Question for the racers - Sharkfin

[scooble]

I got one of these chain/toe guard sharkfin things some time ago, but haven't had a chance to offer it up to the swingarm as its been down the machine shop.
When I did my CTC test, the ACU Rep said that you need to fit a shark fin. when I read the ACU handbook, it says fit a shark fin.
I looked online to see how they are fitted and saw a few R&G ones, which seemed to make sense.
So I got a 'Universal' shark fin from Projection components, and it really doesn't look right when offered up to the swingarm.

It was my assumption that the whole point of them was to cover the gap where the chain meets the sprocket to reduce the 'pinch point', however, with mine, it hangs down like a thing that is supposed to scrape the ground.




fitted to the top, it looks useless;


now messing around with some gaffer tape, I managed to make it look like this;

[Rocket]

that looks like 1 for a stunt bike with a large rear sprocket, I use these (221032517531 ebay no) and cut a little off the end to fit round the bobbin mount.

[Luders]

Holy cow, that's more like a killer whale fin!

The idea of the shark fin is to stop your fingers getting razzed round the sprocket if you fall off, so bear this in mind when positioning.

I would replace what you have there with what Mark suggests.

[scooble]

I got a reply from Projection components and they told me it was a 'generic' shark fin designed for all bikes, ranging from supermotos to stunt bikes and can be 'bent' into shape.
I really can not see how it can be 'bent' so that it follows the curvature of the sprocket.
I've ordered the one suggested above.
(Glad I didn't get the KR1S dog bones from projection either)

[Rocket]

If you need photo of how i've fitted them let me know and I will take some, I cut a piece out around the bobbin mount and drill a new hole, also follow line of sprocket and chain as close to them and side of arm as necessary and not the line of arm, will look on the piss against the arm but straight againsts the chain and sprocket, also take in to consideration when positioning fin changing of the rear sprockets, smallest to largest will alter the amount the fin covers the sprocket.

[scooble]

Hi Rocket, a picture would be useful as a guide if it isn't too much trouble

[Rocket]

testing at Cadwell tomorrow with the kr's, if all goes well and I get chance I will get some photo's of the fin.

[si.likes.guiness]

i know its on my nsr,but the idea's the same,heres a picture of mine when it was fitted

[Luders]

Good luck tomorrow Mark, I'll try to phone you this week to find out how you get on.

I'm probably not racing at Cadwell this month, but I will be there covering break down if you're racing.

[Rocket]

swinger with fin removed (you can see the outline in the dirt)

some measurements


1 on race bike




hope these help, sorry it took so long but bikes, camera and pc all needed attention.

[Luders]

Mine is like that, but I have it a bit forward of the paddock stand bobbin.

[andy#176]

How do. The shark fin u have pictured at the start would be useless. I tied to scrutineer my bike last month with one like that and they wouldn't pass it as the holes in them should be no bigger than a pen. I usually make them by cutting it out of checker plate but I had been out the weekend before and it had broke off without me realising and got the lend of one like u pictured on the morn of the race. To get through I ended up having to bolt a heel plate to it. This is mcui rules in northern Ireland unless yours are different. Hope this helps.

[scooble]

the ACU handbook was pretty useless, it didn't specify sizes, dimensions or positions of the guard, only that you should have one fitted