Cool Videos

Alzero said:
We built a bike for a guy called Turbo Rick who eventually joined the 200 mph club at El Mirage dry lake. The big problem they all have is traction on salt or dirt trying to push the bike against the air. Eventually they hit the wall of wind resistance and the tire breaks traction and spins without pushing the bike any faster. Lots of guys can build the motors and make the power to theoretically get the speed. But actually doing it is difficult. Turbo Rick had about 100kg of lead on the swingarm of the bike to try to get the back tire to hookup on the dry lake. Jet cars have it easy and so do the guys who run at airstrips.
Click to expand...
Exactly the problem they had with a Rotary engined Norton they took to Bonneville, couldn’t get it to hook up - too light, too short and too torquey.
 
Jo said:
It's suspiciously quiet after your last post, Mr. Sock. I would classify this as a quiete muted reaction ...
:D
Click to expand...
One doesn't laugh at funerals.
The ashes of Mr Sock and his long suffering 3C will be dispersed by a drone over the site of the 1973 factory along with the remnants of a double Decker bus and some London soot.
Paul
 
Bit of an ad but interesting. I thought these Carbs were modern versions of Lectrons, but obviously not if they run Presured Float Bowls.
italianiron.com

Italianiron & BritIron Classics Maximize Performance with Hand Held Dyno & SmartCarb Flat Slides

At Italianiron & BritIron Classics, let us "Fuel Your Race Passions" is not just a slogan but a commitment, whether you are building a vintage Ducati TT or Pantah racer for competition, a Ducati F1 vintage street bike or restoring a Norton Commando or Manx racer. We continue to offer a...
italianiron.com italianiron.com
 
Vince said:
Bit of an ad but interesting. I thought these Carbs were modern versions of Lectrons, but obviously not if they run Presured Float Bowls.
italianiron.com

Italianiron & BritIron Classics Maximize Performance with Hand Held Dyno & SmartCarb Flat Slides

At Italianiron & BritIron Classics, let us "Fuel Your Race Passions" is not just a slogan but a commitment, whether you are building a vintage Ducati TT or Pantah racer for competition, a Ducati F1 vintage street bike or restoring a Norton Commando or Manx racer. We continue to offer a...
italianiron.com italianiron.com
Click to expand...
Not entirely convinced by their theory- carb is a fuel metering device, if you add more more fuel by pressurising the float chamber where is more air coming from? Kawasaki pressurised float bowls twenty years ago but also pressurised the entire air box- one doesn’t work without the other. The other thing troubling me is the air entering the bell mouth fluctuates massively all the time ( remember plenum chambers on two strokes or YICS) and you also get fuel spray backing out of carb that I would have thought would send shock waves to the float chamber instead of steady, calm pressure through a conventional breather pipe. Using words like “ram air” and “ injection like” don’t help to convince me. Don’t get me on “hand held dyno”😂
 
I'm not familiar with Smart Carbs, but I just did a bit of investigation. The "pressurised" float bowl description is a bit misleading. The float bowl isn't actually pressurised by some external source of compressed air. It just has the float bowl vented to the intake side of the carb, so it's balanced with the air pressure in the plenum. However, the vent hole faces the incoming air flow (like a pitot tube) so there would be a velocity pressure component that's applied to the float bowl. I suppose in that sense the float bowl can be considered to be somewhat pressurised, but it would only be marginal and the float bowl pressure would be linked to the air velocity flowing into the carb. That velocity is dependent on throttle opening and revs, so you get more fuel pressure as the engine works harder. It's plausible that the system works better than a float bowl vented to atmosphere external to the carb, but without doing a whole lot more research I'm unable to offer an educated opinion. It seems to make sense though.
 
My pressurised comment came from one sentence in the site's description of what they sell as suppliers. That was the first time I heard of those carbs having that feature. From the info I got over the years 2nd hand and guesswork, the cv carbs I ran for a while on my 3c needed their breather hoses connected to their airbox or they ran like crap, that was correct as I forgot once and it did run like crap. Lots of carbs run their breather into their airbox for emissions, cannot leak fuel on the ground. Tell old Amal owners that. And I was advised not to run the carb breather into the air box on my Atlas as bad things will happen, that came from someone who knows way more than me. I watched someone chase an overflowing carb issue once for a good while, till he noticed that carbs breather hose melted shut on his bikes exhaust. They used to sell tiny filter kits you could add to Keian Flat Slide carbs because people would find fine dust in their carb float bowl apparently sucked in from the breather hose. So carb breathers are complicated.
 
Vince said:
They used to sell tiny filter kits you could add to Keian Flat Slide carbs because people would find fine dust in their carb float bowl apparently sucked in from the breather hose. So carb breathers are complicated.
Click to expand...
Probably not important on my FCRs cos it's fundamentally a road bike, but I don't even have hoses attached to my breather T-pieces. Maybe I should add some tubes for good measure.

The overflow for my Kwaka flush filler cap that goes through the tank and exits underneath is also un-tubed - I've overfilled a couple of times and sure enough the fuel drains straight down into the well under the starter motor. I'll sort both vent and overflow at the same time. Bloody tricky getting the last 500ml into that tank - the SF tank is flat on top and holds a lot of fuel - I've lost about 2L or more capacity I reckon going for the bling factor. If I do any serious touring I have a std tank almost ready to go.

On that note, does anyone know the actual capacity of a std later SF tank?
 
I just remembered another carb-breather thing. The first time I crossed a deep wide creek, knee high and a good 10mitre wide my Husky stalled mid-crossing. Thats because if you submerge the carb breather hoses, they hang down below the engine for a reasonable time that stalls the vacuum and balance getting into the float bowl. The fix is adding T pieces to those breathers near the carb and running one hose from that T down and one hose up as high as possible. That fixed that issue. Here is another Tank breather problem, lots run that tank breather hose into a hole in the middle of their fork tube, tip the bike over and fuel runs out the breather washing gearse right out of the steering head bearings. BTW you might think most Laverdas don't cross deep creeks, mine has twice heading to Bruises farm. Not common but it happens.
 
Vince said:
My pressurised comment came from one sentence in the site's description of what they sell as suppliers. That was the first time I heard of those carbs having that feature. From the info I got over the years 2nd hand and guesswork, the cv carbs I ran for a while on my 3c needed their breather hoses connected to their airbox or they ran like crap, that was correct as I forgot once and it did run like crap. Lots of carbs run their breather into their airbox for emissions, cannot leak fuel on the ground. Tell old Amal owners that. And I was advised not to run the carb breather into the air box on my Atlas as bad things will happen, that came from someone who knows way more than me. I watched someone chase an overflowing carb issue once for a good while, till he noticed that carbs breather hose melted shut on his bikes exhaust. They used to sell tiny filter kits you could add to Keian Flat Slide carbs because people would find fine dust in their carb float bowl apparently sucked in from the breather hose. So carb breathers are complicated.
Click to expand...
Wasn’t being critical of yourself- I hadn’t heard of these carbs before and I love reading about new stuff, so I was glad to see the article.
I have a special interest in Lectrons ( similar adjustable jet set up) because Dr Witner used them on his Guzzi and found them to work really well. Before those we had Gardner which were popular on the grass/speedway for methanol and still used on classic roadracing.
The pressurised carbs on the Kawasaki only really made a difference when you were going quite fast (100 +) but if you left the float bowl breather/pressure pipe off the air box it would run like a dog at any speed- we did loads of testing of these on a Dyno back in the day to see what difference it made. Same goes for reverse cylinder head ram air, only works at speed..unless it’s a Suzuki GT380 then it’s just writing on the cylinder head!
 
Those Smart Carbs look like a nice bit of gear. They appear to be machined from billet, and apparently work well if you can believe the stuff people are posting about them (there's plenty of reviews on YouTube). Similar design concept to Lectron (using a metering stick rather than jets) but more expensive. They seem to be aimed at the off-road market of 2-stroke and 4-stroke singles so they only come with cable operation. Multi-carb installations using a throttle shaft through the tops of the carbs doesn't appear to be an option. Although if you have deep pockets and like a bit of bling, there's no reason you couldn't fit a pair to a twin cylinder engine that has two cable-operated carbs.
Quentin, you know they'd look good on the SFQ!
 
Always good to learn stuff, my only personal experience on Lectron and I think it was a precursor called an EI Carb fitted to an early 250 KTM 2 stroke. It had a very flat-running engine. Virtually no hit on its expansion chamber. BTW I think Cripin was experimenting with Lectrons fitted to his Space Frame, but he had so many balls in the air with not much sussess.
Quote
An Ei Carburetor is a normally aspirated carby designed and built by Red Edmonston while he owned Edmonston Industries (Ei) and S&W. Red is the inventor of the Lectron carburetor which is very similar to the Ei.31 May 2013
 
You must log in or register to reply here.
Back
Top