OzVMX Forum
Clubroom => Vintage Track => Topic started by: Natroy on August 27, 2014, 02:36:33 pm
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I was at the Nepean charity day and saw some bikes with a rear sprocket guard.
Can someone tell me what's the go with the guard?
Cheers.
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To stop the amputation of stray fingers. ;)
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refer GCRs
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GCR 16.15.4.6. A chain guard made of suitable material must be fitted in a way to prevent trapping between the lower drive chain run and the final drive sprocket at the rear wheel.
2014 MOMS page 150. On more modern bikes this is achieved by the chain guide.
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I'm just fabricating one of these at the moment. It had a chain guide mount about half way along the swingarm and I'm using this as the mount. It runs back about 6" at the top and 8" at the bottom. Looks a bit chunky. If I cut holes in it what do we think restrictions might be re size of holes and how close I can come to where the chain re enters the sprocket?
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A rule that is currently extremely loosely enforced it would seem.
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If you can't push a finger through the hole, I reckon you'll be somewhere around the mark... ;)
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Hi GD66 was looking to do 2 or 3 cut outs about an inch in diameter rather than the old horrible drilled out look. Via the rule it says no access where the chain enters the sprocket so technically if I go about 40-50mm before this point it should be ok, but you might see the chain through the hole. Big fuss when the bike raced for 6 years without a guard and it never seemed to hunt down little children to hack their digits off.
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Can someone let me know sizes/dimensions for this guard?
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Natroy there is no specific size or shape it needs to satify the rules as the requirements of each bike is very different.
My YZ250L required a small piece of plastic sheet (old number plate) added to the rear of the rear chain guide to make sure it complied which was about 50mm x 40mm. My 77, 80 & 81 Montesa Cappras required a small triangle of aluminium 50mm x 50mm x 50mm added to the rear chain guide. My VR250 needed a much larger guard made to cover from the brake stay mount back to the sprocket (about 75mm by 125mm aluminium).
The rule states
16.15.4.6 A chain guard made of suitable material must be fitted in a way to prevent trapping between the lower drive chain run and the final drive sprocket at the rear wheel.
People seem to be very put out about this but is seems logical to me that the rear sprocket is just as likely to cause injury as the front sprocket. Yes we have raced for years with no problems but it is not really a big issue. It is like a lot of safety items it is only when your finger or someone elses is stuck in the chain that you think a guard would have been so much easier ::)
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Natroy there is no specific size or shape it needs to satify the rules as the requirements of each bike is very different.
My YZ250L required a small piece of plastic sheet (old number plate) added to the rear of the rear chain guide to make sure it complied which was about 50mm x 40mm. My 77, 80 & 81 Montesa Cappras required a small triangle of aluminium 50mm x 50mm x 50mm added to the rear chain guide. My VR250 needed a much larger guard made to cover from the brake stay mount back to the sprocket (about 75mm by 125mm aluminium).
The rule states
16.15.4.6 A chain guard made of suitable material must be fitted in a way to prevent trapping between the lower drive chain run and the final drive sprocket at the rear wheel.
People seem to be very put out about this but is seems logical to me that the rear sprocket is just as likely to cause injury as the front sprocket. Yes we have raced for years with no problems but it is not really a big issue. It is like a lot of safety items it is only when your finger or someone elses is stuck in the chain that you think a guard would have been so much easier ::)
The mission statement of the Politicaly correct movement ;)
So at what point do we start fitting covers over those nasty spokes , shit theres 72 of the dangerous buggers spinning at speed on a jap bike and 80 on the Pom bombs and some euros just waiting for somebodys hand to be lured in ::)
And surely all those nasty hot exhaust should be wrapped in 3 foot of abspestos cloth something heat proof but PC , just in case ;)
Any sane person would replace those ridiculous nasty handle bars and dreadfull lever things with a nice padded steering wheel , paddle controls and air bags just in case ;)
Who in their right minds would risk life and limb by putting their feet on those medievial looking sharpened devices :o Surley a nice set of big running boards would be so much more in keeping with the modern PC way , you know JUST IN CASE ::)
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SOOOOOOOOO glad I live in NZ we have 6 fingers so loosing one is not a problem, like Bill said PC rubbish Im all for safety but where does common sense draw a line. Next you will have to find foam racetracks.
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its a risk reward thing guys, the risk of falling off is high. the probability of falling off and sticking your hand in the sprocket is low. the consequences of actually doing that is Huuuge. thus to lower the risk factor to "safe levels"... fit a simple guard. problem solved.
its all good until some one does a finger and sues the crap out of all and sundry for his own incompetence.... this has probably happened in the USA and MA is covering the bases. once the lawyers get involved, all bets, gloves and wanky statements are off...hard written statements are all that matters. ie GCR's
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It's such a simple fix, why all the fuss. I agree we managed without it for years and it seems an overkill, but in this litigious world it would seem a simple low cost preventive measure is not a bad thing. I've had a leg caught up in the rear spokes and thanks to good boots no real damage, but fingers in the chain/sprocket instant amputation.
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I've seen the damage that can be done so I don't have a problem with the it.
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Sorry to disappoint but by fingers went into a back sprocket when I was about 12 , still got all 10 functioning well ;)
I agree the act of fitting something is a minor feat of engineering ;)
The problem is and im generalising here ( just to be clear that im not digging out MA or anyone in particular ) is that our generation needs to stop taking it up the arse over every "little Opps that might happen" bullshit ::)
I know that 99% of you wont get it as you are happy to sell out to the system as long as the system delivers it in little jabs rather than a big left hook.
This is how OUR generation has let the PC monster creep in and control our lives . Our fathers were real men who fought for what they believed in and went to war ( real wars not rich pricks and media funded bullshit oil wars )
But we roll over every time someone says "BUT IT COULD HAPPEN" and say yes sir no sir 3 bags full sir . I am ashamed and embarrassed by my generation :-[ ( we are a generation of Pussies ::) Dog help our kids and their kids >:(
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I agree Bill.
Pretty soon the litigious will have the world riding Vespas made from Nerf.
Motor racing is a dangerous sport and we accept this as a consequence of the sport.if you dont accept it dont do it...Simples.
I cant wait till riders get red carded for not having both wheels in contact with the ground or excessive wheel spin.
Kind of funny that my Road registered machine does not require a rear sprocket guard just a chain guard and i dont have to wear half the protection i do if engaged in a sporting event. Yes protection is wise but enforcing the fitting of an alien device to a machine based on historic correctness is shooting yourself in the foot...... naa thats dangerous too.
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Col , I think the point is were does it all stop. We all sign a waiver to enter each event and reminded at riders briefing that motorcycling is dangerous and we ride knowing this.
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I've always wondered why Vintage riders walk so funny, used to think it was the lack of suspension on their bikes but now I know it's because most are happy to bend over and cop it every time someone at MA tries to justify there existance by inventing something new.
Think it is quite funny this bit about fingers getting in and comparing it to the front sprocket covers that we only need to have if the sproket is further than 30mm from the swingarm pivot. A lot off the factory covers had holes big enough to get fingers through if you are stupid enough to try(TM an RM suzuki's spring to mind) but they seem to be ok.
Next it will be Lanyard kill switchs like they have forced onto those out of control Trials bikes.
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FFS,it's your boot/foot going in, not fingers,might have started off on tar 1st,(Beatty lost top of his foot on the factory yamaha when he crashed shoving his foot into the rear chain),same deal with open primaries,hate to have 3 spring AMC clutch do a number on my leg when it all goes pear shape,(oh look,NEB's are flush ::)),s/cars use lanyards,so too a few guys on tar,(generally you only havta experience "shit happens "once to get the gist of it??), :P
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again its all good until the lawyers step in...your a fully employed fitter and turner working a specialist lathe and one day your short 2 fingers... (unhappy wife for a start!) then you get the boot... what do you do? no job, feeling shat upon? you can complain about PC all you like but every bugger in this spot immediately googles See you Later and Gordon. then all the poor bastards down stream get bent over big time.....real cash real court orders etc. just grin and take one for the team....
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Not debating the need for the guard was only looking for a bit of guidance as to where I could do a couple of cut outs . Don't want to arrive somewhere and find someone says it's not legal because.......
Not trying to over complicate things, don't want a philosophical debate just some guidance from those about. As I said guard was easy to fabricate and mount cos of an existing bracket, just wanted to do a couple of cut outs to take the junky look away as it mounts from the midpoint of the swingarm on a slider. Engine sprockets I reckon are a different matter as slots, holes etc shouldn't see finger protrusion but they are much smaller to what I'm looking at.
Rosco
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don't you luv the way this forum shifts and turns.... ;D
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This rear sprocket guard is the biggest load of crap in the rules.
Blah Blah Blah to prevent trapping between the lower drive chain run and the final drive sprocket Blah Blah
Last Friday afternoon i stood there and watched 73/74 Hondas breeze through with their chain guide halfway down the swingarm wIth at least 6 inches of nothing behind it up to the sprocket teeth.
Then I witnessed two Huskys knocked back because their chain guides were fixed to the brake stay
( standard ) and totally enclosed the front of the sprocket. They were made to CABLE TIE a cutting from a fruit juice bottle to the swingarm to get through scrutineering.
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selective interpretation is a bastard >:(
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its not selective anything; to the observant you would have noticed that CMX was exempt for a couple of years while the Commission sort to define what it was that we would have to be compliant to. It was decided (and I agreed at that point to add to the GCRs) that if a bike came from the factory with a chain guide that was fitted to the swing arm such as a CR or a TM125 then it would be acceptable. If as in the case of the Husky it wasn't (on torque arm)then something will have to be added. If a bike had nothing then it would have to have something - my AJS is a classic case.
That someone out there decided that it should look like half the stuff I saw on the weekend isn't my problem, some guys did a great job but others with nothing (and there were quite a few) were asked to do something about it.
211
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The rule is a reasonable rule and was put in the GCRs after a flag marshal at a road race received an injury when picking up a fallen bike. Darryl Beattie also lost all the toes a one foot after a freak accident on a GP500 bike. So the potential for permanent injury is there.
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The rule is a reasonable rule and was put in the GCRs after a flag marshal at a road race received an injury when picking up a fallen bike. Darryl Beattie also lost all the toes a one foot after a freak accident on a GP500 bike. So the potential for permanent injury is there.
So if a flag marshal grabed a hot exhaust and burnt his hand? Or he was hit by a bike?
If someone grabs the sproket their finger are going to go between the spokes and the sprocket and still get jamed up even with the cover on the outside.
Wouldn't it have been better to tell flagies not to touch fallen bikes?
What about the top of the sprocket incase the bike rolls backwards?
Sorry but your reasoning hasn't convinced me that this is a good rule and I still believe we are being screwed.
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The rule is a reasonable rule and was put in the GCRs after a flag marshal at a road race received an injury when picking up a fallen bike. Darryl Beattie also lost all the toes a one foot after a freak accident on a GP500 bike. So the potential for permanent injury is there.
So if a flag marshal grabed a hot exhaust and burnt his hand? Or he was hit by a bike?
If someone grabs the sproket their finger are going to go between the spokes and the sprocket and still get jamed up even with the cover on the outside.
Wouldn't it have been better to tell flagies not to touch fallen bikes?
What about the top of the sprocket incase the bike rolls backwards?
Sorry but your reasoning hasn't convinced me that this is a good rule and I still believe we are being screwed.
only by the guys (not me) telling you to do more than you have to.
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Peter Sunderland told me he was shown the x rays of his scrotum,(apparently you could see the valve collets plainly),think thats why scatter sheilds came in for drag bikes,(his rebuilt JAP went back to Alf Hagon as birthday prezzie, from memory ::)),
turn 6 East creek,matcho spits the primary chain,i quickly park,go running back down track waving arms,yelling at marshall,DONT PICK IT UP,he picks it up,burns the shit outa his hand,then after dropping it,kicks it into the dirt inside track,(it was nowhere near the race line!!), :P
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Round and round we go, anything that increases my chances of turning up for work on Mondy is fine by me. ???
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its not selective anything; to the observant you would have noticed that CMX was exempt for a couple of years while the Commission sort to define what it was that we would have to be compliant to. It was decided (and I agreed at that point to add to the GCRs) that if a bike came from the factory with a chain guide that was fitted to the swing arm such as a CR or a TM125 then it would be acceptable. If as in the case of the Husky it wasn't (on torque arm)then something will have to be added. If a bike had nothing then it would have to have something - my AJS is a classic case.
That someone out there decided that it should look like half the stuff I saw on the weekend isn't my problem, some guys did a great job but others with nothing (and there were quite a few) were asked to do something about it.
211
Dave, I can't find any reference in the GCR's stating that a chain guide has to be mounted to the swing arm. It only says " In a way to prevent"
I also cannot find any reference as to " If a bike came from the factory with a chain guide halfway down the swingarm ( eg CR 125 ) it would be acceptable
Could you please point me to where these are written?
The rule simply says " in a way to PREVENT trapping " Having 6 inches of nothing between the guard and sprocket is hardly prevention.
I agree with this prevention rule if it is done to the letter of the law.
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Ted ... Ice cream lids and zip ties come to mind ;)
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If anyone still has a copy of last year's MOMS (2013) on page 101 there is an add for a rear chain guard that, it would appear was acceptable for Road Racing. The wording of the rule is the same in the Road Race section So!!!!
I think everyone knows that if you drive your car less or park it under cover your insurance can be cheaper because you reduce the risk.
What is the difference here. Fitting a guard reduces a risk.
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On behalf of steven.how does your interperation of the rule ie crv/tm being suitable meet with the complance requirement of preventing traping ?
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Ted ... Ice cream lids and zip ties come to mind ;)
Exactly , how the hell can that prevent anything other that the ice cream now melting ::)
If there is going to be a rule then surely it would have to have a std ??? I can see an ice cream lid offering all the protection of a G string against a Tiger attack ::)
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Round and round we go, anything that increases my chances of turning up for work on Monday is fine by me. ???
Fair enough but why impose it on everybody else ??? Nothing stopping you from wrapping yourself in cotton wool , or making sure your fit for work Monday by staying home and watching it on telly from the safety of your couch , whatever makes you happy ;)
But this is where the world in general falls over , people expect EVERYONE else to change the ways they do things to suit the noisy minority ::)
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If anyone still has a copy of last year's MOMS (2013) on page 101 there is an add for a rear chain guard that, it would appear was acceptable for Road Racing. The wording of the rule is the same in the Road Race section So!!!!
I think everyone knows that if you drive your car less or park it under cover your insurance can be cheaper because you reduce the risk.
What is the difference here. Fitting a guard reduces a risk.
Yep
and CMX/CDT is exempt = other than CMX/CDT is I believe what it says
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its not selective anything; to the observant you would have noticed that CMX was exempt for a couple of years while the Commission sort to define what it was that we would have to be compliant to. It was decided (and I agreed at that point to add to the GCRs) that if a bike came from the factory with a chain guide that was fitted to the swing arm such as a CR or a TM125 then it would be acceptable. If as in the case of the Husky it wasn't (on torque arm)then something will have to be added. If a bike had nothing then it would have to have something - my AJS is a classic case.
That someone out there decided that it should look like half the stuff I saw on the weekend isn't my problem, some guys did a great job but others with nothing (and there were quite a few) were asked to do something about it.
211
Dave, I can't find any reference in the GCR's stating that a chain guide has to be mounted to the swing arm. It only says " In a way to prevent"
I also cannot find any reference as to " If a bike came from the factory with a chain guide halfway down the swingarm ( eg CR 125 ) it would be acceptable
Could you please point me to where these are written?
The rule simply says " in a way to PREVENT trapping " Having 6 inches of nothing between the guard and sprocket is hardly prevention.
I agree with this prevention rule if it is done to the letter of the law.
Ted
suggest you write a clarification of exactly what you think everyone should do, once you have it send it to MA and get it in the rule book. Right now it is what it is.
In my 40 years in the sport I've never seen it as a problem however I've seen plenty more rate more attention.
What I should do is a post with all the crap I see in scrutineering that is prevented from getting on the track. Now that's some serious safety matters.
DT
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I didn't single anyone out William and just as you are, I'm only voicing my opinion.
You've made a lot more noise than me so does that put you in the noisy minority?
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I didn't single anyone out William and just as you are, I'm only voicing my opinion.
You've made a lot more noise than me so does that put you in the noisy minority?
If you like ;) Like I sat whatever makes you happy :)
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I put a "fin" on the lower chain run on both my bikes as soon as the risk was brought to my attention.
I heared about the passer by at Nepean who hastily helped a bloke having difficulty unloading his bike, losing a finger in the back sprocket.
I put a chain guard on the upper run of my back chain on my slider when the joiner unclipped resulting in the chain flicked UP and whipped me on the bum! I have never seen a chain flick UP before, but it wasn't gunna get me twice!.
I'm also reminded that there is not much chance of me losing fingers in some-ones uncovered primary chain which was the norm in "the good ol' days",
And the modern generation on their new road machines don't have things designed to rip their nuts off as the slide up the fuel tank of their Triumph TBird over the tank rack and then the steering damper knob!
COMMON SENSE I say!
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On behalf of steven.how does your interperation of the rule ie crv/tm being suitable meet with the complance requirement of preventing traping ?
I just did. Im happy for you to create something that everyone understands and put it up for inclusion in the book. For me I held off until such time as I was sure that we were all not going to make our bikes look like an Agg bike. Really in the greater scheme of things I could put a shark fin on my swing arm and be 100% compliant while really making sure that my fingers were directed thru the sprocket. That's the alternative.
More fingers are lost loading bikes on a ute than on the track and if that's true then we should all have guards on the top of the sprocket not the bottom.
We let guys ride with a half face helmet and little else - I know what I would be more concerned about.
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its not selective anything; to the observant you would have noticed that CMX was exempt for a couple of years while the Commission sort to define what it was that we would have to be compliant to. It was decided (and I agreed at that point to add to the GCRs) that if a bike came from the factory with a chain guide that was fitted to the swing arm such as a CR or a TM125 then it would be acceptable. If as in the case of the Husky it wasn't (on torque arm)then something will have to be added. If a bike had nothing then it would have to have something - my AJS is a classic case.
That someone out there decided that it should look like half the stuff I saw on the weekend isn't my problem, some guys did a great job but others with nothing (and there were quite a few) were asked to do something about it.
211
Dave, I can't find any reference in the GCR's stating that a chain guide has to be mounted to the swing arm. It only says " In a way to prevent"
I also cannot find any reference as to " If a bike came from the factory with a chain guide halfway down the swingarm ( eg CR 125 ) it would be acceptable
Could you please point me to where these are written?
The rule simply says " in a way to PREVENT trapping " Having 6 inches of nothing between the guard and sprocket is hardly prevention.
I agree with this prevention rule if it is done to the letter of the law.
Ted
suggest you write a clarification of exactly what you think everyone should do, once you have it send it to MA and get it in the rule book. Right now it is what it is.
In my 40 years in the sport I've never seen it as a problem however I've seen plenty more rate more attention.
What I should do is a post with all the crap I see in scrutineering that is prevented from getting on the track. Now that's some serious safety matters.
DT
Dave
The wording as it is written is perfect. " Prevent trapping " is spot on.
The enforcement is the issue.
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If anyone still has a copy of last year's MOMS (2013) on page 101 there is an add for a rear chain guard that, it would appear was acceptable for Road Racing. The wording of the rule is the same in the Road Race section So!!!!
I think everyone knows that if you drive your car less or park it under cover your insurance can be cheaper because you reduce the risk.
What is the difference here. Fitting a guard reduces a risk.
Yep
and CMX/CDT is exempt = other than CMX/CDT is I believe what it says
Yes that is what it said in 2013, but that is not the case now.
The reason I mentioned the 2013 MOMS is because it has a picture of what is acceptable for a rear chain guard.
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it must have been just my Aura that attended the meetings to determin what was required.
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Looks like I have to get some tabs welded onto my nice White Brothers swing arm so I can mount a chain guard..... Grrrrrr.
JUST ANOTHER PAIN IN THE ARSE RULE!
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Trials bikes have never had a rear sprocket guard...
Modern or Classic...
Most of those riders have scrambled well to comply with this rule while most of us in our classic mx/dirt track scene already have these fitted to our bikes.
The ones without it fitted are the minority group...
Here's a financial tip...
Invest your money into companies that manufacture cut out lanyards...
We dont want em...theres no talk of them in our sport as far as im aware but they're now mandatory in trials ::)
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Looks like I have to get some tabs welded onto my nice White Brothers swing arm so I can mount a chain guard..... Grrrrrr.
JUST ANOTHER PAIN IN THE ARSE RULE!
I'd be asking MA to give you a written letter excepting responsibility for any damage or injury caused if your swingarm fails due to the welded on brackets.
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Looks like I have to get some tabs welded onto my nice White Brothers swing arm so I can mount a chain guard..... Grrrrrr.
JUST ANOTHER PAIN IN THE ARSE RULE!
is it roundish in shape,just use "P" type clamps to attach a guard without resorting to welding??, :P
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Looks like I have to get some tabs welded onto my nice White Brothers swing arm so I can mount a chain guard..... Grrrrrr.
JUST ANOTHER PAIN IN THE ARSE RULE!
I'd be asking MA to give you a written letter excepting responsibility for any damage or injury caused if your swingarm fails due to the welded on brackets.
Not a bad idea....But I think we both know what the answer will be.
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Looks like I have to get some tabs welded onto my nice White Brothers swing arm so I can mount a chain guard..... Grrrrrr.
JUST ANOTHER PAIN IN THE ARSE RULE!
is it roundish in shape,just use "P" type clamps to attach a guard without resorting to welding??, :P
It's a square section arm. I suppose I could make up some type of clamp...... Grrrrrrr
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squares good,at least it won't rotate into the chain ;), :P
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Looks like I have to get some tabs welded onto my nice White Brothers swing arm so I can mount a chain guard..... Grrrrrr.
JUST ANOTHER PAIN IN THE ARSE RULE!
is it roundish in shape,just use "P" type clamps to attach a guard without resorting to welding??, :P
It's a square section arm. I suppose I could make up some type of clamp...... Grrrrrrr
What for?
Two cable ties and a ice cream lid were all the rage ( and legal ) just over a week ago. The best thing with this setup is you can change sponsors ( Devondale, Peters, Streets etc ) for no set up cost ;D
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I have a gut feeling that the ice cream lid set up won't be legal for much longer
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Looks like I have to get some tabs welded onto my nice White Brothers swing arm so I can mount a chain guard..... Grrrrrr.
When this was introduced for historic roadracing a few years back, many just tapped a couple of 6mm holes into the underside of the arm and mounted a nice looking bracket from there. Look upon it as an opportunity to engineer something natty you can show off, rather than an excruciating burden...
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I have a gut feeling that the ice cream lid set up won't be legal for much longer
So does that mean my mate will have to refund Streets the sponsorship money he secured for the swingarm advertising. He'll be pissed. He locked them in for 5 years. 8)
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This topic has already had a pre-nationals gallop a couple of years ago. Check out Jimg1au's $10 effort at the bottom of page 1 : nice. And simple...
http://forum.ozvmx.com/index.php?topic=23808.0
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How come this rule is never enforced:
26:27:3:4:6 - A clothes peg is to be affixed to the swingarm encompassing a sturdy piece of cardboard which must protrude 22mm to the inside of the outer edge of the wheel spokes so as to create sufficient noise to warn of approaching machine.
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How come this rule is never enforced:
26:27:3:4:6 - A clothes peg is to be affixed to the swingarm encompassing a sturdy piece of cardboard which must protrude 22mm to the inside of the outer edge of the wheel spokes so as to create sufficient noise to warn of approaching machine.
Ah ha! So that explains why we have to muffle our old bikes to choking point....... so we can hear the cardboard noise maker :o