8/900 Timing Curve/ Timing Key discussion

Idcatman3

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We don't run timing keys in our sleds. With the timing curve in the CDI, you can get awfully advanced in the midrange, and depending on your jetting/clutching/riding style, that gets dangerous.

Also, on high hp motors, you reduce the area of the flywheel key when you put in an offset one, and you increase the possibility of shearing the key.

All that being said, I'm sure there are as many (if not more) people that will say run the key, no problems. Ideally IMO, you would have the CDI reprogrammed to just add the 2-3 degrees to the top end of the RPM range. That's a bit more money than a cheap timing key though.
 

1Mike900

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Idacatman, Is this the same timing set-up that the 03's had without the advanced key? The std. low elevation box # for the 04's and later is #3006-479 and can be reprogrammed to 03's if needed? With a larger bore, I would assume advance would be needed to get a complete burn, But maybe not as much as the 03's?

Mike
 

Idcatman3

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I've never been sure exactly what the '03 timing curve is. I know that the only difference in the later years between the ZR and 1M CDIs is 2.5 degrees on the top end. 10 degrees advance for the ZRs, 12.5 for the 1M.
 

1Mike900

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Someone on here in the old posts last yr. was looking for the '03 Mtn. cat CDI I cannot find the post, But he posted the #'s of the full curve. IdaCman do you think this obtainable? Was about last Nov/Dec.?

Thanks
Mike
 

Meatman

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i got a CDI box off an 02 800 mountain cat i believe....i know thats what it came off of. however it was off a carb sled
 

Idcatman3

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Someone on here in the old posts last yr. was looking for the '03 Mtn. cat CDI I cannot find the post, But he posted the #'s of the full curve. IdaCman do you think this obtainable? Was about last Nov/Dec.?

Thanks
Mike
I'll see what I can dig up.

Edit:
This is what I found, this curve for the 900s was posted a couple times:

Mtn Cat
1800-26*
2000-26*
3000-26*
5000-21*
5500-19*
6000-17*
6500-13*
7000-12.5*
8500-12.5*

ZR same to 6000 rpm
6500-12*
7000-10*
8500-10*

I'm not going to vouch for the accuracy at this time. There appears to be no confirmable info about the '03 curve being different, or any numbers at all about the 800. One guy did say that he thought the 800 curve was hotter throughout the range.

http://www.snowest.com/forum/showthread.php?t=128505

http://www.snowest.com/forum/showthread.php?t=129939

I'm also going to (try) and prune this off into a separate thread about timing curves.
 
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mattymac

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Ive had cut reprogram my CDI's in the past, they would do it for free its been a while since ive done one but had the best luck with the 03 MC 900 curve.


More timing to a point will also loose topend, its a balancing act. If you just go with a good curve in the mid with less advance on top its what I prefer, just like the cats have always been known for.

On my 1200 wc I run 12* past 8000rpm most people run em 16* all things equal I can pull more weight in the primary and am faster on topend on less octane.
 
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