Mikuni BS34SS

[JG122]

I've got these on my '83 GS450, and am thinking of replacing them...

I gather new ones aren't for sale anymore ?

are there equivalent/substitutes out there ?

thanks in advance

[kparkfan]

No need to replace just rebuild them. Much cheaper and easy to do.

[Colin Green]

I've got these on my '83 GS450, and am thinking of replacing them...

I gather new ones aren't for sale anymore ?

are there equivalent/substitutes out there ?

thanks in advance

Why replace them. Unless something in them is worn so badly that it doesn't work any more I would suggest a good strip and clean.

Are they not working or what?

Click here to down load a tutorial on the CV carb cleaning (courtesy of Basscliff's web site.)
http://www.mtsac.edu/%7Ecliff/storag...ing_Series.pdf

and another link on tuning them

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

[pete]

There is also a PDF on BassCliff's site by Flaming Chainsaws specifically about cleaning the 450's BS34SS carbs and I'm going through cleaning mine right now, although I'll be a week or two away from the actual cleaning part.

[Flaming Chainsaws]

Just asking why you want to replace them. Are they broken or something? Do you want performance?

You can replace the stock BS34SS carbs with a CR carb although I'm not sure which one. That should give you better performance. Maybe a GS500 carb will work??? I don't know but why not try rebuilding them first?

My bike ran like crap but after I finished cleaning and rebuilding them, it was like a new bike.

Check out the guide I wrote on BassCliff's website.

[JG122]

thanks everyone

I gave them a major cleaning last year :

pilot jets cleaned, idle mixture plugs removed and the mixture screws taken out and cleaned... accelerator pump diaphram checked... valves adjusted... replaced the o-rings, and the intake boots...

I think I'm experiencing a combo of the ethanol in pump gas, plus some of the rust in the tank getting loose and winding up in the carbs.

really getting fed up

[Colin Green]

Try cleaning them out then installing an in line filter. If your tank is rusty and causing a problem for your carbs, swapping them out won't fix the problem for long.

There is also a tutorial on tank cleaning on Basscliff's website. But a good quality in line filter should solve the problem if tank cleaning isn't for you. Of course you will still have to clean the carbs out if indeed they have become blocked.

Another thought.... I have just been through the whole 'bike runs like schit' scenario and figured it to be dirty fuel so stripped and cleaned my carbs three time (busted a diaphragm in the process) only to find that the problem was simply a dud coil. Check to make sure all your plug caps are ok (haven't worked loose from the HT lead) and borrow a coil from somewhere to swap out and see if that sorts it out.

[cowboyup3371]

Colin, there've been a lot of posts here about those in-line filters causing other problems with getting the fuel to flow properly.

JG, you said the pilot jets were taken out and cleaned. Did you actually soak the carburetor bodies as well for at least 24 hours? There are smaller passages inside which you cannot see that can get clogged. I'd take them apart again and really soak each carb for 24 hours (be sure to strip it down first). You can put the jets into the same solution as the body while it is soaking and still come out ahead.

Plus, Colin is right you might want to consider getting some Por-15, Kreem, or vinegar and really clean out the tank. Just make sure you get a good liner in there or you'll have more problems later. A search will turn up a lot of info on the process.

Good luck and hope to see pictures.

[Colin Green]

Colin, there've been a lot of posts here about those in-line filters causing other problems with getting the fuel to flow properly.

You're not wrong, but while I also have had problems with fuel restriction when using filters, I figured it was the way they were installed as since I installed a filter like this http://www.z1enterprises.com/detail.aspx?ID=293
vertically (between carbs 2&3) the fuel has flowed fine.

[JG122]

that's the exact filter I use Colin

but I'm figuring that if there is rust getting loose and flowing downstream, it can get past the filter...

ok, first order of business is taking the tank off and cleaning

[Billy Ricks]

I've used Por-15 and it's really a good product. Quite a few reports here about Kreem failing and being a real pain to undo.

[Johnny Drummond]

Hi JG, I'm afraid that I can't say with absoloute certainty but mabye GS500 carbs might fit(although the GS500 may be a Europe/uk bike only), I have just looked on Alpha-sports suzuki parts website and they list the GS500 in the states in '95(GS500ES) and '96(GS500ET), sadly they do not give the carb size but the main jet size for both is 122.5 so they are the same carbs on both models.You could also try the Honda CB500 or the Kawasaki GPz 500 as alternatives, sorry that is all I can suggest but mabye it will give you a direction to look in.
Yours Johnny