[Aufitt]

LOl @ 'scrub the chain' not too sure I even want to ask what that involved.

 

[Aufitt]

Too high a gear on a single will cause chain chatter, or poor rear wheel alignment or a dry chain.. but we're a bit off topic, the OP is talking about an 'engine rattle'
i'd let the Honda dealer sort it.. they are ones that carry the 2 yr waarranty.

 

[Aufitt]

Was going to ask.. are you guys sure its not just a usual 4 stroke single 'pulsing' feel?

Like on an XR or a TTR when its labouring in the fat part of the powerband?.. or like an engine running low octane fuel etc?

Happy to be corrected by anyone with lots of single cylinder experience.

 

[Aufitt]

Does it do it just free revving it to 6,000rpm?

or just under load.. if under load.. put 20,000k's on it and cane the ring out of it.. Its a Honda.

 

[Aufitt]

Mate, do yourself a favour. Ask your dealers about it before you buy. Say that reports are that around half the bikes suffer from this noise, and that it is putting you off buying it until Honda rectify the issue.

http://www.cbr250.net/forum/honda-cbr250-general-discussion/1110-people-about-buy-cbr250r.html

My personal belief is that it is something connected to engine, not inside the engine.

Since 'Half the bikes suffer it' It isnt detering me one bit.. Ive owned dozens of singles and at one speed the mirrors are always unusable
Nature of the beast.
Hell all my racebikes ran like swiss watches when I sold em after 2 yrs of enduro racing but when new they sounded like every mechanical noise under the sun.

As for your exhaust transferring vibrations..
fit all bolts (with never seize)...
then tighten it at the header to the head..
start the bike..
then tighten the clamp at the muffler.. then tighten the muffler clamp.
new systems always have some misalignment. even stock.

disclaimer- I'm not dismissing that YOUR bike may have a problem
go to a diff Honda dealer for a 2nd opinion.

 

[Aufitt]

If it was an issue.. cbr250's would be dropping like flies around the world.

ya not a Kawasaki marketing agent as a day job are ya? lol

JOKING!

 

[Aufitt]

Why not just keep the stock header and put a slip on on to save weight and look better? was there a problem or havnt you tried that?

 

[Aufitt]

It is a single cylinder, just ride it.. it has character.