deputy dawg Posted June 22, 2015 Report Share Posted June 22, 2015 Hi could someone please tell me what the shock length is on a mkii Mar please. And also apart from price what advantage is there to putting a flat sprocket on the rear with the spacer? Does it help prevent the spindle from bending Many thanks Quote Link to comment Share on other sites More sharing options...
feetupfun Posted June 23, 2015 Report Share Posted June 23, 2015 If you use a spacer that has an outrigger bearing, then yes it does reduce the risk of bending the rear axle. Some outrigger kits from the 1970s are intended to be used with the standard dished sprocket (they fit on the outside of the sprocket) My 250 Explorer (which shares most mechanical parts with the MK2 MAR) came with mid-1970s 350mm Betor shocks which I suspect are the originals. I use 360mm Falcons for competition Quote Link to comment Share on other sites More sharing options...
deputy dawg Posted June 23, 2015 Author Report Share Posted June 23, 2015 Thank you replying, being new to ossa I don't now a lot many thanks Quote Link to comment Share on other sites More sharing options...
goudrons Posted June 24, 2015 Report Share Posted June 24, 2015 As feetup explains, the flat sprocket kit should come with a third bearing/spacer. This is meant to help support the very narrow rear spindle which are prone to bending. When I bought mine is was like a dogs back leg and did not want to come out even with the sprocket conversion, I found a pit bike spindle (12mm I think)that fitted. 350mm should be fine, I can't comment on spring rate as mine is a Mk3 with the shocks leaned right over and needed 65lb springs. 1 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted June 24, 2015 Report Share Posted June 24, 2015 As feetup explains, the flat sprocket kit should come with a third bearing/spacer. This is meant to help support the very narrow rear spindle which are prone to bending. When I bought mine is was like a dogs back leg and did not want to come out even with the sprocket conversion, I found a pit bike spindle (12mm I think)that fitted. 350mm should be fine, I can't comment on spring rate as mine is a Mk3 with the shocks leaned right over and needed 65lb springs. Another option for the rear axle: I used a TY250 twinshock swingarm axle as my OSSA rear wheel axle because mine had been straightened a few too many times, and I don't think that one was the original either. Quote Link to comment Share on other sites More sharing options...
trialsrfun Posted June 24, 2015 Report Share Posted June 24, 2015 When (not if) the rear wheel spindle bends it has to be driven out through the bearings which forces the bearings from the hub making them a looser fit and ruining the rear hub. The dished sprocket looks elegant but is best replaced with a flat one. Steve Sell Marlimar OSSA manufactures a sprocket carrier which uses sprockets from Beta, Gas Gas and the like so lots of sizes available at reasonable prices, he also makes a stainless steel rear spindle that should not give any trouble again. Quote Link to comment Share on other sites More sharing options...
deputy dawg Posted June 24, 2015 Author Report Share Posted June 24, 2015 Thanks for the replies,this is a great help, am trying to get everything organised so I can rebuild it in the winter as it is a jigsaw at the moment. how do I get contact details for Steve sell. Quote Link to comment Share on other sites More sharing options...
trialsrfun Posted June 24, 2015 Report Share Posted June 24, 2015 Message sent to you Quote Link to comment Share on other sites More sharing options...
deputy dawg Posted June 24, 2015 Author Report Share Posted June 24, 2015 Thank you for the replies will be a great help,Where could I get the contact details for Steve Sell marlimar ossa While I'm on is there any other things to consider whilst it still in a load of bits. many thanks Quote Link to comment Share on other sites More sharing options...
deputy dawg Posted June 24, 2015 Author Report Share Posted June 24, 2015 Sorry for the double post old duffer syndrome. Thank you for that trials run much appreciated Quote Link to comment Share on other sites More sharing options...
lbhbul Posted June 24, 2015 Report Share Posted June 24, 2015 Just a note to any use of after market dished sprocket; I hope you have a machinist handy. 1 Quote Link to comment Share on other sites More sharing options...
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