GX390 and Comet 40

[lpadd]

I have a new GX390 (not a clone) motor and a comet 40 series torque converter. The problem is that the shaft is too short to go all the way through the driven unit. I'm sure there is some kind of shaft extension or something that I cannot find on the net...or maybe I just don't know what to search for. Does anyone know what I need?!?

Thanks!

 

[newrider3]

I think that is normal. The bore on the 40 series driver is huge.

 

[Murray92589]

me too...

I have the same problem, have you found a fix for this yet? on mine the first section of the driver comes exactly to the edge of the shaft, so an extension would work even if the key lined up different. ihavent found any such thing as an extension though...

 

[lpadd]

I found one here...sorta


http://www.fineentertaining.com/ipl...and_name=Atlas+Copco&image=335106_3.gif&part=

 

[Murray92589]

except they dont give you the price or tell you what size extension it is, i need a one inch diameter shaft to screw into a 5/8" bore..

try looking for a motor arbor, i feel like ive gotten closer to what we need by looking for that, still haven't found anything for a 1 inch shaft...

 

[Stumbo]

I have a new GX390 (not a clone) motor and a comet 40 series torque converter. The problem is that the shaft is too short to go all the way through the driven unit. I'm sure there is some kind of shaft extension or something that I cannot find on the net...or maybe I just don't know what to search for. Does anyone know what I need?!?

Thanks!

You are suppost to mount the driven unit on the jackshaft, not on the engine shaft.

The engine shaft is not meant to go all the way through the driver unit, you are suppost to use a bolt to secure the driver unit.

You can see what I mean on this picture:
http://www.metropartsmarket.com/gokart/torque_converter_2.jpg

 

[Stumbo]

Here is another good pic as an example:

http://www.starbuckdesign.com/towrig/P1010002_800.jpg

 

[lpadd]

I misspoke...I meant the shaft on my GX390 is too short to go all the way through the driver unit...not the driven unit. My driven unit is connected to a jackshaft.

 

[Murray92589]

here are some pictures of my go cart showing the issue I am having..

http://www.facebook.com/album.php?aid=81632&id=600621405&l=f8284

 

[jr dragster T]

Its that short with only half the clutch on. You still need to get that 4 sided clutch post on. You might be out of luck....

 

[Murray92589]

im going to take it to a metal/welding shop tomorrow, hopefully they will have some ideas. does anyone know if its okay to weld the clutch to make it one piece?

 

[Kevin Noah]

Couldn't you put a keyed pulley on that shaft. They do make different sizes to fit your application. Check out a farm and garden (like someplace they sell BIG tractors) type place to find what you need. OR a bushing that's stepped to hold everything together. I think I have what you're looking for at my shop.

 

[Murray92589]

i dont think so, but I'm not sure what your talking abut either, can you post a picture of one or a link?

 

[lpadd]

Here are some photos...


This one shows the side of the engine with the driver unit on but not bolted down:

This picture shows how far the shaft goes into the unit:

 

[Murray92589]

your pics dont work

 

[Buick455]

I think as long as you have the crank to the red line in the picture below you should be alright using a long bolt and thick washer. All the bolt does is keep the pulley from walking off the crank, the key keeps it from spinning. Most of the lateral forces are on and around the flat spot on the pulley.

Murray your still screwed though b/c you crank is like 1" long from the deepest point of the keyway on your motor & you have the TAV plate to add to the depth.

edit: added pics of mine
I have been running this setup on this 13hp honda for years with no problems... my crank is 1" short of the end of the Driver pulley.

 

[Murray92589]

what if i use a little spacer behind the first section to push it out and add another shaft under that section so that the keyway of pulley section one is at the joint of my two shafts.. see this picture:
http://www.facebook.com/photo.php?pi...5&id=600621405


or option 2, buy the 40 series parts and install it on the plate that comes with the tav2? will the 40 series stuff fit on that plate, or will it cause to much stress? (the 40 series clutch is a solid piece, so i dont have to worry so much about getting 2 things on shorty.)

 

[Stumbo]

Might have to ditch the TAV plate and use a frame mounted jackshaft.....

 

[Murray92589]

im trying to avoid that... comet makes a belt for the 40 series that is for 7-1/4" center length which i think is the same as the TAV plate... i need to double check my measurements though. but would the 40 series put to muh stress on the plate? it seems to me it wouldnt make a difference cause im using an 8hp motor whether i go with the 40 or 30 series.

 

[Kevin Noah]

Do what Buick455 did. Stack some smaller washers inside if you want, then a big one with lock washer and snug it down. It will work fine.