king cat 900.. cdi low altitude?

[motocrazy2006]

After seeing a post about someone having a low altitude cdi I'm curious...
So is the low altitude box necessary for low elevation? What is the difference between it and the high elevation? Also does anyone have one laying around?

 

[puddytat]

I was my post that you seen. It changes the timing curve and I am not sure why but I think I read that it is a necessary mod for riding at low altitude with the 1m's. The guy I bought mine from had a friend that basicly built him one or reflashed one or what ever so it is like halfway between a 1m and a zr. I am not sure but I think it is supposed to help with the dreaded lean midrange but I don't know how or why. If you can't tell yes I am electronicly challenged!!!!! LOL

 

[diggerdown]

Should be some old zr ones laying around somewhere. Usually the guys tried to get one from a 1M to put on the zr.

 

[KMMAC]

HCS

Should be some old zr ones laying around somewhere. Usually the guys tried to get one from a 1M to put on the zr.

Check at hard core sledder,, or ebay powers sports under snowmobile parts.

 

[1Mike900]

They backed off the curve a little and took away total advance by a few degrees for low elevation. The 1M/KK had the hotter curve for the higher elevation power that is needed and only recommended for 4000' and above. I would not try and run a KK at low altitude due to possible burndown, unless jetted/ZR needles installed and higher octane fuel is used.

Mike

 

[motocrazy2006]

So can anyone give me the correct part number? Coming back to cb7227 and cb 7220 both are zr900 cdi.. both the same? Heard the 7220 is the early build zr900... and its the same... but just making sure

 

[cubby]

Wow they are not cheap I see!! On ebay they are going for alot.

 

[Idcatman3]

It's only different on the top end. 10 degrees on the ZR vs 12.5 on the 1M. only the very top of the curve is different, low-mid range is the same

The best cure for the midrange lean spot is using '01-'02 T-cat needles.

 

[01ZRTCAT]

FWIW.....I tried to run a high elev. box @ 2500ft and I did have mid range hot spot (detonation) , I never did try better fuel? But I could tell a difference @WOT!

Cat re flashed my boxes, I went through Oregon Trail Sports Michelle took care of it, great person to deal with!

 

[motocrazy2006]

Just broke down and bought one. Id do a reflash but like to keep the mnt one for out west. Which even after the cdi new rails jets needles belts.. im still ahead on the sled... gotta love buddies that need $$$

 

[cubby]

So now I'm confused? Do you need to run the zr cdi for low alt or not. Maybe I will just let my buddy do his own research on this sled LOL. I sure don't want to be blamed for a melted down sled.

 

[motocrazy2006]

Yes u need to run the box to be safe. Also make sure u jet it correct and use the low alt. Needles

 

[01ZRTCAT]

X2 on having to run the low elevation box! I tried every possible combo I could come up, with no luck!

What is the Tcat needle a 58?....I also tried that with little success, seem to fat in the midrange even with a .010 shim on the needle

I tried out the low elevation box this weekend, short rip across the lake, happy with the overall performance. First ride/observation. Bigger mains for the next time