Sprockets Space in Rag Joint & Chain Resistance

[Frankenstein]

Sweet, sounds like I'll be doing that. I'll keep you folks updated!

Today I was pushing the bike around, at very low speeds on carpet, and even then I could see the entire rag joint twisting in its current configuration. Good thing I'm planning to fix that.

Yeah don't ride it like that at all, you'd be just temping the wheel to implode on you which is a pretty nasty thing to be sitting on with a burning hot running engine between your legs, good way to ruin your week.

 

[jeffreybrown]

wheel to implode on you which is a pretty nasty thing to be sitting on with a burning hot running engine between your legs

That definitely would make for a less than dandy day!

I bought one of those ultra cheap Harbor Freight rotary tools. Very cheap, but impressive for 10 dollars (80 pieces!). I tried crassius' suggestion for moving the exhaust, which worked like a charm.

I've also widened the hole in the sprocket, and it now sits close enough to the spokes to put significant pressure on the outer rubber piece, so the joint now seems very solid. I would still like something better than a rag joint, but for something I'll most likely use only two or three times a year, I'm sure this will suffice.

Now I'm just dealing with some chain tensioner stuff. I would get one of those spring tensioners, but I don't have enough time before the camping trip. The chain seems to need a little stretching still, and it also appears I may need to file down some of the teeth on the drive sprocket. And then I'll probably wedge a file between the chainstay and the tensioner, as recommended in another thread, to hold the tensioner steady. The chain snags and catches right now, but hopefully these improvements and a bit of break-in should make it better.

 

[gary55]

I'm guessing your talking about the sprocket on the engine though it wouldn't surprise me if it was the wheel sprocket. I have run to this prob. of the poorly cut gears on the engines. For a while easing the edges on the sprocket teeth from one supplier became a routine in assembling their engines. You can see the burrs causing the snagging and knock them off with a dremel tool.
Another cause for snag might be the gear cover. If you pull it and look inside the cover you may see wear marks from the chain hitting it as it goes around the gear. I remove this portion of the cover with a cutoff wheel on a grinder on every engine I build.

 

[jeffreybrown]

Yeah, it's the engine sprocket. The chain does fit rather tightly around the wheel sprocket (at first I thought they gave me they wrong chain or sprocket), but otherwise seems pretty okay. I already did file some burrs off of the engine sprocket when I first got the kit, but I may need to file some more. I'll have to consider getting rid of part of that sprocket cover, it does seem like it would make like a little easier.

 

[jeffreybrown]

Got the new tensioner installed, this time with a file wedged in between the tensioner and the chainstay. Seriously, it works like magic to keep the tensioner from moving. The bolts aren't insanely tight, and it takes a significant amount of force to rotate the tensioner. So I guess that's a win! Doesn't look like the file is bending the chainstay, either.

That, taken with the properly installed sprocket, seems to have eliminated the issue of the chain snagging and such.

I've also installed a .64 jet to account for high altitude (9,000 feet). I'm a little nervous to test the bike at my lower altitude now (I live just under 6,000), fearing it may be too lean, but we'll see.

 

[Street Ryderz]

Got the new tensioner installed, this time with a file wedged in between the tensioner and the chainstay. Seriously, it works like magic to keep the tensioner from moving. The bolts aren't insanely tight, and it takes a significant amount of force to rotate the tensioner. So I guess that's a win! Doesn't look like the file is bending the chainstay, either.

That, taken with the properly installed sprocket, seems to have eliminated the issue of the chain snagging and such.

I've also installed a .64 jet to account for high altitude (9,000 feet). I'm a little nervous to test the bike at my lower altitude now (I live just under 6,000), fearing it may be too lean, but we'll see.

Sounds good your ready to roll! ride safe!

 

[Steve Best]

I have a better way to true the rear sprocket. The same way you would true a wheel.
Take the chain off and mount the bike up to let the wheel spin free.

Here you can see I am using a dial indicator to measure the wobble.
You can do the same thing with a piece of wire wrapped around the wheel stay and the tip pointed at the sprocket.
Spin the wheel and loosen the low spots, tighten the high spots.
If you cannot get it right, move the rubber around.
You can get it near perfect if the sprocket is.

I'd suggest you true and tighten the wheel and spokes while you are at it (before you start the sprocket).

Tighten (or rarely loosen) the spokes to get the wheel running true, then set all of them up to give the same "PING" when you tap them.

 

[jeffreybrown]

Ah, thanks for the tip. I was doing a bit of that, tightening in the farther out areas, and it has around an eight of an inch of runout currently. A little more than I'd like, but if it becomes problematic I'll definitely use your trick.

Weather permitting, I'll hopefully be able to test this thing out in the parking lot before long. I live at an apartment, which makes things a little difficult lol. I'm on the third level so getting it down to the parking lot will be annoying. My biggest concern is noise... How loud are these things? I hear they're quieter than a lawnmower, which isn't too bad. The parking lot also runs parallel to a pretty substantial city street, so I'm sure people won't think much of the noise.

Oh, to avoid creating another thread, I might as well ask this here. The handlebars are getting a little crowded with two brake levers, a clutch lever, and the throttle. I'm considering moving to just one brake. Is that a bad idea? I'm sure it is, lol. But, if I have just one brake, which one should I use? It seems like most people here recommend using at least the front brake, but I'll be riding this on dirt roads with much less traction. Because of that, I'm thinking it would be safer to use only the rear brake, perhaps?

 

[FurryOnTheInside]

Ah, thanks for the tip. I was doing a bit of that, tightening in the farther out areas, and it has around an eight of an inch of runout currently. A little more than I'd like, but if it becomes problematic I'll definitely use your trick.

Weather permitting, I'll hopefully be able to test this thing out in the parking lot before long. I live at an apartment, which makes things a little difficult lol. I'm on the third level so getting it down to the parking lot will be annoying. My biggest concern is noise... How loud are these things? I hear they're quieter than a lawnmower, which isn't too bad. The parking lot also runs parallel to a pretty substantial city street, so I'm sure people won't think much of the noise.

Oh, to avoid creating another thread, I might as well ask this here. The handlebars are getting a little crowded with two brake levers, a clutch lever, and the throttle. I'm considering moving to just one brake. Is that a bad idea? I'm sure it is, lol. But, if I have just one brake, which one should I use? It seems like most people here recommend using at least the front brake, but I'll be riding this on dirt roads with much less traction. Because of that, I'm thinking it would be safer to use only the rear brake, perhaps?

Removing the front brake will at least triple your stopping distance. I have two bicycles with only a front brake and got used to it okay but those are really for paved road and they're pedal powered bicycles, I would never want just one brake or not-independent brakes on any off-road or motorised bike, I'm certain.
But the bikes I'm building up to motorise, I just got one set of bar controls how I want them now, and there's no feeling of overcrowding. I have just put the right combination of levers on to get what i feel is the comfortable arrangement. I started with a 720mm flat and fairly straight bar. I put front (thumb) and rear (twist) gear shifters, front button clutch and rear brake levers all on the left hand side. Bike isn't running yet but sitting on the trainer I can play at pedalling it and trying out the lever arrangement. I had to raid a few of my other bicycles and swap parts around, but I think it's easily possible to have everything including independent front and rear brakes and not feel cramped and cluttered.

 

[Frankenstein]

Well I had a tight squeeze with my handlebars in the last place I lived to get it in the back, I loosened my handlebar stem so the bars could be made almost parallel with the front wheel (then retightened,) then it was easy enough to roll through with me walking next to it.

It might not be a viable solution for you, or elegant, but I did it and I had 2 5mm Allen head bolts I did it to every single time I brought the bike back or left with it for a year. It's not that much of an annoyance once you get used to it, and it saved more time and frustration than it could have ever caused. Don't know how easy it would be to drag your bike up or down with the bar turned but it's worth trying if you think it will help