Help with my Chainsaw bike

MisterSteve124 · Mon Oct 29, 2007 2:35 pm

too tight? When I have it running it just starts wobbling if I loosten it then it will wobble even more. I think I just need a different gear ratio unfortunately.

Mon Oct 29, 2007 6:39 pm

MisterSteve124 wrote:too tight? When I have it running it just starts wobbling if I loosten it then it will wobble even more. I think I just need a different gear ratio unfortunately.

Yep, to tight, also to straight up and down. Any slack will accumalate at the bottem causeing derailment.

Now i know that i'm conderdicting myself by saying to tight, then saying the slack derails it, but think about it.

Like i said the first time, most chains run 1/2" slack at the longest free floating streach. I see you still have the gear changing mechinisem beneath the gear rack. If it were me building it, i would remount that to run inbetween the two sprockets. That would fix your problems.

MisterSteve124 · Mon Oct 29, 2007 7:00 pm

Well I also just figured out that I have a horrible gear ratio for this. I should have abou 14:1 and I think I have something like 2.7:1 but I would rather not try and try and make a new setup for getting the gear ratio higher. So I'll give what you said a try tomorrow and then if that doesn't work I'll have to set up something to change the gear ratio.

iknowmy3tables · Mon Oct 29, 2007 7:33 pm

wow thats some thing,

uhm I don't have much experience with this man but maybe add some shrouds on both sides of the gear , f

MisterSteve124 · Mon Oct 29, 2007 8:07 pm

I think I might be able to somehow reposition the derailer so that the chain runs through it. I wonder if it will just get worn down the sprockets on there are plastic so I don't know what will happen to them running at high speeds.

shud_b_rite · Mon Oct 29, 2007 11:51 pm

What are you planning on using it for? Going up hills or just assisting with pedaling?

Tue Oct 30, 2007 5:07 am

Just make sure that the derailer has room to float freely. Don't want it to get jammed into the other gears.

MisterSteve124 · Tue Oct 30, 2007 1:56 pm

I want to not have to pedal at all. And go fast

Update: Well I tried out riding it today and it worked but I only went about 10mph (just on idling speed) and nothing really happened when I gave it some gas but I didn't want to rev it too much. And then after about 10 minutes of riding the clutch started smoking. If I just took the springs out of the clutch would that just totally disable it and then it wouldn't overheat? Because I don't really think its even working now because it was a really tight fit getting it on so it may not even be rolling on the needle bearing.

babyJ · Tue Oct 30, 2007 6:25 pm

make sure the output shaft outta the motor is 90 degrees to the chain and make sure the gear on the output andthe gear that u are using on the bike are in line. but u cant change gears or it will come off.

Tue Oct 30, 2007 6:35 pm

Removing the springs will probly disable it all together. If your clutch is smoking, it's either pulling to much weight, (changing the gear ratio should help), or, it's not working rite to begin with, fly weights/outer drum worn???

MisterSteve124 · Tue Oct 30, 2007 8:05 pm

Ok I'm just gonna suck it up and change the gear ratio. I'll buy a jackshaft on ebay and mount it under the engine and I'll have to move the wheel so the sprockets are on the other side. If I'm using a jackshaft what are two size sprockets I want to use to get my gear ratio to 14:1 is that even possible? I know how to calculate the gear ratio for just 2 gears but I don't know what to do for 4 of them.

ammosmoke · Tue Oct 30, 2007 8:18 pm

What if you just remove the clutch altogether? The wheel itself already has a mechanism that allows it to coast...

EDIT: Oh wait, duh... Because then you can sit with the engine running...

MisterSteve124 · Tue Oct 30, 2007 8:32 pm

Well that's what is happening now because I had to ram the clutch drum into there so hard that the bearing won't allow the drum to not spin. But still without the clutch I don't have the correct gearing. So I am just going to bite the bullet and buy a jackshaft and some new sprockets if anyone can help me calculate the gear ratios I would appreciate it.

Wed Oct 31, 2007 3:06 am

Any gears you add to tension the chain wont figure into the ratio. The thing about drive gears is if you go up (more teeth) on the wheel gear, you have to go down (less teeth) on the engine gear, or it wont have the power to turn the wheel when it's pulling a load. From looking at the pictures, it's looks like the engine gear is kinda big. Count the teeth on the wheel gear and try and find a engine gear with 14 times less teeth, if that makes any sence. If you have to force a clutch drum on, something aint rite. The drum should spin freely with approx. .002 to .004 of a inch clearance. You need to pull that back apart and find out why it's jamming up. I have to tell ya, thats not much engine to pull you around so don't expect to break the land speed record even when you do get it rite. 40 CC's if your lucky.

battlemonkey · Wed Oct 31, 2007 3:18 am

I race motorbikes and know a bit about them (I hope) and from all my knowledge the chain should always be able to move about 1cm left to right when youn push it. you will need a swicher device from a bike because as what was stated above the chain ratio will change so will the length that is required. You will need about a 5-60 ratio or tougher cluch springs so it inganges latter.

Help with my Chainsaw bike

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