How important is running in a new engine properly?

I'm just curious because I know someone who doesn't care and treats a new bike as he would a fully run in bike. I'm talking modern sportsbikes, twins and fours.

i think its important if your going to keep the bike for years and years and clock up 30 - 40k on it, if you only keep the bike a few years then get rid i dont think its that important, running in properly prepares the engine for maximum engine life but who ever keeps a bike for that long?

Originally Posted by kwak zzr

...if you only keep the bike a few years then get rid i dont think its that important ...

Just coz you will be getting shot of it before it causes problems don't mean it doesn't matter ... well that is unless you are a bar steward and don't care about the future owner!!

There are 2 clear schools of thought on this, run it in fast, everything seats properly and quickly, do it slow and the engine is likely to be less powerful and use more oil.

There is plenty of blurb on this nature on the net if you are truly interested

Originally Posted by Blue_SV650S

Just coz you will be getting shot of it before it causes problems don't mean it doesn't matter ... well that is unless you are a bar steward and don't care about the future owner!!

MIGHT cause problems ive had plenty of used bikes and cars and i might add that not many people look after them like i do.

I've seen some of the blurb Blue but it looks like a big advert trying to sell you something at the end of it!

[northwind]

Originally Posted by Blue_SV650S

There are 2 clear schools of thought on this, run it in fast, everything seats properly and quickly, do it slow and the engine is likely to be less powerful and use more oil.

There is plenty of blurb on this nature on the net if you are truly interested

Yup, but how much do we trust it is the question? I know I'd rather have a bike that was broken in hard than too soft, that's the worst option of all. Barrels and rings definately seem to like a fast break in, who knows about the rest? If I ever do my busa piston swap, I'll be getting YPE to run it in on their dyno for me, since the bottom end's nicely run in at 30-odd thousand miles (plus, it was a demonstrator once so it was probably doing wheelies the day after its 500 mile service

Originally Posted by northwind

Yup, but how much do we trust it is the question? I know I'd rather have a bike that was broken in hard than too soft, that's the worst option of all. Barrels and rings definately seem to like a fast break in, who knows about the rest? If I ever do my busa piston swap, I'll be getting YPE to run it in on their dyno for me, since the bottom end's nicely run in at 30-odd thousand miles (plus, it was a demonstrator once so it was probably doing wheelies the day after its 500 mile service

My dad is old skool ... last couple of cars he has bought he has asked about running them in ... they have said 'you don't need to, just drive normally sir'.

Not only is engineering so precise these days and oil so good, to be fair, who can mercilessly 'thrash' a bike for long periods anyway (on the road), things get in the way like villages or tractors!! for it to be on song too long

[northwind]

I just opened up one of the broken engines I had in the garage, some bits of it look like they were machined out with a wood chisel

Originally Posted by northwind

I just opened up one of the broken engines I had in the garage, some bits of it look like they were machine out with a wood chisel

Now I know you love your SVs, but you trying to tell me Jesus makes SV engines?!?!?

I know of a guy who blew up two kawasaki zx6r engines from thrashing it from new

He had to pay for the third engine after he fessed up that he didint run it in as per the book

Matt