How to take care of a 2 stroke engine ( 84 250r )

[bebeav]

How do you take care of your engine?
What do you do and don't?
How can you keep away your engine from rebuild?
Is a motomaster 2 stroke oil with a 20:1 mix is good?
How do ride your 2 stroke engine?

I'm new to two stroke and want to learn the most I can.

Since my engine blew, I'm doing my first rebuild ( ride the trike 45 min after i bought it ). It while took some time cause i don't have cash now to buy all the stuff needed.

But after my rebuild i want my engine to run perfectly or near this at least one or two summer, cause i don't want to rebuild it each year exept changing my ring each winter.

ALP
Beav

[Dirtcrasher]

You just rebuilt it?? Make sure you break it in nice and easy for a few rides always vary throttle but no more than 1/4 throttle then 1/2 then 3/4 etc etc then pin it wide open constantly and trust me you will not hurt that motor.
Biggest mistake is people throwing in top ends and then the lower going out. Anyone can do a 2 stroke piston but the crank and mais are much more difficult and more expensive.
Not just 2 strokes but any bike for longevity purposes - change the oil often and keep the filter clean. Every single bike I've ever owned leaks dirt where the back carb boot mates to the airbox EVERY ONE!!! Take that apart and silicone it well. Then the filter can do it's job and always put a ring of grease around where the air filter meets the air box front flange.
I've had some bikes last years with proper maintenance.
2 strokes love to be held wide open, not hurting it a bit as long as it's fresh.
And let that air cooled engine cool off once in awhile, I always use to give mine a rest.
Unfortunately 2 strokes seem to run the best just before they blow up, it's hard to know if your getting an old beat ready to die motor or one half way there. When they're ready to blow up they seem fastest because everything is all worn out and smacking around.

Have fun!

[bebeav]

didn't rebuuild it yet, just finish to remove the cylinder and try to evaluate the damage.

look at the pic and tell me what you think.

oh and is it normal that i can move to the left and right my crank like an 1/10 inch ( sorry really not sure about the form of the sentence )

ALP
Beav

[smokinwrench]

Mix the gas a little rich the first couple tanks (32/1 with a hight quality oil) ride it nice at first and get a little more throttle all the time by the end of three tanks ride the dog s**t at of it.

Josh

works for me

[bebeav]

ok thx for the infortion guys

i'm learning, i'm learning one days i'll ask to those question hehehe

ALP
Beav

[bebeav]

hay can the jetting of the carb may be a cause of this engine damage?

ALP
Beav

[plkmonster2]

most likely, most premature wear is from the wrong jetting for being too lean. running the engine too lean during breakin can cause the engine to run wierd and wear down in a week. you should only need to change the rings when needed, not every winter... overtime, all the honing would cause too much slap.

[kr rz350]

The reason your piston melted by the exh. port like that was due to extreme detonation. Thats why the top of the piston looks sandblasted, along with the combustion chamber. Detonation is caused by a few things, most commonly from running lean (air/fuel NOT oil/gas). I'm geussing by the fact that you asked about the jetting of the carb that this is where you should look first. Put a bigger main jet in it and move your clip down (raise needle up). The best way to avoid toasting your motor while jetting is to start WAY rich and work your way down. When the jetting is close the bike will rev out cleaner, and make more power. Two-strokes make the most power right on the fine line of being to lean. When you think you are getting close to the proper jetting, start doing some plug checks. Ride it around and warm it up, then put a brand new plug in it, ride hard for a few minutes, going through the gears and really getting into the band. Then hit a long straight away and hold it WOT for as long as you can, then, pull in the clutch and kill the ignition real quick. Roll it to a stop with the clutch pulled in. Take the plug out and take a look, being very watchful for tiny specs of aluminum or any cracks in the insulator, which would indicate detonation. remember, don't be afraid to start rich with the jetting.

As for the rebuild, do it right! Make sure you have a manual, and when you get the new rings, that you file the ring end gap (Read in the manual for this) and double check the piston to cylinder clearance of the shop that does the re-bore (Which I know you need) You also might want to consider smoothing out all of the pits in your head from the detonation, they can cause hot spots which will lead to pre-ignition and eventually detonation. I also HIGHLY recommend that you perform a leak-down test. I gaurantee you that even if you think you put it together good it will piss air out of the base gasket and reedcage gaskets. If you rode it like this it would suck in lots of air which leans out your mixtures and causes detonation. As for the crank, it is supposed to have side to side play, but if it has up and down play it is definitly junk. The correct way to know for sure if your lower rod bearing and/or rod has issues is to measure the 'little end side shake' but this requires tools you probably don't have.
You can find alot of good 2-stroke info at macdizzy.com (especially on the bb). Have fun on that trike, it doesn't handle to well but my 82 air cooled still hangs with my buddies banshees and 400's. Of course thats with a few mods ;)

[kr rz350]

oh and one more thing: The correct way to break in a fresh top end on a two-stroke (especially with a stock cast piston, which is what I recommend over a forged wiseco for your trike) is to put it through "heat-cycles". Basically, you start it up and blip the throttle and rev it up and stuff until you can feel the cylinder getting hot to the touch. Then shut it off and let it COMPLETELY cool down. Do this twice. Then the 3rd time ride it around, do not wail on it, but don't ride it like a pussy either. After it warms up again, let it COMPLETELY cool down, do this 2-3 times ridding a little harder each time.

Another good measure to make your top end last longer is to always let it warm up before wailing on it, especially with a cast piston on such a large bore 2-stroke.

[plkmonster2]

yup, cold engine starts are the hardest on em. if you don't let it warm up, and you ride the piss out of it, the tolerences are too close and it will ruin both the sleeve and piston quickly.

[bebeav]

damn!!! great information kr rz350, really helpfull.

i just mailed recreationunlimited.com to know if they got .75 oversize top end rebuild kit for my R and if they got em i'm gonna buy them and do my rebuild next week-end.

but i don't have any manual. where can i get one. at a honda dealer?
you said "smoothing out all of the pits in your head from the detonation" how can i do that? with a buffer?

ALP
Beav

[atc86r]

need to get a leak down tester. don't want to jet it if its not holding pressure. new bore job needs a compression test. gives you a baseline for wear.

[bebeav]

ok, nice but where can i get an air leak tester.
and compression tester also??

ALP
Beav