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

Mini Bike & Go-Kart Parts

#41
Well put the juggernaut on and while it does feel better all around, its revving to 5k on the limiter but still only hitting like 36 mph~

Anyone know how to remove the limiter on this thing? LOL

In all seriousness, what should the ducar 212 be safe to rev out to?

Or does it make more sense to change gearing if im looking for more speed?
 
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MJL

Active Member
#42
Well put the juggernaut on and while it does feel better all around, its revving to 5k on the limiter but still only hitting like 36 mph~

Anyone know how to remove the limiter on this thing? LOL

In all seriousness, what should the ducar 212 be safe to rev out to?

Or does it make more sense to change gearing if im looking for more speed?
You'll need an aluminum flywheel, billet rod, and heavier valve springs to (reliably) push past 5k.

You might be able to swap chain sprockets and pick up some more speed without increasing RPMs.
 

SAS289

Well-Known Member
#43
Well put the juggernaut on and while it does feel better all around, its revving to 5k on the limiter but still only hitting like 36 mph~

Anyone know how to remove the limiter on this thing? LOL

In all seriousness, what should the ducar 212 be safe to rev out to?

Or does it make more sense to change gearing if im looking for more speed?
There you go. Now you have to gear for better performance or build the engine to safely get higher RPM.

I wouldn't rev it higher than 5800. And I still wouldn't hold it there long on the stock rod. If I needed 5K or higher I would get a billet rod.
 
#44
You'll need an aluminum flywheel, billet rod, and heavier valve springs to (reliably) push past 5k.

You might be able to swap chain sprockets and pick up some more speed without increasing RPMs.
The Ducar 212 comes with a PVL flywheel, tested at 17,000 rpm...
 

mustangfrank

Well-Known Member
#46
Well put the juggernaut on and while it does feel better all around, its revving to 5k on the limiter but still only hitting like 36 mph~

Anyone know how to remove the limiter on this thing? LOL

In all seriousness, what should the ducar 212 be safe to rev out to?

Or does it make more sense to change gearing if im looking for more speed?
What gear ratio is on it now, and what tire diameter? I looked back in the thread and I only saw where SAS289 guessed at your setup, if you're running 6:1 now with 19" tires you'll need more power to pull any much lower ratios IMO.

The Juggernaut is not a solution by itself, you just introduced another clutch that needs tuning to your combo. What RPM is it set to engage at and is it actually engaging near that RPM? If I had to guess you are getting belt slip and/or your secondary clutch still needs tuning.
 

SAS289

Well-Known Member
#47
If the belt is not slipping it's because with the Jugg you don't get the gearing change with the belt shift that you get with the stock driver. With the speed and RPM he got, that would mean the Jugg got to only around 1.55/1. After the belt shift it would be around a 7.75/1 final ratio. Those numbers assume no belt slip, 19 inch tire, and 10/50 sprockets.
 

MJL

Active Member
#48
Have you seen 5000+ rpms at any time with your tach? Just wondering if it is the govenor holding you back or if you have hit the power limit of your engine. Personally I like a governor so I don't have to watch a tachometer while screaming across rough terrain. With this in mind, I'd see if you could adjust yours for a couple hundred more RPM. This is easiest to do if you unbolt the gas tank and just shift it to the side a bit, careful not to disconnect the gas line. Under the gas tank, you will see a spring connected to the governor arm. You will also see a thinner spring, don't mess with that one. There is usually a series of holes in the governor arm. Take the spring out of the hole it is in and put it in the next hole that will tighten it. Then put it back together and give it a try, repeat as necesary.

Are you still running the stock airbox and exhaust? If so, you might be reaching the power limit of the engine. Install a high flow intake/ exhaust, rejet the carb accordingly and see what that does for you.

All that said, 36 mph on an off road minibike is plenty fast for me. Stopping distances with just a rear brake start getting mighty long at that point. I've got a mikuni sitting in a box just because I have no desire to go any faster. Call me old if you want, but I like my parts the way they are!
 

SAS289

Well-Known Member
#49
Have you seen 5000+ rpms at any time with your tach? Just wondering if it is the govenor holding you back or if you have hit the power limit of your engine. Personally I like a governor so I don't have to watch a tachometer while screaming across rough terrain. With this in mind, I'd see if you could adjust yours for a couple hundred more RPM. This is easiest to do if you unbolt the gas tank and just shift it to the side a bit, careful not to disconnect the gas line. Under the gas tank, you will see a spring connected to the governor arm. You will also see a thinner spring, don't mess with that one. There is usually a series of holes in the governor arm. Take the spring out of the hole it is in and put it in the next hole that will tighten it. Then put it back together and give it a try, repeat as necesary.

Are you still running the stock airbox and exhaust? If so, you might be reaching the power limit of the engine. Install a high flow intake/ exhaust, rejet the carb accordingly and see what that does for you.

All that said, 36 mph on an off road minibike is plenty fast for me. Stopping distances with just a rear brake start getting mighty long at that point. I've got a mikuni sitting in a box just because I have no desire to go any faster. Call me old if you want, but I like my parts the way they are!
The throttle spring should already be in the outer hole on the governor arm on the Ducar. That's how they are governing above 5K out of the box.
 

MJL

Active Member
#50
The throttle spring should already be in the outer hole on the governor arm on the Ducar. That's how they are governing above 5K out of the box.
Possible to drill a new one? Or tie off the spring just for testing purposes? (Mod feel free to delete if needed, the OP does have a PVL flywheel).
 

SAS289

Well-Known Member
#51
Possible to drill a new one? Or tie off the spring just for testing purposes? (Mod feel free to delete if needed, the OP does have a PVL flywheel).
That's what I would do for a one run test at least. You would have to be careful with spring length so the governor operation during start up isn't effected. The governor needs to be able to pull the throttle to the idle position when the choke is opened. When doing this test the back wheel should be off the ground on first start to verify idle first.

It may run right into valve float. Then there's the added risk of spinning the governor assembly too fast. How much can it take? But again, just a one run test to see if max RPM changes.
 

MJL

Active Member
#52
That's what I would do for a one run test at least. You would have to be careful with spring length so the governor operation during start up isn't effected. The governor needs to be able to pull the throttle to the idle position when the choke is opened. When doing this test the back wheel should be off the ground on first start to verify idle first.

It may run right into valve float. Then there's the added risk of spinning the governor assembly too fast. How much can it take? But again, just a one run test to see if max RPM changes.

Just remembered that some of the kart racing guys are allowed to ziptie just a few coils of spring to tune their governors.

Good point on valve float. For the OP, if the engine starts to stumble at high rpms, you have hit valve float and are over the 'red line'. Stay below that point to avoid engine damage. More experienced folks here could probably tell you how close you can flirt with that point. And, obviously, your engine will last longer the less you pull high rpms.

Are you wanting to cruise at 40+mph or just peak out occasionally?
 
#53
What gear ratio is on it now, and what tire diameter? I looked back in the thread and I only saw where SAS289 guessed at your setup, if you're running 6:1 now with 19" tires you'll need more power to pull any much lower ratios IMO.

The Juggernaut is not a solution by itself, you just introduced another clutch that needs tuning to your combo. What RPM is it set to engage at and is it actually engaging near that RPM? If I had to guess you are getting belt slip and/or your secondary clutch still needs tuning.
Whatever the stock coleman 200 setup is, I havent changed the gearing or tires on the bike.

Its possible theres some belt slip, belts pretty old at this point and was outside in the winter etc.

I didnt adjust anything with the juggernaut out of the box, threw it on there. Tried moving around the spring on the secondary a bit but didnt seem to change too much.
 
#54
Have you seen 5000+ rpms at any time with your tach? Just wondering if it is the govenor holding you back or if you have hit the power limit of your engine. Personally I like a governor so I don't have to watch a tachometer while screaming across rough terrain. With this in mind, I'd see if you could adjust yours for a couple hundred more RPM. This is easiest to do if you unbolt the gas tank and just shift it to the side a bit, careful not to disconnect the gas line. Under the gas tank, you will see a spring connected to the governor arm. You will also see a thinner spring, don't mess with that one. There is usually a series of holes in the governor arm. Take the spring out of the hole it is in and put it in the next hole that will tighten it. Then put it back together and give it a try, repeat as necesary.

Are you still running the stock airbox and exhaust? If so, you might be reaching the power limit of the engine. Install a high flow intake/ exhaust, rejet the carb accordingly and see what that does for you.

All that said, 36 mph on an off road minibike is plenty fast for me. Stopping distances with just a rear brake start getting mighty long at that point. I've got a mikuni sitting in a box just because I have no desire to go any faster. Call me old if you want, but I like my parts the way they are!
its tapped over 5k a few times, but its def on the governer, it jerks around pretty noticeably when its there

yes stock airbox and exhaust, I dont think its a power issue as it runs up into that limiter pretty quick now.

I guess I just like to have the option to go faster if I want, I mainly drive the thing off road and never hit those speeds anyways but just seems like wasted power when I get rolling.
 
#55
So just an update, ended up grabbing a new belt and moving the governer spring a bit, getting about 40mph at 5300 rpm with no governer interference.

overall bike runs great and rips wheelies like a boss so im happy, dont need any more top speed, just glad the annoying governer isnt jerking me back and forth now lol
 

SAS289

Well-Known Member
#56
So just an update, ended up grabbing a new belt and moving the governer spring a bit, getting about 40mph at 5300 rpm with no governer interference.

overall bike runs great and rips wheelies like a boss so im happy, dont need any more top speed, just glad the annoying governer isnt jerking me back and forth now lol
That's good. You're just topping out at a lower RPM than max governed at full throttle.
 
#57
I don't get the obsession with top speed. Are you guys running these bikes at Bonneville?
Because going slow is boring. It's fine for just tooling around the neighborhood for a bit or with friends that have slow bikes. A friend of mine and I both have bikes that will do 60mph and it's fun as fuck to race each other. It all comes down to who gets the launch (my CT200U is very difficult to get a good launch). I've got a drag project that's going to have a fully built 236 stroker in it that I want to get 80mph+ out of too.

Different strokes for different folks.

BTW, my friend that's also into going fast has run a bike at Bonneville that he made from scratch in his garage. He's working on another setup now to try and go for a record in the class it'll be in.

edit: Pic of the bike below. He was in the A-G 175cc class IIRC.
 

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#59
My drag bike will go 80mph as well.
But I don't think there is anywhere around here where i could even get up to 80.
I'm looking for 80+ in the 1/8 mile out of it. There's a spot by my friend's house (dude mentioned in the other post) that we can run those kind of speeds. He's marked out a 1/8 mile stretch there too and it's got plenty of slow down space. Completely flat as well. It's right behind a residential area so we can only get away with doing 2-3 runs at a time.

My CT200U will get to 60mph in under 600'. It's topped out for the last bit of the 1/8.
 

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