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CR 33s on a 1045 gord bush MOTOR
- Old Man Rock
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1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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- Injected
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- mark1122
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- Keep twisting it
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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.
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.
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- jeffasaki
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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
78 Z1R
78 KZ1000
76 KH500 gone
71 HS1B 90
81 GS 1100 gone
80 PE400
02 KLR
Ontario Canada
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- mark1122
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- Keep twisting it
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76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.
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- PLUMMEN
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yeah ive got that picture saved in my library,just needs a turbo force feeding it where the air cleaner sits! :woohoo:Mark1122 - If you have a low RPM bog with the RS34's this is how my buddy solved it...
Still recovering,some days are better than others.
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- DoubleDub
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Injected wrote:
yeah ive got that picture saved in my library,just needs a turbo force feeding it where the air cleaner sits! :woohoo:Mark1122 - If you have a low RPM bog with the RS34's this is how my buddy solved it...
Hmm...is that going to be the one that has throttle bodies made out of gutted Miks?
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- larrycavan
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- mark1122
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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)
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.
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- PLUMMEN
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i think that its more of an aerodynamics issue with way air moves around a sport bike
Still recovering,some days are better than others.
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- Injected
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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.
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- Injected
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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.
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