DT125R ARCHIVE

i,ve found on some sites that when running in a new piston and rings that say to ride the bike hard and to use alot of engine braking to get a good seal between the new rings and the barrel and some sites say do not use more than half throttle for a hundred miles then use you can use up to three quarters of the throttle for a further two hundred miles what would you recommend the method i use to use on my rm125  was take it easy for a couple of laps let it cool down then basically ride as normal i never had any trouble with that but i,ve never had run in a 2 stroke road bike before so this may not work any help would be much appreciated

since i've had it done its making a rattling noise i used a standard size piston and rings the same size as the one that was in it but it does not sound right it pulss nicley and the temprature is fine it only goes about a 3rd of the way along is it possible it needs reboring and a new piston to match the rebore

In the haynes manual it says something like -


Run in should be done for 500 miles (just to be sure but don't see why 300 shouldn't do the job)

No point in restricting yourself to any certain speed or revs as it needs to be worn in gradually throughout the rev range - if you ride like a nanny up to 4k revs for 500 miles and then floor it to 10,000 it's not going to do it good.


Just take it easy on the throttle, for the first 100 miles only go up to 4 / 5k revs then now and again go a bit further

The main concern is to not put excessive strain on the gearbox if you are going to go to high revs for the first few hundreds miles don't open the throttle fully and rag it just ease it open and let it naturally get there



There is no 'method' as such, take it easy, use common sense and you will be fine.

Good quality oil is a must too.

-- Edited by Harry on Thursday 15th of November 2012 10:13:59 PM

I ran my piston in for 50.

Did you have a rebore ?

Cheers Harry, i've got the casteral racing 2 stoke shiz in there atm, this good enough? i've also read to use normal (non-high octain) fuel duriong the break in too, can anyone enforce this?

Yeah Cal i got it rebored. So should be honed properly etc.

I have alway been a little weary about screwing the ****e out of a newly built engine...

Looks like ill do what i was going to do and warm her up, take her for a gradual ride increasing the revs the more miles i go.

Cant Wait!! Come PJ hurry up and send my barrel back!!

-- Edited by St0fxxx on Friday 16th of November 2012 11:55:55 AM