yep another bike carb thread

[turabaka]

Well guys, I've been looking into upgrading carbs again after I finish all my headwork. 45 DCOE's are just too expensive for me, so I've been looking at bike carbs.

Obviously I'm going to want to go with something decently big. 40 or 45mm from what I'm reading.

I've got a couple of questions though that I can't really find the answers to.

Is it relatively easy to setup quad bike carbs? Obviously not as easy as a Weber, but I kinda want to know what I'm getting into. :help:

What psi do these things like to run at? Am I going to be okay with my holley blue pump, or am I going to have to get a higher psi fuel pump?

I thought we had some threads about bike carbs, but I'm having trouble finding them. If you guys know where they are pretty please point me toward them.

and lastly. For the few people on here running bike carbs. What kind of carbs are you using?

[Rendon LX-i]

I would ask Zeph with i havent seen on here for awhile...i seen it in person...big cam and think sound NASTY...in a good way...Anywho....all he did is cut enought to put some couples to the big carbs off the intake runners...not hard at all if say. BUT i would upgrade the pump like you said and idk what else you would need since your carbed already bro.....ASK john also he knows whats up

[2ndGenGuy]

Here, I just fired mine up. Need a bit of jetting. These are completely stock jetting for the motorcycle, and I will say it's pretty fucking close to being drivable. They run much better after warming up a little bit. These are 38mm, you can get bigger for about the same price. Remember that a 40DCOE will only take a 38mm choke, and a 45DCOE will only take like a 42mm choke.

http://www.youtube.com/watch?v=pPs92KrCaj8

That obnoxious loud noise at the beginning is the Holley red fuel pump. The bike carbs will only take about 2psi tops. I already flooded them out once or twice fucking with the regulator.

The carbs are Mikuni BST38SS CV carbs from a GSXR 750. I paid about $80 for them.

Also, here you go, every Motorcycle Carburetor listed on eBay.

http://motors.shop.ebay.com/items/Motorcycle-Parts__W0QQPartQ2520TypeZIntakeQ2520Q2526Q2520Fuel Q2520SystemQQIntakeQ2520Q2526Q2520FuelQ2520SystemQ 2520PartQ2520TypeZCarburetorsQQ_dmptZMotorcyclesQ5 fPartsQ5fAccessoriesQQ_flnZ1QQ_sacatZ10063QQ_ssovZ 1QQ_trksidZp4506Q2ec0Q2em282

I hope that link works...

[turabaka]

Here, I just fired mine up. Need a bit of jetting. These are completely stock jetting for the motorcycle, and I will say it's pretty fucking close to being drivable. They run much better after warming up a little bit. These are 38mm, you can get bigger for about the same price. Remember that a 40DCOE will only take a 38mm choke, and a 45DCOE will only take like a 42mm choke.

http://www.youtube.com/watch?v=pPs92KrCaj8

That obnoxious loud noise at the beginning is the Holley red fuel pump. The bike carbs will only take about 2psi tops. I already flooded them out once or twice fucking with the regulator.

The carbs are Mikuni BST38SS CV carbs from a GSXR 750. I paid about $80 for them.

Also, here you go, every Motorcycle Carburetor listed on eBay.

http://motors.shop.ebay.com/items/Motorcycle-Parts__W0QQPartQ2520TypeZIntakeQ2520Q2526Q2520Fuel Q2520SystemQQIntakeQ2520Q2526Q2520FuelQ2520SystemQ 2520PartQ2520TypeZCarburetorsQQ_dmptZMotorcyclesQ5 fPartsQ5fAccessoriesQQ_flnZ1QQ_sacatZ10063QQ_ssovZ 1QQ_trksidZp4506Q2ec0Q2em282

I hope that link works...

Awesome. I guess I don't need to upgrade my pump then, since I've got my holley choked down to 3 psi now, and it'll go lower if I need it to.

as for the size on those, should I go a little bigger than what you were doing since I'm doing a lot of headwork or does that seem plenty big for the carbs?

[2ndGenGuy]

Yeah bike carbs usually run on gravity feed. So you should be A-OK with whatever pump you want. I really don't know what size to go with. I think it's going to be mostly trial and error. I think Zeph was running 32s on his, I wanna say? I think 38s would be fine to start with. I'm probably as new to this as your are...

Remember, I'm also running a B20A, which is making about 40 more HP than a stock A20. I think 38-40 is a good starting point. 45s are going to be pretty much flat slide race carbs. I don't know how driveable they are, mostly used on drag bikes from what I understand. Good for WOT but not so driveable. I think the CV carbs are a good way to from what I understand they're the easiest to tune and won't bog down and hesitate like the Webers or other race carbs. I'll be tuning my carbs over the next couple weeks, I'm sure so you can follow my thread and see how it goes. Looking for jets and air cleaners tonight, probably will order them ASAP.

[turabaka]

awesome dude. I'll definitely be following. Probably make the switch to bike carbs after I do all my headwork. We'll see. Thanks for all the info.

[turabaka]

Would something like these work pretty well for our cars?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=120416383266

plenty big? I'd rather go too big than too small.

[2ndGenGuy]

Yeah I was just looking at those the other day. I was thinking about picking them up myself. :-P Do you have any idea how big those are?

Looking on Wikipedia, I see that they went with 38mm from 1996 to 1999. So either they are the same or smaller from 93 to 95.

The best way to get the diagrams and part info for OEM carbs like these, is to get the FSM for the bike that they come off of. I found the GSXR manual online in PDF format, and extracted all the pages having to do with the carbs.

For the price, you sure as hell can't go wrong! Wanna upgrade? Buy a new set!

[turabaka]

Yeah I was just looking at those the other day. I was thinking about picking them up myself. :-P Do you have any idea how big those are?

Looking on Wikipedia, I see that they went with 38mm from 1996 to 1999. So either they are the same or smaller from 93 to 95.

I'll keep my eye on them, and probably pick them up as long as they stay cheap. Can't hurt with how cheap bike carbs are. I figure if these are too small I'm only out a little bit. I'd have to buy a shitload of bike carbs to equal the cost of dual 45 webers.

[2oodoor]

there is a little info on some other sites if you look around, one would be redpepperracing, also dont be afraid to look at other models forums like toyota, minicooper, opel etc.

[Hauntd ca3]

45s are going to be pretty much flat slide race carbs. I don't know how driveable they are, mostly used on drag bikes from what I understand. Good for WOT but not so driveable. I think the CV carbs are a good way to from what I understand they're the easiest to tune and won't bog down and hesitate like the Webers or other race carbs. I'll be tuning my carbs over the next couple weeks, I'm sure so you can follow my thread and see how it goes. Looking for jets and air cleaners tonight, probably will order them ASAP.

with flat slides, as long as they are sized, jetted and balanced right, there is nothing wrong with them for day to day use.
i,ve ridden many bikes with flat slides, and they were generally fine at most throttle openings
not as nice as a cv type carb but you can live with them.

[turabaka]

Woot. picked up those bike carbs I linked too earlier. So I'm gonna go pick up a junkyard manifold to mess with later this week, and probably buy a rebuild kit for them. I might experiment with them a bit before I finish all my headwork since I'm a bit of an impatient tinkerer. I get new toys, and can't wait to play with them.

[turabaka]

Alright guys I've got another question.
Where's a good place to pick up jets for these honda bike carbs?
Also can the stacks be changed out on these or am I stuck with the really short, ugly ass stacks that's on them stock?

[2ndGenGuy]

Yeah, I'm trying to work out the details of getting jets for the OEM carbs too. You got Keihein's right? You should hit up the forums from whatever motorcycle those came off of... I hit the GSXR forums, and got some good insight. You might have to compare pictures of the jets and see what you can find.

[turabaka]

For some reason I was thinking the cbr900rr's came with mikuni's, but they have keihein stamped right on the side so I guess that's what they are. lol. I'll try lurking around some of the motorcycle forums and see what I can see.

[Hauntd ca3]

any decent motorbike tuner should be able to get jets for them