Piston And Rings

[knight_ripper]

I have a '97 stock engine with all the exterior mods. My buddy has been trying to talk me into doing the rings...just for the hell of it. I was wondering how necessary it was...and if I even would want to just do the rings? Or Should I put in a whole new stock Wiseco kit?

 

I have wanted to do the top end for awhile now...just cause. But at the same time I would like to put on a NOSS head, and V-Force reeds.

 

Should I wait?

[frocashmoney24]

well its a 97 so i say its overdate for a rebuild, if you can afford it do it all, if not just do the weisco, but if u wanna be sure, do a compression test and post what u got, its not very hard and if u need any help theres tons of people on here that'll help

[knight_ripper]

what do you mean by rebuild? You dont think new pistons and rings will be good enough?

[knight_ripper]

also, how do you do a compression test?

 

Put my mouth on the pipe and have a buddy kick it....if my head is still on, the compression test failed!

 

Will I need a special tool?

[Banchetta]

Top end rebuild= new pistons/rings, boring......I'd check the compression. If its low, then pull the head and measure the roundness of the cylinder...The cylinders will wear egg-shaped over time since the force of the crank is from front to back, the sides won't wear much at all...If its out of round, then bore it and put some oversize pistons in there...You have the right idea, rebuild it now while everything is intact. Once it goes, then you have to pull the crank and inspect it and worry about the metal that went into the lower end bearings....

[SyNtAxx]

Lol...got 2 posts while i was writing my reply to his question....o well readu p anyhow...

 

Hello,

 

When he said "rebuild" he meant rebuild the topend of the motor. The topend is the pistons and rings. If your going to change the rings...you may as well spend the extra hour it takes to put the new pistons in.

 

I just rebuilt my 95 banshee for the first time this winter. It was on its stock bore and still made about 110psi in each cylinder. I took it to .10 over.

 

If you do decide to rebuild, take the cylinders off and have them mic'd or measured to make sure they have not gone out of round at any point in the cylinder. If it within specs then just put in a new piston set with rings.

 

If it is out of round...have them bored to the next size up, you want to bore as little as possible but as much is needed to make the cylinders round again. For example .10 or .20 over.

 

Also VERY important....check your crankshaft and rods for excess play. If you havent already get yourself a Clymers manual and become familiar with this stuff...it is not difficult at all.

 

Top end rebuild only takes a few hours......oh...and dont forget to use all NEW gasgets....

 

Nick

Edited April 26, 2004 by SyNtAxx

[Banchetta]

also, how do you do a compression test? 

 

Put my mouth on the pipe and have a buddy kick it....if my head is still on, the compression test failed!

 

Will I need a special tool?

That might work, but could have various reading depending on the person....I'd just buy a compression tester at an automotive store or get a good one from Snap-on or Craftsman....Put the guage in the spark plug hole, hold the throttle wide open, keep kickin until the needle stops, thats your compression.....

[.]

I'd also warm your engine up for a couple minutes before you do it. I was reading 90 lbs cold and 115 warm when my engine first started wearing down.

 

I'd start thinking about a rebuild at 105-110.....mine let a ring go at like 105

 

If everything is still round, I'd go with a wiseco setup anyway. The pistons are lighter than stock and will rev faster. Make sure you always do a hone on the cylinder walls when ever putting in new rings so they will seat together.

[knight_ripper]

I love you guys man......

 

I feel all tingly inside.

 

I love this place.

 

I will try all the above. I will go get a compression tester today, and see what it reads.

 

What is the stock compression? Do I want it to read something specific? Like, it has to be over 100? Or below 80? Or do I just want both cylinders to be the same?

[knight_ripper]

Aw shit....what does Hone mean? lol

[Banchetta]

You should have around 120-128psi at or about sea level...You want both cylinders to be within 5psi and honing is when they rough up the cylinders a bit after boring or before changing the rings...Its helps the rings and cylinders wear together....Honing is usually done w/ honing stones in a drill or other devices. While spinning the stones, you pull the drill in and out of the cylinder causing a x-design in the cylinders.....You might even still see some honing lines in the cylinders now...

[knight_ripper]

Ok....I got the compression tester.....took it camping this past weekend in Hollister, Ca. The place is awesome. 90% of the trails are one way roads. They have street signs pointing you in the right direction....Do not enter sighns and such. The place is top notch. Not to mention they have 3 or 4 tracks. And I only wrecked once. Why is it that I always wreck when Im doin stupid shit like fishtailin or wheeleein. Always on the simple stuff. I guess I should be thankfull, I never want to have a 6th gear spill. NO THANK YOU.

 

Ok back to compression.

 

At about 1000ft ---nice and warm after bout an hours ride--

 

100psi on the left

105psi on the right

 

Time to do it or what....I know, I know.

 

Im down for a little while anyway. My buddy---drunk buddy--ran into me (on the last ride) just barely bumped me from behind. Took the left T-5 right off. Slamed it into the pitcock, head, A-Arms, and frame. Buckled it in 3 places and bent the tip. Luckily I had extra hangers and we were able to bend it back in place and get it hung. now where the pipe meets the engine looks like my grandpa smokin a pipe.....puff puff

[.]

go try warming your cylinders (if you still can) up for like 3 or 4 minutes (probably not even that long, just long enough that the cylinders are warm to the touch, and then do the reading again. (make sure its screwed in nice and snug).

 

Leave the gas on, give it full throttle, and kick it over again until it stops.

 

I'm pretty sure it should read the same, but I've never done a comp. test after riding for a good while. At 1000 ft you should be sitting right at about 120. I'm guessing you are at the point that you'd want to start really looking into a rebuild before something lets go and you have bigger worries on your hands. Get a clymer manual, pull the cylinders (make sure you untorque the head in reverse sequence to help not warp it.), take the cylinders to a machine shop, (35 to 40 a side about, any machine shop in the phonebook should be able to do it)and see what they need to be bored to. Then order the piston kit (150 shipped from a couple different places) and take the pistons and cylinders to the machine shop and they will machine the cylinders for the pistons.

 

Install and your ready for a break in. We've got lotsssss of tips for that as well

[knight_ripper]

Cool man. I wasnt holding the gas on at all....And now Im home in sacramento....so Im at sea level. And I was doing it way warm. So my fingers are crossed that it will go up. I doubt it though. She is a '97 and has been ran pretty hard the last few years (Im finally starting to ride her the way she is sapposed to be ridden)

 

Nice....Sounds easier than it is....Im sure. But Im all over it. I will be getting the funds together next week.

 

I will run another compression test tonight...just as stated.

 

Thanks