I thought I would post some pics of the Vis 8)ion dirt track bike I spotted at the Sacremento Mile last summer. Notice the carbs and chain drive!, http://s1143.photobucket.com/albums/n635/muukow/
Wonder if this is the same bike?
http://ridersofvision.net/rovforum/index.php?topic=8008.0
BDC
Both are very cool! ;D Quite a few differences between them including the racing number but they both have Memphis Shades sponsorship.
how does that carb set up work out?....im guessing they are off of a cr (it says cr on them..)
I don't think they're from a "CR" but rather Keihin CR series flat slide, downdraft racing carbs.
Anybody got any thoughts on the CR carbs street manners?
I don't see why they wouldn't work well although I'm sure they are pricey. Appears to be a smooth bore, slide throttle (w/roller bearings!) carb with conventional main jet, slow jet, etc. It also has an accelerator pump which is nice. Most of them I've seen have been in banks of 4 on lay down cylinder sport bikes.
The Suzuki VX800 uses a downdraft CV I think(?) and might be a candidate worth looking into. Actually, the one I worked on, the carbs were different for the front and rear cylinders but I recall one to be a downdraft. It's been a while.
edit - after thinking about it the carbs mount at the rear of both cylinders so the front carb nests in the "V" between the cylinders and is possibly a downdraft. The rear carb was a conventional sidedraft as I recall.
so many motorcycles, so little time
maybe those carbs are from a crf 250, if so their are a ton of them on ebay.
Quotemaybe those carbs are from a crf 250, if so their are a ton of them on ebay
To my knowledge the Honda CR's (2 & 4 stroke) use sidedraft carbs.
Just looking at one of my mates ducati 600 monster, they use downdraught CV type carbs. Has anyone considered using a pair of these?
Another possibility is CV carbs from a Suzuki SV650 '99 - '02. After '02 they went to EFI.
Quote from: muukow on November 15, 2011, 02:27:16 AM
I thought I would post some pics of the Vis 8)ion dirt track bike I spotted at the Sacremento Mile last summer. Notice the carbs and chain drive!, http://s1143.photobucket.com/albums/n635/muukow/
Among all the other coolness, the exhaust is pretty darn nice!
David
QuoteAnother possibility is CV carbs from a Suzuki SV650 '99 - '02. After '02 they went to EFI.
Even nicer than SV650 carbs would be the SV fuel injection ;D ;D
The thought has more than entered my mind to put EFI from an SV on a Vision but the CV carbs wouldn't need any electronic support, so I assume would be an easier and simpler upgrade. I can't complain about the performance of the carbs on my '02 SV but there would probably be some improvement with the EFI version, especially when first warming up the motor.
Does anyone here know and understand how the EFI system works? There are several sensors that are critical to the operation, and a computer I know. The SVs have a cam position sensor that the Vision does not have, which would have to be managed/fabricated somehow. What other points would need to be addressed? ??? ;)
Yes I agree the CV's would seemingly make for a much easier swap - I just lust after the thought of fuel injection! SV's EFI may not be the best choice either. Maybe some here are SV forum members? I thought I remember reading some complaints about the FI SV's low speed manners. Overly touchy throttle response or the like?
Another carb swap idea I haven't seen proposed yet are carbs from a Jet Ski. A friend of mine (his idea BTW) had a few stand up Kawasaki's and thought the carbs were compact, reliable, and easy to tune. They have no floats and should therefore run at any angle(?). The carbs and rebuild kits seem plentiful on ebay. I seem to remember slide throttle carbs having a different needle jet shape when installed on 2-strokes. I'm not sure if the jet ski carbs have some similar peculiarity .
Quote from: Rikugun on November 21, 2011, 09:48:36 PM
Yes I agree the CV's would seemingly make for a much easier swap - I just lust after the thought of fuel injection! SV's EFI may not be the best choice either. Maybe some here are SV forum members? I thought I remember reading some complaints about the FI SV's low speed manners. Overly touchy throttle response or the like?
Another carb swap idea I haven't seen proposed yet are carbs from a Jet Ski. A friend of mine (his idea BTW) had a few stand up Kawasaki's and thought the carbs were compact, reliable, and easy to tune. They have no floats and should therefore run at any angle(?). The carbs and rebuild kits seem plentiful on ebay. I seem to remember slide throttle carbs having a different needle jet shape when installed on 2-strokes. I'm not sure if the jet ski carbs have some similar peculiarity .
this would be nice! I'm tired of the bowls draining when I'm doing a wheelie down the freeway at 80mph..... Haha
Would Jet ski carbs actually be practically functional for a vision? Jet skis are 2 cycle motors and operate in water (no govt. highway efficiency standards), would they be sufficiently efficient (fuel thrifty) for street use? They remind me of the carbs on my chain saws and weed whackers, which will operate at just about any angle. Called "pumper" carbs as they have little diaphragms that pump the fuel by means of intake vacuum pulses. Without float bowls there are no floats to shut off the incoming fuel. On a "regular" motorcycle the fuel is above the carbs and is delivered by gravity, on a chain saw the fuel is below and pumped up to the carb negating the need for a fuel shut off. I have so much to ponder, and with such a lazy mind.
I don't know if having come from two strokes makes them necessarily problematic. They do have an inlet valve that is activated by a diaphragm. With their accelerator pumps I don't see the Vision as being terrribly thrifty for it's displacement especially around town. I don't see the diaphragm carb as being the main factor in 2 stroke fuel efficiency. The inherent design of the engine makes it inefficient as a good deal of intake charge is used to evacuate exhaust. This is the main reason for their demise, not their carb choice. Remember most 2 stroke bikes used slide throttle carbs just like 4 strokes with the exception of a modified needle jet. And, there was at least one 4 stroke V twin that used diaphragm carbs as original equipment for a short time. Harley Davidson :)
http://www.ebay.com/itm/Classic-Tillotson-HD2D-Carburetor-Body-OEM-/270861044409?hash=item3f10938ab9&item=270861044409&pt=Motorcycles_Parts_Accessories&vxp=mtr (http://www.ebay.com/itm/Classic-Tillotson-HD2D-Carburetor-Body-OEM-/270861044409?hash=item3f10938ab9&item=270861044409&pt=Motorcycles_Parts_Accessories&vxp=mtr)