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what could cause this???
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t3rmin
Regular should be fine unless it pings. For whatever reason my 750 pings on regular in weather above 70 deg F, so I put plus in it and no more pingey. Probably carbon buildup or something. Ultimate ping test is going up a hill in a fairly high gear at low RPM. Peg the throttle and listen.
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Calvin Blackmore
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NATEO
Originally posted by Calvin Blackmore View Post
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I still stand by the molten lava. (Not too close though) :-D1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
1985 GS1150ES stock with 85 Red E bodywork.
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Originally posted by chef1366 View PostI still stand by the molten lava. (Not too close though) :-D:) The road to hell is paved with good intentions......................................
GS 850GN JE 894 10.5-1 pistons, Barnett Clutch, C-W 4-1, B-B MPD Ignition, Progressive suspension, Sport Demons. Sold
GS 850GT JE 1023 11-1 pistons. Sold
GS1150ES3 stock, V&H 4-1. Sold
GS1100GD, future resto project. Sold
http://i155.photobucket.com/albums/s...s/P1000001.jpg
http://i155.photobucket.com/albums/s...s/P1000581.jpg
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Forum LongTimerCharter Member
GSResource Superstar
Past Site Supporter- May 2002
- 17921
- The only Henniker on earth
Originally posted by NATEO View Postwhat is the recommended grad of gas for these bikes? last summer I was using premium, but I read over the winter that I dont need to, that regular is fine for the older engines...Currently bikeless
'81 GS 1100EX - "Peace, by superior fire power."
'06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."
I ride, therefore I am.... constantly buying new tires.
"Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt
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How long did you run the bike before you started having problems? That sure looks like an oil issue to me. I'd suggest pulling the rod on that hole and have a look. Can you get a picture of the cylinder that the piston came from? As it is the exhaust side (most heat), check out the valve(s) as well. Quick and easy is nice, but with that much debris I wouldn't be able to put that thing back together without a complete teardown and sleep at night. Hey....02 cents.
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Originally posted by focus frenzy View Postthe remaining piston crown is black, a lean condition would lieve the crown a light grey to white, also lean conditions will normaly melt a hole in the thinest point in a piston and with GS's that is dead center.
detonation is the spontanious uncontroled ignition of the AF mixture and is commonly caused by several factors, wrong grade of gas, excessive combustion chamber temperature, carbon build up, fault or defect in piston allowing a hot spot to form, incorrect timing advance.
if you gouged the piston while scraping it with a screw driver (bad idea) that could have givin it a place to form a hot spot, combine that with running hard and poof toasted piston.
a coworker of mine has a PWC and melted a piston in a similar but not nearly as severe fashion and his crown was a very light grey pointing to a existing lean condition I had warned him about (he had been complaining about stumbling and a surge) your piston crown looks black from that picture.
Check out the posted link by Calvin Blackmore for confimation of the cause of this piston failure. It also has some good info on piston suitability for vaious states of engine tune.:) The road to hell is paved with good intentions......................................
GS 850GN JE 894 10.5-1 pistons, Barnett Clutch, C-W 4-1, B-B MPD Ignition, Progressive suspension, Sport Demons. Sold
GS 850GT JE 1023 11-1 pistons. Sold
GS1150ES3 stock, V&H 4-1. Sold
GS1100GD, future resto project. Sold
http://i155.photobucket.com/albums/s...s/P1000001.jpg
http://i155.photobucket.com/albums/s...s/P1000581.jpg
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NATEO
Originally posted by Dave8338 View PostIt is hard to tell, however, it looks as if the rings were all put on with the ends lined up...this could also cause a melt down. Just can't quit looking at those pictures and trying to figure out why! Broken ring starting a chain reaction?
right now I have the causes being a combination of slightly lean condition, hot spot from screwdriver (preignition), lack of oil (the bike was leaking pretty good. I thought I had enough oil in it, but I could have been wrong.)and whatever the hell could have gone wrong going wrong at the same time... I blew a fuse, too, but I doubt that would have anything to do with it... and my headlight.
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U.P.dragracer
better check the intake boots for air leaks cracks etc. I bet you had a bad seal at carb #4 and it burned up that piston . I have seen this numerous times on older bikes and snowmobiles :shock:
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catfishk
i once ran WAY too much boost and a turbo car and it had pistons like that when i tore it open. i think you need to check your turbo pressure! haha
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SPARKSS
If the other 3 are normal, then it's a one-of-4 problem (obvious eh) and was most likely caused by excessive lean condition in that one cylinder. That took a lot of heat to melt that badly. You'll be into more than a light hone on that one cylinder (besides the obvious). Had you synched the carbs recently.....did this one take a considerable adjustment (may indicate carb problem or intake leak between the carb and head)......a leaking intake or exhaust valve will compound the problem as well. If the companion cylinder seems to have aluminum deposits on it's plug, indicating that it also is experiencing heating, you might also check the ignition timing for that pair.
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