Topic: Who has Keihin CR parts? slides needed

[brandEn]

mods: I am posting this here cuz most of the hi-po guys never make it to the wanted section. I apologize in advance if it must be moved.


After taking my bike on the Dyno today it appears I need some leaner "throttle valves" (slides) for my CR29's. Our friends at Sudco want almost $200 for a set of these suckers and I am just not paying that much. Any chance someone here has a set of size 3.0mm carb slides? I can swap you for my like new 2.5 slides or just buy them. CR 26-33's all use the same slide part numbers. Any help appreciated.


Keihin part # 018-642
item #22

[turboguzzi]

cant help you with slides

but from my experience, CR are highly adaptive through just main jets, needle height and idel mixture screw. thats all i needed to touch and my 29 have already moved three bikes with 500, 600 & 810 cc... you have also the simple option of changing the external air jet in the front (never needed to touch it)

are you sure your dyno guy knows slide carbs? most of them nowadayswork only on injected bikes and are usually quite surprised that you cnat wack the throttle open on slide carbs without the engine bogging 

[Darvill Racing]

I also have a question:

Are all the float bowls the same size...?

I won't bore you with the reason but looking through the parts manual they all seem to have the same part number.

Regards,
A

[brandEn]

I also have a question:

Are all the float bowls the same size...?

I won't bore you with the reason but looking through the parts manual they all seem to have the same part number.

Regards,
A

Yes, bowls are the same size.

[brandEn]

cant help you with slides

but from my experience, CR are highly adaptive through just main jets, needle height and idel mixture screw. thats all i needed to touch and my 29 have already moved three bikes with 500, 600 & 810 cc... you have also the simple option of changing the external air jet in the front (never needed to touch it)

are you sure your dyno guy knows slide carbs? most of them nowadayswork only on injected bikes and are usually quite surprised that you cnat wack the throttle open on slide carbs without the engine bogging 

Yes, my tuner is our own Doctor_D. We messed around with everything and she just runs rich down low.

[Terry in Australia]

Ah, good ol' CR carbs, great on WOT race applications, but I wonder how many owners have blown their brains out after spending a weekend trying to get them to work properly on a road bike?

I've got a set of new 31mm CR's in a box, and a set of 33mm Mikuni smoothbores as well. After the drama's I had with the 29mm CR's on my K1, I think I'll use the Mikuni's on my 1060cc build. Cheers, Terry.

[turboguzzi]

Ah, good ol' CR carbs, great on WOT race applications, but I wonder how many owners have blown their brains out after spending a weekend trying to get them to work properly on a road bike?

I've got a set of new 31mm CR's in a box, and a set of 33mm Mikuni smoothbores as well. After the drama's I had with the 29mm CR's on my K1, I think I'll use the Mikuni's on my 1060cc build. Cheers, Terry.

+1, and yes, i know there are people who have managed to make them work on the street, but why bother for a few extra hp at redline?
if you are 200% sure you need bigger slide cutout, you could always grind them, though there's no way back....

[Doctor_D]

CR's are some of the most intuitive and easiest to tune carbs made.  Now, if we were talking Amal GP's - I'd understand the carping.  Those carbs are most definitely not for street use.

The issue he's having is that 1/8 to 1/4 throttle, steady state, Branden is running about 11.5:1 A/F.  He has very good vacuum at low rpm's, unlike higher strung motors. The rich slide cutaway was supposed to help compensate for the lack of vacuum signal.  It's a simple, albeit pricey, fix.

Sure, I can tune that out with the needle and air screw, but then we're left with a huge lean-out condition on throttle opening.

Branden, we'll raid my CR31's.  You'll be fine.

[MRieck]

CR's are some of the most intuitive and easiest to tune carbs made.  Now, if we were talking Amal GP's - I'd understand the carping.  Those carbs are most definitely not for street use.

The issue he's having is that 1/8 to 1/4 throttle, steady state, Branden is running about 11.5:1 A/F.  He has very good vacuum at low rpm's, unlike higher strung motors. The rich slide cutaway was supposed to help compensate for the lack of vacuum signal.  It's a simple, albeit pricey, fix.

Sure, I can tune that out with the needle and air screw, but then we're left with a huge lean-out condition on throttle opening.

Branden, we'll raid my CR31's.  You'll be fine.

I have to agree with David. I ran them for over 20 years. They certainly have their issues (cold start system sucks) but they are pretty easy to work with.

[turboguzzi]

mike, dave

didnt mean they are hard to work with, just that they wouldnt be my choice in a street bike where you might want to be able to cruise in 5th with a whiff of throttle or idle at a stop light for a few minutes, think that's also what terry meant.

they work great on my road racers and are easy indeed to tune for that kind of application, but to say that i can get from them consistent idling? not realy, there must be a reason why so many people fit to CR's remote idle screw adjusters....

[Retro Rocket]

Hi Branden, Give Forum member Ilbikes a pm, he has a very sweet running 836 with CR's, he's a very knowledgeable guy...

http://forums.sohc4.net/index.php?action=profile;u=2968

Mick

[brandEn]

Thanks Mick, My bike runs great as well but we are just fine tuning it. David has me covered.

[bochnak]

I'm trying to tune the same carbs, CR26, and have noticed what I believe to be a rich spot right around 3k RPM and 1/8 throttle setting.

I'm running 65 pilots, YY8 needles - 7P, 1.5 turn out air screw, to give you an idea of 0-1/2 jetting.

I have tried 60 pilots and 3P through 7P on needle clip and the problem persists, so I'm thinking it's the slides. 2.0's are currently installed.