BDT 38mm carbs on a GS 1150

[GS1150Pilot]

I've had only great experiences buying from members here, however. Too bad the GSX-R forum is not up to par.

[Joe H]

No I didn't. The 38mm GSXR carbs I purchased on the GSXR forum were completely disassembled and sent directly from the seller to a carb rebuilder trusted & recommended by members on the GSXR site including the seller. The rebuilder condemned the carbs as being so worn they were not worth investing any effort or more money in. I contacted the seller through the GSXR website and told him what the carb rebuilder he had recommended said about the carbs he sold me. No reply from him after he talked to the recommended carb rebuilder.

I decided to stick with what I know works and bought a new set of MIC 36mm flat slides.

I have had a spotty experience buying used parts from members of forums as opposed to parts from sellers on sites like Amazon.

Thats too bad, I have had good and bad experiences. Been burned on evil bay more than once!
But I still think is WAY better now than years ago, finding info and parts way back when was interesting for sure!!!

I am running 38mm cv gsxr carbs on my 1150, I had 36 RS's and still wish I had them!
The street manners of the 38mm cv is better for sure at low rpm, low speed around town stuff, they are more forgiving with ham fisted operation also.
The 38 cv I have had a standard dyno jet kit for the GSXR750 when I got them. I had to buy new needle jets and I then switched to Factory Pro jet kit, they make a kit specifically for running 38mm cv's on the 1100/1150. It worked MUCH better but Im still to rich in the midrange. It wants 150 mains but then the needle ends up at full lean lowest clip position! If I run 130 mains the midrange is much better but its really lean on top! It's driving me a bit crazy.
Factory Pro suggests removing the stock air jet, re-tapping it to more common mikuni air jet size and putting in one .2mm smaller than stock.
I also have been thinking of really lowering the float height which may help some seeing the carbs don't sit exactly as they would on a gsxr.

So I was hoping for some good advice……. Maybe I should buy some RS's

[rapidray]

Or a set of FCRs!!
Ray.

[Joe H]

Are they better?????
They sure cost a bunch but defiantly have a bling factor!!

If I could get these jetted perfectly they would be great but over the last couple years its been a compromise….although overall they work well with ZERO drivability problems. Just a wee bit fat right between 5 and 7 grand and thats with the needle all the way down, I think running a needle all the way down isn't the best compromise. I may go back to 130 mains even 140's the needle wants to be all the way down, I don't run full throttle much anymore, or maybe the float height, these are simple enough and don't require drilling and tapping!
I wish they made different needle jets it, the progression of the needle seems good just need to lean it out right in middle.
But what I know about carb tuning is very little! Although my collection of carb jets and needles would suggest otherwise…LOL

[chef1366]

http://www.thegsresources.com/_forum/showthread.php?223469-Bill-(Chef1366)-Carb-clean-and-Jetting-review&highlight=chef1366

[jstewart]

Joe I would liked to try the 38 CV's on my 1150. The set of 89 GSXR 38's I bought on the GSXR forum were cheap ($150) so I didn't lose to much. They were advertised as completely disassembled but all there. The seller sells a lot of stuff over there and suggested these carbs be sent to another GSXR forum member who rebuilds a lot of carbs for GSXR forum members. The rebuilder has a excellent reputation with other GSXR forum members and no negative feedback on that forum. I bought the carbs and had the seller send the carbs directly to the rebuilder he recommended for cleaning, assembly and repair if necessary. The carb rebuilder the seller recommended called me 4 weeks later and said this set of 38's could not be assembled because of damage to the throttle shaft/butterfly parts and other issues that made them not worth putting any more money into. Nice guy, he didn't charge me anything. I had him send the carbs back to the seller and contacted the seller about refunding my money. The seller who recommended this carb rebuilder responded that he thought the rebuilder may have damaged the carbs trying to assemble them and he was going to send the carbs to a professional carb rebuilder for evaluation. That was 6 weeks ago and no further response.


I just decided that it was probably more effort and expense to find a good set of GSXR 38mm CV's and then tune them for my 1150 than I am willing to expend. I sonic cleaned, rebuilt, and painted my stock CV carbs and bought a new set of Mickuni 36 flat slides. I am a member of the vintage Japanese motorcycle club and when I want to show the bike at VJMC events I will use the stock carbs/airbox and stock exhaust system and for general street fun run the V&H header and the 36mm flatslide carbs.

Rapidray I would have rather bought a new set of Kehin side draft flat slides but they are no longer available and I could not find a used set smaller than 41mm which are just to big for my application on the street.

Thats too bad, I have had good and bad experiences. Been burned on evil bay more than once!
But I still think is WAY better now than years ago, finding info and parts way back when was interesting for sure!!!

I am running 38mm cv gsxr carbs on my 1150, I had 36 RS's and still wish I had them!
The street manners of the 38mm cv is better for sure at low rpm, low speed around town stuff, they are more forgiving with ham fisted operation also.
The 38 cv I have had a standard dyno jet kit for the GSXR750 when I got them. I had to buy new needle jets and I then switched to Factory Pro jet kit, they make a kit specifically for running 38mm cv's on the 1100/1150. It worked MUCH better but Im still to rich in the midrange. It wants 150 mains but then the needle ends up at full lean lowest clip position! If I run 130 mains the midrange is much better but its really lean on top! It's driving me a bit crazy.
Factory Pro suggests removing the stock air jet, re-tapping it to more common mikuni air jet size and putting in one .2mm smaller than stock.
I also have been thinking of really lowering the float height which may help some seeing the carbs don't sit exactly as they would on a gsxr.

So I was hoping for some good advice……. Maybe I should buy some RS's

[Joe H]

I actually would recommend them even with the problems I am having. chef1366 is a good resource, he offered some great advice and will provide the services if needed. I am debating another rebuild, if I knew a couple years ago what I leaned in the past few days I could have saved myself a lot of trouble and some money!
They defiantly have better manners around town than the RS 36's (but the rs's were not bad just not as smooth) the 38's also pull very strong down low when the emulsion tubes are good ( I call them jet needles ?? don't know why??) but the RS's had a more liner directly connected to the wrist feel and sounded way cool!


So the two main draw backs of theses 38's from my limited understanding are slide guide wear and emulsion tube wear and they are linked so if I would have known that I would have replaced theses parts at the same time.
When I replaced the emulation tubes a couple years ago it was great, very crisp throttle, great manners I was happy. I had made some mods to motor, going to a 1260 piston and some shorter duration cams, so theres more than one factor in play here, which never helps diagnosis!
I am going to take a look as soon as I get some time and check the wear on the slides and tubes again, seems like that those may be the suspect as to why they seem so difficult to tune.

[jstewart]

So the two main draw backs of theses 38's from my limited understanding are slide guide wear and emulsion tube wear and they are linked so if I would have known that I would have replaced theses parts at the same time.
When I replaced the emulation tubes a couple years ago it was great, very crisp throttle, great manners I was happy. I had made some mods to motor, going to a 1260 piston and some shorter duration cams, so theres more than one factor in play here, which never helps diagnosis!
I am going to take a look as soon as I get some time and check the wear on the slides and tubes again, seems like that those may be the suspect as to why they seem so difficult to tune.

So where do you get replacement slides & emulsion tubes????? Are the replacement parts new or are you taking your chances in the used parts market? The slides are not listed as available from Suzuki and I don't think the emulsion tubes are either.

[chef1366]

I have a source for the slide guides.

[limeex2]

I picked up a set of 36's from a member , and had them rebuilt by a member. Have not had a chance to run them yet. Nice to know someone with lots of experience is here for help. 2-3 weeks hopefully, I should be able to burn some fossil fuel.

[Joe H]

So where do you get replacement slides & emulsion tubes????? Are the replacement parts new or are you taking your chances in the used parts market? The slides are not listed as available from Suzuki and I don't think the emulsion tubes are either.

I bought the emulsion tubes through bike bandit if I remember correctly, they should still be available, they are listed.
I think the DJ kit comes with emulsion tubes also, but not slide guides.
The slides are not listed anywhere on OEM stuff.
Bigger question for me is if the tubes are worn then it would suggest the needles would be worn also, to some extent. The emulsion tubes where around 30 bucks each, you can buy the entire DJ kit with the tubes for just a bit more.

My R/R is shot now so I may also take the time to check the wear on the slides and tubes again now that I have to dive into it, I am actually hoping they are bad it would explain a lot!

[Carter Turk]

I've have some chubby blunt DJ needles that came with the 36mm BST's I bought used. When I kept fouling plugs, I bought a Factory jet kit, still fouled plugs, then I heard about the emulsion tubes ovaling out. So I replaced those and finally had bike that ran on 4 cylinders. Later I changed all the 0-rings and my mileage improved by 10 mpg. There's also an 0-ring under the plastic slide guide that can easily be overlooked. Mine were all smashed and showing early signs of cracking, maybe presenting a richer condition than ideal.

[Joe H]

Thought I would post some pics of the worn slide glides on the BDT38's I have. The emulsion tubes are worn out again and after only about 2000 miles… because of the guides! I would have liked to post some pics of the tubes but I don't have any way to take anything but cell phone pics, the wear on the emulsion tubes can only be seen through a magnifier.
I will be replacing the guides, and the emulsion tubes and o rings. I am also hoping to get the emulsion tubes electroless nickel plated, I have been told this should make them last.
On a side note the needles from the Factory kit have NO wear marks, so they are made with a material that is much harder than the brass emulsion tubes. I will see if the nickel plating wears them, I have been told it won't that the nickel plating has lubricity to it and the new guides help a lot.
On the lower pic in the upper right corner of the guide you can see a small dot and a "crescent" shape, they are supposed to be on both sides and deeper, I don't know how much but several thousandths. You can feel a very slight ridge where the slide wore into the guide.
Interesting stuff Im learning!

[chef1366]

Thought I would post some pics of the worn slide glides on the BDT38's I have. The emulsion tubes are worn out again and after only about 2000 miles… because of the guides! I would have liked to post some pics of the tubes but I don't have any way to take anything but cell phone pics, the wear on the emulsion tubes can only be seen through a magnifier.
I will be replacing the guides, and the emulsion tubes and o rings. I am also hoping to get the emulsion tubes electroless nickel plated, I have been told this should make them last.
On a side note the needles from the Factory kit have NO wear marks, so they are made with a material that is much harder than the brass emulsion tubes. I will see if the nickel plating wears them, I have been told it won't that the nickel plating has lubricity to it and the new guides help a lot.
On the lower pic in the upper right corner of the guide you can see a small dot and a "crescent" shape, they are supposed to be on both sides and deeper, I don't know how much but several thousandths. You can feel a very slight ridge where the slide wore into the guide.
Interesting stuff Im learning!

I have seen them worn all the way through.

[Joe H]

All the way through!! Can they even work like that???
I am noticing the problem now I can't imagine….

The way they are now it still pulls fairly cleanly all the way through the rpm range, just can't seem to get it lean enough on the bottom or midrange and my milage has decreased noticeably. Im going to keep running it the way it is until winter. I ordered parts and they should show up soon.
I am debating electroless platting the emulsion tubes myself with a kit, have been doing some research seems easy enough. I will do an old one first to get a feel for it if I go that route.