Sportsman project coming up...questions

[harry76]

yeah my gascap is always spewing a little fuel..... But seeing as I don't have paint to worry about I don't worry as much........I'm not sure of the setup of your gascap, but you can get a small length of copper tubing and put a coil in it and braze it to your cap, cobrafreak uses this setup on his 1911 Indian build. Hope that helps

 

[brett7777]

Interesting test rides.
A bolt fell outta the sprocket whilst riding. Have locktited the sprocket on now. The sprocket adapter has moved a little on the hub & is now pressing a little against the spokes. Not sure how to get that any tighter on the hub.
So it's normal for gas to be flooding outta the cap? I guess that's a weakness of having a hole in your cap as the vent?
Another observation is that there's a huge amount of vibration in the bike as you accelerate, it's smoothes out once you're going flat out.

 

[cobrafreak]

I rode with Pat and Rich with their Sportsman's and fuel wasn't leaking out of their caps. I would say you have a cap that doesn't work right due to a defect or missing part maybe? You could make the hole bigger and solder or braze a short coiled copper tube in it which will fix your problem. It looks vintage too. Look at my cap on the Indian and see. I think the sprocket adapter normally will press against the spokes but it will not do any damage. Always locktite bolts. Good insurance. Huge amount of vibration? That doesn't seem right. Is everything tight? Is your carb jet adjusted properly for smooth acceleration? Do a plug check to get the dark creme color you are looking for on the porcelain.

 

[brett7777]

Thanks CF. Yeah motor is mounted tightly.
Where would I find instructions on how to adjust the carb jet? The motor revs smoothly with clutch pulled in, & revs smoothly as you accelerate, so I wouldnt have thought jetting, but - these motors & MB's are new to me. So any suggestions or info would be helpful.
Thanks again.

 

[curtisfox]

Does your gas cap have a secondary washer (gasket) inside with a offset hole? That sometimes is all it needs. Look inside a lawnmower gas cap...........Curt

 

[cobrafreak]

Take the spark plug out and look at the color of the porcelain on the combustion chamber Side of the plug. If it is white or a light color you are running too lean and need to add more fuel by raising the needle in the carb. You take the needle out and you will see a small C clip with four or five grooves. Lower the C clip to raise the needle for more fuel. If the plug color is black it means too much fuel. Raise the clip to give less gas. Ride the bike for 10 minutes and pull plug to see color change. You are shooting for a dark cream color which is perfect air fuel mixture.

 

[itchybird]

I have to second Cobrafreak, these caps normally work just fine, we use them on our bikes and if they were a problem we'd be running something else. The only time you normally have fuel splash problems is when they're over filled. Otherwise, you should be fine. It is possible that your cap has a defect.

Also, you mentioned chain rub on youir tool box, sounds to me like you have your sprocked adapter incorrectly adjusted ie pushed too close to the wheel centerline, which would pull chain inward toward the box. And if its rubbing on the box, I suspect you have tire rub as well. Stand behind the bike and see if the chain is coming straight back or does it angle inwards toward the center of the wheel.

 

[brett7777]

Used a straight edge on the chain idler/rear & front sprocket, plus eyed it up from the rear/top view. It's just designed to run very close to the oil tank from what I can see. Would work ok if you're not painting it. If I keep the chain very tight it doesnt seem to hit it as much.
Hey the tank is half full, it's not half empty haha there's an attempt at a positive attitude.
Fuel cap has something similar to that Curt, a barrel thingee with a slot down the side. Spat out less with this taken out. I think a vent tube system like they have on motorcycle tanks or a different type of vented cap might be better, just my opinion. Ive no idea why it spat like a volcano at the beginning, or why it kept seeping out so much whilst riding. Will see what it's like on next rides.
I think my main issue to sort out is the shuddering/vibration that happens on acceleration.

 

[cobrafreak]

I know that if you fuel up when it's cold and then the temperature rises the gas expands and then it could volcano out any fuel vent. This happened to me once. If you top it off when it's cold make sure you ride enough to consume some of the volume of fuel before the temperature rises.

 

[brett7777]

Yeah the heat expansion thing. I put the fuel in a few mins before startup. Warm day. May have expanded. But kept seeping for quite some time after that. Like a reaction happening in the tank or something. Only other thing I can think of is that there was some other substance in the tank that reacted with the fuel?

 

[brett7777]

Went for some more fuel spattered test rides!
If the cap is defective as you suggest, then Im not sure what defect there would be in a simple fuel cap like this.
I've found if I remove the gauze filled bolt & nylon insert that it's not as bad. The chamber that the bolt creates is like a little 'ejection' chamber. Without this chamber then it just seeps a bit rather than being ejected all over the bike.
But then the bike stinks of fuel as the gauze bolt & insert must act as something of a fumes gate.
I think I will have to get my local engineer to modify the cap or tank for me & add a vent line that can be routed down towards the bottom of the bike. Most motorcycles have a vent tube built into the tank, or a vented cap (that works without spewing fuel haha!)
I think the shuddering of the bike is either something to do with the clutch, or the way the motor is geared. It shudders heaps on acceleration or deceleration, but not once you get up to speed.

 

[brett7777]

Well it looks nice anyway
Like I said before, the aesthetics of the design of the fuel tank & oil tank is second to none.
Ive put it up for sale. Ive kinda realized MB's are not really my thing. But I guess doing the project helped me figure that out.

 

[brett7777]

I think what has changed my mind about board track replicas done with bicycle frames is that they just dont feel very good at any sort of speed, compared to a motorcycle. A bicycle feels fine being pedalled but being motored I just see & feel all the things that make it a bicycle not a motorcycle, like the light frame, skinny tyres, lack of comfort & suspension etc
Im sure that's not a very popular view point around here.
But...they look great. Excellent for display & a discussion point etc. I cant help looking at the ones like that one that's appeared here on the forum from North Germany, just too cool.
I think that's what spoils them for me; I go for a ride on a motorcycle afterwards & just compare everything. If I didnt ride motorcycles I'd probably love it!

 

[harry76]

Personally i was never a fan of the chinagirls for long, they just vibrated a little too much for my liking. Thats why i decided to look for alternative engines, and although my Villiers isnt any faster then a chinagirl it is 1000 times better to ride............ rather then being dissapointed by the slowness of my bike im often amazed by how nimble it is,how light it is and how nicely it turns, and most importantly i ride it with great pride knowing i built it..... theres no vibrations that shouldnt be there and just a joy to ride, but im guessing they aint for everyone.

And although your other roadbikes are nice they dont have the same impact as your Indian, and im guessing youd get far more attention on your Indian........ maybe rather then selling it you should at least think of a bigger powerlant?????

 

[harry76]

Im not trying to talk you out of getting out of motorized bikes..... its your call, but you did say that your bike doesnt feel really good at any speed. To be fair you are only running cheapo tyres of very low quality...... you wouldnt expect your roadbikes to ride very well on cheapo tyres that werent DOT approved would you? And you are riding a hardtail bike, are you comparing it to your softails? Big difference there.

Anyway its your call, i absolutely love this hobby and just getting the other point of view across to you. I hope you build more bikes but like i said they aint for everyone

 

[brett7777]

I had been thinking about the drop loop frame with the morini, but apparently those engines are hard to get & morini may be going outta business or something. I imagine the morini would have been closer to what Im used to maybe.
I think it's a great hobby Harry, & the Villiers motors are great & look the part.
Yes I do get more attention with the MB, but I dont enjoy riding it (except for just pedalling). maybe I should just take the engine drive chain off & pedal it haha!
(& yes you're right, Im sure cheap tyres dont help)

 

[brett7777]

Well I want it to be running the best I can get it, for the new owner, so Ive been working on the 'motor shudders the whole bike thing'. Moving the needle clip to the lowest setting helped. But it still hasnt sorted it yet, so looking at maybe a smaller jet. The people over on the motor trouble shooting section are very helpful.
Haven't sorted the fuel cap yet, but leaving the gauze bolt & nylon insert out means it only seeps a bit rather than ejecting it in the air.
I also found out that if you use metal shims to shim the chinagirl mounts into a worksman frame that you need to silicone RTV them in (fell out while riding, & yes, my mounts were tight). Take note anyone who's putting a china 2 stroke into a worksman.
Best way would probably be just to buy the drop loop frame with the mounts, rather than a standard worksman, if you are going this way.

 

[sportscarpat]

Hi Brett,
I have read some of your problems and maybe I can offer some suggestions. Vibration is a common problem we all face, but in my experience the biggest culprit is usually an engine that is not centered in the frame. Because the engine mounts are low on the case and they only clamp to the frame it can start to rotate on its mounts and cause misalignment in the chain leading to vibration. It is hard to see as the chain will appear to be straight, but in fact the engine sprocket is leaned over a degree or two. I use the spark plug as a guide and make sure it is centered relative to the frame center tube under the tank. The gas caps have a somewhat effective baffle that the cap manufacturer came out with after complaints about gas seepage. He is working on a better design, and this may be it and it is less effective than the previous one. Same part, different slot. A small piece of scotch brite or stainless steel wool inserted in there may help. As for engine mount angles, there are so many different frame shapes these engines fit into that getting a perfect fit is next to impossible. I have always adjusted the engine mount by modifying the engine case, which is to say I grind in a different angle right into the engine case. I take off as little material as possible until I get better frame tube to engine mount angles. Not a perfect solution but it works. As for expectations coming from the world of motorcycles to the world of motorbikes, don't expect to be impressed with the high speeds and smooth operation of a motorized bicycle. It's a just a small engine hard mounted to a bicycle afterall. Probably not what you want to hear.

 

[brett7777]

Yep Ive been using the plug as the centre point reference already.
Decided not to grind into the engine case, the gasket is there as well so decided I didnt wanna grind into it.
Yep I'd say that new insert in the fuel cap is a design fault for sure. It's like a freakin volcano when it shoots up. I need to find something cunning to put in there. I suspect gauze will still let the fuel out, Im thinking some kind of absorbent material (that still breathes) would be handy.
It tis surely a nice bike anyway. I think in hindsight the China motor would be better in your drop loop frame. But you gave me a good deal on the stock frame so I cant really complain

 

[brett7777]

Played around more with the fuel cap. Basically the least amount comes thru if you just leave out the bolt & insert altogether. As soon as you put anything at all into that cavity it seems to act like a pump, to pump fuel out the top.
I think the fuel cap guy maybe needs to look at the diameter of that cavity? Maybe it needs to be narrower? Im no expert but I imagine the best thing for him to do would be to copy the design of a vented motorcycle cap. With all due respect, I think it should certainly be tested so that it doesn't do what it did to me.