Pulling the head

Z1R rider · May 18th, 2017, 05:44 PM

The '99 was down on power at the track last year compared to the other 250's in our group (6 total) so I pulled the jugs and found huge rust pits in the cylinder walls. (it had been sitting for some time before I bought it) Replaced the pistons and cylinders with the ones from son's blown motor, and it ran much better (best it's idled since I've owned it). This spring was tuning on it and it just didn't seem right compared to the other two I have, still down on power and running a little rough. At this point I did a compression test and it was at 160 lbs. on #2 and 100 on #1, hooked the air to it and the exhaust valves where leaking so much you could feel the air coming out of the muffler and the intakes leaking enough you could hear the air coming out of the carbs. Pulled the head again and had the valves sharpened and seats ground, now it has 180 lbs. on #2 and 170 on #1 and I think it's the strongest running one of the bunch now.

Triple Jim · May 18th, 2017, 06:19 PM

It's amazing what a good piston-cylinder seal can do. Enjoy your "new" engine.

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May 18th, 2017, 05:44 PM	#1
Z1R rider ninjette.org certified postwhore Name: Roger Location: Mitchell, South Dakota Join Date: Apr 2014 Motorcycle(s): 1978 Z1R, 1999 EX250 Posts: A lot. MOTY - 2018, MOTM - Oct '16	Pulling the head The '99 was down on power at the track last year compared to the other 250's in our group (6 total) so I pulled the jugs and found huge rust pits in the cylinder walls. (it had been sitting for some time before I bought it) Replaced the pistons and cylinders with the ones from son's blown motor, and it ran much better (best it's idled since I've owned it). This spring was tuning on it and it just didn't seem right compared to the other two I have, still down on power and running a little rough. At this point I did a compression test and it was at 160 lbs. on #2 and 100 on #1, hooked the air to it and the exhaust valves where leaking so much you could feel the air coming out of the muffler and the intakes leaking enough you could hear the air coming out of the carbs. Pulled the head again and had the valves sharpened and seats ground, now it has 180 lbs. on #2 and 170 on #1 and I think it's the strongest running one of the bunch now. __________________________________________________

May 18th, 2017, 06:19 PM	#2
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	It's amazing what a good piston-cylinder seal can do. Enjoy your "new" engine.