2017 kxf450 Top end rebuild

JTH92
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JTH92
Edited Date/Time 4/15/2019 9:50am
Just about to throw a piston in, went for a JE Piston, out of interest are the stock OEM pistons cast or forged?

Also, does anyone have a torque spec sheet for a top end on the 2017 kxf450? I know there's one pinned to the forum but wondering if they've changed?

Thanks
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Titan777
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Titan777 4/12/2019 11:01am
4/12/2019 11:01am
Is there a torque spec sheet for the 250 as well? (2018, top end).
kb228
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kb228 4/12/2019 4:19pm
4/12/2019 4:19pm
The 18 and older kx450 motors are the same for the most part.
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Titan777
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Titan777 4/13/2019 7:39am
4/13/2019 7:39am
kb228 wrote:
The 18 and older kx450 motors are the same for the most part.
Can you upload the torque specs for the 18' 250 ?
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JTH92
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JTH92 4/13/2019 11:42am
4/13/2019 11:42am Edited Date/Time 4/13/2019 11:43am
All I need is cylinder head torque (44ft.lb on older models) and 87inch lbs on the cam caps earlier models also, just wondering if they'd changed on the 2017 kxf450?

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JTH92
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JTH92 4/15/2019 2:44am
4/15/2019 2:44am
JBecker 72 wrote:
From the 16-18 KX450F service manual [img]https://i.postimg.cc/Kv01b1kw/B4769-D78-BD00-4-C07-9-D0-B-5-D2122-CF7543.jpg[/img] [img]https://i.postimg.cc/DfBvJtvb/C78-BF08-E-82-A6-4-B62-A05-B-B1454-A4-CF9-CE.jpg[/img]
From the 16-18 KX450F service manual



Thanks a lot mate really appreciate it!! Doing the top end as I type and checked one last time lol ?? what you guys think?

JBecker 72
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JBecker 72 4/15/2019 4:34am
4/15/2019 4:34am Edited Date/Time 4/15/2019 5:05am
No problem! Doesn’t look bad at all. How many hours on the bike?
JTH92
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JTH92 4/15/2019 9:16am
4/15/2019 9:16am
The guy I got it off said it's done about 10 hours when I got it, so I'll assume 20/25 is more accurate, and Ive done around 50 so in the 70-75 hour mark would be my guess, that's a stock cast OEM piston, the JE piston I've thrown in will probably be more durable as it's forged, valve gaps etc all checked out perfect ?
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JBecker 72
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JBecker 72 4/15/2019 9:50am
4/15/2019 9:50am
Nice. I bought my 16 new in 2017, just broke 50 hours last weekend. Probably going to run it to about the 75 hour mark and do the same JE forged piston. My intake valves were a hair tight new, I adjusted them and they haven’t moved since. Gonna do a cam chain then also for peace of mind.

Pretty happy with how mine has held up. Still starts very easy and has plenty of snap. Only repair so far was a leaky water pump impeller seal at 48 hours. Used an Athena kit for that as Kawi wants a fortune for the inner clutch cover gasket. Sucker loves to eat chains and rear tires though.
JTH92
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JTH92 4/15/2019 10:22am
4/15/2019 10:22am
JE piston is much nicer, my valve gaps measured 0.004" on both intakes and 0.008" on both exhausts which is in spec, so far the bikes been super reliable, allways started 2nd kick, although I was starting to notice a very small puff of white smoke every now and again but wasn't noticing any oil loss/ contamination of any kind and doesn't look like it was burning oil, hopefully the top end rebuild will sort that, the top ring was starting to look a tad manky and defo needed changing



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JTH92
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JTH92 4/15/2019 10:34am
4/15/2019 10:34am
Yeah a couple of very minor scuffs, which pretty much dissapeared after a quick hone with the honeing brush

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