RS flat slides vs vintage smoothbores

[pano]

What is the better carb?

Seems to me if you were going to pony up 400 bucks for a used set of vintage 33mm smoothbores you may as well get brand new RS flatslides for a few hundred more and not have to worry about what condition they are in.

Are there performance advantages of one over the other?

 

[Hoomgar]

What is the better carb?

Seems to me if you were going to pony up 400 bucks for a used set of vintage 33mm smoothbores you may as well get brand new RS flatslides for a few hundred more and not have to worry about what condition they are in.

Are there performance advantages of one over the other?

I believe everyone will tell you the flatslides are better. The smoothbores are just as you said, vintage. They are a vintage performance upgrade if that is your thing. If you are only looking to upgrade performance and are more interested in the performance than you are the vintage part of it go with the flatslides. Smoothies are good when you find them at a good price. Flatslides I believe are going to run a little more than 400 new.

 

[skip]

the flatslides are better as long as you dont over carb your bike. a common mistake is putting to much carb on and not having enough air and cc to make them work. you will lose some of your bottom end grunt with most performance carbs but after midrange you will see the difference,on the 1150 I had it was more responsive with the stock carbs and pulled harder under 4000 rpm. From 4000 to 6000 they was very similar, but from 6000 on up there was no comparison. With the carb change ( 38 rs flatslides) alone the bike picked up 3 mph in the 1/4. May not sound like alot but ask the dragracers and they will tell you it is, especially for one mod.

 

[oldschoolGS]

For me putting a new set of RS36's on my 1157cc Bandit has been one of the easiest mods I have ever done. Baseline settings out of the box were very close with only small tweaks to the low speed jetting required.

I bought new as I wanted to start from a known point and not have to mess around trying to sort out someone else's mess. Cost wise used they go for around $400 and new deals can be had around $650.

I replaced the 36CV's with the RS36's as I plan to stay stock bore and compression for a while and felt the RS38's would sacrafice too much midrange. All I can say is WOW, these things rock. They are very streetable and power wise below 6000rpm is very similar to stock. As Skip said, above 6000rpm they really make a difference (I am also running GSXR750 cams). Totally transformed the bike and highly recommended overall.

Good Luck, Ed.
2005 GSF1200SZ
1983 GS750ED
1992 Ducati 900SS

 

[minutemen]

I have two sets of 33 smoothbores. i paid 235.00 for one set and 190.00 for the other.I've seen stock 1150 and 1100 carbs with jet kits go for 150.00-200.00 on ebay.I think the 33s are adequate for an 1166 with 340 web cams .I ran a 10.92 at the strip and on top end its still pulling hard at 140mph.

 

[katanarama]

I believe everyone will tell you the flatslides are better. The smoothbores are just as you said, vintage. They are a vintage performance upgrade if that is your thing. If you are only looking to upgrade performance and are more interested in the performance than you are the vintage part of it go with the flatslides. Smoothies are good when you find them at a good price. Flatslides I believe are going to run a little more than 400 new.

I agree. I started with 33 Smoothbores on my 1166.They were hard on the right wrist and temperamental to set up. Keep in mind that these are an old school racing carb and my set had been around the block a few times. I have RS36s on the bike now. They are a more modern carby, were simple to set up and are more street-able and easy on the right hand. The accelerator pump the RS36's use works very well. To temper all of this, the RS36s came from another HP Kat, and were ready to go with just minor tuning. My 33s went to that other HP Kat. "That Kat" is this one http://www.thegsresources.com/_forum/showthread.php?t=74779
The bike runs very strongly with them ;-)


Just a note here about the noise the carbs make. The 36s make one of the product’s idiosyncrasies. The smoothbores make an amazing induction noise, like a mean snake with a head cold.

 

[don_gibb6512]

When I bought my set of 34mm FS's for my GS1100GLD, I had no plans on racing (and probably never will) and was told that the 34mm's would be better for overall street riding than the Mikuni recommended 36mm's. I have since moved on to a GS1000G and put the FS's on that. I had it Dyno tuned but it's got a lean surge in mid-range. I think this can be fixed by moving the needle up (it's at the 4th position right now). My real question is: was the advice I got about the 34mm's being better for overall street riding correct? Now, that I'm just about ready to start my project bike, a 1980 GS1100ET, I kinda wish I had the extra size in the 36mm's but like I said, I'm probably never going to race this bike and sure would like a smooth ride again. There's no doubt the FS's open up the power of the motor. I've got this set up with a V&H 4-1 pipe and K&N pods. I'm asking this question here instead of starting a new thread in the Tech section because it seems to have caught the attention of other FS mod guys and it might benefit Pano also. Thanks.

 

[oldschoolGS]

IMHO, RS34's belong on a modified 750 and RS36's on a mild 1100. If I was building a radical 1100, I would probably go with RS38's.

My 1157cc Bandit is currently set up:
---stock 9.5-1 compression
---.355 lift GSXR750 cams
---5 degree advancer
---Yosh RS3 pipe

It absolutely loves the RS36's. Power everywhere with no flatspots and a real kick at 6500rpm. Overall a highly recommended carb choice.

Another option to retaining mild street manners is to find a nice set of jetted 36CV carbs. Several years of GSXR bikes came with the 36's as well as all Bandit 1200 models (although the 2001 and up models have a TPS system).

Good Luck, Ed.
2005 GSF1200SZ
1983 GS750ED
1992 Ducati 900SS

 

[Baatfam]

I've got the 33 smoothies on the drag bike runnin' low nines....

On the advice of more than one person, I'm lookin' for a set of 36 or 38 FS to put on over the winter.

I want to see 8s \\/

Later,
Bob T.

 

[don_gibb6512]

***********
IMHO, RS34's belong on a modified 750 and RS36's on a mild 1100. If I was building a radical 1100, I would probably go with RS38's.

It absolutely loves the RS36's. Power everywhere with no flatspots and a real kick at 6500rpm. Overall a highly recommended carb choice.
***********


That's what I thought. Dang it anyway. I bought these when I was truly ignorant (more than I am now at least) of what these were all about. I'll see how the 34's perform on the 1100ET and probably end up selling them on ebay along with a set of 33mm SB's that I have to raise the money for a set of 36mm FS's.



**************
Another option to retaining mild street manners is to find a nice set of jetted 36CV carbs. Several years of GSXR bikes came with the 36's as well as all Bandit 1200 models (although the 2001 and up models have a TPS system).
**************

Yeah, I heard that. As long as the spacing is the same, I should be good to go with a set of CV's from about '86-'92. I keep an eye open for a set of those popping up on ebay.

Thanks !!!

Don

 

[pano]

Thanks for all the replies. It looks like a set of RS36's would be a good fit for my 1100 project.

 

[johnnay]

Can anyone point me to a good guide on stockers vs. flatslides vs. smoothbores etc., preferably with pictures? I'd like to be able to tell the difference... thx!

 

[pano]

You can see RS Flatslides here

https://www.sudco.com/

vintage smoothbores here

http://cgi.ebay.com/ebaymotors/ws/e...tem=130021777963&rd=1&sspagename=STRK:MEWA:IT

stock carbs here

http://cgi.ebay.com/ebaymotors/ws/e...tem=170025018362&rd=1&sspagename=STRK:MEWA:IT

 

[johnnay]

Cool - thanks!

 

[jgordon]

You can see RS Flatslides here

https://www.sudco.com/

vintage smoothbores here

http://cgi.ebay.com/ebaymotors/ws/e...tem=130021777963&rd=1&sspagename=STRK:MEWA:IT

stock carbs here

http://cgi.ebay.com/ebaymotors/ws/e...tem=170025018362&rd=1&sspagename=STRK:MEWA:IT

Looks like the guy with the smoothbores forgot to put the reserve in there. They went for Waaaay Too Cheap (-:

I'm surprised that no one has mentioned the GSXR carbs for an upgrade.

 

[U.P.dragracer]

:-D I put a set of GSXR carbs on my 1100 low and mid RPM performance was like night and day compared to the stockers . {would be awesome on a streetbike } but I did not pick up any top end perormance . I did not get to finish jetting them because of a stripped out main jet emulsion tube . But I'll have them fixed up soon for more testing .

I could do 2nd gear burnouts at 1/4 throttle with the GSXR carbs . with the stock carbs I have to screw it on quite a bit more LOL!!:-D

 

[Motoplas]

Setting up information

Setting up information

Hi Guys,
I recently aquired a set of 33mm Cr's which need setting up.
Does anyone know where this information can be found.eg suggested pilots, needles, float heights etc.I am running an GSX 1100 with 1170 kit with cams.
They came with 140 mains which were too big I went down to 130's but it was still fluffy. Low down was eratic. There is certainly a lot more power than cv's.

Thanks,

Noel