Keihin carburetors

[tall-mike]

Test ride completed and the cr33's worked as advertised, just bolt on and ride. I'm running 16 -42 gearing so the top end speed is faster than you want to be rolling. Mike

[xtrider]

What did the carbs set you back $$, if you don't mind saying. Did the bike seem to pull harder or run hotter/cooler ect... Details, we want details
I've got my Raptor carbs all cleaned and freshened to install(I'm using the bike and hate to take it out of action right now). I want to compare and see if it would pay to sell my carbs and go the CR route , or another (efi).

[tall-mike]

say hey Xtrider, I got the carbs from PJ Motorsports, you let them know what you've done to your motor(for mine it was pod filters and hi-flow muffler) and they will jet it accordingly. The price plus shipping was $453.90. ,and it took a little over a week to get them in the mail. I had to install the intake manifolds to the carbs and then bolt them to the motor due to the tight fit. Go back and look at the top linkage picture and you will see I had to use 10 mm hex bolts for the inside manifold bolts , so I could get a small open end wrench on them to tighten them down. I also had to shim up the rear of the gas tank, about 1/2 inch, so there would be enough clearance for the throttle linkage to work. The carbs are big, the velocity stacks that came with the carbs won't fit due to lack of clearance. I used the insides of a pod filter, and just slipped them over the mouth of the intake., and it worked fine. The carbs are a huge upgrade, 95 mph in fourth and still pulling hard when I had to shut it down ,because of a wall of traffic just ahead. I haven't got the starting ritual down yet (how much choke , gas etc) when cold. But fires on 1 kick when warm. I am very happy with the upgrade, my motor is stock as far as piston, cam etc.but there is a huge improvement with these keihin cr33 carbs . Mike

[tall-mike]

Ok a few changes, new petcock ordered to match 5/16 gas line, needed for Keihin cr33 carbs. Matched up the rebuild kit on the petcock to get the correct distance for bolt pattern on my clark tank. I'll get it in two days. Filter system changed out ,to Velocity stacks that came with the carb, just trimmed down due to the tight fit. (a little dremel tool magic and sanding block). Filter system is a scotch-brite zipped tied to these stacks. Remember " It never rains in California".

[xtzrick]

Filter system is a scotch-brite zipped tied to these stacks. Remember " It never rains in California".

Yeh, but you do have dust.

How about foam trumpet socks zip tied over your stacks for proper filtration.


What do the open carbs sound like

Rick

[xtrider]

Ya dust will be more harmful than a little water, a scotch bright pad isn't a filter by no means, dust will go right through. Those socks look good, even a K&N clamp-on would be better than the scotchbrite.. Even a cotton t-shirt (cut into squares)folded over two or three times would work "ok" not the best. Maybe with some filter oil they would be pretty good.

McMaster Carr, an industiral material supply company, will have all types of filter media and such. Online you should be able to find something workable.

[tall-mike]

Those trumpet socks look good, I'll hunt down a pair. The bike is loud, I'll probably add a baffle after I get the starting ritual down.The choke system is useless, it floods easily when trying to start the bike cold. Take out the wet plug, put in a dry one, and it fires right up. Throttle control is needed when accelerating, a wide open throttle to soon pours too much gas into the combustion chamber and it will stumble. There are a lot of racing shops in the neighborhood, I'll probably have it looked at in the near future. Thanks Mike

[xtrider]

Drop the needles down 1 position and see if the stumble goes away. You may need a needle that has less of a taper so it gives more time for the air to get in before duel is increased. It sounds like you also need to get smaller pilot jets and a starter jet. If it stumbles now ,it will get real bad with more intake restriction.
Get a Denso or NGK Iradium sparkplug, it won't foul out then.

[brage]

Hi Mike.

Conqrats with your new carbs, I`m realy looking into purchasing one of them myself. Still I have a some quastions for you, I remember I read in another forum some time ago that an other guy also have some issues with the engine stumbleing - his conclusion was that maybe the CR33 is a little bit too big, he tought you maybe be better of with the CR31. what you think?
Original carbs 27mm total throttle areal is 1144 mm2
( pi=3,14 x radi=13,5 x radi=13,5 x 2=dual carbs )
Keihin CR33 carbs total throttle areal is 1709 mm2 That is a huge difference.

The CR31 total throttle areal would be 1508 mm2, also a big difference,
Just me thinking and doing some , before I throw in some

But still, they also offer you FCR carbs in dual up to 39mm for the same bike. How much fuel mix can this bike realy swallow?

any input anyone on this matter.

And mike please post some more pics on how it sits together, and keep us updated on the progress.

Best regards Brage

[xtzrick]

Those trumpet socks look good, I'll hunt down a pair. The bike is loud, I'll probably add a baffle after I get the starting ritual down.The choke system is useless, it floods easily when trying to start the bike cold. Take out the wet plug, put in a dry one, and it fires right up. Throttle control is needed when accelerating, a wide open throttle to soon pours too much gas into the combustion chamber and it will stumble. There are a lot of racing shops in the neighborhood, I'll probably have it looked at in the near future. Thanks Mike

The trumpet socks I pictured are Pipercross.
Can you fit hoses so you can mount the filters behind the shock or refit the airbox with different hoses. Alot of single cylinder racers seem to think the inlet needs to be as long as physically possible.

Is the "stumble" much worse than other bikes you've ridden with slide carbs, could it be you are used to CV carbs & lost some of the feel slide carbs need

Rick