How many hours until a 450 rebuild

Greenguy
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Greenguy
I know there are some variables, but what is the normal number of hours for a topend on a '16 KX450?
Always having a clean air filter and fresh oil.
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mxb2
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mxb2 9/1/2016 12:28pm
9/1/2016 12:28pm
What did the manual, service manual say?
MXD
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MXD 9/1/2016 1:41pm
9/1/2016 1:41pm
mxb2 wrote:
What did the manual, service manual say?
The 16 KX450 manual says 15 hours for a top end and the same for oil changes. They lost me with that one.
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MxKing809
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MxKing809 9/1/2016 1:51pm
9/1/2016 1:51pm
I would think 20-30 all day. My brother just got his pro card and pushed his 2016 YZ450 to 40 hrs before his first top end, but I won't be waiting that long on mine.
mxb2
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mxb2 9/1/2016 1:56pm
9/1/2016 1:56pm
MxKing809 wrote:
I would think 20-30 all day. My brother just got his pro card and pushed his 2016 YZ450 to 40 hrs before his first top end...
I would think 20-30 all day. My brother just got his pro card and pushed his 2016 YZ450 to 40 hrs before his first top end, but I won't be waiting that long on mine.
X2, always better safe than sorry. Imo.

The Shop

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mxtech1
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mxtech1 9/1/2016 2:17pm
9/1/2016 2:17pm
Evidently the Kawasaki engineers who developed and designed the bike are wrong so here's what I would do...

I would ring it and fresh gaskets at 15 hours and then a complete top-end before 40 hours.
racinstation 9/1/2016 3:07pm
9/1/2016 3:07pm
I would say if you are doing moto, rebuild the top end at 40 hours. If you are doing trail, weekend warrior type riding you should be able to go 50 or 60.

I would adjust/check valves every 15 hours and do a leak down test at 30 hours just to be safe. On a 4 stroke, the leak down will tell you everything you need to know.

r.sal923
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r.sal923 9/1/2016 8:12pm
9/1/2016 8:12pm
I was just informed by my buddy that his 350xcfw has 390 hrs on it. And it is still running. He uses it 90% off road and 10% street
mark1960
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mark1960 9/1/2016 10:08pm
9/1/2016 10:08pm
I had a 450 yamaha, i know not a Kawi.
Fast novice vet MX if you like.
Air filter ever ride, oil and filter every other.
70 hours and i put rings in it and checked valves, sold it after 100+ hours and it was still running like a champ.
Surely the KX must be similar?
DC323
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DC323 9/2/2016 6:59am
9/2/2016 6:59am
A well maintained 450 ridden by a fast motocross guy will easily go 60 hours on a topend (piston,rings, timing chain). This is as long as you're not doing stupid shit like bouncing off the Rev limiter in the air.

For your average joe/trail rider I would push it to 80-100 hours. The key is frequent oil changes and a clean air filter.

EEE299
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EEE299 9/2/2016 10:05am
9/2/2016 10:05am Edited Date/Time 9/2/2016 10:06am
DC323 wrote:
A well maintained 450 ridden by a fast motocross guy will easily go 60 hours on a topend (piston,rings, timing chain). This is as long as...
A well maintained 450 ridden by a fast motocross guy will easily go 60 hours on a topend (piston,rings, timing chain). This is as long as you're not doing stupid shit like bouncing off the Rev limiter in the air.

For your average joe/trail rider I would push it to 80-100 hours. The key is frequent oil changes and a clean air filter.

Agreed, I have a (slow) buddy with 150 hours on a 2010 yz450f. Hasn't touched the top end yet.

I wouldn't suggest this obviously... but freakin 15 hours? really?
mx621
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mx621 9/2/2016 3:27pm
9/2/2016 3:27pm
Middle of the road B rider. I ride in the meat of the power, almost never on limiter. Oil changes (rotella t) every 3-4 hours, air filters almost every ride. My crf450 has 60 hrs on it. Haven't touched it. I may tear it down this winter.
staz51
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staz51 9/4/2016 12:30am
9/4/2016 12:30am
2014 Ktm 450 EXC with 285 hours, air filter done every ride and oil dropped every 5 hours.
She was still going strong when i did the top end at 285!
mingham97
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mingham97 9/4/2016 2:21am
9/4/2016 2:21am
I guess doing a top end every 15 hours might be a security thing and makes you trust your gear, but I think that is extreme. 100 hours top and bottom. It's a 450...250f is different, it was rebuilt at 75 hours by the previous owner who was quite quick and pushed the bike.

I feel like the guys doing extremely premature maintenance do it to tell everyone "ahh yeaah i gotta do a piston on my 450 every 15 hours" to give a fast or factory impression.. thats just me though
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adam8781
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adam8781 9/4/2016 1:19pm
9/4/2016 1:19pm
100 hours on the top, if i owned the bike from new and it never missed a service 200 hours on a crank is more than doable
Porter122
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Porter122 9/4/2016 3:31pm
9/4/2016 3:31pm
Believe it or not, The kx 450 top end is damn bulletproof. the 12-13 were the worst years for the Piston itself. they were different but still failed on occasions. I myself have put over 300+ hours on multiple Kx 450s. and from personal Experience being a "Pro" or a "A" rider on moto only, i run stock OEM Kawasaki pistons for about 40-45 hours. Can you stretch to 55-60? Yeah.. is it worth it? If your on a budget or trail riding then yeah i mean you can. But Change your oil every 2 rides with a oil filter every other change. I only use the best Twin Air filters with Bel-Ray filter oil!

Good Luck!
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lumpy790
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lumpy790 9/5/2016 7:11am
9/5/2016 7:11am
To cut weight on the piston every modern race 4 stroke has a piston with a tiny skirt. The smaller skirt can not withstand the hours and the skirt starts crushing in untill it snaps and causes major damage.

My KTM 450 manual has 40 hours for the top end.
lumpy790
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lumpy790 9/5/2016 7:14am
9/5/2016 7:14am
mxtech1 wrote:
Evidently the Kawasaki engineers who developed and designed the bike are wrong so here's what I would do... I would ring it and fresh gaskets at...
Evidently the Kawasaki engineers who developed and designed the bike are wrong so here's what I would do...

I would ring it and fresh gaskets at 15 hours and then a complete top-end before 40 hours.
This was true on 2 strokes but there is Really no reason to ever just do rings on a modern 4 stroke.
aees
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aees 9/7/2016 4:37am
9/7/2016 4:37am
I was told that the pistons in 2016-2017 Kawi is of shit quality (they break, split a part), and first piston should be changed at no more then 20h. Then install a 3rd part piston and you are good to go.

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TSCHAM101
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TSCHAM101 9/7/2016 6:38am
9/7/2016 6:38am
I did my top end on my 16 kx450 at about 35 hours.. i did mine because i noticed it wasnt pulling as hard up top.. the only thing you need to worry about on the piston is the pin.. typically the piston digs into the pin for whatever reason.
dionpaid
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dionpaid 8/13/2024 12:44am
8/13/2024 12:44am

I have a buddy with 500+ hours on a YZ 450 i’ll take a picture next time I see his hour meter

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stimacr
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stimacr 8/13/2024 8:29am
8/13/2024 8:29am

22 ktm 450xc-f raced at local hare series so about 8-10 events mostly desert riding fast whoops and sand tracks. Oil change with belray every 10hrs, filter typically every other ride unless it was super dusty or I was eating a ton of sand. I also drowned it once as well. Replaced my piston at about 220 hours and it fine. Jug still seemed to be in spec. Adjusted valves at the same time only 1 of the exhaust valves were out of spec. 

Currently at 305 hours with 2 hare and hound races and one night of AX. Still running good. I will replace piston in another 20-30hrs depending on how the jug looks it will most likely get sent in for a replate. 

I know some guys with ktm 450s as timbersleds with like 500hrs still running well. I cant believe some of these bike need a new piston in 20 hrs, I feel like I am just getting to know how to ride the bike at that point.  

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526
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526 8/14/2024 7:45am
8/14/2024 7:45am
mxtech1 wrote:
Evidently the Kawasaki engineers who developed and designed the bike are wrong so here's what I would do... I would ring it and fresh gaskets at...
Evidently the Kawasaki engineers who developed and designed the bike are wrong so here's what I would do...

I would ring it and fresh gaskets at 15 hours and then a complete top-end before 40 hours.

15hours the rings are wore on out Nikasil cylinder? I would never buy a green bike again. 

You should leak down test it that will tell everyhting you need to know. 

 

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