92 kitty crank questions

[snoeproe]

Hi
I'm into a '92 kitty motor that was the victim of a seized drive side crank bearing. It looks like I can get the motor going with 2 new crank bearings and seals. I'm also going to replace the seal on the secondary drive gear shaft.
Should I have the run-out checked on this crank since it was the victim of a seized bearing, before I proceed any further? The cylinder and piston measure out fine.
Also, is the lower crank to rod pin removable, meaning can I change the lower connecting rod needle bearing? It looks like the lower rod pin can be tapped out.

[72]

It would be a good idea to check the alignment of the crank. Sometimes seized crankbearings slow the engine to a nice stop other times they stop right now, sometimes spining the bearing in the bearing pocket of the case (might want to look at that also). Anyways because you have it apart, you should look into having the crank rebuilt. That involves seperating the two halves replacing the pin / rod bearing and reassembly/alignment. Any competent engine machine shop specializing in two strokes should be able to do this for you, along with inspecting for any other possible issues. If you have a press, parallel v-blocks, and an indicator you could try it yourself but I wouldnt recomend it. You may also want to look into the popular option of opening up the clearances and rod oil slot. This will alow you to safely run without the gov. . If you search this site you be able to find more information on that option. Hope this helps.

[Jonn]

You received good advice from 72. I'd only add a couple things. 1) Out of 100s of Kitty Cat cranks I've seen there was only one that came from the factory that I could call "straight". Otherwise, almost all of them are out by some degree. The worst I've seen was .014" out. As long as you're in the engine I'd straighten it. 2) Make sure whoever straightens it knows what they are doing. There are many ways to straighten a Kitty Cat crank, and the recommended V-blocks is not the answer. Make sure the engine shop that does the work for you doesn't use the V-block method, or find someone else. 3) Because of the tolerances, whoever presses your crank apart and back together needs to know what their doing. It's not something that a backyard machanic should do. 4) You should consider replacing the connecting rod with a "slit rod" The slit rod has grooves cut into the sides for direct lubrication to the crank pin bearing and is the replacement rod that you can get through Arctic Cat for $84. If you need one of these, my current pricing is $60. jonn@obups

[kidsperformance]

over the past 20 yrs that's all I've ever aligned cranks with is a set of V blocks....go-kart engine builders do it that way(that's who taught me) also along with shifter kart guy's...just have to add 1.5mm of shims under the flywheel V block because the flywheel sahft is 17mm and the PTO side is 20mm

[72]

Sometimes people confuse the importance of precision (-.0005) alignment of single and multicylinder engines. A multicylinder engine can be balanced and the harmonics related to the design and crank alignment is way more critical than a single cylinder engine which cannot ever be balanced. While everyone should want their crank to be set “perfect”, if you can get it within .002 you should be good . Now if your going to be twisting 15K rpms+ for long periods of time then you should cut that in half. Its your money, if you want to pay for a ”between centers alignment” go for it, but unless your there, how will you know your getting what your paying extra for?

[1121racinkitty]

Because you get what you pay for and you pay for what you get.
when it comes to kitty cats people aint out two get rich. im with Bill 2 v blocks a little shim and wamy.

[1121racinkitty]

actually my dad made a really cool jig for pressin
i use the v blocks for straighten