Go Back   DIY Go Kart Forum > Building Plans And Advice > Engines & Clutches

Notices

Closed Thread
 
Thread Tools Display Modes
  #1  
Old 02-28-2010, 05:55 PM
cb1000rider cb1000rider is offline
Junior Member
 
Join Date: Jan 2010
Location: Austin, TX
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Default Help removing Comet 40-Series Driver

We've taken an import Kart and have been adapting a Honda 11hp motor. The motor is 2nd hand and came with what appears to be a Comet 40-series torque converter (driver and driven).

After adding a jackshaft, we've got it lined up and powered up. It has dual gear reduction, once at the torque converter and again at the jackshaft. Final gearing is undetermined right now.

Issue: This thing just doesn't have much power from a stop. The motor will spin up to about 2000-2300 rpm and start to engage the torque converter, but it simply moves very slowly. We have a new belt on order, but I'd like to pull apart the driver side and make sure everything looks good.

I can unscrew the cover bolt on the driver unit, but can't budget it from the shaft. I've tried using a blind gear puller and even tried tack welding the puller to the driver itself... It's on there pretty good.

There is a large nut welded into the driver.. If I lock the motor, can will unscrewing this disassemble it?








Unloaded, the driver and the driven unit seem to work fine, the grab OK and the ratio obviously changes as RPM rises to about 3500 rpm.

If the driver and driven unit are OK, that leaves gearing - or an actual motor power problem....
  #2  
Old 02-28-2010, 06:00 PM
Kaptain Krunch's Avatar
Kaptain Krunch Kaptain Krunch is offline
Pro Junk Collector
 
Join Date: Jan 2009
Location: vermont
Posts: 4,520
Thanks: 66
Thanked 279 Times in 260 Posts
Default

What is your gear ratio/tire diameter?
__________________
"If you want, I can teach you how to make a bomb out of a toilet paper roll and a stick of dynamite"
  #3  
Old 02-28-2010, 07:28 PM
cb1000rider cb1000rider is offline
Junior Member
 
Join Date: Jan 2010
Location: Austin, TX
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I need to calc gear reduction at the jackshaft.
Tires are 20".
  #4  
Old 02-28-2010, 07:33 PM
Kaptain Krunch's Avatar
Kaptain Krunch Kaptain Krunch is offline
Pro Junk Collector
 
Join Date: Jan 2009
Location: vermont
Posts: 4,520
Thanks: 66
Thanked 279 Times in 260 Posts
Default

Just count the number of teeth on the jackshaft sprocket, and then the number on the axle sprocket and let me know.
__________________
"If you want, I can teach you how to make a bomb out of a toilet paper roll and a stick of dynamite"
  #5  
Old 03-01-2010, 06:59 AM
cb1000rider cb1000rider is offline
Junior Member
 
Join Date: Jan 2010
Location: Austin, TX
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Default

The jackshaft ratio is 2.5:1. 12 teeth on the jackshaft, 30 teeth on the driver.
  #6  
Old 03-02-2010, 05:41 PM
Doc Sprocket's Avatar
Doc Sprocket Doc Sprocket is offline
Moderator
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 15,518
Thanks: 684
Thanked 2,073 Times in 1,638 Posts
Default

Quote:
Originally Posted by cb1000rider View Post


I can unscrew the cover bolt on the driver unit, but can't budget it from the shaft. I've tried using a blind gear puller and even tried tack welding the puller to the driver itself... It's on there pretty good.

There is a large nut welded into the driver.. If I lock the motor, can will unscrewing this disassemble it?
It has been quite a long time since I cracked into my Comet 40. But I seem to remember (or THINK I remember) that the bolt that you removed is the only thing you have to remove. I seem to remember the driver just sliding off the PTO shaft once that bolt was out. If my memory is defective, I'm sure it won't be long before someone comes along and straightens me out.
If I AM right, your driver is likely just frozen to the shaft. Douse repeatedly with WD-40, Liquid Wrench, PB, Fluid film, etc. Let soak. Lovingly massage with soft-faced of rubber mallet. Repeat as necessary. I don't know if it's safe to use a hot wrench on a 40 driver...

EDIT- I looked over your numbers- you have a jackshaft at 2.5:1, and the 40's low ratio is 2.43:1. I can't see much of your kart, but it looks like it might be an offroader with decent-size tires. Your low ratio is then 6.08:1, which, without further information, seems a bit high. My kart (again, rough memory) I believe a 5:1 jackshaft ratio, for a final of 12.15:1 low, and 5:1 high speed with my Comet 40. It's heavy kart with fair-size tires and a live axle. When I mash the gas, I spray gravel everywhere. Accelleration's pretty good and my top speed is in the neighborhood of 65km/h (40 mph). Believe it or not, I have plans to lower the gearing further...
Hope this helps. -Chris
__________________
Treat it as you would an aircraft frame and you should have no problems. -Name Withheld
The Manual- "Just the manufacturer's opinion of how to put this together."- Tim "The Tool Man" Taylor
Put down the wrench, and come out with your hands up!- Me!
Wrench, Wheel, Wreck, Repeat...

Last edited by Doc Sprocket; 03-02-2010 at 05:55 PM. Reason: Add'l info
  #7  
Old 03-02-2010, 05:43 PM
Kaptain Krunch's Avatar
Kaptain Krunch Kaptain Krunch is offline
Pro Junk Collector
 
Join Date: Jan 2009
Location: vermont
Posts: 4,520
Thanks: 66
Thanked 279 Times in 260 Posts
Default

We figured out the problem, had a little conversation though pm's, and gearing appears to be his problem. He had 20" tires and 2.58:1 ratio.
__________________
"If you want, I can teach you how to make a bomb out of a toilet paper roll and a stick of dynamite"
  #8  
Old 03-02-2010, 05:48 PM
Slow rider Slow rider is offline
Junior Member
 
Join Date: Mar 2010
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Did you get the driver off? I'm newat this stuff and I just got a cart with a 40 on it. I've been trying to get the driver cover off with no luck. I got the bolt out no problem but then nothing. Does the drum screw off or slide off? If it screws off, how do you hold the shaft so it does not just spin as you are trying to loosen it? Help.
  #9  
Old 03-03-2010, 08:27 AM
cb1000rider cb1000rider is offline
Junior Member
 
Join Date: Jan 2010
Location: Austin, TX
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Default

No, I've been unable to remove it, although I may not get that motivated to do so, since I need to regear. I was using a gearing calculator that was giving me bad numbers and Kaptain Krunch pointed me to a good one... I'm going to regear first, then see if I still need to tackle the torque converter in the future.

I believe the converter is frozen on the shaft, I've got it soaking in the event that I need to get it off in the future.
  #10  
Old 03-04-2010, 07:29 PM
Slow rider Slow rider is offline
Junior Member
 
Join Date: Mar 2010
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I got my driver off the shaft. After lots of penetrating oil I was able to slowly tap it off. Now I'm trying to figure out how to dissassemble it. I'm guessing the drum screws off but it's not budging. More penetrating oil and we will see. Any suggestions anyone? Thanks
  #11  
Old 03-05-2010, 09:15 AM
cb1000rider cb1000rider is offline
Junior Member
 
Join Date: Jan 2010
Location: Austin, TX
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Tap it off from the motor side?

Sorry, no hints on disassembly yet.
  #12  
Old 03-05-2010, 10:07 AM
Daveon Daveon is offline
Senior Member
 
Join Date: Jan 2010
Location: Kent, Ohio
Posts: 162
Thanks: 23
Thanked 10 Times in 10 Posts
Default

The driver slides off the pto, held in place by a key. After you have the clutch off the two pulleys are threaded together. You really want to get the rust off of the pulleys, it will act like sandpaper and destroy your belt. He a link to a similar thread.
http://www.diygokarts.com/vb/showthread.php?t=6922
__________________
I have a belly full of crab bolts
Closed Thread

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:09 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.