How long did it take you to Re-do the top end of your bike?

[MotoCruse]

I just got a '98 YZ 125 last night :) and the compression is bad enough that I could use my hand to crank it, but still won't fire up :| . I'm going to order parts today and just curious from start to finish how long on average it took for you all to do your top end. Thanks in advance!

 

[mkelly04]

On a 2 stroke if everything is good once its opened up, it takes me about 2 days..... Well, really it only takes about 2 hours, but I end up driving one town over to get the cylinder honed so It ends up taking a couple days.

 

[MotoCruse]

Did you put in a new piston or just replace the rings? I've read in here that some hone the cylinder and some do not...I guess that's up to the individual.

 

[FruDaddy]

Honing depends a bit on the cylinder. According to the instruction steet that comes with a Wiseco piston, cast iron sleeved cylinders MUST be honed, whil plated cylinders may or may not need it, depending on condition. It also states that you should not use a ball hone on a plated cylinder.

Budget 3-6 hours for your first time, and don't start it the day that you plan to ride. Take your time, stuff a rag into the bottom end opening, and be careful with the circlips (they are the worst part, IMO).

 

[_JOE_]

My last one took 2 weeks. I thought that was good turn around time from Forward Motion in the spring. But seriously, like fru said a few hours if all goes well, up to six or more with issues. TAKE YOUR TIME, look closely at EVERYTHING you touch and take pictures if you aren't too confident. A little extra time being cautious can save alot of time and money.

 

[Solid State]

It also states that you should not use a ball hone on a plated cylinder.

That's news to me (and I'm sure a lot of other people around here).

Plan for more time if you disassemble the power valve (recommended). Make sure you replace all the gaskets and you may have to replace more parts after disassembly based on condition. Check the rod play. Use quality parts. Have all the necessary tools and manuals. Take your time and record the position of all the components prior to disassembly so you don't scratch your hear when reassembling. Also, rings are installed with the writing side up.

Good luck.

 

[mkelly04]

It also states that you should not use a ball hone on a plated cylinder.

Is that a mistype? The service manual for my 03 kx250 specifically said that only a ball hone should be used.


I believe that a 2 stroke requires a ball hone so it doesnt hang in the intake and exhaust ports, and a 4 stroke can use a blade style hone since the bore is smooth.

 

[adam728]

My last one took about 6 1/2 weeks. Stupid work sending me away and stupid parts getting back ordered.

If I have everything layed out ready to go I can do a new piston/ring in around 2 hours.

 

[Bunya]

The hone / no-hone of a plated cylinder is a long standing debate. The Wiesco instructions absoulutely state not to use a ball hone. If the cylinder is in good condition, many just use a Scotch-Brite pad, trying to follow the angles of the original honing to clean it up. Others will insist on using a ball hone. If you do a search of this site you'll find plenty of threads on the subject. Read thru as much as you can stand then decide which procedure you think is best. Personally I feel that since there is no definitive data pointing to one method being better than the other, either will result in approximately the same engine life. With that in mind, I'd go with the cheap Scotch-Brite. Whatever route you take, make sure you thoroughly clean the cylinder afterwards to remove all traces of abrasive compounds.

 

[whenfoxforks-ruled]

You definitely need to remove the flashing,ESPECIALLY at the exhaust bridge! Nothing wrong with a 00 ball hone,not to argue with wiseco,but wtf! Muriatic acid,q tips and a scotch brite pad works also,caution to the fumes and getting it on the aluminum. A complete engine kit is available at hot rods for about 320.

 

[FruDaddy]

If deglazing is necessary, DO NOT use a ball hone. Use a rigid or brush type diamond hone.

Also:

Any time a cylinder is bored, all ports must be chamfered. The top of the cylinder should be deburred, and the bottome should be generously chamfered for ease of piston and ring installation. When boring a cylinder with an exhaust bridge, the face of the bridge must be relieve .002"-.004" to allow for bridge expansion

I don't know what the best way to deal with this is, but this comes directly from my source. I cannot find this information in my owners manual, and I do not yet have the service manual for my KX250, the last time that I needed one, I borrowed it from a friend. Like has been said, read all of the arguments, until you are disgusted with the subject, then decide what makes the most sense to you. If you are lucky, you won't have to hone it anyway.

 

[jeredh]

Is that a mistype? The service manual for my 03 kx250 specifically said that only a ball hone should be used.

This is not correct. I have a service manual for a 2003 KX250 M1 (M1 just designates two stroke machine) in front of me, and it states:

"If any of the cylinder inside diameter exceeds the service limit, the cylinder must be replaced with a new one since the PLATED cylinder cannot be bored or honed".

You can have the cylinder replated, but I would be safe and stick with the manufacturer's suggested and DO NOT bore or hone a plated cylinder. You can replace the cylinder at a fair price, and save yourself a huge headache down the road. Wiseco does make a piston/ring kit for bored cylinders for the 2003 KX250. So you can bore it, but i wouldn't. Boring it will remove the electrofused plating. If you read the benefits of this plating, you'll understand why you do not want to bore or hone the plating. GET A SERVICE MANUAL!

I also recommend not using anything abrasive to clean the cylinder. This means no scotchbrite pads, etc. Soap, water and elbow grease is all I do.

I just put a new piston, ring and gaskets in my 2003 KX250 yesterday, for what it's worth. Removing the cylinder and jug took about 1-1/2 hours. Replacing the piston, rings and gasket and putting it all back together will take about the same time.

I'm also replacing the reeds and putting a new exhaust on.

:)

 

[whenfoxforks-ruled]

Here is the thing, kawasakis plating is some of the worst and thinnest in the industry! Follow what your manual says, its there for a reason. Though buying a stock cylinder is a viable alternative, so is sending it to US Chrome, you can even open it up! Call Eric Gorr and find out whats the hot size for that year bike. US Chrome's plating is probably the best and thickest!

 

[jeredh]

Update on my repairs.

I bought a Wiseco piston/ring kit for my 2003 KX250. Note: i bought the Wiseco piston that is designed for a electrofused cylinder.
The piston replacement was very easy on this bike. From start to finish it went without a hitch. Removed seat, gas tank, plastics and radiators. Pulled the cylinder jug off and it looked really good. Minimal signs of burn below the rings on the factory piston, and zero signs of nicks/scratches/gouges on the cylinder walls (in fact, the cross hatching from the factory was extremely visible). The piston removes quite easily: removing the two clips on the piston barrel was a cinch, and the piston slid right off the crank.
Installing the new Wiseco took 10 minutes. Putting the new gaskets on and the cylinder jug, along with reassembling the power valve took 20 minutes. The radiators gave me now problems...all hoses were in good shape.

The entire project took about 4 hours of labor. I feel very confident with the work b/c i did it myself.

The good news is that the bike started on the 2nd kick, and sounds great. The bad news is that the Pro Circuit Works exhaust and Pro Circuit Nature Friendly exhaust system were no where close to matching up to the factory mounting holes. More on this in another thread.

Going to Loretta Lynn's this weekend. First i will break the piston in on Saturday with casual riding.