100 hours on 450 SXF

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9/28/2018 1:33 AM

I am closing in on 100 hours on my 2016 SXF450 and was thinking on doing a top end in the off season but now after reading 350s doing 180 on first piston I am thinking about postponing it till 150 which would mean another season of riding for me.

Bike runs super, oil changes 6-8 hours, meadium fast rider, 90%mx, 10% wood...

What is your take on the matter?

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9/28/2018 8:55 AM

500+ more to go?

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9/28/2018 9:05 AM

I put a new piston in at 60 hours along with a new cam chain (cheap, so why not?) and a new set of clutch plates. Now I'm at 110 hours with no issues what so ever. I ride A class, and my 17 has been bullet proof.

Throw in a vertex piston. Super easy to do and you'll have peace of mind.

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9/28/2018 10:50 AM

100 hours is pushing it. Regardless of what people say.

If your valves are still sealing and you havent shimmed them, do a piston and timing chain.

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9/28/2018 12:22 PM
Edited Date/Time: 9/28/2018 12:23 PM

Absolutely not more than 100h, unless you ride on like max 5-6k revs. 105h is the longest i ran on SXF 2013 piston and the tuner (mechanic company) i took it to, to measure it, said it was well over time for that piston. He builds a lot of race engines for ktm directly so i do trust him and his skills.

Adding: 70h if you ride much on bottom and mid end. 50h if you like to rev and run higher gearing

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9/28/2018 12:55 PM

kb228 wrote:

100 hours is pushing it. Regardless of what people say.

If your valves are still sealing and you havent shimmed them, do a ...more

This.

I wouldn't go over 80 hours on a piston in a 450. I'd rather spend a few hundred on a piston now vs spending a few thousand for a full rebuild because I decided to push it.

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
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9/29/2018 7:19 AM

I did a top end at 105hours on my 17 450sxf. Everything was in good shape. I think you could wait till 140-150.

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9/29/2018 7:35 AM

70 hours on my 350 brought it in for top end mechanic did leak down and said don’t bother valves etc were in great shape. If you trust your mechanic bring it in and have them do a leak down

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9/29/2018 3:02 PM

opyguy wrote:

70 hours on my 350 brought it in for top end mechanic did leak down and said don’t bother valves etc were in great shape. If ...more

I’d go this route. Bring it to a place you trust so they don’t upsell you.

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9/30/2018 6:54 PM

kb228 wrote:

100 hours is pushing it. Regardless of what people say.

If your valves are still sealing and you havent shimmed them, do a ...more

mattyhamz2 wrote:

This.

I wouldn't go over 80 hours on a piston in a 450. I'd rather spend a few hundred on a piston now vs spending a few ...more

I’d put a new piston and cam chain in for sure. Sounds like you take good care of your bike, and this regular maintenance should ensure many more hours of riding without wondering if you have stretched to far.

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9/30/2018 9:40 PM

430hrs in my 16 350xcf, haven't touched a single thing... Just finished a 3+hr cross-country racing AA and came in 2nd, bike never missed a beat...

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9/30/2018 9:48 PM

Monk wrote:

430hrs in my 16 350xcf, haven't touched a single thing... Just finished a 3+hr cross-country racing AA and came in 2nd, bike ...more

That's impressive!

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10/1/2018 7:03 AM

Monk wrote:

430hrs in my 16 350xcf, haven't touched a single thing... Just finished a 3+hr cross-country racing AA and came in 2nd, bike ...more

But why? Throwing a new piston and cam chain every 100 hours would be well worth it and easy. Why chance a catastrophe, and give up performance of a fresh top end? I hope you changed your clutch plates a few times!

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10/1/2018 7:15 AM

Monk wrote:

430hrs in my 16 350xcf, haven't touched a single thing... Just finished a 3+hr cross-country racing AA and came in 2nd, bike ...more

Hudd_421 wrote:

But why? Throwing a new piston and cam chain every 100 hours would be well worth it and easy. Why chance a catastrophe, and ...more

I have no justification to why or why not. Best answers being A.) It runs near perfect as is B.) Its a good test of durability, and C.) Its not someone else's bike, it's mine. As long as it works I see no reason why.

I've run a fan since day 1, run fresh 15/40 Rotella, keep a dozen clean air filters around and always use good fuel.

No, stock plates. I do run a Rekluse and I have never been a clutch abuser...

The only thing I have invested a large amount of time and money is the suspension...

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10/2/2018 3:29 PM

Had a 2006 Yz450f that had over 300 hrs. Never touched the motor other than oil and filter changes every other ride. Air filter every ride. Still ran fine when I sold it.


That being said, I'm older and wiser now and will be changing my piston and cam chain on my new bike at 50 hrs. I don't want to risk a grenade.

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2018 CRF250R

10/20/2018 9:51 PM
Edited Date/Time: 10/20/2018 9:51 PM

If you don't have any signs of excessive wear on the piston and ring end gap is in great spec, I would just clean up the carbon and leave it alone. As far as top end, check valve clearance.

If all the above looks good, I'd say just throw in a fresh cam chain and maybe fresh rings, and continue on.

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A wise man once said nothing

10/21/2018 6:58 AM

I have a 16.5 450sxfe...with 92hrs. Top end at 70hrs, valves in spec. Piston looked great. Bike runs like new. I have been trying to sell it, everyone is afraid of a used 4t with 100 hrs....I may just keep it...

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