have just put an earlier sportsman 90 cdi box on my new predator 90 plugged straight in no rev limiter revs alot higher now also had cylinder head off and noticed piston comes about 2mm or so shigh of the top of the cylinder so i have turned the top of the cylinder head so that the combustion chamber dropped into cylinder so i have got 0.7mm gap between piston sides and the head, 165psi compression and the combination has given it double exceleration i will start to try lighter variable rollers so it will keep the revs because it seems to change up to quick at the moment, p.s. thanks to mod81 for suggesting sportsman 90 cdi. seems to work good.[img]i/expressions/face-icon-small-smile.gif[/img]

 

glad it worked for you ,did you just remachine the gasket surface so the head would fit in the bore....

 

yes just the surface area the gasket covers i could of just taken a couple of mms off top of cylinder just incase of error it is cheaper to modifie head

 

Hey guys,
sounds like you two have some info i need bad. What year's of the sportmans cdi do i need to look for?
on my son's pred i took .016"off the head (planed the head true to center)- is this what you are talking about or did you "bore" the inner diameter of the head/combustion area? i also installed a WRH race pipe and rejetted the main. Thanks for any info you can give me, we need some low end since when we race they now put his bike in the mod class because of the pipe.
thanks

 

Dunno if this will work for you, but there is a guy on e-bay (steamoman) selling CDI's that might work for $24.99 each. They are Eton CDI's, but I and another person have put these on our '02 Scrambler 50's and they work great. They have the rev limiter wirre to clip, and after that is cut, will rev wide open. All factory kill switches will work too.

search for eton sundiro polaris cdi on ebay.


I know the CDI for the '02 and '03 are not the same, but I don't know if they are that different that they cant be interchanged.

Bryce

 

the part # on the packet was #0450722 and also had #30410-152-000 it is a sportsman 90 cdi with no rev limiter i went to my local dealer and looked on there micro fiche and the new predator and sportsman had the same cdi so we went back on the sportsman until the part number changed approx 1999-2000 year. the cdi is smaller but plugs straight on no wiring change. i skimmed 2mm off the head but not the combustion chamber area,so in theory the combustion chamber drops down into cylinder as the piston does not come to the top of the cylinder.

 

One of my friends had an early 90 scrambler model and i switched cdi's with him. You are right- it has made a big difference in the bike. Would you happen to know the distance from the spark plug tip to the top of the piston after you did your head work? I have a WRH race pipe and i went into the cylinder and polished the exhaust port and made it the same dimension as the pipe, chamfered the intakes and exhaust ports ( they had very sharp edges) and opened up the intake just alittle- made it run alot better. Lost alittle bit of low end but not much. we installed a 27 tooth rear sprocket to give it some speed. later this week i will put some picks of the 90 with it's new heat shield and some of my xplorer with foot pegs and nerfs.
later
hunt

 

Where can you get gears for the Pred. 90 ?

 

i got mine from sprocket specialtys- local shop got them for me.

 

Bought one of the sunduro cdi's. What wire are you clipping? Is it the green one that loops around on the box? It limits lower on my Pred. 90 than the stock one. All kill switches work as normal.