Rear chain guide

[tim2007]

Has anyone else had problems wih chain derailing? I did today,

 

I think the rear guide caught a log in the bottom of a deep rut. Out of 100+ riders this only affected my Beta & 1 guy's KTM.  

 

Dismantled everything & all seems straight, maybe Boano Beta's nylon rear guide would flex less? Or maybe make up a alloy outer guard to protect the stock one? 

[GP]

I just ordered the BRP guide. I was a little hesitant because the mounts are cast into the swing arm like a KTM, and a really strong guide may transfer a lot of force to the mounts. The stock guide is quite soft and mine is chewed up pretty bad from rocks and I was due. I had a BRP on my GasGas and it was excellent. That bike had a mount that bolted to the swing arm which is a better idea for a woods bike IMO as it was easily replaced if bent. Maybe I'll just use a weaker alloy or brass bolt in the rear single bracket until a reinforcement plate like the one made by BPD for KTMs is available.

[tim2007]

Thanks, BRP looks good but is troublesome to order- google throws up some hefty security warnings about their site. I got onto my dealer today & have ordered a TM Designworks one, meant to be even stronger (and easier to obtain) than the Boano one. Hopefully that will solve it. 

 

The BPD plate you mention looks a good idea, let us know if you notice them doing a Beta one. 

[tim2007]

Hmm. Well the TM Designworks one has arrived at long last. Has anyone actually fitted one of these? It doesn't fit, the mounts are out laterally by around 6mm. I'm reluctant to chop it about in case in has to go back (not another 3+ week wait, surely???), and I'm not too certan where to chop it  anyway, seems that both mounts are out by a few mm, front one is too wide to fit into swingarm even. 

 

Pics below comparing old v new using a file to show how far alignment is out.

 

 

 

 

All thoughts welcome.... 

[tim2007]

By the way, it's the TMD Factory Ediion 2 model, "RCG-BETA-RD"

[Neomxdave]

Had loads of issues with my old sx250 derailing chains but never on the Beta. Get the sprocket as close guide so it cant flex when in a rut, problem with the alloy guard is once they bend they stay bent. 

Edited July 5, 2014 by Neomxdave

[FulThrotl]

Hmm. Well the TM Designworks one has arrived at long last. Has anyone actually fitted one of these? It doesn't fit, the mounts are out laterally by around 6mm. I'm reluctant to chop it about in case in has to go back (not another 3+ week wait, surely???), and I'm not too certan where to chop it  anyway, seems that both mounts are out by a few mm, front one is too wide to fit into swingarm even. 

 

Pics below comparing old v new using a file to show how far alignment is out.

 

 

 

 

All thoughts welcome.... 

looks like you have the wrong part... everything is half a bubble off?

 

as far as a super strong chain guide, george at uptite was getting ready to

weld a broken swingarm that i think was broken by something hitting the

chain guide, but i wasn't paying that much attention.... but my thought is

i want a chain guide that bends and trashes itself instead of breaking the

bosses off the swing arm... it's a consumable part anyway, so when i ordered

my beta, i didn't upgrade it.... figured i'd run the original one and see what 

direction an upgrade needed to take.

 

sometimes stronger isn't better. husky used a grade 12 bolt on the main

rear motor mount, way back when.... it was expensive, and broke pretty

regularly. i went to home depot, an bought a 1/2" bolt that was long enough

to do the job in a pinch, so i could go riding... ungraded, soft, pos bolt.

 

it never came loose or broke. ran it till i sold the bike.

[tim2007]

I know what you mean,, but when the stock one bent it derailed the chain which then wrapped around the front sprocket- scarily close to wiping out the crankcases ( I actually had to remove the swingarm to get the chain out, it was wedged in there that tight).  I've ridden for years & years with Suzukis & their alloy guide and never had a chain derail once. 

 

And yes,  think it is the wrong part - although I checked the number etc on their website & that is correct, maybe it is the wrong one in the right packaging. Anyway, it's screwed up yet another weekend's riding. 

[FulThrotl]

I know what you mean,, but when the stock one bent it derailed the chain which then wrapped around the front sprocket- scarily close to wiping out the crankcases ( I actually had to remove the swingarm to get the chain out, it was wedged in there that tight).  I've ridden for years & years with Suzukis & their alloy guide and never had a chain derail once. 

 

And yes,  think it is the wrong part - although I checked the number etc on their website & that is correct, maybe it is the wrong one in the right packaging. Anyway, it's screwed up yet another weekend's riding. 

i think what i'd be looking at is making my own at that point.

 

the best material for the situation is UHMW, or "poor mans teflon" as it is called.

 

http://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene

 

this is what is used in industrial applications for severe wear points on conveyors, etc.

it has about the same coeffecient of friction as teflon, and extremely durable.

it's probably what is used in that part you just bought, dyed red. it can be machined

and cut and drilled easily. woodworking tools do nicely.

 

i'd get two 3/8" pieces, shape them to act as the side plates, and cut two pieces the

width of the chain pins. make it beefy, and bolt togeather with allen button head cap

screws and nylocks.

 

so you are gonna end up with a square box section the chain fits thru. chamfer the inlet,

and get it positioned so it'll attach to the swingarm. it'll be nearly indestructible, and it'll

flex somewhat and spring back, not just deform.

 

search amazon with uhmw, and you'll get hits that you can get in a couple days. about $20

for enough to make a couple of these....

[dirtbird]

Hmm. Well the TM Designworks one has arrived at long last. Has anyone actually fitted one of these? It doesn't fit, the mounts are out laterally by around 6mm. I'm reluctant to chop it about in case in has to go back (not another 3+ week wait, surely???), and I'm not too certan where to chop it  anyway, seems that both mounts are out by a few mm, front one is too wide to fit into swingarm even. 

 

Pics below comparing old v new using a file to show how far alignment is out.

 

 

 

 

All thoughts welcome.... 

Mine was difficult to install and slightly wider as well.

It takes a hammer and some 'persistence' from your side. Just don't hit the swing-arm.....

[tim2007]

Yes, I'd been thinking this evening about making one too- I was looking at adapting the Suzuki one though, which are a quite hard aluminium alloy, but unfortunately fit the swingarm in a very different way to the Betas. That UHMW stuff does look good too, thanks, and our design sounds very good indeed. However as I've spent $130 on the crap TM Designworks one I need to sort out what's happening there first...

[hawaiidirtrider]

I just ordered the BRP guide. I was a little hesitant because the mounts are cast into the swing arm like a KTM, and a really strong guide may transfer a lot of force to the mounts. The stock guide is quite soft and mine is chewed up pretty bad from rocks and I was due. I had a BRP on my GasGas and it was excellent. That bike had a mount that bolted to the swing arm which is a better idea for a woods bike IMO as it was easily replaced if bent. Maybe I'll just use a weaker alloy or brass bolt in the rear single bracket until a reinforcement plate like the one made by BPD for KTMs is available.

Doesn't the reenforcement plate from BPD for ktm's fit Beta? I figure if the ktm plastic guards fit Beta that the holes would line up fine. I think it does but didn't put one on yet.

 

Edited July 6, 2014 by hawaiidirtrider

[hawaiidirtrider]

Hmm. Well the TM Designworks one has arrived at long last. Has anyone actually fitted one of these? It doesn't fit, the mounts are out laterally by around 6mm. I'm reluctant to chop it about in case in has to go back (not another 3+ week wait, surely???), and I'm not too certan where to chop it  anyway, seems that both mounts are out by a few mm, front one is too wide to fit into swingarm even. 

 

Pics below comparing old v new using a file to show how far alignment is out.

 

 

 

 

All thoughts welcome.... 

So when you bolt it to the mounting bolts doesn't it even out?

[tim2007]

So when you bolt it to the mounting bolts doesn't it even out?

 

If I bolt it to the rear one the front is miles out, and the sprocket won't even go in the groove in the guide.! If I cut the rear mount down by enough to make it fit, it will only be a few mm thick & will be weak as anything. The front is too wide to fit into it's mounting, and at $130 I'm not going to hammer & hacksaw this piece of crap from TM Designworks to try to make it fit. 

[hawaiidirtrider]

If I bolt it to the rear one the front is miles out, and the sprocket won't even go in the groove in the guide.! If I cut the rear mount down by enough to make it fit, it will only be a few mm thick & will be weak as anything. The front is too wide to fit into it's mounting, and at $130 I'm not going to hammer & hacksaw this piece of crap from TM Designworks to try to make it fit. 

Holy crap! $130 is ridiculous.. yea that's messed up.. now you have me thinking ..I have to check out the  09 and earlier ktm guide that I bought to see how that fits.. but mine is a ktm one that I bought for around $70. I thought that was expensive. That's the same one that fit my 525 Beta so I just figure it fit my 300 . I just held it up to the bike in the parking lot and it seemed like it would go... holes match up. actually I have a brp ktm one on and that one was for ktm 09 earlier... should be same thing though.

Edited July 6, 2014 by hawaiidirtrider

[ballisticexchris]

If I bolt it to the rear one the front is miles out, and the sprocket won't even go in the groove in the guide.! If I cut the rear mount down by enough to make it fit, it will only be a few mm thick & will be weak as anything. The front is too wide to fit into it's mounting, and at $130 I'm not going to hammer & hacksaw this piece of crap from TM Designworks to try to make it fit. 

 

Sorry it's not working out for you. TM Designworks products are some of the best out there. Sounds like you just got the wrong one. It's only "a piece of crap" because you got the wrong one. FWIW, all mine have fit perfectly. 130 bucks is a little steep. Even in the UK.....

 

 

The BRP lasted less than one season. It peeled back like a can of tomatoes the first rock it scraped over. Still works though.

 

[GP]

Doesn't the reenforcement plate from BPD for ktm's fit Beta? I figure if the ktm plastic guards fit Beta that the holes would line up fine. I think it does but didn't put one on yet.

 

 

No, the hole center dimension is shorter on the Beta.  

[hawaiidirtrider]

 

Doesn't the reenforcement plate from BPD for ktm's fit Beta? I figure if the ktm plastic guards fit Beta that the holes would line up fine. I think it does but didn't put one on yet.

 

 

No, the hole center dimension is shorter on the Beta.  

 

Did you try it and adapt? or can it not adapt?

[GP]

Did you try it and adapt? or can it not adapt?

 

No, I measured a KTM and my Beta and found the difference, and didn't bother.  Also not crazy about drilling the swingarm there. I beleive BPD changed the design and the newer parts are just a bolt on reinforcement with no third tab requiring drilling.  One key difference with the Beta is that the chain guide mounts to the outside of the rear tab, unlike the KTM which mounts inside.  This in itself protects the tap from a direct hit.  The front mount on the BRP is thicker so the tab is recessed in the plastic as well.  We will see how it holds up but I suspect it will be OK.  A lot of the KTM tab failures have been from direct rock hits on the tab/bolt itself.  If I break something and have to weld it I will design/fab a different mount altogether.

Edited July 7, 2014 by GP

[mtdirtbag]

Yes, I'd been thinking this evening about making one too- I was looking at adapting the Suzuki one though, which are a quite hard aluminium alloy, but unfortunately fit the swingarm in a very different way to the Betas. That UHMW stuff does look good too, thanks, and our design sounds very good indeed. However as I've spent $130 on the crap TM Designworks one I need to sort out what's happening there first.

tim; do you want me to call TM Designworks for you and direct him to this thread - or maybe you could do it in an email off their site. When I purchased one of their first skid plates I talked to a Tim there and gave him my observations and sent him pictures. He was very helpful and appreciated the suggestions. It's worth a try and my get you a replacement sooner than later.  Tom