OzVMX Forum

Clubroom => General Discussion => Topic started by: Toolboy on February 18, 2013, 04:28:28 pm

Title: Sprocket Guard
Post by: Toolboy on February 18, 2013, 04:28:28 pm

Gday all,

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

(http://img.photobucket.com/albums/v318/Airfireman/IMG_1258_zps4e61b9e2.jpg)

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

Thanks

Tim
Title: Re: Sprocket Guard
Post by: Noel 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?

Title: Re: Sprocket Guard
Post by: oldfart 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.
(http://i72.photobucket.com/albums/i180/mutchoo/001-9_zpsfd9a7857.jpg)
Title: Re: Sprocket Guard
Post by: Zakk 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.
(http://i210.photobucket.com/albums/bb143/Yokkachi/roadready14.jpg)
(http://i210.photobucket.com/albums/bb143/Yokkachi/roadready15.jpg)

got the bike through a roadworthy inspection as i didn't have an original cover at the time
Title: Re: Sprocket Guard
Post by: Toolboy on February 18, 2013, 06:16:44 pm
Thanks guys,

Good idea's to make one

Cheers

Tim
Title: Re: Sprocket Guard
Post by: evo550 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.
Title: Re: Sprocket Guard
Post by: Tim754 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
Title: Re: Sprocket Guard
Post by: Noel 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
Title: Re: Sprocket Guard
Post by: Curly3 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.
Title: Re: Sprocket Guard
Post by: Tim754 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
(http://i951.photobucket.com/albums/ad360/tdee754/Picture754covers0063_zpsc32af1d5.jpg)
Title: Re: Sprocket Guard
Post by: evo550 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.