CNS Frankin carb

turkman · #1 02-06-2010, 01:59 PM

A month or so I acquired a CNS carb from my mb connection and I loved the performance and dialed it in for the 35mph my bike needs to do, but after a week or two the carb backed off the manifold so I did an inspection on it and discovered the clamp to the manifold was cracking on both sides ,(they started because of the flash not being cleaned off )so some research and I know that my carb is junk , throw it away. I check the new posts everyday and I read a post from Venice about the same kind of prob so then I think about how I hate the restrictive intake manifold and I got nothing to lose so I started " The CNS Frankincarb project"-------- I started looking at all the pieces I had and it came to my mind that I hate the intake so that is where I started the intake on the cab is for 15/16 in tube so I saw a handle bar in my yard and cut a section form it keeping the part where the gooseneck mounts it is about 1 in and used some of the bend to finish with 3/4in ID, cleaned it up , ground it down to the 15/16in, made an intake flange as big as I can some welding and a new better intake is born. Then it was time to look at the carb,I ground off all the broken stuff and ruffed up where the J-B weld was gonna go bent up two little grabbers and made it all fit ,glued it together let it sit on the mantel overnight , paint and final fitting,I made the air cleaner out of a sink drain and some AC air cleaner material. The carb interfered with the nifty clutch assist I made so I had to remake one to accommodate it. The motor fired right up and works great I'm resetting my speedo to see who long this thing lasts I will keep you posted.---Later Bob

turkman · #2 02-06-2010, 02:02 PM

here's the rest of the photo's

Outrunner · #3 02-06-2010, 02:32 PM

Turkman,
I for one, am impressed! That is exactly what makes these cheap little frustrating
machines interesting and hopefully fun. It brings out the creativeness in most MB'rs
and you are a fine example of "makin' things work" . I do wonder if the vibrations may
shake the carb loose again. Do you think you could add a little support bracket to the
top of the carb or elsewhere? I think that would help a lot. Nice job!

turkman · #4 02-06-2010, 04:50 PM

I thought about that and when I assembled it I added these tabs , we'll see if its enough thanks Bob

Fuji Moto · #5 02-06-2010, 11:11 PM

thats too funny I made the same kind of custom intake but i just welded the handlebar to the stock flange, and I couldnt get it to run right then I lost spark, but im guessing the pipe is too big that i used im going to try and make one with a 18mm pipe or so, whatever the stock one is

sportscarpat · #6 02-06-2010, 11:12 PM

I also had one crack. It was moving around on the intake manifold so I tightened it up and then it broke while riding. I think the plastic bushing could not tighten down any further and basically stopped the carb clamp from squeezing tight enough to the manifold. I will widen this gap a little and see if it allows me to tighten the carb enough to keep it from moving.

**BarelyAWake** · #7 02-07-2010, 10:06 AM

Hmm... a tip that might help with the nylon bushing slipping on the intake manifold - I scuffed mine up pretty good when I cut and rewelded the manifold for a better intake angle... I prolly outa have been more careful, but after wire brushing the grinder marks took a nice texture to "grip" the plastic - I can hardly turn mine even if the fastener isn't tightened *shrug* Actually it was somewhat of a pain to get alla way on there lol

I suppose you could rough the chrome up a bit on purpose and thus do a nicer lookin' job

I wonder if ya mighta tightened it so much tryin' for grip that ya squished the spacer a bit and that's why the carb cracked?

PaulFlorida · #8 02-07-2010, 01:19 PM

Ya know my CNS carb on my billet intake rotates left to right and over time separates from the nylon bushing. I just bundles all the vent lines together between the bowl and clutch, kinda wedged in there. That stops it fine. Too scared to over-tighten though. Gotta recommmend adding vent lines to the spigots- they WILL eventually grab a few grains of dirt, and f-up the carb function.

PaulFlorida · #9 02-07-2010, 01:22 PM

There isn't a modern motorcycle on earth that had the carb solidly mounted to the the manifold and jug. We need a rubber boot style carb mount. That should solve a whole load of issues.

turkman · #10 02-10-2010, 01:16 AM

well here's an update,l Really like the performance of the oversized intake, Think it is a little too long ,it took a few runs to dial in the carb but now my top speed is 39mph on level ground ,and a little more torque on hills , the J B Weld is holding up fine with 47 miles on the" Frankin Carb" Later Bob