Author Topic: Sprocket Guard  (Read 1731 times)

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Offline Toolboy

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Sprocket Guard
« on: February 18, 2013, 04:28:28 pm »

Gday all,

I am unsure of the ruling with sprocket gaurds for racing, is this acceptable??



Or do i try to search for a RM370 cover??

Thanks

Tim
82 RM250Z
79 RM400N
76 RM370A
74 TM400L
05 M50 Boulevard
1986 RM80G
1974 RV125
1994 DS80
2005 JR50

Offline Noel

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Re: Sprocket Guard
« Reply #1 on: February 18, 2013, 04:41:46 pm »

12.8.8.5
 "A counter shaft sprocket which is more than
30mm from the outside of the swing arm
pivot, must be covered."

In the case of your picture  I think you would need to cover the gap between sprocket and swingarm

12.8.8.6
" Other than CMX/CDT, 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."

It would appear that for 2013 you are not required to have this, this his an update from last year?


oldfart

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Re: Sprocket Guard
« Reply #2 on: February 18, 2013, 05:40:44 pm »
Tim, make a template out of cardboard first.... use the chain guide as a start and allow 25mm to cover top of chain .... alllow 25mm above chain @ rear fixing.

Offline Zakk

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Re: Sprocket Guard
« Reply #3 on: February 18, 2013, 06:08:23 pm »
couldn't you rivet a small peice of aluminium sheet to cover your current guard?

here's one i made up for my IT250, this is a strip of aluminium that mounts between the engine and footpeg and has a thin sheet riveted to it.



got the bike through a roadworthy inspection as i didn't have an original cover at the time

Offline Toolboy

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Re: Sprocket Guard
« Reply #4 on: February 18, 2013, 06:16:44 pm »
Thanks guys,

Good idea's to make one

Cheers

Tim
82 RM250Z
79 RM400N
76 RM370A
74 TM400L
05 M50 Boulevard
1986 RM80G
1974 RV125
1994 DS80
2005 JR50

Offline evo550

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Re: Sprocket Guard
« Reply #5 on: February 18, 2013, 06:59:16 pm »

12.8.8.5
 "A counter shaft sprocket which is more than
30mm from the outside of the swing arm
pivot, must be covered."

In the case of your picture  I think you would need to cover the gap between sprocket and swingarm

12.8.8.6
" Other than CMX/CDT, 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."

It would appear that for 2013 you are not required to have this, this his an update from last year?


Noel,
The 30mm rule is for modern MX, for VMX countershaft must be covered irrespective of gap.
I can't quote the rule number as it's outlined in each class eligibility rules.

Offline Tim754

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Re: Sprocket Guard
« Reply #6 on: February 18, 2013, 07:03:45 pm »
From one Vmx Tim to another,
 I have found when constructing safety fittings for your motorcycle, I use the notion of      <is it safe for everybody else to use???> .   ;) Cheers Tim754
I may not agree with what you have to say, but I'll defend to the death your right to say it.
                                                   Voltaire.

Offline Noel

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Re: Sprocket Guard
« Reply #7 on: February 18, 2013, 08:58:36 pm »
Evo550,
I am not a scrutineer,
but the rule I quoted is in  2013  "All disiplines."

CMX/ CDT specific chapters  also makes reference to sprocket covers

Curly3

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Re: Sprocket Guard
« Reply #8 on: February 18, 2013, 09:16:27 pm »
You can never be too safe.
If you think it should end at a point then give it an extra bit to be certain.
If weight's an issue for what you fit on your bike for VMX or VDT, then go on a diet.

Offline Tim754

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Re: Sprocket Guard
« Reply #9 on: February 18, 2013, 09:32:02 pm »
Good move seeking an original cover in the wanted section Tim ;)
 No matter what you fit it will most likely only weight a miniscule amount compered to my little VMX toys (lightened....) cover and unseen internal steel case protectors (630 chain..) :D :D :D Cheers Tim754
« Last Edit: February 20, 2013, 11:50:07 pm by Tim754 »
I may not agree with what you have to say, but I'll defend to the death your right to say it.
                                                   Voltaire.

Offline evo550

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Re: Sprocket Guard
« Reply #10 on: February 18, 2013, 09:55:30 pm »
Evo550,
I am not a scrutineer,
but the rule I quoted is in  2013  "All disiplines."

CMX/ CDT specific chapters  also makes reference to sprocket covers

 I only read the MX stuff  ::) Those weird road race sidecar guys can please themselves what they do. ;)
If there's a contradiction in the rule book (I know who'd have thought right) between "All disiplines" and "Disipline specific" rules, always refer to the Disipline specific rule.
In this case, "Countershaft sprocket must be fitted with a cover"
Pre 60 18.5.1.9
Pre 65 18.5.2.8
Pre 70 18.5.3.8... and so on and so forth.
« Last Edit: February 18, 2013, 10:17:53 pm by evo550 »