problems with intake valves

dirtyrottenninja · July 23rd, 2011, 02:30 PM

has anyone had problems with only thier 2 intake valves and or rocker arms breaking or jumping out,or cam damage from the rocker arm jumping out after break and spring retainer shooting off? i cant be the only one with a super noisy valvetrain from only the intake valves on cylinder one, is this a problem contributed to from the chain tensioner always whacking cylinder # 1 hard constantly?maybe wearing the rocker arms or bending the valves or?

Alex · August 5th, 2011, 03:33 PM

There haven't been many posts of that type of damage here, are you already noticing strange wear?

greg737 · August 7th, 2011, 05:46 PM

I've seen a number of threads about broken rockers over the last 6 years, both here and on the other EX-250 forum. Usually happens after a valve adjustment but not always. And as far as I remember the failures aren't limited to any particular cylinder or intake vs. exhaust.

Apparently it's not hard to end up either stressing the rocker arms or maybe starting a hairline crack in one or more of them, or simply finishing the adjustment improperly with one valve accidentally set too tight.

Of all the parts in the EX-250's valvetrain the rocker arms are definitely the most delicate. This may be intentional to the engine's design. Usually guys post about their bike being "down on power" or "top speed of only 70 or 80" then after a bit of investigation they find a broken rocker (usually only one).

On the good side there's usually no damage. The flow of engine oil washes the pieces of the broken rocker into a quiet corner of the engine head or down the cam chain valley and into the clutch area.

Although I did see one post were the broken rocker had damaged the cam chain. Here's a link to one of the worst, most damaging rocker arm fails I've seen: http://forums.ninja250.org/viewtopic...27e0a84#808531

Good luck with the bike.

July 23rd, 2011, 02:30 PM	#1
dirtyrottenninja ninjette.org member Name: steve o Location: phoenix Join Date: Jun 2011 Motorcycle(s): ninja 250 Posts: 22	problems with intake valves has anyone had problems with only thier 2 intake valves and or rocker arms breaking or jumping out,or cam damage from the rocker arm jumping out after break and spring retainer shooting off? i cant be the only one with a super noisy valvetrain from only the intake valves on cylinder one, is this a problem contributed to from the chain tensioner always whacking cylinder # 1 hard constantly?maybe wearing the rocker arms or bending the valves or?

August 5th, 2011, 03:33 PM	#2
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	There haven't been many posts of that type of damage here, are you already noticing strange wear? __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

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August 7th, 2011, 05:46 PM	#3
greg737 - Name: - Location: - Join Date: May 2009 Motorcycle(s): - Posts: A lot.	I've seen a number of threads about broken rockers over the last 6 years, both here and on the other EX-250 forum. Usually happens after a valve adjustment but not always. And as far as I remember the failures aren't limited to any particular cylinder or intake vs. exhaust. Apparently it's not hard to end up either stressing the rocker arms or maybe starting a hairline crack in one or more of them, or simply finishing the adjustment improperly with one valve accidentally set too tight. Of all the parts in the EX-250's valvetrain the rocker arms are definitely the most delicate. This may be intentional to the engine's design. Usually guys post about their bike being "down on power" or "top speed of only 70 or 80" then after a bit of investigation they find a broken rocker (usually only one). On the good side there's usually no damage. The flow of engine oil washes the pieces of the broken rocker into a quiet corner of the engine head or down the cam chain valley and into the clutch area. Although I did see one post were the broken rocker had damaged the cam chain. Here's a link to one of the worst, most damaging rocker arm fails I've seen: http://forums.ninja250.org/viewtopic...27e0a84#808531 Good luck with the bike.