Gear ratios again

[Rat]

So I've made it fairly known my 208 is mildly built and has no hesitation to yank the front end off the ground, which to be fair the engine was designatwd high torque/winter/snow thrower use before I started tweaking it.

As is I've got a 9t on the Tav2 (6" driver, Yellow Comet spring in driven) turning a 56t on the axle for a final drive ratio of 6.22, a final drive ratio of 5.6 also stands right up.

The wheels are 1970's Takasago 185B-18 wrapped in 2.50-18 (40L rated) tires.

The real question is how drastic could I go in final drive (guestimate obviously) before I'd be burning up belts?
My on hand options currently are:

48t* 4.8/5.33
36t* 3.6/4.0
28t* 2.8/3.11

@Denny ?
@Functional Artist ?

 

[Denny]

For me my comfort zone would be no higher than 10/54 with an18” tire.

 

[panchothedog]

My Trail Master M B 200 mini bike, purchased brand new 3+ years ago, came powered by a clone 196 cc. 30 series torque converter, 10 tooth driving a
48 tooth with 19" tires . 4.8 to 1. Ran very good on the street. I changed it to a
60 tooth, only because all of my riding is off road, and I am about 225 lbs. With a 9 x 48 you should be OK. On the 36 sounds pretty tall , 4 to 1. Only way to know for sure is to give it a try and watch the belt.

 

[Rat]

For me my comfort zone would be no higher than 10/54 with an18” tire.

It was all good at 10/56 until I got to chasing flaws out of the system and by then I had the 9t for it. I have no shortage of torque at this point

 

[Rat]

My Trail Master M B 200 mini bike, purchased brand new 3+ years ago, came powered by a clone 196 cc. 30 series torque converter, 10 tooth driving a
48 tooth with 19" tires . 4.8 to 1. Ran very good on the street. I changed it to a
60 tooth, only because all of my riding is off road, and I am about 225 lbs. With a 9 x 48 you should be OK. On the 36 sounds pretty tall , 4 to 1. Only way to know for sure is to give it a try and watch the belt.

196 versus a mildly built and torquey 208... 4.0:1 shouldn't be too bad considering I used to run it 3.6:1 without smoking belts before I really started upgrading it. That was of course city riding and a lot more flat ground than I'm ever going to get in these mountains down south.

Also bearing in mind the bike itself weighs right around 110 wet, and I'm only 195 +/- 10 depending on what riding gear I'm wearing... it's proving to be quite a learning curve trying to gear accordingly. I'd prefer it not to lug up steep inclines because there are so many I deal with, but I also don't want to be screaming redline to make speed in the few flats I do get... As is (9/56* 6.22:1) I can pull a standing launch at the base of a steep slope and accelerate to 35 easily while climbing

 

[Rat]

I've got the 48t on, still debugging the alignment and clearances but that puts me at 5.33:1.

Considering 5.6:1 was just as quick to stand up previously as the 6.22 the 9t gave me IDK if 48t is going to be the one.

I don't care that it can launch into wheelstand... thats funny to me because no one (myself included) really expects to see that happen. I do however care a lot that my forks don't appreciate the abuse and I'd rather not have them fold up on me.

 

[panchothedog]

Then you need to gear it taller. You know that.

 

[Rat]

Then you need to gear it taller. You know that.

I've never liked how bassackwards that phrasing is... 48t remains TBD.
I'm using what I have on hand to determine the best course of action because I know I will inevitably end up ordering a new rear gear (due for a new chain anyway) but I need a reference point as to what that's going to be.

I know it can drag the 36t up a slope in a 3.6:1 arrangement and I'd like better than struggling to make 30mph up a steep incline since that's all I have around the region on way or the other.

I've Also have not yet ran the 36t with the 9t, so if the 48t doesn't tickle the way I want than 36t is the next step and I'd venture its a pretty big step between a 3.6 and a 4.0 final drive ratio.

 

[Rat]

I couldn't convince the 48t to line up properly (flat sprocket) so I went ahead and plopped the 36t (¼" dished) on, and all seems good. Takes off more timid, no more wheelies, and still accelerates quite well up steep inclines.

My next possible issue is whether I need to replace some hardware or not.

What all can make a driven bind aside from the obviousness of being dirty?
I've taken it apart, wiped it out real good and reassembled it, but it usually only operates normally for a few rides before it only wants to open half way or not at all.

I wouldn't suspect the yellow spring might be too stiff if I'd never pulled belts down into the rivets and chewed them all to hell in the past using the same spring in its current spring position.

 

[Rat]

This is the final update I think.
After putting on the Dover coil and split lock valve retainers, I decided to shave a timing key (nobody has my 1/4" key in an offset and I'm not paying extra to have a set made) so I now have about 5° advance +/- 0.25°.
After debate and digging around I've gone back to 6.22:1 FDR and oddly enough the wheel stand issue is not as bad; needless to say bringing the nose up is nolonger done accidentally but it will still lift off if I want to risk my neck to showboat a little

 

[Alex.bikes]

nice

 

[Rat]

nice

More like nasty.
Yes that IS a 208cc with an remote oil filter, remote pump, and an oil cooler.
Why?
Because someone said I couldn't, but refused to answer a very valid "Why not"... and So I did.