Race bike for Oregon Gambler 100

[ezcome-ezgo]

Can you work it where the clutch on the crankshaft is the other way around?

 

[mckutzy]

Judging the look of it, the sprocket won't have anything to hold onto... Equally speaking the clutch run inboard, won't be able to engage the keyway with the internal integral key not fully broached...
Had there being any engagement... Any good load on the shaft might strip the end an f-up the key...
I'm guessing...

 

[wardog]

You pretty much nailed it mckutzy...... not enough key engagement with the clutch turned around.

The little 9 tooth sprocket has a built in key and it is slid on as far as it will go in the pics. I could grind off the corner of the built in key to allow it to slide further up the "ramp" where the crank keyway ends, but not much room for chain to engine clearance.

 

[mckutzy]

On the wee sprocket... Is the said integral key all the way through the bore... Or half like the clutch....

 

[Nosandwich]

On the wee sprocket... Is the said integral key all the way through the bore... Or half like the clutch....

"Wee" sprocket??? Is it Halloween in Canada, and you're going as an Irish man?

alibaba by now is worlds largest B2B platform for all I know..

Anywho, when you hit a wall on alibaba, then try aliexpress, which is the same thing but for "endusers"..
no need to buy 200 pieces a month or fullfill a 1000 pieces min order..

'sid

 

[wardog]

Yup, the key is full width.

Here is what I came up with. The spacer only helps support the clutch, no torque is transferred through it. Just ignore the snap ring groove in the spacer.

 

[mckutzy]

I was going to suggest, cut off some of the hub for the sprocket...add a few washers to keep it spaced where you need it, but could almost eliminate appears to be 3/8-1/2"

 

[wardog]

Would 3/8" of key engagement be enough for the clutch? for the 9 tooth sprocket? If so, then I think I can grind the sprocket like you suggested and flip the clutch around like I originally wanted. Then the extension only has to be 1/2" instead of 1".

 

[mckutzy]

Typically those sprocket will break in manners that have no relation to the keyed portion of the "hub"(this type), as the force is transmitted to the shaft via the key and surrounding sprocket.
The motor is of lower power and of relatively low revs.
So if the given sprocket has enough support so it wont be torqued in other directions(in which the hub helps serves this support), itll be fine.....
Maybe half of the hub section or up to the rebated section of the hub might be as far as you would want to go.....

With that being said... having proper alignment, axial movement of this sprocket must be avoided... so as to not allow it to be torqued in directions, other than the line of transmitted force.

I hope this kinda make sense.... Had a quick look through some transmission texts on drivelines...

 

[wardog]

I will have to basically cut off the entire "shoulder" of the sprocket for space on the shaft and because of the set screw holes. Is the roughly 3/8" of sprocket key left strong enough?

 

[mckutzy]

I couldnt find any info on that sprocket... but Im going to take a good guess Yes itll work... and based on what you have for the power plant.. it should last at least the race....

 

[wardog]

I hope so, because I cut it down and flipped the clutch around. It looks much better now. I think the clutch key will be fine, but the sprocket has a tiny bit of play since the set screws are now gone. I just keep telling myself its only 79cc..... ha!

---------- Post added at 02:21 PM ---------- Previous post was at 02:02 PM ----------

The next question is will a single 1" sch 40 pipe be strong enough for single sided forks? Its about 1 3/8" od and 1/8" wall thickness. Keep in mind the wheel width will be 13"

 

[ezcome-ezgo]

I am guessing that will not be strong enough. I personally would not do it.

 

[wardog]

I used 1 1/4" sch 40 for the main part of the forks on my big bike and 1" for the brace..... It is extreme overkill.

What if I use 3/4" pipe for a brace just like a smaller version of the big bike?

 

[mckutzy]

Why not stick to the conventional fork design?

 

[wardog]

It will save a few pounds and I like being able to bolt the wheels on like a car, but mostly it is just to be cool

 

[wardog]

So Ive added a performance intake and exhaust and removed the gov, now I need to rejet the carb. What are the cons of drilling the original jet out a size or two?

 

[mckutzy]

If you go past... It's harder to return to OEM or the previous size...

What I did was... Got a bunch of jets and E-tubes from the local rental shop... They had a small parts bin and let me pick through... Cost me a few $..
I kept the OEM, gauged it through the small bits I bought. Found the other and started drilling up and testing...

 

[wardog]

I read that if you only go up one bit size at a time, drill it by hand (twisting the bit in your fingers), and get a good plug reading with each increment it should work fine....

 

[mckutzy]

Yup... That's what I did... I had a small bit holder... But the same thing...