changing the ring on a 98 yz80

[yzpowerband]

Hello, i am farely new to 2 stroke bikes, and this would be my first time doing something with the topend.My bikes compression totally went, and bogged out and wouldn't start on me, when i was couple miles from my house. Fortunately, i rolled it down a huge hill, and click it in gear and was able to ride it home.But it sounded and rode so not right, like it sounded like it was stuck at a low rpm the whole time i was riding it home. I was told that since it started up like that, just a new ring was needed. So im ordering a new ring, new base gasket, and new orings just incase mine are cooked. Im getting my jug honed at a near by motorcyle place. I am wondering how i should break in the new ring. I was told i would have to mix a 15:1 tank instead of the 32:1. But how should i break it in with out scoring the cylinder? Thanks for the help.

 

[84cr125]

i found this break in procedure a while ago. its meant for breaking major engine work but you could follow this aswell. The more sensible breakin you do the better and longer it lasts.

Break In Procedures
1) Start your engine and let idle occasionally blipping the throttle for four to five minutes. Allow the engine to cool completely. Repeat this "heat cycle" process four more times.
2) Warm up the engine again and ride the bike for five to seven minutes at a very easy pace, vary the rpm, don’t ride at one speed. Don’t ride at more than 1/3 throttle or more than 1/3 rpm. Let the engine cool down completely and repeat the initial break in ride. Let the engine cool down.
3) Check the base nuts and head nuts for proper torque, check the coolant level and add coolant as necessary.
4) Ride the bike for five to ten minutes at a moderate pace, vary the rpm, don’t ride at more than 3/4 throttle or more than 3/4 rpm. Let the engine cool completely and repeat this secondary break in twice more.
5) Replace the spark plug with a new one. Ride the bike for five to eight minutes at a moderate pace, vary the rpm and shift up and down the gears. Once the engine is up to operating temperature you can make a jetting pass. Start in second gear and ride at full throttle through fourth gear, fully revving out fourth gear. With the throttle wide open in fourth hold the kill button down, pull in the clutch and stop. This is called a "plug chop"
6) Read the spark plug. With a pocket flashlight and a magnifying glass look at the porcelain part of the plug only, as you view the plug from the center electrode look down the length of the porcelain to its base, at this point there should be a dark chocolate colored smoke ring. There was not sufficient time to thoroughly color the whole plug, so the nose of the insulator may still be white, as long as there is a visible dark ring at the base everything is OK. Remember we want break in jetting so the plug should read rich/dark. Richen the jetting as necessary. If your having a hard time reading the spark plug, after the jet pass put the plug in a vice and hacksaw around the plug at the washer. Break the threads off with vise-grips, and the porcelain will be easy to read.
7) Complete the break in by riding at an aggressive pace for fifteen minutes, vary the rpm and don’t cruise at part throttle, ride hard without revving the engine too high. At the end of this final break in session do another jetting pass/plug chop as described above. Check the spark plug for the correct dark/rich condition. Wiseco Piston equipped engines will require another one or two break in cycles, ride at a recreational pace not revving the engine hard, full throttle should only be used for very short periods, fifth and sixth gear should only be used to cruise, ride one tank of gas through the engine in this manner to complete the break in. We feel it take about two gallons of gas to break in a motor equipped with a cast piston and five gallons for a motor equipped with a Wiseco.
8) Replace the spark plug with a new one, ride the bike aggressively for eight minutes and do a jetting pass/ plug chop in fifth gear. If the porcelain color is still dark/rich, lean the main jet size one at a time until the smoke ring at the base of the porcelain is a light brown. If the porcelain base is white, don’t run the engine. If the plug color looks good, continue riding at a race pace for ten minutes. Stop and let the engine cool. Check the torque on the cylinder base and head nuts.
9) More on jetting. If you generally run your engine flat out in sixth gear then make your jet pass/ plug shop in sixth. Motocross jetting is checked in fifth gear, therefore it is not safe to run MX jetting in the desert or down a road wide open in top gear. Desert jetting is richer than MX jetting. When running an engine at full throttle for extended periods be sure to chop the throttle decisively to slow down, just rolling out a little can seize a well jetted engine.

 

[yzpowerband]

Thank you, very helpfull information.

 

[84cr125]

dont worry about it ;)

 

[yzpowerband]

Today i took apart my top end, I took off my piston (1 ring) and notice my piston ring was snapped in half, and there was probably a 3/4 inch long scuff/scratch on the inside of the cylinder. Is this serious? Or when it gets honed , will it solve it. I think im going to order basically a new top end kit. The small end bearing seemed to have some play in it. Does this come with the top end kit? Thanks for your time.