Rotax chains coming off

Austin Gaddy · Joined: 14 Jul 2002 Posts: 2 Location: Coppell Tx.

if you cannot feel the chain move from up to down about 3/4 inches its too tight

Timothy Breuer · Joined: 24 Jun 2002 Posts: 11 Location: South Florida

Last practice session, my chain was getting thrown off with some regularity. After some digging, I found my motor mounts to be loose. Not the bolts holding the mount to the chassis, but the bolts holding the motor to the mounts...just something else to check.

Dick George · Posted: Tue Jul 23, 2002 6:12 pm Post subject: Rotax chains coming off

I've forgiven my motor after the last race. I added a chain tensioner against the motor mount, not one problem with the chain all day.

Shannon Schmidt · Posted: Thu Jul 25, 2002 6:11 pm Post subject: Rotax chains coming off

I am proud to announce that I have had no problems with my chain since I changed chassis. Thanks agian everyone for all the tips and good luck to those that have suffered similar problems in the past. If I can help anyone else, drop me a note

Oscar Aguilera · Joined: 18 Jul 2001 Posts: 1614

Just my opinion but this is a chain problem and not a Rotax Chain problem. I think with the new Rotax people, we are of course getting new karters and the 219 chain is a little tougher to maintain than a gear box chain.

Some tips,

I always square the holes drilled to the alxe. Put a framing square against the axle and scribe a line along the top of the motor mount where the two right side bolts should go. (motor mount on chassis with no motor snug tight at least) You can check your motor now by doing the same technique and hold the framing square against the bottom of the motor where it meets the mount.

After placing your bolt hole pattern on the motor mount you can make sure the new holes are square to the axle. Not all mounts are square and most cast style mounts have some play. So don't assume that if you drill square to the mount by itself that the holes will square to the axle which is the part that it needs to be squared to.

Since the holes are easiest marked on top, make sure you drill the holes perpendicular to the top surface. An angled mount put on top of a drill press and drilled straight down will be the wrong angle of the bolts to the motor. Most mounts are angled and then your holes will not match the angle of the mount.(seen it done after the fact)

Check that your gear hub has no run out or is bent.

Check that your sprocket is true as well. A one piece is best so that run out is usually not present on the sproket. (Two piece sometimes need to be filed at both ends where they meet for proper line up and no run out.)

If the sprocket gearing you use is below the frame rails it is time to change the driver to a smaller size and re-gear.

I always use three bolts on a one piece so that if I do go off only the sprocket will be bent. (Some clubs require all six bolts so follow the rules) and yes I'm good for an off at least once per day.

Always use a motor stop and don't forget to adjust it.

A tip from the dirt guys (Mr Jeff and Jacob Hull) Keep simple green and water mixed in a bucket and an oversized tooth brush and scrub off all the old chain lube after every heat. Then dry off with brake clean and re lube. AWESOME TECHNIQUE BY THE WAY

Check the chain for a high spot, if you have one a $15.00 new chain is worth every penny. Replace it.

Keep your chain well lubed. A new or good chain with no high spots should have a 1/2 inch from center up and down play. That is 1 inch overall but not anymore. If your not sure measure it.

Line your front driver sprocket with a straight edge to the rear sprocket. I always hold the straight edge across the rear sprocket face near the bolts where there is no question of the straight edge moving. Then slide the hub and sprocket assembly until you touch the front sprocket. Always have enough straight edge to go by the entire front sprocket and not just hit the teeth. If the front driver has minimal play like on a Rotax split the difference.

Common mistake is to line up the hub without a sprocket against the front driver, which you have now just misaligned the two by the width of the rear sprocket itself. Always align with the sprocket so this does not occur accidently, my rule I did it once and toasted a new sprocket.

Always check the bolts to the motor as stated above and always lock tight them to begin with. If done properly they should never come loose.

Your chain generates a tremendous amount of heat while driving it will tighten up and getted stretch.

Oscar

Rob Linders · Joined: 18 Jul 2001 Posts: 725

$15 chains? I think I pay at least $30 for those. What kind do you run, I've been running the DID gold.

Matt Golden · Posted: Fri Aug 23, 2002 7:43 pm Post subject: Rotax chains coming off

quote:
Originally posted by Oscar Aguilera:
Just my opinion but this is a chain problem and not a Rotax Chain problem. I think with the new Rotax people, we are of course getting new karters and the 219 chain is a little tougher to maintain than a gear box chain.

Some tips,

I always square the holes drilled to the alxe. Put a framing square against the axle and scribe a line along the top of the motor mount where the two right side bolts should go. (motor mount on chassis with no motor snug tight at least) You can check your motor now by doing the same technique and hold the framing square against the bottom of the motor where it meets the mount.

After placing your bolt hole pattern on the motor mount you can make sure the new holes are square to the axle. Not all mounts are square and most cast style mounts have some play. So don't assume that if you drill square to the mount by itself that the holes will square to the axle which is the part that it needs to be squared to.

Since the holes are easiest marked on top, make sure you drill the holes perpendicular to the top surface. An angled mount put on top of a drill press and drilled straight down will be the wrong angle of the bolts to the motor. Most mounts are angled and then your holes will not match the angle of the mount.(seen it done after the fact)

Check that your gear hub has no run out or is bent.

Check that your sprocket is true as well. A one piece is best so that run out is usually not present on the sproket. (Two piece sometimes need to be filed at both ends where they meet for proper line up and no run out.)

If the sprocket gearing you use is below the frame rails it is time to change the driver to a smaller size and re-gear.

I always use three bolts on a one piece so that if I do go off only the sprocket will be bent. (Some clubs require all six bolts so follow the rules) and yes I'm good for an off at least once per day.

Always use a motor stop and don't forget to adjust it.

A tip from the dirt guys (Mr Jeff and Jacob Hull) Keep simple green and water mixed in a bucket and an oversized tooth brush and scrub off all the old chain lube after every heat. Then dry off with brake clean and re lube. AWESOME TECHNIQUE BY THE WAY

Check the chain for a high spot, if you have one a $15.00 new chain is worth every penny. Replace it.

Keep your chain well lubed. A new or good chain with no high spots should have a 1/2 inch from center up and down play. That is 1 inch overall but not anymore. If your not sure measure it.

Line your front driver sprocket with a straight edge to the rear sprocket. I always hold the straight edge across the rear sprocket face near the bolts where there is no question of the straight edge moving. Then slide the hub and sprocket assembly until you touch the front sprocket. Always have enough straight edge to go by the entire front sprocket and not just hit the teeth. If the front driver has minimal play like on a Rotax split the difference.

Common mistake is to line up the hub without a sprocket against the front driver, which you have now just misaligned the two by the width of the rear sprocket itself. Always align with the sprocket so this does not occur accidently, my rule I did it once and toasted a new sprocket.

Always check the bolts to the motor as stated above and always lock tight them to begin with. If done properly they should never come loose.

Your chain generates a tremendous amount of heat while driving it will tighten up and getted stretch.

Oscar

I know this in an old thread but these tips are very useful for a newbie like me. Pitched my chain twice today and trashed my sprocket. Now I know how to get started on fixing it the right way.

Thanks Oscar!

[ August 23, 2002: Message edited by: Matt Golden ]