Piston Ring Rookie

[renrip]

I'm rebuilding my first engine on a '80 175KDX and having a blast.

I have completed the bottom end and am just to install the piston.

I installed the piston on the rod and was going to drop the cylinder over top but I'm having a "fun" time with getting past the rings. :|

Any experienced tips to help me out here?

 

[gwhII]

I put two-stroke oil on both the rings and on the inside of the cylinder wall. I made sure that the ring gap and the pins in the grooves were close to each other and then squeezed the top ring and got the jug over the first ring. I then did the same for the second, making sure that in each case that the ring gap stayed on the pins. If each is lubed, the piston and rings should slide into the bore.

I'm also assuming that you have the correct ring gap and that your rings aren't too tight. Also, if the tops/bottoms of your rings are marked, check your manual to make sure that the mark should be facing up.

Best,
Greg

 

[kdxtaz]

Yeah, what he said. It's much easier with two people. One to compress the rings & make sure they are seated right with the pins at the gaps and one to lower the cylinder on. :)

 

[rickyd]

I make a mark w/a felt tip pen where the locating pins are.. Always best too get an extra set of hands for your first time.. Also, i like too cover the opening into the bottom end w/a clean shop rag, just too lesson the chance of something falling down inside of the case..
Rick

 

[kdxtaz]

I like the pen idea :thumb: . DEFINATELY cover the case opening with a rag. Believe me, you don't want drop anything down there including dirt. Do this especially when installing circlips.

 

[wibby]

From Eric Gorr:
The traditional way to assemble the top end is to install the piston assembly on the connecting rod, compress the rings, and slide the cylinder over the piston. That can be difficult with larger bore cylinders, or if you're working by yourself. Try this method instead. Install one circlip in the piston, install the piston into the cylinder with the pin hole exposed, install the piston pin through one side of the piston, position the cylinder over the connecting rod and push the piston pin through until it bottoms against the circlip, install the other circlip. It only takes two hands to install the top end using this manor and there is less chance that you'll damage the rings by twisting the cylinder upon installation.

More here
http://ericgorr.com/techarticles/twotopweb.html#Top End Assembly

 

[renrip]

"I'm also assuming that you have the correct ring gap and that your rings aren't too tight" - from gwhII

How do I know this - I had my cylinder bored out to 67mm (and honed) and received the piston w/ rings from Wiesco. Would these not come gapped correctly.

 

[kdxtaz]

The way to find out for sure is to insert a ring without the piston into the cylinder & check the gap with a feeler gauge. Check your service manual for the correct tolerances.

 

[louis]

Yes. They would come gapped correctly on paper. We live in the real world where mistakes are made. Don't assume. Double check part numbers and dimensions on everything.

 

[Coolector]

Did you have to have the cylinder replated? Or was it a sleeve.

 

[renrip]

The cylinder was sleeved - bored from a 50mm to a 66mm.
I tried installing the piston into the cylinder instead and it went extremely easy - I won't even humor you guys in telling how long I tried the other way - oh well I guess this is the best way to learn!!!

Since you guys were so good on that one - how about this one. (and yes I did try and check the archieve!!!)

Engine's in, spark plugs are new and gapped, new gas - the engine won't fire.
I kicked for about 10 minutes with not even a hope from the engine. There is gas going to the carb (tipped the bike to push thru the overflows).

I did notice that my kick start has some play in it - if the full kick is 100% there is probably 25% of slack?

This is my first rebuild and I was really hoping to hear it run tonight - know I'm just frustrated. I expected it turn run after three of four kicks.

Any suggestions? Keep kicking?

 

[bake]

Is there spark, possibly a wire got missed, pinched or your kill switch is on. Better start diagnosing. I am not positive about the KDX's but most kickstarts have slack in them.

 

[rickyd]

First thing, check too see if there is spark, then be sure there is no shop rag blocking the airflow??

 

[kdxtaz]

"I have completed the bottom end..."

Are you sure the timing is right?

 

[renrip]

I'm pretty sure the timing is correct I marked everything before it came off.

I'm really going to show my lack of knowledge with this question but to check if there's a spark? - from what I read do you unscrew the spark plug, hold the end onto the engine and proceed to kick it over?

Oh, by the way - no rag, but I did run a check that right away!!!!

 

[rickyd]

Did you install the piston in the correct position?? Usually there is and arrow or some sort of marking that goes towards the exhaust side..
Rick

 

[renrip]

No Spark!

I checked the wiring and Magneto - Magneto had a chuck out of it when I tried to take off the cover - I used the three screw holes, screwed until it hit something solid and then popped the cap off - Yes I realize how stupid that was, lesson learned.

Any idea who would carry something like this - I tried local Kawasaki dealer and wreckers with no luck.

 

[rickyd]

I'm really going to show my lack of knowledge with this question but to check if there's a spark? - from what I read do you unscrew the spark plug, hold the end onto the engine and proceed to kick it over?

Too check for spark, plug the spark plug into the spark plug wire, rest the tip of the plug on the head, then kick, or have somebody kick the motor over, you should see a spark.. Dont hold onto it, or you can get a shock..
RIck