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kitty cat performance quesions

Races where and when, also fine tune your Kitty Cat for the local track or back yard.

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catpride22
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Joined: Wed Dec 05, 2012 3:12 am
Location: United States

kitty cat performance quesions

Post by catpride22 » Wed Dec 05, 2012 3:39 am

1st; I have a 99 kc need more out of it read if you disable governor you need to put slit rod in it,if i put the slit rod in it with governor disabled would it be reliable as a stock governed motor.
2;what is the best all around gear for stock set up with the governor still working i heard a 28 tooth is a good choice i have stock 42 on it now.
3rd;best all around gear for ungoverned motor.
4th;what would be the most rpm's you can run on a stock rod and is there much of a performance gain at that rpm.
5th;heard you have to have slit rod machined to fit kc motor.
This is just a sled that my kid rides in a 8 acre field and around the house.


JonnO
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Joined: Sat Nov 03, 2007 8:47 am
Location: North of Twin Cities

Kitty Cat Performance

Post by JonnO » Mon Jan 07, 2013 8:44 am

1) You can run with the governor disabled, but you should gear the sled down before you do. Gearing it down will help keep the engine from over-revving, which is ultimately what burns out the crank pin bearing. If you do put a slit rod in, it definately increase the reliability and is what every race Kitty Cat has installed in them. Keep one thing in mind. You can't just install a slit rod. The crank has to be pulled apart, replace the rod, press the crank together again with specific tolorances, then you have to straighten the crank. It should be done by someone who works on these.

2) The gearing can vary because each kitty cat is different. Track tension, bearing or bushing bogies, rolling resistance, etc. can impact what gear you can run. On average, you can run between a 27 and 34 tooth sprocket. Generally I'd start with a 30 tooth. If you choose to change the driven gear you'll need a quick change hub and sprocket, about $60 worth. You can also increase the size of the clutch sprocket and achieve the same thing for about $26 to $29. I carry hubs, driven gears, clutches and clutch sprockets, everything you need for kitty cats.

3) Same as #2 above. The torque of the engine is the same, it's just that your top speed will change.

4) Top rpms are very different engine to engine. The crankshafts are so out of straight that it depends on by how far and that affect the top rpm. You should hope to see rpms in the 6000s. The change you'll notice is on top speed.

5) Slit rods are available and you do not need to have your rod machined, nor is it cheaper. The slit rod retails for almost $120, but I currently sell them for $75. http://obups/products/clutches.htm They do not have to be custom fit to your engine.

I hope this information helps you. Let me know if you have any other questions or need clarification.

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72
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Post by 72 » Mon Jan 07, 2013 7:41 pm

Hey John, whats the target clearance on the rod big end for a 10K rpm peak engine considering the pin and needles are nominal size, I had this info at one time but cannot find it now, I want to say its .0003" over but cant remember for sure.

Another question, will drilling through the length of the crank pin, say around 5-6mm then cross drilling through the pin 1-1.5mm in the center of the bearing journal area allow for enough lube to get to the bearings at 10k rpm without a slotted rod? I just had this idea as some mfg's have use this method. Should I still put a couple notches on the side of the big end while I have it out?

kidsperformance
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Location: Yorkville, IL.

Post by kidsperformance » Sat Jan 12, 2013 1:35 am

the lower end rod clearance should be .0014 to .0016....the stock clearance is fine for 6000 rpm's....anymore than that it needs to be clearanced...

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72
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Post by 72 » Mon Jan 14, 2013 7:55 pm

kidsperformance wrote:the lower end rod clearance should be .0014 to .0016....the stock clearance is fine for 6000 rpm's....anymore than that it needs to be clearanced...


Thanks, any thoughts on the aforementioned crank pin mod I brought up? Are the sizes you mentioned around .0003" over what had came from the factory?

kidsperformance
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Joined: Tue Dec 20, 2005 1:32 pm
Location: Yorkville, IL.

Post by kidsperformance » Tue Jan 15, 2013 11:31 pm

you are saying .0003 which to me is 3 tenths of a thousands.....I'm saying you need to clearance it at 1 and 4 tenths to 1 and 6 tenths of a thousand..(.0014-.0016) ...drilling a hole in the crank pin would be ok it the motor ran at slow rpm's...the 2 slots are the way to go as the fuel mixture has a better way of washing in there...standard clearance on a stock rod is .0008....8 tenths of a thousand....that's way to tight for 10K rpm running even if it's has the 2 slots....been there done that....once I clearance to the above mention....I've never had a failure

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72
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Location: Ohio

Post by 72 » Thu Jan 17, 2013 1:27 am

Thats what I wanted to know, thanks . If I need this info again in a couple of years, I know where to find it, better than my memory. Thanks again

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