CNS performance carb?

[HeadSmess]

and more on that isolation block...yes, it is 100% necessary. so no, there will be NO bolting of carbs directly to cylinder.

i think the closest walbro is a rare, expensive, 27mm bore type with 35mm studs... i think...

 

[Fabian]

not all walbros NEED a crank pulse.

I agree and disagree with your statement. The diaphragm carburettor previously installed on my engine will work without the pulse line attached to the carburettor, but the carburettor works a lot better and the jetting settings have noticeably more effect when the pulse line is attached to the carburettor.
If the carburettor is designed to have a crankase pulse signal, then you can be sure that it was engineered for the pulse signal to play a relevant part in the operation of the carburettor.

the NT does the job, easily, simply , and properly. anything else is just having yourself on.

From my experience, i completely agree with your statement.

better atomisation? the crank does that better than any carb can.

I completely agree with your statement, which is why you can run a 2-stroke engine on diesel once it's warmed up. I am not saying it runs well (or the exhaust runs clean), but as an exercise to prove the intensity of mixture motion imparted into the gas stream, when passing through a 2-stroke crankcase and transfer ports, it amply demonstrates the significant turbulence added to the air/fuel mixture over the 4-stroke method of operation.

dont know about everyone else but my carb has basically two settings.... idling and WOT.

I am presented with the same scenario every time i ride my motorised bicycle, except that i change gears when momentarily closing the throttle.

 

[HeadSmess]

yep, looking through walbro site a few weeks ago before that lil experiment, and some are specifically for the fourstrokes, some can be used either way, and some are 2 popper only... so confusing. gravity vs suction has some bearing on the matter, im sure.

that pulse is part of the pump, part of the metering circuit...walbros are extremely complex inside! what i didnt know is that by adjusting that lever that opens and shuts the fuel valve, you can tweak the midrange but now it makes sense.

 

[nashy10]

I know i havent provided much detail asked of me but im noticing great top speed once i baby it up to WOT it gives tons of power but once i do this (slowly open throttle to achieve WOT, simply opening it will bog so much the engine will die) the bike no longer idles or gives good low power torque. seems to idle and run normally fine for about 15 mins then once warmed up just constantly dies at idle and revs really high when giving gas, tried nt needle but i believe the cns one is set properly. ALSO, if i have the air filter on this thing barely runs! wont run with filter basically and this is a big problem, have cleaned filter out etc

 

[Fabian]

For the newbie, these engines are nothing but a nightmare of problems. If you have no real mechanical experience or you don't have good problem solving skills or you don't want to spend hours and hours and hours reading books or reading about engine design and operation and carburation and electrical theory, then it's best that the bicycle is used as a plain bicycle.

Even with reasonable skills when starting in this hobby/transport, it still took me 2 years of pain and heartache to bring my bike up to a level where it was virtually 100% reliable.

The newbie doesn't have even half a chance if they're jumping in without any knowledge; just expecting to bolt in the engine and have it work properly.

 

[nashy10]

Dear fabian i have had this 2 stroke kit for a year and a half now, i take an automechanics shops class in my school and am inheriting a motorcycle repair shop. This is not something i am dumbfounded with i have been working with this engine for a fair time now. Of course, knowledge on CNS carbs are limited to a point that is why i seek information from this forum. Please do not imply that i expect the engine to bolt on and run properly.

Regards, Nash

 

[Fabian]

Honestly, the standard NT carburettor works perfectly well when jetted correctly.

If you have only been working on the engine for a "fair time", expect a fair amount more time for the pain and heartache to continue.

 

[nashy10]

Okay Fabian. Totally aware the NT carb works fine jetted correctly. I never said i was not expecting "pain and heartache" its also called "trial and error" and I come on this forum to learn and better educate myself, so I do not see what you're contributing to this thread. If you have more fun facts to post, please do so elsewhere. IF it pertains to the problems i am having with this carburetor i would gladly accept any advice to do with this specific carb. No personal irritation intended, just trying to keep things clean.

 

[Fabian]

A trial is what you get when going to court. Error (and lots of it) is what you get when working on these engines.

I do understand where you are coming from and I'll do my best to keep my mouth shut.

 

[Fabian]

The best carburation option is the following method - give the web page time to load the photos:

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