CNS performance carb?

[Deleted member 12676]

"simple" maybe to home fabricators but not to the common buyer.
Unless all the extra hardware needed comes with the Walbro with a detailed instructions for installation then it isn't worth recommending to the common Joe in my opinion.

 

[Fabian]

Jaguar, think about what you are saying.

You are well aware of the troubles newbies are presented with when motorising their bikes; the forum being packed to the rafters with newbies asking the most basic questions which have solutions both more simple and more complex than plumbing a crankcase pulse return line.

If a newbie is incapable of plumbing a crankcase pulse line, then they shouldn't even think about motorising their bike.

 

[johnny skidemarks]

walbro

Id like a little more info on were the best place to drill and tap a hole for vacuum/pulse i think a walbro maybe the way togo. Can you get walbro that will bolt to gt5 jug

 

[Fabian]

Rock Solid Engines sells all the parts you need to convert the intake system to both a reed valve and/or diaphragm setup.

This is my setup tutorial: http://motorizedbikeforum.the-talk.net/t341-walbro-style-carburettor-for-rock-solid-engines-reed-valve-intake

If you do install a diaphragm type carburettor you "MUST" order the thermal isolation spacer.
Make absolutely sure that you order the thermal isolation spacer. I cannot emphasise this enough.

As an alternative to drilling out a 4mm capscrew, you can use a rear derailleur cable adjuster screw, which happens to be 4mm and already has the centre drilled out.

 

[johnny skidemarks]

Do you really need the reed valve ,cant you just find a walbro carb with the i believe is 31mm bolt spacing and bolt it direct to the jug and tap for vacuum. Iam look for best hp for best buck spent. I have a hp cns carb that i just bought i think with the right tune up it should work ok for the money.For walbro kit and its a nice kit its a bit pricey .thank you

 

[Fabian]

It doesn't matter where you get the crankcase pulse signal from, so long as you get a crankcase signal to the diaphragm carburettor.

From a technical perspective, you do not need to install a reed valve intake, but, from a practical perspective, the reed valve system noticeably boosts low and midrange torque, whilst at the same time it reduces intake noise.
For me, the reduced intake noise is more desirable than the boost in low and midrange torque.

I have tried just about all of the carburettors on the market, and have always reverted back to the standard NT (with regards to a float style) carburettor.
In my opinion, there is nothing wrong with the NT carburettor when jetted correctly, it performs equally as well as any other carburettor that's correctly jetted, and that includes a diaphragm carburettor.

If you want to save money, just make sure that the NT carburettor is correctly jetted and you will have equal power potential as to any other carburettor of comparable venturi size.
My bike is currently running with an NT carburettor because i've been lazy to change it over to the diaphragm carburettor; after using the NT as a last ditch effort in trying to solve an electrical issue, of which the problem didn't turn out to be electrical.

Considering the engine in my bike uses the older style caged needle roller big end connecting rod bearing, i was expecting it to fail before 3,000 kilometers, but with the Jaguar CDI, it just keeps on running perfectly, so i'm at the point where i'll be switching back to the diaphragm carburettor.

 

[johnny skidemarks]

Thank you fabian for all your help. Iam going to play with this hp cns carb ,but how in the world do the these guys get almost 10 horse out of these little motors

 

[Fabian]

Power is dependent on money and is also inversely proportional to engine longevity.

If you want 10 horsepower, you'd be foolish to invest large sums of money into a Chinese bicycle engine when much better options are available straight off the shelf.
My opinion is that 9.4 horsepower being pushed through a bicycle frame is simply inviting disaster and very likely to see the rider end up in the hospital emergency ward in a fairly short time; with life threatening injuries, but, if you really want to put your body on the line on an urban roadway, the info is below:


http://www.morinifrancousa.com/engine2.htm

 

[johnny skidemarks]

Just want to thank fabian for your help and link thanks again

 

[HeadSmess]

not all walbros NEED a crank pulse.

hell, i just ripped one off a stihl lawn blower, drilled a hole in the top as i was going to attach a line there, decided i would just bolt it onto my lil huasheng 25cc fourstroke with no pulse at all as an experiment...FOUR STROKE, i repeat FOUR STROKE, and, well..its sucking fuel up 200 mm from a coke bottle, running quite happily with the "pulse" side of the diaphgram open to atmosphere. makes no difference if i cover it with my finger or not
yes, the carb spacer block has no pulse orifice. its a 4 stroke. and i epoxied the orifice in the carb itself, because, as mentioned, i was going to attach an external line, and two, the spacer didnt happen to cover the orifice. if i had known it would make no difference i would have left it!

oh, and theres the bing diaphgram carb from my old fichtel sachs km48 rotary... that has no pulse as the fuel pump is separate and locates elsewhere...

on every other aspect i agree wholheartedly...the NT does the job, easily, simply , and properly. anything else is just having yourself on. better atomisation? the crank does that better than any carb can. better mixture control over the throttle range? erm... dont know about everyone else but my carb has basically two settings.... idling and WOT. its not like i have to nurse the throttle in case it rears up and spits me off at 200km/h+ down the freeway...