how long is break in on new piston and rings

chuck russo /

i took my ped to the shop yesterday and the guy called me last night and said that the ped needs new piston and rings. i was wondering how long the break in period is for this 87 tomos golden bullet lx

Re: how long is break in on new piston and rings

If they're not replacing the cylinder it won't take long at all.I know some say less,but to be on the safe side I'd baby it for a hundred miles if it were mine.Just increase the oil ratio to 32:1 or so and don't use synthetic `til it breaks in,IMHO.

Re: how long is break in on new piston and rings

chuck russo /

can i just put it on the kickstand and let it run for like 4 or 5 hours>?

Re: how long is break in on new piston and rings

No, you should operate it with a load on it, besides it might overheat if it just sat for that long with no air flowing over the cylinder, not to mention what might happen to you if you did it in an enclosed garage. Just go easy on it for the first tank of gas.

Re: how long is break in on new piston and rings

chuck russo /

ok, im picking it up from the shop most likly tomarrow and at the latest on thursday

Re: how long is break in on new piston and rings

I havent changed the piston and rings on my moped yet but for my dirtbike i just start it, rev it at alot of different postitions besides full throttle for about a minute or so, kill it and let it sit for about 30 min so it cools down fully then repeat the process once more and your ready to go. I probly wouldnt go as far as putting the ratio as low as 32:1 but maybe 40:1 for the first tank of gas. Why did the shop say you NEEDED a new piston and rings? was it seized?

Re: how long is break in on new piston and rings

Rich King /

Like Don said "baby it" for a few hundred miles. After I put a 70 cc kit on the PUCH I ran a 32;1 mixture and never over 3/4 throttle for a hundred miles. Then occassion wide open for short bursts, then back to 3/4 throttle. It is basically like this, baby it for several hundred miles (at least 300) then you can cruise around w/o a worry. I usually cruise at 3/4 or 7/8 throttle on level and wide open on the upgrade. I never have it wide open going down hill (you are looking for real engine trouble). How long is enough. I don't really know, other than to describe it as this, the sound of the engine will let you know.

With my Derbi, I babyed it for several hundred miles. One day I (around 350 miles) suddenly noticed an improvement in preformance and sound of the engine. MOPEDS are like high preformance cars, break them in according to the manufactures instructions and they'll run well forever. Break them in at full throttle and 10K or 20K down the road you are rebuilding the engine. (Testimony is my '86 vette I bought used w/60K. It is still just as fast as it was the day it rolled off the truck in Richlands, VA according to the former owner who recently drove it). Rich

Re:new piston and rings question

I just got a brand new shiny piston for my sachs. I was wondering if I should cut the skirt on the intake side to match the old one or leave it alone?

The new piston is a little taller from the pin to the top, and will increase compression a bit. The sachs usually runs with a 50:1oil ratio, so I'm going to break it in at 40:1

Re:new piston and rings question

chuck russo /

the shop didnt really say it needed a new on but he said the piston has slight scoring and the rings didnt have very good compression but he said it was ridable ao i decied to just get it fixed while it was in the shop

To Mbartell:

Don't go messing with piston skirts unless you know what you're doing.Pistons that are replacements should be the same weight I would think and you don't want to throw your crank out of balance,do you?Research it before you try it.

Re: To Mbartell:

well, I don't want to mess with it, that's why I posted. I guess I should have done a new thread.

The repacement piston is a lot lighter than the original, and it has thicker rings. It fits in my bore exactly like the old one. The diffrence is that on the old piston, the skirt on the intake side is about 1/8 of an inch shorter than on the new one. I recently got annother sachs motor, and it has a piston exactly like the repacement one I just got, but the motor has the tapered cooling fins and smaller ports than the square-fin one, which is what I'm going to use. The encourageing part is that there is a line drawn (very lightly with marker) on the replacement piston where I would need to cut.

If there was a place to research specifically, I would. Untill then If I screw it up, I at least know that it was me who screwed it up.

Re: To Mbartell:

M.,make SURE they sold you the RIGHT PISTON. I don't like the sound of the new one being lighter.You may want to look into it.It should fit to a `T'.If you ruin the one they sent you you're out the money,man! Maybe Fred or someone on here has a different idea on this?

Re: Thanks

I think the piston that it originally came with has been totaly and permanantly discontinued. It had 1.5mm rings, and the pin-locater was in the middle of the groove. The "replacement" has 2mm rings and the pin on the edge of the groove, like most other mopeds. I got the replacement from handy bikes, and even sent in the original one to match it up. I guess that I'll have to give them a call, and Talk to sombody who should know what to do. I'm just glad I didn't just jump in and do it. It would suck to be out the money, but damn I want to ride again.

Re: Thanks

Bob Jones is their best man on mopeds.If he says it's o.k. then you're probably alright.But you can do a double-check thru Mopedwarehouse if you're still in doubt.

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