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Discussion Starter #1 (Edited)
My Duke 390 currently has only 300 miles from new.
The first 130 miles were partially motorway/freeway (constant speed) as l had to ride it home from the dealer.
Not ideal, but it wasn’t safe to go much slower than the maximum running in speed of around 60mph
As soon as possible l left the motorway and travelled across country so was able to vary the engine speed and loading.
After that l have done a further 170 miles of varied riding.
However l need to make another motorway trip of 200 miles....will this harm the engine? I can’t really vary the speed much as 55-60mph is pretty slow to be riding on this type of road. I could possibly vary it from 50-70mph and ignore the 6,000 rpm limit.
The bike has not yet had the first service/inspection

Or l could go in the car! But it’s forecast really nice weather so it would be a shame to do that.
 

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My Duke 390 currently has only 300 miles from new.
The first 130 miles were partially motorway/freeway (constant speed) as l had to ride it home from the dealer.
Not ideal, but it wasn’t safe to go much slower than the maximum running in speed of around 60mph
As soon as possible l left the motorway and travelled across country so was able to vary the engine speed and loading.
After that l have done a further 170 miles of varied riding.
However l need to make another motorway trip of 200 miles....will this harm the engine? I can’t really vary the speed much as 55-60mph is pretty slow to be riding on this type of road. I could possibly vary it from 50-70mph and ignore the 6,000 rpm limit.
The bike has not yet had the first service/inspection

Or l could go in the car! But it’s forecast really nice weather so it would be a shame to do that.
It's 6000rpm now?

It was 7,500 for my 2017....
 

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Discussion Starter #3
The shift light comes on at 6,500 so l assume they don’t want you to exceed that figure.
I am more bothered about doing 200 miles at a constant speed as l’ve read it not the best way to break in the engine.
 

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The shift light comes on at 6,500 so l assume they don’t want you to exceed that figure.
I am more bothered about doing 200 miles at a constant speed as l’ve read it not the best way to break in the engine.
I suppose you could get off at an exit every now and then and get back on to run out through the gears or something similar....
 

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Lightning, you are right to be concerned.
Leave early and take the back roads or if you must take the highway, take your car.
This is too important of a time to put 400 kms on the wrong way.

I noticed break-in produced increasing power and fuel mileage well over 3000 kms.
I'd suggest using a fair amount of throttle (3/4?) for short time periods, revs under 6500, varied speeds.
 

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Always gets a smile when I take a running in bike back to dealership after they see my throttle . Something I was taught many years ago , using tippex or similar mark on twistgrip 1/4 1/2 3/4 throttle opening forget rev counter . First 250 miles 1/4 throttle max next 250 1/2 throttle up to 750 miles 3/4 throttle this has worked exceptionally well for me for the past 50 years . Modern bikes probably don't need such gentle running in .
 

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Discussion Starter #9
Thanks for all the advice. I will look to see if there’s a cross country route, avoiding motorways, that won’t take too long. I’m happy to detour for some good riding!
 

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Thanks for all the advice. I will look to see if there’s a cross country route, avoiding motorways, that won’t take too long. I’m happy to detour for some good riding!
I like your style Lightening!
"I bought this thing to ride and darn it, I'M GONNA RIDE!

Some guys sit at home polishing it, I'm out riding the heck out of it. I ain't just talking about bikes either! :)
 

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Discussion Starter #11
Modern bikes probably don't need such gentle running in .
Quite right.

There are engine builders who think driving the bike like you stole it works best for break in.
I think it can in the short term make for more power.
But in the longer term the engine will die sooner.
Probably long after you have sold the bike.
 

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I think it can in the short term make for more power.
But in the longer term the engine will die sooner.
Probably long after you have sold the bike.
Yamaha RS125DX I had back in the 80's was over 30000 miles without any major repairs needed to engine only had one new set of points in that time . It was still going strong three owners later . It was not babied run flat out for miles on the motorway it held an indicated 90 mph , timed it managed a 70 mph average round the TT circuit on open roads . >:D . Just saying careful appropriate running in has always paid off for me .0:)
 

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Yamaha RS125DX I had back in the 80's was over 30000 miles without any major repairs needed to engine only had one new set of points in that time . It was still going strong three owners later . It was not babied run flat out for miles on the motorway it held an indicated 90 mph , timed it managed a 70 mph average round the TT circuit on open roads . >:D . Just saying careful appropriate running in has always paid off for me .0:)
I still have a 2000 KTM 125 EXC. It was bought for harescramble racing and I bought it after a season. I made it street legal and road it 7 years without a problem, at speeds up to 70mph but generally at 50-60mph. It would have lasted longer than 7 years on the original piston and rings, but I dumped it in a river, and still managed to ride home in spite breaking a ring! With no compression it would start on a push and run me home!

Still have the 2000 KTM. Drowned it a couple more times in muddy water. Eventually I had to replate the cylinder and my crank started getting noisy so rebuilt it. I still ride it, still street legal. Love it.

https://www.ktmduke390forum.com/forum/attachment.php?attachmentid=49043&thumb=1

Your RS125DX was iron cylinder wasn't it? Keeping good oil to them was everything. Did you rely on the injection pump? Good working pump and good oil meant long life in those engines. Dang! Ain't a two stroke fun in the twisties?
 

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Quite right.

There are engine builders who think driving the bike like you stole it works best for break in.
I know of zero engine builders who think this. There are engine builders who suggest this is a good way to break in new rings in an already broken in motor - especially in a race engine where you need it to quickly be competitive again. No one can reasonably argue that this is a good way to break in bearings.
 

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I know of zero engine builders who think this. There are engine builders who suggest this is a good way to break in new rings in an already broken in motor - especially in a race engine where you need it to quickly be competitive again. No one can reasonably argue that this is a good way to break in bearings.
I'm not sure which bearings you're referring to specifically but here is no break in period for bearings. That's why bearing clearances are measured before hand...so they ride on a film of oil.

And engines coming out of a production facility are run up to redline before they leave the factory...
 

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And engines coming out of a production facility are run up to redline before they leave the factory...

Triumph used to do that back in the day. But before they added the oil. It was no surprise everyone switched over to Japanese bikes whose long term reliability was considerably better.

Blipping an engine to redline once is not the same as doing it for extended periods. It works for race builds on small engines since they may be rebuilt before they even reach run in mileage.
 

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I'm not sure which bearings you're referring to specifically but here is no break in period for bearings. That's why bearing clearances are measured before hand...so they ride on a film of oil.

And engines coming out of a production facility are run up to redline before they leave the factory...
To your second point, do they do that under load, or is your comment not related to the topic?

To your first point, others disagree.

"There are two important considerations to breaking in a new streetbike. One is that all the various bearings and other internals with mating surfaces need sufficient low-load and low-rpm running time to bed in. High spots on bearing surfaces and other machining imperfections can cause increased friction and excess heat until this happens, so some period of light duty is required."

https://www.cycleworld.com/sport-rider/break-in-procedure
 
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