212cc swap, torque converter, top speed only 32?

Mini Bike & Go-Kart Parts

#22
Another thing you could check: remove the chain, prop the wheel up and spin it to check for drag. The brake or bearings could be dragging.

Even the chain could hold you back a bit if it's not in good condition and/or lubricated.
Yea, Ill check the brakes/chain, maybe loosen the chain a hair, I did just put new bearings in the rear wheel as well with all this.
 

mustangfrank

Well-Known Member
#26
well I dont really care to go 60 mph on this thing but im just trying to verify its running properly.

Seems like I should be getting more RPM and speed out of this combo?
You mentioned belt length in the beginning if the thread, did you get a new belt? It's obviously not over-revving but belt length can affect shifting (early or late) and ability to RPM on a TAV. I do the marker stripe test on both clutch sheaves on a new setup to test shift out (belt travel).
 
#28
You mentioned belt length in the beginning if the thread, did you get a new belt? It's obviously not over-revving but belt length can affect shifting (early or late) and ability to RPM on a TAV. I do the marker stripe test on both clutch sheaves on a new setup to test shift out (belt travel).
No, didnt get a new belt, same belt that came with the TAV and was using with the old engine.
 
#29
My bikes all "run properly" but they don't have to run a top speed of 60mph.
Top speed is not an indicator of a properly running engine.
Top speed is all about gearing.
I understand that, just seems like it should be performing better from what ive read, but im not sure, thats why im here asking the question see if I was missing something or maybe this is just normal for my ebay TAV setup?
 

SAS289

Well-Known Member
#30
Yep backed that out.

So I got the tach on it today, with wheel in air, no load, revs to 5k and governor kicks in.

With my riding the bike full out it would settle around 3600-3700 RPM.
With stock gearing 3700 RPM isn't bad. Isn't that somewhere in the mid 40's mph?

At one point just for fun I put a 10 year old completely stock 196 (Utility engine) on my Coleman with the torque converter and 9/50 gearing. The belt shift came on early and just killed it. Couldn't have gotten much more than 3K RPM. Probably less than 35 mph.
 
#31
With stock gearing 3700 RPM isn't bad. Isn't that somewhere in the mid 40's mph?

At one point just for fun I put a 10 year old completely stock 196 (Utility engine) on my Coleman with the torque converter and 9/50 gearing. The belt shift came on early and just killed it. Couldn't have gotten much more than 3K RPM. Probably less than 35 mph.
Its registering like 36-38 mph roughly on my GPS max.

So maybe could be the way the torque converter is setup? It kinda "flares" to 4000 rpm or so then rpm actually drops to 3600-3700 as I gain speed and just levels off.
 

mustangfrank

Well-Known Member
#32
No, didnt get a new belt, same belt that came with the TAV and was using with the old engine.
Get a new, genuine COMET belt, not only will it last longer but the length is true to advertised size. Clean the sheaves, install the new belt and then start clutch tuning. If you want to test something while you're waiting for it, move the spring in the secondary clutch over one hole to give it more preload. Idea is to slow the upshift and let the engine RPM.
 
#33
The TAV driver can be tuned with different springs and weights. You can tune the engine for a certain RPM. Like was said, the driven can be tuned by different spring positions as well as different springs.
if the engine is hitting the RPM it's supposed to, then the gear ratio and TAV needs to be optimized for the engine's RPM.
Agreed with the actual Comet belt, they work great zero issues.

You might have to monkey around with the TAV to get it to where you want it. I ended up swapping out the stock driver weights and springs and it made a world of difference.
 

SAS289

Well-Known Member
#34
The TAV driver can be tuned with different springs and weights. You can tune the engine for a certain RPM. Like was said, the driven can be tuned by different spring positions as well as different springs.
if the engine is hitting the RPM it's supposed to, then the gear ratio and TAV needs to be optimized for the engine's RPM.
Agreed with the actual Comet belt, they work great zero issues.

You might have to monkey around with the TAV to get it to where you want it. I ended up swapping out the stock driver weights and springs and it made a world of difference.
I wasn't happy until I got the yellow spring and put it in the tightest position. Belt starts it's shift around 4300 under full throttle. Haven't did anything yet with the drive pulley/clutch. Engages around 26-2700.
 
#35
Also, my off-road bike has 14" tall tires, so that is totally different TAV and gearing setup than a bike with say 9-10" tall tires. There's a lot of variables that have to be considered.
 
#36
Get a new, genuine COMET belt, not only will it last longer but the length is true to advertised size. Clean the sheaves, install the new belt and then start clutch tuning. If you want to test something while you're waiting for it, move the spring in the secondary clutch over one hole to give it more preload. Idea is to slow the upshift and let the engine RPM.
Thank you, that is helpful, does kinda seem like its just the way the converter is designed.

Does it make sense to try and set it up for more RPM? I will have to do some research on it I suppose, I guess different spring would make it grip later in the RPM range and maybe get me some more speed from it
 

mustangfrank

Well-Known Member
#37
Thank you, that is helpful, does kinda seem like its just the way the converter is designed.

Does it make sense to try and set it up for more RPM? I will have to do some research on it I suppose, I guess different spring would make it grip later in the RPM range and maybe get me some more speed from it

Your engine is capable of more RPM and you want more top speed...yeah. Might as well get the full usable range out of the powerband, even if you don't use it. Start with the belt to baseline it, you may even notice better performance with it alone. You will probably need to order springs and/or weights for the primary and secondary, the spring tension hole adjustment on the secondary will clue you in if you need a stiffer spring if it responds to that. In an ideal world I like it when the new spring ends up liking it in the first or middle hole for adjustment later.

Re-read your last question...don't think of it as grip, I like to think of it as more time in the lower gear to build rpm...or how about this over simplification...a car that WILL do 120mph in 4th gear, but won't get to top speed (or take forever) if you shift 1st to 4th skipping 2nd and 3rd.
 
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MJL

Active Member
#38
A lot of people neglect to mention their top speeds are measured going downhill! Even an ever so slight downhill grade will significantly increase your top speed.

I messed around for months with a clone, then a Genuine Comet driver on my Baja, using various combinations of springs and never could get it to perform the way I wanted. It would upshift too fast and bog the motor even with a yellow driven spring in the tightest hole then refuse to down shift when I slowed down, despite the fancy moly lube. Got a Juggernaut Super 30 driver and it felt like I was driving something off of the Honda production line, revs to the moon now. I run it hard and it is still cool enough to put my hand on, vs the Comet which would blister. Really shows how much power it was wasting.

All said and done it'll probably hit 40 or so on relatively flat ground in the 200 yard straight stretch we have in the riding area and I weigh around 225.

Put one on my oldest son's Trailmaster a few months back, runs great even with the throttle limited to keep the speed down. Just ordered a third for my youngest son's Coleman.

Because of the lower final drive ratio vs the Comet, I can see where some get a lower top speed, but, to me, the increased off road performance is worth it.
 
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#40
A lot of people neglect to mention their top speeds are measured going downhill! Even an ever so slight downhill grade will significantly increase your top speed.

I messed around for months with a clone, then a Genuine Comet driver on my Baja, using various combinations of springs and never could get it to perform the way I wanted. It would upshift too fast and bog the motor even with a yellow driven spring in the tightest hole then refuse to down shift when I slowed down, despite the fancy moly lube. Got a Juggernaut Super 30 driver and it felt like I was driving something off of the Honda production line, revs to the moon now. I run it hard and it is still cool enough to put my hand on, vs the Comet which would blister. Really shows how much power it was wasting.

All said and done it'll probably hit 40 or so on relatively flat ground in the 200 yard straight stretch we have in the riding area and I weigh around 225.

Put one on my oldest son's Trailmaster a few months back, runs great even with the throttle limited to keep the speed down. Just ordered a third for my youngest son's Coleman.

Because of the lower final drive ratio vs the Comet, I can see where some get a lower top speed, but, to me, the increased off road performance is worth it.

Yea, I was about to buy springs and weights and mess with the current setup, but I decided to just spend the money on the juggernaut as that seems to be the way.

About to try it today to see how it does.
 

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