Hi guys,
I'm pretty frustrated with the stock carbs and my slides are worn very unevenly, if I can find replaments they seem more expnsive than a new set of VM seris carbs. If the float sticks or leaks at all, gas sits on the two small jets at the bottom of the inlet side and varnishes them in a hurry.
Anyone ever try swapping out the carbs?
I considered it.
VM's are very easy to tune. There is a set available for the GS500 already set up but they are very expensive.
Quote from: Scubasteve1 on June 14, 2018, 11:19:50 AM
Hi guys,
I'm pretty frustrated with the stock carbs and my slides are worn very unevenly, if I can find replaments they seem more expnsive than a new set of VM seris carbs. If the float sticks or leaks at all, gas sits on the two small jets at the bottom of the inlet side and varnishes them in a hurry.
Anyone ever try swapping out the carbs?
Can you link to an example of his VB carb which is compatible with the GS500?
seems much easier to replace the float needle valves so they don't stick and cause the pilot jet clogging you describe :dunno_black:
FWIW I considered putting in VM carbs but it'd be a tuning adventure to say the least, a real project. Making the stock carbs work right is way, way easier.
If you have the 3-circuit carbs then those are everywhere, should be able to buy a replacement used set without the worn slides (which, this is the first I have heard of) for $50-100 and then another $30 to replace all of the o-rings and float needle valves, viola, problem solved for less than 1/3 the cost of one VM carb.
IMHO.
How did you diagnose the worn slide issue?
My saved link for the carb set is no longer valid. Found another very interesting one but too expensive for me. Looks pretty good though. Kehins not mikunis, which are harder to get jets for I have found.
http://speeddealercustoms.com/product/keihin-33mm-round-slide-carb-kit-cr-33-suzuki-gs500-e-f/
It's not just the carbs that will need swapped. You'll lose your choke cable, and need a different throttle cable (and maybe throttle housing, but check MikesXS.com for the throttle cable at least). Your intake boots should be good, but you'll probably need a new air filter setup too. Oh.... VM carbs don't come with the proper slides / needles / jets, so those will need swapped too.
As far as jetting goes, look around for what guys have figured out for the XS650 and jet down.
Totally feasible to put VM carbs on a GS, but understand it's a good bit of work and money.
I am really curious about the Mikuni VM swap. I have always preferred the regular slide carbs to the vacuum carbs, but my head is stuck in the '60s and '70's.
These are rough-jetted these, I'm still waiting on parts to make a throttle cable to take it on a road test and put some kind of load on the bike... and see here it just falls on its face. I will not take credit for the jetting.
The slide wear is totally visible and can be measured. One slide has rubbed down something like .020", and these have been a bear to balance at the shop. New slides and slide guides would already put me at say $200 already.
Edit: This idle is pretty slow, I was curious if it would stay stable here or not and I was playing with the carb sync. 1/4" turn of the idle screw and it will idle just fine and RPM vs throttle position is pretty darn smooth and does not drop or suddenly raise. Obviously this thing needed to be on the road (or test road/track, under a real load) to test not just on the center stand.
I will definitely play with these more and make these work long-term.
Quote from: Scubasteve1 on June 14, 2018, 11:19:50 AM
Hi guys,
I'm pretty frustrated with the stock carbs and my slides are worn very unevenly, if I can find replaments they seem more expnsive than a new set of VM seris carbs. If the float sticks or leaks at all, gas sits on the two small jets at the bottom of the inlet side and varnishes them in a hurry.
Anyone ever try swapping out the carbs?
I sent my carbs out to be cleaned and rebuilt over five weeks ago to a guy in the UK. Reason it is taking so long is because he told me the slide guides were worn and needed replacement. He had a tough time finding some new ones. He told me he found some at an BMW specialist in Poland as the BMW F650 used the same BST33 carbs. He had said previously they were estimated to cost £50 Pair. I have not received the final price for him though.