# Newbie question? What Power Gains from r1 carbs on a exh cammed 9a 2.0 16v will I get over cis-e, thats running good?



## chipperdavis2305 (Mar 5, 2010)

What gains will I net, I have seen countless videos, and have yet to really understand where I will get gains....Throttle response, mid range, reliability? I have the r1 carbs, but in the last week I have my 2.0 16v runnin pretty solid on cis-e. I would hate to switch to carbs, and it be the same, or just a trade off in location of powerband... Do they rev higher and still make power in the higher rpms. :thumbup:

Any opinions appreciated.....


----------



## Snatcher (Apr 3, 2009)

You'll get insane throttle response that's for sure. Plus you can rev to whatever RPM until your engine blows. You get insane sound. As for HP, you'll probably gain a few. There's a dude on this section that did CBR900 carbs on his 16v and to me it looks like a good result. If you want power, go boost!


----------



## antichristonwheels (Jun 14, 2001)

What is this supposed to be? The magic 8-ball dyno?


----------



## Snatcher (Apr 3, 2009)

antichristonwheels said:


> What is this supposed to be? The magic 8-ball dyno?


:shake8-ball: "Not today..." lol


----------



## bmwquick (May 17, 2010)

Can someone else PLEASE chime in on this topic? I have a 9a 16V with mild-medium headwork (P'n'P), cams and exhaust. I'm currently rebuilding the engine and debating whether I should keep the stock CIS-E Motronic system or convert to bike carbs. Would 165-170 hp at the crank be a reasonable expectation? 

Also, tuning bike carbs is mainly swapping main jets and maybe pilot jets, correct? So tuning should be super easy if I have a wideband 02? Why does everyone say bike carbs are super hard to tune? They seem to have less adjustable parameters than Webers (just pilots and mains).


----------



## The Python (Aug 1, 2007)

Just go ahead and do it:thumbup:
The throttle response will be better, and the HP gains will be just on the high side of noticeable.

The #1 bonus is the decrease in clutter factor under the bonnet.

You will notice that for nearly every modification there will be those who claim it is :
-not worth it
-too hard
-will blow up your car
-etc., etc., etc...

You will likely be surprised at how easy it is to install and tune.


----------



## Wildkard9 (Nov 26, 2002)

For the record the original poster of this thread did ultimately stay with the CIS-e. But only because I bought him out of what parts he had. 

bmwquick to really answer your question, I have to ask one. Is there really anything wrong with your current setup? Is there power to be made in a carb swap? Sure. How much depends on what your baseline before was. I started with a stock motor. Ran the crap out of it. Beefed up everything and had a dyno sheet of 143. That was on CIS-e. It went to crap on me. So Im making the change over to get rid of headaches. No worry about vaccum leaks. Cold start valve issues? gone.

When the system works. It works.


----------



## bmwquick (May 17, 2010)

Well my stock setup does not run well. The engine was rebuilt


----------



## Wildkard9 (Nov 26, 2002)

a bouncing idle sounds more like a vaccum leak. So do a few other symptoms. But ultimately it is your decision on changing over or not. Just to give a quick list of what Ive spent on mine and still havent finished everything.

250 for the carb and flange
~100 for flange to be tig'd up for the carbs
130 for fuel pressure regulator
15 for choke cable
75 for fuel pump
16 for nipples to FPR
20ish for hose
15 for wiring odds and ends


----------



## B4S (Apr 16, 2003)

bmwquick said:


> Can someone else PLEASE chime in on this topic? I have a 9a 16V with mild-medium headwork (P'n'P), cams and exhaust. I'm currently rebuilding the engine and debating whether I should keep the stock CIS-E Motronic system or convert to bike carbs. Would 165-170 hp at the crank be a reasonable expectation?
> 
> Also, tuning bike carbs is mainly swapping main jets and maybe pilot jets, correct? So tuning should be super easy if I have a wideband 02? Why does everyone say bike carbs are super hard to tune? They seem to have less adjustable parameters than Webers (just pilots and mains).


If this is what you truly believe that carb tuning will be like (bike or car)...then I wish you all the luck in the world . Having fewer things to mess with on a carb does not make it easier to tune...it makes it less likely you'll get it right quickly .

Try it and see, there's a nice thread about converting to bike carbs. That's the best place for info IMO. :thumbup:.


----------



## bmwquick (May 17, 2010)

Wildkard9 said:


> a bouncing idle sounds more like a vaccum leak. So do a few other symptoms. But ultimately it is your decision on changing over or not. Just to give a quick list of what Ive spent on mine and still havent finished everything.
> 
> 250 for the carb and flange
> ~100 for flange to be tig'd up for the carbs
> ...


No, there are no vacuum leaks I've checked that. The only things I did not fully look over were the o2 sensor and the knock sensors. The engine harness is also super brittle and I've already had to fix several broken wires. I'm thinking there might be more wireing that is broken/shorting that might be messing with a sensors signal and causing poor drivability. 

Basically I'm going to put a bit of money in new sensors and harness to get the CIS-E running 100%. So that's why I've been interested in carbs and also because I need a project this summer. thanks for the price list.




B4S said:


> If this is what you truly believe that carb tuning will be like (bike or car)...then I wish you all the luck in the world . Having fewer things to mess with on a carb does not make it easier to tune...it makes it less likely you'll get it right quickly .
> 
> Try it and see, there's a nice thread about converting to bike carbs. That's the best place for info IMO. :thumbup:.


I wasn't saying tuning carbs would be easy, I was asking how much more difficult are they to properly tune than say Weber's?? Because I've seen people say they are super difficult to set up/tune then others say just rejet, get proper fueling, and bolt them in. That doesn't sound super difficult if that's all that's needed.

Anymore advice??? I'm like 50/50 on CIS-E/carbs right now. thx


----------



## Wildkard9 (Nov 26, 2002)

Notta problem with the pricing. I literally just got the final items to complete my swap so most of those are current (except the flange and carbs, I lucked out and got those a little cheaper) And if you do decide to forge ahead make sure you have a buddy that can tig weld or has the stuff to do it. The professional shops in my area wanted 200 to 300 just to do the job! :S


----------



## B4S (Apr 16, 2003)

bmwquick said:


> I wasn't saying tuning carbs would be easy, I was asking how much more difficult are they to properly tune than say Weber's?? Because I've seen people say they are super difficult to set up/tune then others say just rejet, get proper fueling, and bolt them in. That doesn't sound super difficult if that's all that's needed.
> 
> Anymore advice??? I'm like 50/50 on CIS-E/carbs right now. thx


I don't have any experience with bike carbs, so I can't really say how hard they are to set up. I'm a VERY picky person when it comes to my sidedrafts, and probably would not be satisfied with the way bike carbs perform when bolted on with a redrilled main and nothing else.

The one thing I've noticed over the years is that everyone has different ideas as to what "proper" tuning is. So take that into mind when deciding your path. These same people who bolt them on and go may be getting 15mpg due to improper tuning...but without follow up, there's no way of knowing.


----------



## bmwquick (May 17, 2010)

Well if I do go carbs I would really like to get them to be (somewhat) drivable on the street, even if it requires frequent tuning. And by drivable, I'd like relatively smooth power delivery and a decent idle once the engine warms up. Is that too much to ask out of carbs? I am NOT planning on just slapping them in with redrilled jets and calling it done. I do want to properly tune them. 

And as far as tuning goes, I need would need to adjust: 1. main jetting, 2. pilot jetting (heard people dont mess with pilots?), and 3. mixture screws, 4. adjust float bowls, 5. proper fuel pressure. What I've gathered from other bike carb treads is that these are really the only things you are able to tune on bike carbs. Is that correct?


----------



## B4S (Apr 16, 2003)

Pilot jets control the cruise and idle fuel mixture...so they're very important to get right . Most folks just drill out the mains (which is perfectly fine), but leave the cruise fueling alone...which can cost $$$ in gas bills. The mixture screws are just for idling, so pretty much any size pilot jet will work to get it running (more or less). Once you're rolling though, at part throttle, those jets will come into play bigtime. The mains are for WOT, or high rpm, high throttle conditions.


----------



## bmwquick (May 17, 2010)

Wildkard9 said:


> Notta problem with the pricing. I literally just got the final items to complete my swap so most of those are current (except the flange and carbs, I lucked out and got those a little cheaper) And if you do decide to forge ahead make sure you have a buddy that can tig weld or has the stuff to do it. The professional shops in my area wanted 200 to 300 just to do the job! :S


Well I'm planning to get a used mani on the forums but I haven't really looked for one yet. Building one is out of the question as I dont have welding/metal fab skills. 



B4S said:


> Pilot jets control the cruise and idle fuel mixture...so they're very important to get right . Most folks just drill out the mains (which is perfectly fine), but leave the cruise fueling alone...which can cost $$$ in gas bills. The mixture screws are just for idling, so pretty much any size pilot jet will work to get it running (more or less). Once you're rolling though, at part throttle, those jets will come into play bigtime. The mains are for WOT, or high rpm, high throttle conditions.


I see, that's mostly what I assumed. I'm thinking about getting the book Weber Carburetors by Braden, or How to Build and Power Tune Weber & Dellorto Dcoe & Dhla Carburetors. I'm much more familier with FI than carbs so I'd like to learn about them a bit before I dive into this.


----------



## B4S (Apr 16, 2003)

I've got both, they're a worthwhile purchase if you'd like to learn more IMO :thumbup:.


----------



## MKIGTITDI (Aug 25, 2007)

Ive ran the r1 carbs for close to 6 months and ive averaged 20-30 mpg depending on my driving style and i didnt find them to difficult to tune. If i remember right based on what i read on the tuning gidlines on a couple of motorcycle sites you should be running on the needles for the majority of your cruising and driving like on the freeway. Personally i was having the same problems with my CIS and once i got the carbs on and even partially dialed in those issues were out the window.
Heres a video of my car semi tuned pulling to 90

http://www.youtube.com/watch?v=Rp8naXNvfp0


----------



## Wildkard9 (Nov 26, 2002)

MKIGTITDI said:


> Ive ran the r1 carbs for close to 6 months and ive averaged 20-30 mpg depending on my driving style and i didnt find them to difficult to tune. If i remember right based on what i read on the tuning gidlines on a couple of motorcycle sites you should be running on the needles for the majority of your cruising and driving like on the freeway. Personally i was having the same problems with my CIS and once i got the carbs on and even partially dialed in those issues were out the window.
> Heres a video of my car semi tuned pulling to 90
> 
> http://www.youtube.com/watch?v=Rp8naXNvfp0


What was your final jet sizing on everything?


----------



## MKIGTITDI (Aug 25, 2007)

i was running the stock 160 pilot jets the needles in their highest setting and 200 mains


----------



## bmwquick (May 17, 2010)

MKIGTITDI said:


> Ive ran the r1 carbs for close to 6 months and ive averaged 20-30 mpg depending on my driving style and i didnt find them to difficult to tune. If i remember right based on what i read on the tuning gidlines on a couple of motorcycle sites you should be running on the needles for the majority of your cruising and driving like on the freeway. Personally i was having the same problems with my CIS and once i got the carbs on and even partially dialed in those issues were out the window.
> Heres a video of my car semi tuned pulling to 90
> 
> http://www.youtube.com/watch?v=Rp8naXNvfp0


Wow, that's almost better mileage than I get stock. How are cold starts and cold running?? Do you bike carb'd guys have to get out the starter fluid on super cold days? Assuming your using a choke of course.


----------



## MKIGTITDI (Aug 25, 2007)

Haven't had to do that ever. I just choke it and it cranks a couple of times and it fires. Then again the coldest it gets here is high 20's


----------



## Wildkard9 (Nov 26, 2002)

MKIGTITDI said:


> i was running the stock 160 pilot jets the needles in their highest setting and 200 mains


sweet, mine should be finished up here shortly


----------



## MKIGTITDI (Aug 25, 2007)

Minor disclaimer. I did have a ported head and 280* cam that rev'd to 7k. Your main jets might need to be a little smaller.


----------



## Wildkard9 (Nov 26, 2002)

I figured as much. By my figuring with the cam change and engine work already done. A 160 or 185 would be about perfect. Now once I finish up my 2.0's machine work Ill probably go even bigger on the cam and really push the envelope by using 200's


----------



## MKIGTITDI (Aug 25, 2007)

Yeah im keeping the 200's in it with my new head im getting next week but in the near future im told ill have to go down to like 150's when i go to boost the bitch.


----------



## Wildkard9 (Nov 26, 2002)

and yours is a 16v correct? Could you shoot me a few pictures of the angles you had to do to keep it under the hood? The machinist is coming out to do a few measurements for cut down


----------



## MKIGTITDI (Aug 25, 2007)

Ill be doing an 8v. i found a heavily ported freshly head built for 500. I really dont do measurments at all i just cut the pieces to work. If your really worried about clearing your hood sell your R1 carbs and buy a set of yamaha RX-1 snowmobile carbs. Their identical in every way except their draft orientation. the RX1s are straight side draft carbs.


----------



## MKIGTITDI (Aug 25, 2007)

eres a pic of a set of RX1s kind of how my cars going to be set up. except this ones turbod so ill have a blower mounter into the picture somehow....


----------

