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TXSledder

975 almost done

Aug 9, 2012
28
5
3
Carnation, WA
And a couple questions.. Have read a lot and the more I read the more convoluted things get, especially going back many years.

05 KK EFI sled w/ Boondocker CB, KOSO dual EGT gauges, now running on premix which will be 32:1. stock everything else engine related.

1) timing key. any issues with not running one? what indicators should I be looking for to determine if I need one? Have read both do it and don't posts.

2) clutching. I plan on leaving the clutching alone through tuning and see how it works- one thing at a time. Any issues with that plan?

3) anything else? Im learning as I go here and don't want to blow this thing up!
 

Meatman

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Nov 26, 2007
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I never ran a timing key, disn't need to. Clutching go with a green snopro spring or cpc silver/red and a straight 53* helix. You could maybe advance your timing by a deg, I heard there's a bit of improvement. If you want a set of jaws efi twins to compliment that 975, I got a set with the headers and silencer I'll let go for 200 for everything. Has holes already for egt probes. Just shoot me a PM
 

Idcatman3

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Nov 26, 2007
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Idaho Falls, Idaho
I am firmly in the "don't do it" camp on timing keys on this engine. The mid-range is hot enough as is. If you could just add a degree or two to the top end, sure, but you can't.

I can get you the clutching setups we are using if you'd like. What elevation will you be running at?

Keep it mild and ride it. Runs like a lightly modded M1000. More power than any new stock 800.
 

Piperock boys

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Nov 29, 2007
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Wondering what the cost of building one of these is? Looking at freshening the top end up on my 900
 

Idcatman3

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Nov 26, 2007
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Idaho Falls, Idaho
Wondering what the cost of building one of these is? Looking at freshening the top end up on my 900
We've done top end exchanges for ~$1000 before. You give us cylinders/heads/valves, we send you finished cylinders/heads/valves and the spacer plate.

Pricing may have changed if plating or other things have changed. It's been a while. I do know a member on Arctic Chat has a top end for sale.
 

Idcatman3

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Nov 26, 2007
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Idaho Falls, Idaho
For riding in Island Park, we're running 68.5 gram weights with the Cat blue spring. That's the softest spring they make. 18/40 gearing, and I'll have to check on the secondary clutch.
 
Aug 9, 2012
28
5
3
Carnation, WA
Went for a ride today. Was a great day to get back on the snow. Sled has a few bugs but was a great day.

The temp light flashes constantly immediately from cold start so I know it is not hot. Flashes seem even so can't decifer any code from that. I'm going to disconnect the boondocker and see if it goes away, but if not any ideas? This was not an issue when torn down for rebuild.

Running issues are bogging throughout the rpm range and what seems to be a miss under load. Seemed like it was running rich to me and plugs are wet with dark brown/black electrode. My max rpm is 7180. Occasionally I got a backfire after clearing a bog at low rpm.

I started with the boondocker set at +2 at 2500, +10-l,m,h @ 5500 up through 8200. I lowered them to zero increase @2500, +5l,+8m/h @5500 and +8l,m,h @6750 and 7500.

I am also running premix at 20:1 on the first tank for break in. Next tank will be reduced to 32:1.
 
Aug 9, 2012
28
5
3
Carnation, WA
Unplugged the boondocker TPS connection and went for a ride. No more blinking lights, bogs or missing. I raised all the settings back to where I initially set with exception of leaving 2500 at zero. After checking the plugs I raised the 5500 to +12 and 7500 to +14 and 8200 to +15. I know it won't push much past 7500 but I don't want it to lean so better safe than sorry. My Max rpm was 7560. Was a night ride so will leave more fine tuning to the daylight. I will need to fatten up the mag side as it is running hotter.

General opinion of the motor is it rips. I actually need to change skid setting to keep it down. I like a motor that pulls strong from the bottom and this meets expectations for sure. For now I am pretty content with the clutching but as I get a few miles on it and learn more a little tweaking is in store.
 

Bearcat

Well-known member
Nov 27, 2007
735
120
43
Rovaniemi, Finland
I'm interested of this 975 big bore. Is there 975 sleeve available to do it that way? I have one broken 800 cylinder laying in carage. Is there any good single pipe available for 975? I've converted to M hoods so fitting twins would be tigth.

Currently I'm running mild diy ported 800 EFI. I'm using 4.5 degree advanced timing and whole fuel table is leaned -3..-5 and -15 from idle area (I'm using 800 HO PCV) at sea level. Temps are still really low, mid range cruising shows barely 1150 and full gas temps are below 1100.
 
Aug 9, 2012
28
5
3
Carnation, WA
Just bore and plate, no sleeves on these cylinders. I haven't given pipes much thought other than having a custom one fabbed when the time comes. I will either build a chassis or drop this engine in a poo chassis like Idcatman did so buying a 1m pipe wouldn't be a long term investment.
 

Idcatman3

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Nov 26, 2007
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Idaho Falls, Idaho
Just bore and plate, no sleeves on these cylinders. I haven't given pipes much thought other than having a custom one fabbed when the time comes. I will either build a chassis or drop this engine in a poo chassis like Idcatman did so buying a 1m pipe wouldn't be a long term investment.
Just for added motivation, the Dragon chassis with this motor is head and shoulders above the stock King Cat. Out full mod 1M/M/Van Amburg hybrid is more fun, but not a lot more fun. It was also a ton more work. Dragons are cheap and the swap is easy.