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ButcherBoy
Roostin Away
Joined: 03 Mar 2010
Posts: 652
Location: Toronto, NSW
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 Posted: Thu Jan 27, 2011 6:40 pm Post subject: What's Happened To My R? |
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This happend Australia Day, thought it was running lean, got to the car park and lost compression. got a tow back to the car park from Shawn
thought I'd try my luck this arvo and test it i just got piston grab but sadly not. What's everyones thoughts and ideas on WTF happened.
Cheers, ButcherBoy
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Yamaha '07 Raptor 700r SE
Honda 1989 TRX 250r
Honda 1985 "70" 125cc
Honda 2012 "70" 200x |
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250Rtony
4fiddy Racer
Joined: 25 Apr 2007
Posts: 200
Location: wherever there is a 250r
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| Posted: Thu Jan 27, 2011 7:14 pm Post subject: |
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too lean
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'86 250R ATC
'07 Pro Shark 90cc RED
'07 Pro shark 90cc BLUE
74 atc 70
84 ytm 200 |
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greenhuman
Roostin Away
Joined: 12 Feb 2006
Posts: 980
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| Posted: Thu Jan 27, 2011 8:08 pm Post subject: |
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Way too lean.
Not timing. It would have a hole or eating in the piston crown.
Not bore clearance. It would grab all the way around the piston.
Maybe blame climate change if you're a tree hugging hippie SOB. |
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Shawn
Blaster class
Joined: 16 Aug 2008
Posts: 175
Location: Central Coast
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| Posted: Thu Jan 27, 2011 8:42 pm Post subject: |
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Looks like the piston grabbed right where the gasket was leaking.
Don't worry about trying to figure out, just get a rebore, piston, rings.
Whats the big end bearing like?
Bet your glad I didn't take you up on that bet earlier? My guess would have been siezed rings earlier.
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Raptor 700R 09' |
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Mart 300r
Roostin Away
Joined: 02 Jun 2008
Posts: 944
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| Posted: Thu Jan 27, 2011 8:42 pm Post subject: |
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lean as i still reckon that head gasket was leakin.
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE |
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HaggLE
Roostin Away
Joined: 16 Mar 2009
Posts: 511
Location: Newcastle
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| Posted: Thu Jan 27, 2011 8:48 pm Post subject: |
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Something isnt right about that head gasket, looks like its overhanging into the bore...
You can see it in the photo from the bottom and from the top its all burred.
You can also see oil on top of the fins around the head gasket area indicating it was leaking. A leaking head gasket would create lean city.
Normally when you have a lean carby blow-up its stuffed on the exhaust port side (the hot side), this is mostly stuffed around the left transfer where that head gasket was inside the bore. |
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ForeverThreeWheels
The Day Starts With OZATV !
Joined: 18 Nov 2008
Posts: 1742
Location: Maitland
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| Posted: Fri Jan 28, 2011 9:14 am Post subject: |
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Defiantely lean. Did you rejet it when you swapped carbys?
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HaggLE
Roostin Away
Joined: 16 Mar 2009
Posts: 511
Location: Newcastle
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| Posted: Fri Jan 28, 2011 12:31 pm Post subject: |
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| Wasn't the carby, it was far too rich. We had to have the idle mixture screw as lean as possible to make it idle and it wouldnt rev out it was so rich. Head gasket leaking would change it all and the reed/inlet boot was leaking too. |
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bullet
The Day Starts With OZATV !
Joined: 09 Sep 2006
Posts: 1518
Location: Middleton SA
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| Posted: Fri Jan 28, 2011 1:23 pm Post subject: |
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It looks to me like most of the siezing was to the top of the cylinder and that there is not a lot of destruction around the exhaust port compared to a general overheat or 'too hot' engine situation.
It looks like it has occured quite quickly.
So i'm going with a 'too lean' spike as well.
It might only be a top end, or main jet issue.
The fact that you have the low speed mixture adjustments set very rich and can't adjust them any leaner will make little or no difference in a top end lean out situation.
Maybe the main is to small and the low speed is too big.
But i'm thinking the problem would be towards the point of the needle (around 3/4 throttle or more), and probably main jet.
An oversized air correction jet can cause this top end lean out too.
or i'm completely wrong 
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Can-Am X Team
Bullet #Y12. MrsB #Y18. |
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Martin
Blaster class
Joined: 21 Jul 2008
Posts: 119
Location: Kempsey, NSW
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| Posted: Fri Jan 28, 2011 2:35 pm Post subject: |
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Too much 'ping-ping', and not enough 'ting-ting'. That sux mate, nothing worse......
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The older you get, the more it hurts..... |
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Mart 300r
Roostin Away
Joined: 02 Jun 2008
Posts: 944
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| Posted: Fri Jan 28, 2011 3:06 pm Post subject: |
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how long did yas have it runnin for up an down the street when yas were jettin it?.Because of the longer run time (gettin warm and expanding)and hot day id say the head started leaking (That gasket looks fair old lol)and if the carb boot was leakin like haggle said that also is helpin to the lean condition.Altough like said above i would say the pilot jet had nothin to do with this.deffinately the needle being dropped and leaking air.And prob the 40 degree day didnt help lol.Shell be right mate knowing you youve already ordered the next oversize and dropped the barrel off to be bored lol.Nothin to worry about almost all 2 stroke owners have at some stage felt this pain 
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE |
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HaggLE
Roostin Away
Joined: 16 Mar 2009
Posts: 511
Location: Newcastle
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| Posted: Fri Jan 28, 2011 5:55 pm Post subject: |
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Probably went up the street 4 times...
We had the thing free revving for 15 mins or so and you couldnt rev the thing wide open, would just bog down it was so rich.
Im thinking that it was probably a bit lean 1/4 to 3/4 throttle which is what leigh would have been doing going back to the carpark. Add that and the fact the head gasket was leaking and the inlet boot was leaking, it had little chance for survival.
The good news is that butcherboy knows when the 2 smoker is crying for help now, he knows when it is talking to him. Its all experience. Gotta remember he has only been at this trike thing since march 2010 and excluding his Victa, he has only been at this 2 stroke thing since May... |
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atcmatt
4fiddy Racer
Joined: 26 Dec 2008
Posts: 207
Location: Sydney
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| Posted: Fri Jan 28, 2011 7:34 pm Post subject: |
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hows the big end? my piston looked like that when my big end went and spat shavings all up into the barrel.
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1985 250es
1978 atc70 |
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