Engine rebuild time..

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cornishwrecker220
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Engine rebuild time..

Post by cornishwrecker220 »

Well my trusty 220 is now in need of an engine rebuild...the main bearings have been slowly getting louder & louder as the months have passed. My bike is a 2003 model which I have owned for the past 4 years & up until recently ( 6000 miles ) the only part I replaced was the piston, which I will add when I took out the old one it still looked in excellent shape with no scoreing at all ! ..the bike has now clocked up 7500 miles & all on its original bottom end, it gets ridden atleast once a week or a few times per month..i recently did a 3 day guided ride with no problems what so ever ( the mains sounded rough but the bike still performed perfectly ) I rode today with a few friends & had a blast as usuall...don't want to tempt fate so I think I should park the old girl & save for the rebuild which she deserves...thinking of having some head work & transfer porting done while its apart...so 7500 miles on an original bottom end is very good going....just goes to show how strong these bikes really are....try that on a ktm!! :grin:
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diymirage
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Re: Engine rebuild time..

Post by diymirage »

and that still leaves 6 years and how knows how many miles out of the equation from the previous owners
newbbewb wrote:DIYmirage has it right.


-1996 KDX 200 woods weapon (converted to 99 green body)
-1996 KDX 200 plated street toy (barney edition)
-2003 Yamaha TTR125-L (wifeys bike)
-1997 KDX 220 project bike
cornishwrecker220
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Engine rebuild time..

Post by cornishwrecker220 »

I was lucky to have purchased the bike from my friend who used to ride with me, he was a novice rider & asked me to keep an eye out for something `friendly` so when I saw the kdx advertised at a local bike shop I told him about it & he went bought it..he owned it for 3 years but being a family man with commitments he seldom rode the bike that often & when he did it was with me...I always said that if he were to ever sell it then I would like the first offer, then in 2009 his wife had another child so the kdx was offered to me..i snapped it up & in time fitted lots of aftermarket parts ( the bike was all standard when I first had it ) ..the bike has had 3 previous owners but judging by the condition of the bike when I first sourced it for my friend, I would say that it had very very little use , it has the original small speedometer fitted which read less than 900 miles..the lower frame rails were like new with no stone marks at all, even the front exhaust pipe was unmarked.. we think the previous owners used the bike on the road more than off. Given its earlier lack of use, or even the time where I never rode or even started it for 12 months due to a back injury, then completely drowning it in a fresh water river after falling off during my comeback ( removed spark plug, turned bike upside down got all the water out, drained carb, squeezed out air filter cleaned plug fired up 3rd kick then rode 35miles home!!..& yes I`m still running the original main bearings & bottom end today!! I recon if the mains weren't bad then I think it would be atleast 10,000 miles before it would be rebuild time, who knows maybe more!...they sure don't make em like they used to :supz:
gwynfryn
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Re: Engine rebuild time..

Post by gwynfryn »

The main bearings on my car have done 500 000km.
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Julien D
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Re: Engine rebuild time..

Post by Julien D »

gwynfryn wrote:The main bearings on my car have done 500 000km.
Unless your car is a single cylinder 2 stroke turning over 10k RPM, this is not really relevant.
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sarrant
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Engine rebuild time..

Post by sarrant »

Julien D wrote:
Unless your car is a single cylinder 2 stroke turning over 10k RPM, this is not really relevant.
Yeah, not even remotely similar. The main bearings in a car aren't ball bearings like a KDX, they're journal bearings with a bath of oil pumped and pressurized directly through their contact surface. In theory, if they were kept properly lubricated, with no contaminants, they could last essentially forever since the metal surfaces, separated by an oil film, never truly touch.

When you start to do the math It's crazy how little lubrication a 2-stroke actually receives. At any given time, there is but a few drops of oil in the whole engine.
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Julien D
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Re: Engine rebuild time..

Post by Julien D »

Don't know about that. A properly jetted 2t running sufficent mix or oil injection, should have at least 1/8th inch of residual oil hanging aroung in the crankcase. Its certainly nothing like a 4t with its oil pumping system though, for sure.

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