 has anyone seen this happen? |
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 Nov 3 2009, 07:00 PM
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#1
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Member  Group: Members
Posts: 21
Joined: 31-August 09
Member No.: 7,199
quad: Ltr450 |
fresh top end, in my bike this weekend. new piston, rings and intake valves. we didn't replace the exhaust valves cause they were good. i had about 45 minutes of ride time on this motor before the exhaust valves snapped. the dome is completely destroyed and has a crack in it as well. the opposite side of the cam chain, the 2 bolts that hold the cams in were loose on the intake and the exhaust journals. just on the side opposite of the cam chain. anyone know why this could have happened?
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Nov 6 2009, 09:24 PM
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#2
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 Advanced Member Group: Members
Posts: 306
Joined: 12-November 06
From: Crystal River, FL
Member No.: 1,808
quad: Suzuki LT-R 450 |
Something similar happened to my cousins race ready 450r last weekend. His exhaust valves snapped off also. He reasoned that it was just because they were old and he was running a 13.5:1 piston on U4.
  Was your timing spot on when you reassembled? Are you running a high grind cam? -------------------- 2006 Suzuki LT-R450
Burgard / Lonestar / DMC / Pro Taper / Tag Metals / HotCams / Twin Air / Maxxis / Quadtech / Factory Effex / One Industries Z4C May 2008 QOTM 2004 Suzuki LT-Z400 Stolen Houser / Elka / Alba / Epic / G-Force / Pro Design / Pro Taper / Nstyle / GT Thunder / Maxxis / K&N / Streamline / Douglas  Special thanks to Fionbar Mcknulty |
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Nov 7 2009, 08:54 AM
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#3
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Newbie Group: Members
Posts: 4
Joined: 22-September 09
Member No.: 7,238
quad: 07 LTR |
QUOTE (Albazuki400rider @ Nov 6 2009, 09:24 PM)  Something similar happened to my cousins race ready 450r last weekend. His exhaust valves snapped off also. He reasoned that it was just because they were old and he was running a 13.5:1 piston on U4. Was your timing spot on when you reassembled? Are you running a high grind cam? I think he put it together wrong , possibly didn't have the motor at tdc when he installed the cams or just didn't pay attention. i would have him get you the parts and find someone else to put it back together personally |
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Nov 7 2009, 09:14 AM
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#4
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Advanced Member Group: Members
Posts: 306
Joined: 12-November 06
From: Crystal River, FL
Member No.: 1,808
quad: Suzuki LT-R 450 |
That is not mine, that is my cousins TRX450r motor, with the engine built by modded motorsports and V&M racing engines. He races A class.
-------------------- 2006 Suzuki LT-R450
Burgard / Lonestar / DMC / Pro Taper / Tag Metals / HotCams / Twin Air / Maxxis / Quadtech / Factory Effex / One Industries Z4C May 2008 QOTM 2004 Suzuki LT-Z400 Stolen Houser / Elka / Alba / Epic / G-Force / Pro Design / Pro Taper / Nstyle / GT Thunder / Maxxis / K&N / Streamline / Douglas Special thanks to Fionbar Mcknulty |
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Nov 13 2009, 10:53 AM
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#5
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Advanced Member Group: Members
Posts: 89
Joined: 3-March 07
From: Virginia
Member No.: 3,490
quad: 2006 LT-R450 |
intresting as i stated in another thread i am attending YTI's Motorcycle Technology Program, we actually went over how this happens. It is called Valve float, which is an occurance when the valves are forced open before they have a chance to close causing them to have a collision with the piston inside of your cylinder. this is usually caused by over revving, if you werent ringing the motor out then the only other thing i could think of is that the timing was set wrong and/or the engine was dissassembled and re-assembled when it wasn't at TDC. that sucks, new head, piston, valves, and possible new cylinder in the works for you there.
Also another thing I though of, what was the condition of your timing chain, if it was old and wore it could have caused it to slip on the cam gears while under force. this would definately cause your timing to get out of wack and to have a catastrofic engine failure like that. This is why its always a good thing to replace your cam chain when doing work like that, cheap insurance so that doesnt happen, usually you can get new ones on ebay for around 30 bucks. This post has been edited by Redbullrider111: Nov 13 2009, 11:02 AM -------------------- 06 LTR 450
JE 13.5:1 High Comp Piston Stage 1 Hotcams (IN&EX) Full Yoshimura RS-5 Pro Design Foam Filter No Airbox Lid Torque Stuffer PCIII CV4 hoses(Blue) Renthal Twinwalls Renthal 50/50 Grips Houser Stem Streamline Billetanium Stabilizer Pro-Armor Fatpeg nerfs (black) Maxxis RAZR's on ITP C-series rims(black) Tag Metals Railer Glide Plate(blue) Tank Vent cap White Brothers parking brake block off Racecut Front Fenders Factory FX tempature stickers |
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