[webragg]

i have measured filter side air venturi , it measures 53 mm

 

[Guest]

i have measured filter side air venturi , it measures 53 mm

I was pretty close!! I think if you check the other side, it will be 32mm.

 

[Guest]

No more basketball games till 2am for me. At work by 6am.

At least it was a gold medal night!

 

[Guest]

The stock carb for the 80 and on GS8850G is the B32, not the B34.