king blew up :(

[mp_2009]

this weekend i was riding my 04 king cat and the lat 2 rides the rpm would drop off on a pull and on saturday it would do it all the time and it would bog and sputter put there was a foot of powder so i thought it was just the infamous powder bog that the 1ms are known for but anyways after an amazing day of riding we were heading back and playing like aways and i decided to track up this little fresh hillside just did alittle loop and was heading down the hill and it was boging and just sounded bad so i killed it no compression mag side pulled er out yesterday me and my buddy pulled the exhaust and dumped some metal out of that and pulled the head lots of metal but any ways we thought it must be a piston skirt but the ehaust side was still there both rings that we could see. taking it apart this week plan on rebuilding is there and thing i should do while i have this bad boy apart crank? seals?

 

[mp_2009]

or part out

or is it even worth fixing should i just part it out ?

 

[Double A]

I would fix it. Look your crank over, bearings etc. Get a set of oem pistons.
Check your plug readings at all rpm ranges next time you run it.

 

[mp_2009]

i guess ill tear it down and see what the damage report is and go from there open to opinions

 

[snailbait]

Really depends on how involved you want to get....and $ of course.
If the sled as a whole is in good shape...build er back up. If you have the time and resources....it's a good idea to true and weld the crank...especially if you've ever blown a belt at wide open throttle. New pistons, and a re-nick...she should be ready to rock again...
Just my .02
Steve

 

[mp_2009]

true and weld?

what exactly is true and welded crank ive heard of it alot but never really learned what it was i have an idea what it is but no 100% sure

 

[Double A]

The crank is pressed together. So they true it (check crank for straightness) then weld it so it wont come apart. SLP Did mine for an additional $50.

 

[mp_2009]

???????????

finally tore down my sled turns out the intake side piston skirt broke off like me and my buddy thought any ideas what would cause this??????

 

[cokingcat]

Check your crank seal. I didn't the first time and it cost me two top ends.

 

[snailbait]

True...usually comes from the bottom...have seen a ring catch on a port and break...then snap the skirt. Be thorough....it could save you more damage down the road!

 

[mp_2009]

yeah if i do it myself ill split the case halfs check the crank seal and also whats the differents between teflon coated pistons and the oem other then the fact the oem arent teflon any positives higher compression? anything like that and is there anything i can to to prevent this from happening again its a real pain in the *** to have this happen on the best day of riding i had all year lol

 

[mp_2009]

also can i take my crank to any machine shop and have it trued and welded? i live in helena montana and im in shelby alot so anywhere close to those places would be ideal

 

[1Mike900]

How many miles on sled? Sometimes pistons have flaws in them and can crack if fatigue sets in over time. 1500-2000 miles is all I would give a 900 if RPM's are in check 7400-7600. Spool it higher and I would replace sooner. Rebuild it and have fun! Any other sled that you replace it with could have the same problem down the road!

Mike

 

[mp_2009]

i estimated the sled to have about 2000 to 2500 miles just today it has an odometer but my bearing went out last year and i rode all year last year and this year i finally replaced the speedo needle the day before it blew up so 2000 to 2500 miles like you said and i think with slp twins it ran 8000 rpm i believe before i ride it again im gonna ditch the twins and go stock

 

[high time]

Engine wear probably caused it.

The pistons rattle a little and as they do they weaken in the skirt area. You should be able to here them rattle when they are loose, Or a bad batch of pistons. At any rate , it does us all good to put in new pistons every few years.

Owen

 

[mp_2009]

teflon coat pistons ? are they better then oem stock pistons?