First Top End rebuild - Need advice - Pics included

[BlackHills]

I am tearing down the top end on my 2001 kx 500 for the first time.  I have owned the bike for 2 years.  I know that I should be doing this more often anyway, but the bike was running so great I didn't want to screw it up. 

Anyway my bike has enough broken parts and the cold starting was getting so bad that I knew it was about time.  I tore the bike apart yesterday and found a few things that need to be fixed: aftermarket reed valves cracked, broken support on radiator, etc.  I new from the previous owner that the cylinder had been sleaved so I expected that, but I didn't expect the amount of metal removal that was done on the intake ports.

I found a couple of small cracks in the "normal" locations on the intake ports, but they don't appear to be cracked all the way through.  My problem is that I really can't afford to put more money into this bike so I wanted opinions on the pictures I took and what you think should/can be done.

Cylinder Walls:







Intake Ports:





Piston:







Also, I am having serious problems removing the allen bolt that holds the KIPS in place.  I am using so much force that I figure I am going to either break the allen wrench or strip the bolt.  Anyone have any advice?

Their is also an issue with the amount of crap in the exhaust ports.  Is this normal?





I can take more pictures of different areas, and of more detail if needed.  I just want to make sure I get this back running and it doesn't self destruct on me in a month.

[stewart]

the cracks i see are from running a sleave in a cylinder not meant for a sleeve .. change to belray h1r oil at 50.to1 to clean up exhast port and be sure to use a wiesco forged piston to prevent future problems

[BDI]

I ran a sleeved cylinder with all the same cracks that yours has for eight or nine years with out problem one. I always imagined the top of the cylinder blowing off the bottom but it never happend unfortutunately, that would have been one cool blow up. 

[kaw rider]

has long you don't have this problem your ok.

[BlackHills]

Thanks guys.  I don't think the cracks are that bad so I am hoping to put it back together the way it is.  I have a Wiseco top end kit that should be here in a couple of days (with piston).

Now a couple of follow-up questions.  How do I clean up the inside of the cylinder?  Not the cylinder walls themselves, but all the ports and areas with all the buildup.  Also what is the best way to clean up bolts and nuts that need a little TLC?

So far I have been cleaning up the outside of the engine with oven cleaner to get rid of the gunk (I had a big crack in my exhaust and a bunch of spooge all over my engine as a result).  For the bolts I was planning on soaking them in gas, diesel or kerosene then cleaning them with a wire brush or an attachment on a dremel.  I would like to get my bike looking somewhat presentable and serviceable again instead of just the hillclimbing beast that it is  .

Anyone have any special tips or advice on cleaning up all the ports on the cylinder and bolts?

[maddoggy]

hey blackhills, i have a friend that cleaned the inside of his ktm550 mxc pipe by chucking up an old piece of speedo cable in his drill. he frayed the end out and put a 90 degree bend on the end and went to town on the pipe. i couldn't believe how muck soot he got out of it. the same method may work for you on those "hard to get to" places on the exhaust ports.    MADDOGGY

[stewart]

go to the car piant store  for car body shops... buy 5 gallon can of piant thinner,,, let cylinder  soak in it over night till comes out like new  ps ithink there are cheap piant thinners that dont work as good and you can ussally blow carbon off with compreesd air when you get done soaking cylinder

[BlackHills]

Thanks for the tips. 

I finally did get the allen bolt (on the KIPS assembly) to break free, I had to put the cylinder back on the bike so I could get more leverage.  After pulling out all the parts I have officially decided to run good quality 2 stroke oil at a higher ratio.  Those things are just COVERED in carbon build up.  I am pretty amazed the bike still ran as good as it did.  I have been using whatever cheap oil I can find and mixing it at 32:1, so I am going to use some quality oil at 50:1 from now on.

Luckily or unfortunately I won't have to remove carbon from my exhaust since I am sending it to the piperepair.com guys to fix an incident I had with a rock while climbing.

I think I will try the paint thinner method to remove all the carbon.  It seems pretty simple and will get all the hard to reach spots.

[doordie]

has long you don't have this problem your ok.

OR like this!

[Jeeks]

I use Permatex spray gasket remover.  Comes right off.  Two cans will be enough, make sure you use nitril gloves.





Ball hone the cylinder



Polished exhaust port

[BDI]

That cylinder looks like the plating is worn threw by the rings at top

[Jeeks]

That cylinder looks like the plating is worn threw by the rings at top

Nope, just the reflection.  When you measure a cylinder you should measure inside the ring groove too.

The groove in that cylinder looks worse than it is.  I should get 2-3 more rebuilds on it before it will need attention.  That cylinder was only out of round 0.001 from top to bottom.

[serafin]

Hi everyone  Correct me if I'm wrong about a top end rebuild.  Its been my understanding that any cylinder that has been chromed, nikasil, plated ect.. is not to be honed?  Is this correct?

Serafin

[nd4speed]

It should be honed but do it quickly as not to eat through the plating.

[BlackHills]

Well I just had a issue with my rebuild.  I got my Wiseco top end kit today, and the cylinder is smaller than the one that I took out (by about 1/16th).  I guess someone before me decided to bore it out to something bigger than a 500cc???

This is where things get over my head and beyond the tools that I own.  I think I will take it to a local machine shop (after its cleaned) and have them hone it and give me an accurate measurement for the piston.  I guess I will have to send my top end kit back and try again....