Old greybeard looking for motorized info

[wacoykc]

Fellow riders:
Been lurking for quite some time now, but have come upon a point of concern in trying to wake up an advertiser. Let me digress a bit for this thread being an introduction. I'm retired and have several interrelated hobbies. Antique aircraft, Cushman & Mustang motorscooters, Model T Ford Speedsters are the major areas of my interest, that is, until someone said that there's no way that a Chinese bicycle motor and a 5sp derailleur could be mounted in my 1st gen, Schwinn Chopper bicycle. I just love to tell these clowns to hide in the bushes and watch. Well, using several of your vendors, including ones that sell the jackshafts, the multicable brake lever, the freewheels for both the peddles and rear wheel, the 5sp rear sprocket cluster, the rear disk brake & caliper, the extractor exhaust pipe, the handle mounted shifter, the 80cc motor (actually cc's at 66.5) boost bottle etc. etc. After custom fabricating a motor mount that positions the motor so its looks right in the bicycle frame, and lot of trial and fitting, I've come up with a little terror that can do 40mph in 4th gear. I'm afraid to put it in 5th (I don't bounce anymore, just splat). Now my reason for joining. I can't get this thing to idle and have not been successful in getting it to 2 cycle, always 4 cycle. Tried all needle settings, and several gas ratios, settling on a 40/1 mix of Amsoil 100/1 additive that seems to run the best, with the given carb. This carb isn't worth the beer cans that was melted down to make it. Now.....I've been trying to get in touch with a Co. called Spooky Tooth about a couple of carbs their advertising, 1 being called a CNS and the other a 66 NT (imagine that) or any other ideas they might have about my problem. Now you would think that a customer ready to spend money would generate a little interest (not). Maby one of your listers might have an idea for carburators. By the way, I've ported the engine out about 75 % of max. and it does run quite well on 4 cycle. I only have a little over 1 tank of gas thru it. I'd be interested in any feedback.....Byron

 

[BarelyAWake]

Welcome to the forum wacoykc, I agree that the stock carb is a POS that outa be chucked into the ocean - but given that you've only put a single tank of fuel through it I'd lay long odds on the engine not being fully broken in yet, they're well known for their four stroking habits for at least the first 100-300 miles.

I'd also cut back on yer oil mix, I'm runnin' 40:1 with Amsoil's 50:1 "Injector" and TBH even that's a lil heavy, to run 40:1 with a synthetic rated at 100:1 could be excessive, it might well be loading up bad - have you checked the piston for carbon build up? (it's a lil early, but worth a glance).

As for good ol' Spooky Tooth, I'm kinda wondering if they're busy or something... Normally friendly & helpful - I too have had problems of late. Have you tried simply calling them or are you emailing them? I did however just get the new CNS carb from them, I was plannin' on getting a Dellorto but I cheaped out at the last second heh

While the new 66 NT is a marginal improvement over the one included with your kit (yours may even have it, they're standard w/grubee now - check for a 2nd fuel shut off on it) - it's not enough of an improvement to warrant calling it an "performance upgrade" and judging from what you've done with yer build already - you'd prolly want far more than what it provides... like a fuel/air mix screw lol

Here's a lil babble and banter about the three main "performance" carbs found for these things - be sure to read till the end of the threads tho as this tends to be a learning curve for us all (and there's more info than jus' these links)

CNS
http://motorbicycling.com/f4/cns-carburetor-5437.html

Mikuni
http://motorbicycling.com/f13/18mm-mikuni-upgrade-1895.html

Dellorto
http://motorbicycling.com/f13/high-performance-dellorto-carb-found-2314-3.html

Defo lookin' forward to some pics of yer ride BTW

 

[MaxPower]

Spooky tooth has been busy. They just started doing 4 strokes.

 

[Saddletramp1200]

Although your writing skills are way to eloquent for me, I welcome you to The Forum

 

[2door]

Byron,
Welcome to the forum. I think you'll find quite a few of us here who are getting a little gray around the chin and long of tooth. After you've played with cars, boats, planes and everything else with wings or wheels where do you go for fun? Motorized bicycles, of course. Your project sounds interesting, and fun. How about a few pictures?
Tom

 

[wacoykc]

Being new to this forum, and having been asked for a picture, I really don't know how to respond, just a picture of the finished Chopper, or maybe some shots showing some of the mechanical makeup. I guess I'll start with just a shot of the completed machine. I have a few shots of the mechanicals if anyone is interested......Byron I hope the picture comes across

 

[professor]

Wow, great work!

 

[BarelyAWake]

A dang fine ride indeed!

Thanks for sharing, I'm sure folks will be inspired by it

 

[2door]

Yeah, we'll keep you around...
Thanks for sharing and no doubt that close ups of the mechanicals and engineering would be enjoyed. Welcome aboard.
Tom

 

[GearNut]

Welcome to this place!
You certainly have built a fine looking machine.
I must say though that that intake manifold is the longest one I have ever seen on an MB. The tuned length of it may be contributing to your poor running issues, alot.
As was stated previously, let the engine break in before you expect any smooth operation out of it, or fiddle with it to smooth it out.. They are rough runners in the beginning.

 

[Ghost0]

Yes let it break in before final tune but in my experience they are way over jetted. This is the most likely cause of your 4 cycling. Stock jet is typically .70 mm and I would suggest a .65 mm.

Not idling could also be caused by a rich condition or lean condition. I think I would try adjusting your float down a bit to see if that helps.

 

[wacoykc]

I think that the length of the carb runner might be a problem. Here are a couple more shots of the bike.

 

[2door]

I think that the length of the carb runner might be a problem. Here are a couple more shots of the bike.

Byron,
I would think you could fabricate a 90 degree intake that would work. As long as you clear the carburetor with your legs it should be okay. Nice work. Very clean build. Congrats.
Tom

 

[wacoykc]

Appreciate all of your inputs. Before I reshape the intake pipe, I think I'll try the "boost" bottle. Anyone tried this thing. I originally thought it was a bunch of snake oil, but in talking to a couple of go-kart people, they said to try it I just might like it. I would like to hear a consensus between the Mikuni (sp) and the CNC (sp) carbs, as I still would like to have a little more adjustment that just jacking the slide up and down. Are included are the last shots I have available of the bike. If you would like any detailed shot let me know. A couple of pro's and con's that went into the build are:
(1)+++ Front brakes & (2)--- Having to peddle to start the engine......With my arrangement there is no 'coaster' brake nor 'compression' braking from the engine. Any thing above 15mph, the rear only brake is an invitation to disaster, with the original brake quickly folded up into nothing, and that's really uncool, don't ask me how I know. On the other hand, a front brake can also lead to disaster if applied incorrectly. So now that both handle bars are occupied with their own levers, how to add a front brake and lever. I remember seeing a brake lever with 2 cables, I guess I'm not the only one with the problem. In replacing the collapsed rear brake (rim squeezer) with a 210mm disk, I used a caliper with a very handy adjuster built in. The front brake had to be a squeezer becaus of the type of lacing used, so I adapted a squeezer from a old 10sp. After rigging up the cables it was quite easy to adjust the braking bias so that the rear brake locks up before the front, so the front tire won't wash out from under you in a panic stop. (another lesson learned the hard way). Now the only thing I really don't like about this build is that you "Have" to peddle to start the engine. I would have been neat to use the inertia of the bike itself to help overcome the compression. As it is, I don't think it would be possible to start a higher compression engine. Enought for now......Byron

 

[BarelyAWake]

There's been much brouhaha about the Boost Bottles, I was tempted by them too at first when I saw them. Yet as we've had skilled members do extensive testing, even going so far as to make their own adjustable variants - and still the results were inconclusive at best with the average opinion being that they do nothing at all, I decided I'd not bother as it seems that the only real "benefit" is lookin' kinda cool.

For more info on both sides of the discussion: http://motorbicycling.com/f13/boost-bottles-670.html

I think it may be unfortunately a bit too soon for a real consensus regarding the Mikuni and the CNS carburetors as the CNS is still so new that of the few people that have them - many are probably still figuring out ideal jetting and fiddling with the mix lol Still I would think it safe to assume that since the CNS is a "knock off" product, the Mikuni would be a higher quality with jets and other replacement parts easier to get.

Sorry to hear of your brake woes, but glad to see you've got it sorted. It's also safe to assume that there's no such a thing as an "excessive" amount of detail pics heh