Problem with driver

[Minichopperchar]

Hey Everyone I'm trying to find out if I should spend the $100 on a juggernaut torque converter or just go with a standard clutch on my bike. I have a thirty seven tooth rear sprocket and I think a 12 or 10 tooth on the torque converter. I spent forty bucks on the aluminum dicast weights and stiffer springs For the driver and my performance has been very bad. I've only topped out at 48 mph and I used to get at least 52 just being stock I'm wondering if I should just go with the straight chain and a normal clutch or get the juggernaut because people usually run clutches with high horsepower engines and I haven't seen enough videos on the juggernaut to make a decision any advice? it is modified with a 272. mongoose cam, billet rod, pvl aluminum flywheel, 30mm carb with an 85 main and 32 pilot, no governor, 0.10 head gasket and 26lb valve springs. I'm not sure how much rpm its turning but I would guess over 6500

 

[sparkwizard]

Before you do anything, try a LARGER rear sprocket with the converter. I suspect it is staying an low range, with the stiff springs, small sprocket, the driver never spins fast enough to shift the belt up.
Maybe you should be looking for a motorcycle?

 

[Minichopperchar]

it

Before you do anything, try a LARGER rear sprocket with the converter. I suspect it is staying an low range, with the stiff springs, small sprocket, the driver never spins fast enough to shift the belt up.
Maybe you should be looking for a motorcycle?

definitely shifts fully up. something feels restricted on the bike now and I thought smaller sprockets = higher top speed I got the smaller sprocket because I thought the torque wouldn't really matter much if I already had the converter

 

[SAS289]

What size is the rear tire?

 

[Minichopperchar]

What size is the rear tire?

19 7x 8

 

[sparkwizard]

Rear sprocket diameter should be approximately 2/3 to 3/4 of tire diameter for best torque converter performance.
(about the size of the wheel)

 

[SAS289]

omg. No wonder it feels restricted. And I don't think you are getting anywhere near 6500 RPM at top speed.

A Juggernaut would help because of the large gearing change it provides compared to the stock driver. You would get higher RPM at top speed and be more into the cam if that's what you want.

In my opinion clutch versus torque converter depends on how and where the bike is ridden. I know that if I had a 100% street bike I would never use a torque converter no matter what the engine power. My bikes spend 99.9% of the time off road, so they have torque converters.

Edit....
The Juggernaut may not be a solution by itself if you have 10/38 tooth sprockets. The hope would be that the engine has the power to fight the load to 5700 RPM and you would have a 60 mph bike.

 

[Minichopperchar]

omg. No wonder it feels restricted. And I don't think you are getting anywhere near 6500 RPM at top speed.

A Juggernaut would help because of the large gearing change it provides compared to the stock driver. You would get higher RPM at top speed and be more into the cam if that's what you want.

In my opinion clutch versus torque converter depends on how and where the bike is ridden. I know that if I had a 100% street bike I would never use a torque converter no matter what the engine power. My bikes spend 99.9% of the time off road, so they have torque converters.

Edit....
The Juggernaut may not be a solution by itself if you have 10/38 tooth sprockets. The hope would be that the engine has the power to fight the load to 5700 RPM and you would have a 60 mph bike.

well I definitely use it for mainly street riding but I like the take off power that a torque converter gives compared to a clutch, and people say that a 37 or 42 sprocket might be too hard on the clutch and burn it out. I'm not sure if that's true though

 

[Minichopperchar]

well I definitely use it for mainly street riding but I like the take off power that a torque converter gives compared to a clutch, and people say that a 37 or 42 sprocket might be too hard on the clutch and burn it out. I'm not sure if that's true though

Sometimes I'll take the bike off to the everglades trails but since I'm in florida I hardly have any hills you might say a clutch works best for me But I don't know if a simple 20 or $40 clutch will do the job for me. And I definitely don't want to spend 300 on a racing clutch If the jug will get me where I want to be

 

[BrownStainRacing]

19 7x 8

You are way under geared, and the t/c is fighting the engine. It's gonna take a BIG torque engine to pull a 3.7:1 gear with a 19" tire.

Do you have any other wheel sprockets or t/c sprockets to test with????

I run the aluminum weights with 1 pink spring and 1 stock spring for 3000 rpm engagement. This is good for stock to mild builds for an experienced rider that has good throttle control.

2 stock springs with aluminum weights should give you 3300 rpm. Good for more mild- not so wild builds, manageable but take caution on slippery surfaces.

2 white springs with aluminum weights should be around 4000 rpm. More for very big cammed engines that don't make much torque under 4000 rpm, only really good for straight line racing, imho.

If you have too much rpm engagement (stall) and the engine peaks torque at less rpm, it will never be able to pull hard into the higher rpm. In other words, you have blown passed peak torque of the engine before the belt engages, and the engine don't have enough power to pull that high gear you are trying to run.

IMHO, you need to START with 3000 rpm engagement, a 50t wheel sprocket, and a 9t t/c sprocket.

This will give you a 5.55:1 gear, but with the overdrive of the 6" driven, you will have a final drive of 5:1.
Your build should have plenty in it to pull a 5:1 final drive with a 19" tire.

You really need a tach to fine tune the t/c driven spring and gear ratio. This way you can see where the rpm drop is when the t/c shifts into high.

If rpm drops too far down, it's gonna take a long time and distance to get more mph. If it drops very lil, there is no more mph to gain.

I set t/c and gear ratios for the riders weight, and a 600ft flat level hard surface run. I live in the mountains and we don't have long flat stretches of roads, mostly old logging road twisty, hilly trails.

If the bike noses over before the 600ft mark, I need to drop gear. If it noses over after the 600ft mark, I need to add more gear. This is for modified non gov'd engines that easily hit 50+ mph in 600ft, and don't need to rev passed 6000 rpm.

Stock gov'd engines, i set for 350-400ft, so the rider still has plenty of power and speed (35-40 mph) to pull the steepest hills and not have to push the bike up a hill because some dummy didn't take time to set it up correctly for the terrain we run on.

Hope this helps, good luck, keep testing.

 

[Minichopperchar]

You are way under geared, and the t/c is fighting the engine. It's gonna take a BIG torque engine to pull a 3.7:1 gear with a 19" tire.

Do you have any other wheel sprockets or t/c sprockets to test with????

I run the aluminum weights with 1 pink spring and 1 stock spring for 3000 rpm engagement. This is good for stock to mild builds for an experienced rider that has good throttle control.

2 stock springs with aluminum weights should give you 3300 rpm. Good for more mild- not so wild builds, manageable but take caution on slippery surfaces.

2 white springs with aluminum weights should be around 4000 rpm. More for very big cammed engines that don't make much torque under 4000 rpm, only really good for straight line racing, imho.

If you have too much rpm engagement (stall) and the engine peaks torque at less rpm, it will never be able to pull hard into the higher rpm. In other words, you have blown passed peak torque of the engine before the belt engages, and the engine don't have enough power to pull that high gear you are trying to run.

IMHO, you need to START with 3000 rpm engagement, a 50t wheel sprocket, and a 9t t/c sprocket.

This will give you a 5.55:1 gear, but with the overdrive of the 6" driven, you will have a final drive of 5:1.
Your build should have plenty in it to pull a 5:1 final drive with a 19" tire.

You really need a tach to fine tune the t/c driven spring and gear ratio. This way you can see where the rpm drop is when the t/c shifts into high.

If rpm drops too far down, it's gonna take a long time and distance to get more mph. If it drops very lil, there is no more mph to gain.

I set t/c and gear ratios for the riders weight, and a 600ft flat level hard surface run. I live in the mountains and we don't have long flat stretches of roads, mostly old logging road twisty, hilly trails.

If the bike noses over before the 600ft mark, I need to drop gear. If it noses over after the 600ft mark, I need to add more gear. This is for modified non gov'd engines that easily hit 50+ mph in 600ft, and don't need to rev passed 6000 rpm.

Stock gov'd engines, i set for 350-400ft, so the rider still has plenty of power and speed (35-40 mph) to pull the steepest hills and not have to push the bike up a hill because some dummy didn't take time to set it up correctly for the terrain we run on.

Hope this helps, good luck, keep testing.

man this gear ratio stuff is so mind boggling I ordered the white garter springs (had no idea people mixed them) and I was thinking it was making it too hard for the weights to expand but what you're saying is if I get a larger sprocket I should get the speeds I want? also I don't have a tachometer but I'll get one soon

 

[sparkwizard]

Put a 60 tooth on the rear wheel and let us know what you think.

 

[Minichopperchar]

Put a 60 tooth on the rear wheel and let us know what you think.

okay great just so you know it came with a 50 tooth so I hope it makes that much of a difference

 

[BrownStainRacing]

man this gear ratio stuff is so mind boggling I ordered the white garter springs (had no idea people mixed them) and I was thinking it was making it too hard for the weights to expand but what you're saying is if I get a larger sprocket I should get the speeds I want? also I don't have a tachometer but I'll get one soon

Yea, you can mix em. I do it all the time.

You can really fine tune em in to the engine, it depends on the terrain more then anything.

I can actually run 3600 springs and pick up quicker times in the 600ft run, but with the layer of leaves on top of this red clay, makes things real sketchy when I hit the trails.

Try the stock springs with the aluminum weights, you will see the difference outta the hole and on the high side.

The white springs with the stock weights will give you 3100, but i don't like the way the zinc weights feel on the high side. I always get the aluminum weights.

Get a good tach with max rpm recall.
It's worth the extra money and you can see where your engine is running outta breath at, then tune it to keep it in the power band for your terrain and riding style.

Here's what I use and love it. I've only had to change the battery once in 14 months. I use it mostly for tuning others people stuff now.

Jus by watching the temps, I can tell how far away the engine is ouuta tune. Ignition timing, plug heat range, low and high speed jet adjustment. It's ez, you'll get the hang of it.

https://www.ebay.com/itm/2959528961...bfwvmiqrr-&var=&widget_ver=artemis&media=COPY

 

[Minichopperchar]

Yea, you can mix em. I do it all the time.

You can really fine tune em in to the engine, it depends on the terrain more then anything.

I can actually run 3600 springs and pick up quicker times in the 600ft run, but with the layer of leaves on top of this red clay, makes things real sketchy when I hit the trails.

Try the stock springs with the aluminum weights, you will see the difference outta the hole and on the high side.

The white springs with the stock weights will give you 3100, but i don't like the way the zinc weights feel on the high side. I always get the aluminum weights.

Get a good tach with max rpm recall.
It's worth the extra money and you can see where your engine is running outta breath at, then tune it to keep it in the power band for your terrain and riding style.

Here's what I use and love it. I've only had to change the battery once in 14 months. I use it mostly for tuning others people stuff now.

Jus by watching the temps, I can tell how far away the engine is ouuta tune. Ignition timing, plug heat range, low and high speed jet adjustment. It's ez, you'll get the hang of it.

https://www.ebay.com/itm/2959528961...bfwvmiqrr-&var=&widget_ver=artemis&media=COPY

okay great I felt like the stock Springs would help me out a little anyway. But people are saying to change them. Because you don't know what they're rated for but I guess I'll figure out when I do it thanks bud

 

[BrownStainRacing]

okay great I felt like the stock Springs would help me out a little anyway. But people are saying to change them. Because you don't know what they're rated for but I guess I'll figure out when I do it thanks bud

It's a tuners game.

No 2 builds and set ups are the same.

What's your weight ????

Most of the mini bikes I tune are 19+" tires. Most are with t/c, some small tire clutch guys, but they don't run the trail system here.

I also weight match the weights. The alum weights are more closer together then the zinc weights.

I've seen new stock zinc weights come outta the box weighing 12 grams different.
That makes a jerky unsteady engagement. It's rough on other parts too.

I use a gram scale from any smoke shop, usally $12-$15, for weighing them. And the wire wheel on the grinder to get em close to each other.
But I also use it for weight matching valve train parts too.

Give that 50t another try with the stock springs and alum weights.

If it's going into high too fast, you can tighten the driven spring up, if it's going in too late, you can loosen it up.

But give it another chance and spend time, hrs, and miles of testing and get a good feel of whats going on before giving up on it.

You being in FL, you got all that flat level long runs.

I lived in Tampa and Lakeland for 20+ yrs, thats some good testing grounds.

 

[Minichopperchar]

I only weigh

It's a tuners game.

No 2 builds and set ups are the same.

What's your weight ????

Most of the mini bikes I tune are 19+" tires. Most are with t/c, some small tire clutch guys, but they don't run the trail system here.

I also weight match the weights. The alum weights are more closer together then the zinc weights.

I've seen new stock zinc weights come outta the box weighing 12 grams different.
That makes a jerky unsteady engagement. It's rough on other parts too.

I use a gram scale from any smoke shop, usally $12-$15, for weighing them. And the wire wheel on the grinder to get em close to each other.
But I also use it for weight matching valve train parts too.

Give that 50t another try with the stock springs and alum weights.

If it's going into high too fast, you can tighten the driven spring up, if it's going in too late, you can loosen it up.

But give it another chance and spend time, hrs, and miles of testing and get a good feel of whats going on before giving up on it.

You being in FL, you got all that flat level long runs.

I lived in Tampa and Lakeland for 20+ yrs, thats some good testing grounds.

I only weigh 135 and I'll let you know how it is with both sprockets with the stock springs I'll test the 37t first since it's already on and then go to the 50 and I'll definitely mess with the driven I planned to but I haven't been at my shop in a little bit but I'll let you know any updates I guess for now I'll hold off on Ordering a clutch or sprocket or juggernaut and just fiddle around with the things I have first.

 

[BrownStainRacing]

I only weigh
I only weigh 135 and I'll let you know how it is with both sprockets with the stock springs I'll test the 37t first since it's already on and then go to the 50 and I'll definitely mess with the driven I planned to but I haven't been at my shop in a little bit but I'll let you know any updates I guess for now I'll hold off on Ordering a clutch or sprocket or juggernaut and just fiddle around with the things I have first.

Only 135#, I gotta feeling you will be loosening that driven spring.

Since you only got a speedometer for now, try to find 2 stationary marks, for whatever distance you will be mostly covering, for testing speed. Not max speed, jus a normal distance for you. Max speed will come later after you get a tach and find out where the powerband is.
Mail boxes, driveways, telephone poles, whatever you can find for testing.

That'll give you some kinda idea of where you are at.

Do a bunch of test and see if you can find out at what distance it's going into high, if it every goes into high with that smaller sprocket.
It might be with your weight. It might jus be too early or too late.

I'm 200#, my youngest son is 165#, he out runs me with less gear, less engine, less driven spring. It's only 3mph different in the bikes at 600ft, but it's that weight I jus can't get around.

Yea, let us know what you find in testing. I'm sure others are very interested too.

I like testing and tuning jus as much as an all day ride, lol.

 

[panchothedog]

Back to your original question. Should I spend $100 on a juggernaut driver?
As the owner of 4 karts, every one of them with a built engine and one of them
running a juggernaut, I don't think that they are worth the money. Get your gear ratio worked out. Your rear sprocket is way too small. You can make a standard driver tweeking the weights and springs perform as good or better than the juggernaut and for less money. Follow the advice given above by BrownStainRacing.

 

[Minichopperchar]

Back to your original question. Should I spend $100 on a juggernaut driver?
As the owner of 4 karts, every one of them with a built engine and one of them
running a juggernaut, I don't think that they are worth the money. Get your gear ratio worked out. Your rear sprocket is way too small. You can make a standard driver tweeking the weights and springs perform as good or better than the juggernaut and for less money. Follow the advice given above by BrownStainRacing.

okay great I will do some adjusting and keep yall updated any further advice is definitely welcome but how do you think a clutch would perform