CR 33s on a 1045 gord bush MOTOR

DOH!!!! Was typing with MR Happy again... :blush: My bad... :laugh: :laugh: :laugh:

Mark1122 - If you have a low RPM bog with the RS34's this is how my buddy solved it...

Injected wrote:

Mark1122 - If you have a low RPM bog with the RS34's this is how my buddy solved it...

Do u have any info on the theory behind this?
in my opinion the issue is a lack of vacuum at low throttle openings, due to the carbs throat being tooo large. this makes it dif to draw fuel. this is why all of the manufacturers whet to vacuum operated slides,and they already had air boxes. vac carbs will not allow u to open the throttle too fast. this doesn't fix the issue but hides it.
I'm certainly not saying this would not work, just wondering why it would?
it would be a large investment to have 1 made.

No bog when going from low rpm to WOT.I was running some homemade filtered velocity stacks.But I may order in some Keihin stacks,also have severl differnt style of pods to choose from,one set joins 2 carbs togeter,so only 2 pods.havet trired these yet.Also I was running some intake manifolds off a zx600 that have a different shape then kz intakes.Im going to order in all parts from keihin that they recomend,as well as a new set of 4 pods.These are set up at the moment with
130 mains
65 pilots
230 airjet
YY8 needle4th from the top
This is how I got em And they worked VERY good.I got em off the bike right now and am taking em to work with me to clean and shine up.Somthing to do after work.Ill update in 2 weeks when I get back
CHEERS(in 2 weeks.DRY camp)
Jeff

Good to know. what are u running on your 1200? are u going to give these cr33's a try?

Injected wrote:

Mark1122 - If you have a low RPM bog with the RS34's this is how my buddy solved it...

yeah ive got that picture saved in my library,just needs a turbo force feeding it where the air cleaner sits! :woohoo:

PLUMMEN wrote:

Injected wrote:

Mark1122 - If you have a low RPM bog with the RS34's this is how my buddy solved it...

yeah ive got that picture saved in my library,just needs a turbo force feeding it where the air cleaner sits! :woohoo:

Hmm...is that going to be the one that has throttle bodies made out of gutted Miks?

If you can get the capacity the motor requires, an airbox is the better choice over open stacks or pod filters...

larrycavan wrote:

If you can get the capacity the motor requires, an airbox is the better choice over open stacks or pod filters...

Larry, i understand that modern bike take advantage of wave signals in the air box, but can u explain how an air how may help for wot from low rpm bog?(as i experienced with the vm33's)

i think it helps more to keep cross winds from blowing the air away from the carbs,i would think it would also smooth out the air being from a common source.
i think that its more of an aerodynamics issue with way air moves around a sport bike

My buddy (guy who make that air box)says its a case of laminar airflow VS turbulent airflow... in any case he had the dreaded "bog" or "flat spot" with a WOT at low RPM being the issue and this seemed to fix it.

Now you can crack it opened at any RPM and it responds...
You can also lug the motor in a high gear and it will not bog at all.

He made the box only because he could not use a stock one (RS34's) He has several places within the box where he built in velocity bell radii to straighten out the airflow... the box is way better than any stock box as it is easy to get on and off without swearing!

Another good thing he noticed going back to an air box from pods (oval K&N's) is that the motor warms up faster and can come off the choke sooner.

I think he said he has about 30 hours into it between machining and design revisions plus he paid $250 to get it welded... if you were to get it fabricated at any shop it would be pricey.

mark1122 wrote:

Injected wrote:

Mark1122 - If you have a low RPM bog with the RS34's this is how my buddy solved it...

Do u have any info on the theory behind this?
in my opinion the issue is a lack of vacuum at low throttle openings, due to the carbs throat being tooo large. this makes it dif to draw fuel. this is why all of the manufacturers whet to vacuum operated slides,and they already had air boxes. vac carbs will not allow u to open the throttle too fast. this doesn't fix the issue but hides it.
I'm certainly not saying this would not work, just wondering why it would?
it would be a large investment to have 1 made.

No theory, just his experience as a Kawasaki mechanic from 1976-1980... he did a lot of pod/pipe conversions and carb tuning for a lot of customers and noticed that the motors were happier with an air box.
Years later he worked with a guy who worked at Roush Racing and he learned about Helmhold tuning - exhaust and intake track lengths for maximum power output. He also learned about laminar flow when working for some small engine producers (Polaris)

He initially thought the carb throat were too big for the motor (1015cc), but we tried several different sets and sizes - this did not remedy the issue.
He made sure there were no other motor issue that could be causing this.
He bought a stock 900 plastic air box at a swap meet for $10, he mounted it to the frame and made some temporary adaptors to seal the box to the carb mouths - this is how we found that it helped. He then modeled the new box using the volume sizing from the stock box.

This was all trial and error which took several weeks just farting around, testing and riding.

I have to disagree with your statement that vaccum operated carbs will not allow you to open the throttle too quickly - Those flat slides were designed for road racing, which requires a lot of throttle input, unlike drag racing which requires WOT all the times. The vaccum signal on those flat slides is extremely strong and I believe that it is those individual combonations (tune up parameters) and not the carburator design that might be at fault.

These RS34's were designed for racing applications and they seem to work fine with velocity stacks (laminar flow) - but as soon as you slap filters on them (a street thing) they act strangely (turbulent flow?)- Is this the same for all high performance aftermarket carbs? We are not sure, but we are convinced an air box does help on the street.

This is just our opinion, again from trial and error.