hi all im new on here and to nsr 250s just got my self a nsr 250 1990 with a rebuilt built engine how many miles do you run the engine in for and how many miles on rings, pistons, cranks do you guys get thank you

Er, mine was run-in on the dyno, then thrashed to the redline, so possibly 3 miles total?

There are many differing views on the running in procedure, from none to a few hundred miles, and nobody can produce any evidence to prove their method was better than any other - that I've ever seen at least.

When I first fitted new pistons & rings I did three heat cycles before I took it out on the road, then treated it very gently for a good few hundred miles. But that was ten years ago, and nowadays I don't bother at all - the coatings on pistons, rings and cylinders is so hard there really isn't much bedding in to be done.

As for how far between rebuilds, it depends entirely on how many miles you do, and if you sieze it before you've worn anything out! Generally, what we're seeing is that seals dry out due to lack of use long before the bearings on the crank get goosed. I think I've read that in standard trim the engine shouldn't need any work for 20,000 miles or so, but I don't know anyone who kept their bike standard for that long to find out!

ha on the dyno ok then ive done 150miles prity slow ill open her up next time then, just got a emax delimiter to plug in is this the same as cutting 4 5 6 gear wires and connecting them to 3. next exhaust tyga air box top (any good?) and reed block in one so only have to jet it one time really like this nsr 250 i have a nc29 and mc19 but all ways loved 2strokes man its so light only have to look at a turn and it goes round it

nice1