Duster M/X Questions

[cwb212001]

Starting to plan my build and I need some help from the Duster & Cat gurus. Thanks to posts from 45t & John G. it looks like I have a Duster M/X frame, and its not in too bad of condition.

The bearings are a little sticky. Anyone have any tips on how to get them out? Know what size they are? I'm sure a local supplier can help me figure it out if I need to.

I'd like to do a drum brake in it which means I'll have to weld in a stud since its not there anymore. All the sizes I see start at 4.5", my sprocket/drum measures around 4.25" diameter. Is this normal, will a 4.5 fit or should I look for a replacement sprocket?

The pics I've looked at show what looks to be a roller tensioner where the chain drops past the engine plate. Anyone know where I can get a replacement or if I should even worry about it?

I've attached pics to help with what I'm looking at. Thanks for the expertise!

 

[mustangfrank]

Starting to plan my build and I need some help from the Duster & Cat gurus. Thanks to posts from 45t & John G. it looks like I have a Duster M/X frame, and its not in too bad of condition.

The bearings are a little sticky. Anyone have any tips on how to get them out? Know what size they are? I'm sure a local supplier can help me figure it out if I need to.

I'd like to do a drum brake in it which means I'll have to weld in a stud since its not there anymore. All the sizes I see start at 4.5", my sprocket/drum measures around 4.25" diameter. Is this normal, will a 4.5 fit or should I look for a replacement sprocket?

The pics I've looked at show what looks to be a roller tensioner where the chain drops past the engine plate. Anyone know where I can get a replacement or if I should even worry about it?

I've attached pics to help with what I'm looking at. Thanks for the expertise!

Scroll down the forum list and check out a post in "Tools" I just had on stuck bearings. Yours don't look too crusty so you could probably get away with a carefully chosen drift.

Bearings appear to be the premium flanged type, probably standard 5/8" ID, measure ID and OD when you get them out, any online mini bike store or local shop has them.

 

[markus]

5/8 ID x 1 3/8" OD flanged bearing, you can probably find a number on the bearings to use. you want to use that style (and those may even be good after a cleaning) as they are upgraded from originals that they used, They have a flange to hold them in and also the inner race protrudes a bit so there is no interference. Originals were very similar to this: https://www.bmikarts.com/Wheel-Bearing-_p_12785.html

The oem brake can be found on the BMI karts site, They list it as a 4" brake but its that one for the later drum brake HPE cats and Lomart bikes used. https://www.bmikarts.com/4-Internal-Expanding-Brake-Slotted-Bracket_p_10853.html

Years ago there was a replacement chain guide being made, but I have not seen any being repro'ed anymore and even sold a used one with wear for a pretty good price on ebay awhile back thanks to that. Maybe someone has done them again since then though.

 

[cwb212001]

5/8 ID x 1 3/8" OD flanged bearing, you can probably find a number on the bearings to use. you want to use that style (and those may even be good after a cleaning) as they are upgraded from originals that they used, They have a flange to hold them in and also the inner race protrudes a bit so there is no interference. Originals were very similar to this: https://www.bmikarts.com/Wheel-Bearing-_p_12785.html

The oem brake can be found on the BMI karts site, They list it as a 4" brake but its that one for the later drum brake HPE cats and Lomart bikes used. https://www.bmikarts.com/4-Internal-Expanding-Brake-Slotted-Bracket_p_10853.html

Years ago there was a replacement chain guide being made, but I have not seen any being repro'ed anymore and even sold a used one with wear for a pretty good price on ebay awhile back thanks to that. Maybe someone has done them again since then though.

Thanks Markus, I appreciate the info and taking the time to provide links. That brake is exactly what I was looking for. I'll get it and the bearings ordered. Meanwhile I'll start working on how to get the old ones out. Once the brake gets here I can figure out how to set up the axle. There was a spacer and a sleeve on it but no brake drum, so hoping it becomes obvious to me when I go to put it together. I'll look for other chain rollers out there, maybe I can make one work. Thanks again!

 

[desert rat]

Axle bolts https://www.mcmaster.com/screws/sys...e-5-steel-hex-head-screws/thread-size~5-8-11/

If you use mcmaster to find a part you can click on a part number, then on the CAD symbol and get this,https://www.mcmaster.com/6383K247/

That may help you decide what you need when you don't have a part in hand.

 

[markus]

Thanks Markus, I appreciate the info and taking the time to provide links. That brake is exactly what I was looking for. I'll get it and the bearings ordered. Meanwhile I'll start working on how to get the old ones out. Once the brake gets here I can figure out how to set up the axle. There was a spacer and a sleeve on it but no brake drum, so hoping it becomes obvious to me when I go to put it together. I'll look for other chain rollers out there, maybe I can make one work. Thanks again!

No problem, good luck with it. No idea on the spacers needed, searched in my computer for saved files, closest I could come up with for a bike was one they called a "Rebel", which is a R 4001, basically the same but with a different fork design. It shows a spacer used, and then #48 is also listed as a spacer with the wording "use only if received on original equipment" so that's no help in a situation like yours. You just going to have to setup a straight edge to your engines drive sprocket to get you spacing setup correctly. Sorry the list does not show measurements of the spacers....thats what I was checking/hoping for.



One thing I will say about the cats I have had and worked on is the frame sort of tensions in a little when you tighten the axle down (wheel when setup wont be super tight fit between the axle dropouts when installing if that makes sense) Just note that if you have the rear fender, you may also want to mount that at the same time as they relies on the frame rails for placement, so any variance in spacing will effect where the fender wants to sit as well. Remember there are no inner spacers to stop any crushing of the bearings and the axle relied on locknuts to keep it in place. Not intended to tighten them down as hard as you can, It should be setup "light snug" Just at the point that everything is together and not wobbling, but not to tight, kinda like setting up old style wheel bearings on a car or trailer axle.

 

[cwb212001]

Axle bolts https://www.mcmaster.com/screws/sys...e-5-steel-hex-head-screws/thread-size~5-8-11/

If you use mcmaster to find a part you can click on a part number, then on the CAD symbol and get this,https://www.mcmaster.com/6383K247/

That may help you decide what you need when you don't have a part in hand.

Thanks desert rat for the info & links. It will come in handy if I have to replace the axle bolt I have.

 

[desert rat]

Thanks desert rat for the info & links. It will come in handy if I have to replace the axle bolt I have.

No problem. I didn't have help in the work place so mcmaster was my go to to see what it should be......then I build it/ fixed it. Good luck i will help you as much as I can. Just have fun, I'm retired now so I can say this CHICK'S DIG SCARS have fun and laugh a lot.

 

[Restoman57]

Scroll down the forum list and check out a post in "Tools" I just had on stuck bearings. Yours don't look too crusty so you could probably get away with a carefully chosen drift.

Bearings appear to be the premium flanged type, probably standard 5/8" ID, measure ID and OD when you get them out, any online mini bike store or local shop has them.

I also have a Duster MX. Seems to be pretty complete. I could help you out with some info and pictures. Let me know

 

[1971_MB1A]

I also have a Duster MX. Seems to be pretty complete. I could help you out with some info and pictures. Let me know

@Restoman57,I also have an original Duster MX. Which color is yours ?

 

[cwb212001]

I also have a Duster MX. Seems to be pretty complete. I could help you out with some info and pictures. Let me know

Thanks Restoman, I will probably take you up on that. I have a new seat, the brake and the bearings on the way. Having the brake should help me figure out how the rear axle is set up. I'll let you know.

 

[Restoman57]

Thanks Restoman, I will probably take you up on that. I have a new seat, the brake and the bearings on the way. Having the brake should help me figure out how the rear axle is set up. I'll let you know.

I also have to fix the rear axle on mine.
Who did your seat? I need mine done too. Where did you find the sprocket and drum? Thanks.

 

[Restoman57]

@Restoman57,I also have an original Duster MX. Which color is yours ?

Burnt orange

 

[FunWithStuff]

I'm also working on restoring a Duster M/X right now. I have almost every part for it including it's original HS40 engine and the switch plate. I'm just missing the long clutch guard (which those are almost always elusive). I recently was able to match a color for the frame at an auto paint store that is SUPER close to its original color (fortunately my frame still had its original paint in some places despite being worn out). I'd be glad to help you out with any information you may need. Good luck with your project and have fun working on it!