Running in

[vicar]

Just had my ETZ251 re bored what are the recommended max rpm, mileage till its run in. I would like to get the best out of my fresh bore/piston what did the factory recommend from new?

[DAVID THOMPSON]

i just run them but not hard and no steady speed on a motorway
if you baby it it will take a long time to seat the rings

but being a mad man will screw things up
remember my rule if its 300cc or less its just a big moped

dave

[vicar]

Thanks Dave ,but what did the people who made them recommend. That`s what I would like to know.

[Blurredman]

Ride it like normal but don't go beyond like 4.5 k if you can help it for a while.

Seeing as the MZ is a bike where the engine needs to be fully utilised in the RPM range in order to get the best out it in every day use, it won't be possible to 'baby' it much. Not least as the ETZ model engine is disputed not to have as great a torque as the TS models. But then you won't want that anyway as that promotes blow back etc as the rings aren't seated in quite nicely. However, it is all somewhat of an academic discussion as the power gained by 'doing it the best way for the engine for power' over 'just riding it' is so negligible it's not really worth mentioning on a bike that'll be used on the road.

I have just under-gone a re-bore and new piston on my 1979 Suzuki TS185ER, and currently I am using it in much the way I have mentioned. It also has a very similar RPM range to the MZ's and maxes at around 7k. I am not really going above 5k at the minute. Though lets admit it, often the lure of experiencing the higher RPM is quite a misguided venture. There isn't really much there. I can quite happily use my MZ under 4.5K if I wanted. After all, 4k is 50mph (or there abouts). If you're commuting through the city then that's not a problem.

[vicar]

Its all run in now. did a plug chop and its dark brown and a bit woolly at the top end. 118 main jet fitted for running in ,changing back to a 115 jet to let it rev out its got a good quality piston fitted so the top wont fly off at 7000 rpm . I will do an other plug chop with the 115 fitted, its got a foam pod filter and an expansion chamber with a stinger pipe in the end so its guess work for the jetting. Wish me luck I don't like the screech noise when they lock up.

[therealche]

Just remember to keep your finger over the clutch lever. I cant get out of the habit even when riding 4-strokes!