Cracked Casing, any suggestions - Sportbike Forum: Sportbike Motorcycle Forums
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post #1 of 8 (permalink) Old 11-11-2003, 09:50 AM Thread Starter
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Angry Cracked Casing, any suggestions

Well I havent posted in a while because I just had a job transfer and have been away from the keyboard for a couple of weeks. Anyway Im not doing so well in the "running bike" department. Let me start from the begining. I was going along on a familiar back road through whats called black woods in W. county maine when I felt/heard a slam from my bike right as I went over a dip in the road. I sounded/felt like I bottomed out my bike so I immidiately stopped and noticed oil (pouring) from my engine while running, it stopped when I shut the engine off. Took my bike to my local mechanic to check it out and he noticed(I dont have all the details as I just talked to him briefly from work today) that a bolt had come loose from the cam shaft and was propelled into the engine casing, he originally thought he could just replace nut/bolt and new seal and have it back to normal but it was still dropping oil so after further investigating he found that the bolt was slammed into engine casing close to tranny and cracked the engine. He says it is to high of a compression area to weld, and my best/only bet is to get a different motor. This sucks but this is the first winter I will be spending in maine in a few years so the timing was as good as it can be. Anyway my parents are both welders and although they dont think they can weld aluminum al that well they have a friend who is a great alum/ heliarch welder. Im wondering if this is worth a shot or if I should just look for a new motor. Any other helpful info is greatly appriciated!!! Anyone selling a 2001 r6 motor low milage in good cond!! By the way my motor had 15,700 agressive but well maintained miles on it!!!!
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post #2 of 8 (permalink) Old 11-11-2003, 10:00 AM
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No matter how good of welders they are, my guess is that the weld will always be a weak point. Best to avoid potential catastrophic failure and get a new motor. I could be full of shit though, it wouldn't be the first time.

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post #3 of 8 (permalink) Old 11-11-2003, 11:39 AM
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Heck, give your friend a try at the welding. What the hell have you got to lose? If it doesn't work, the engine cracks again and you're in exactly the same place as you were before.
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post #4 of 8 (permalink) Old 11-11-2003, 11:41 AM
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Have to admit that a good weld will be a potential or temporary fill in. Back in the late 40s to early 50s such a weld would do the job, but top revs of most bikes were anything from 3.5 to 6 thou. Things have changed so much in the past.

Still when it comes to those that specialize in m/cs I have seen amazing holes in the crank sides of some flat track bikes only to be brought back to perfection. Still a very costly piece of work & in most cases competitors would have replaced the power-unit while said welding job was an experiment to see how long it would hold ------ for a replacement power-unit was waiting to go in when the time came.
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post #5 of 8 (permalink) Old 11-11-2003, 12:15 PM
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Still not enough info to give a definitive answer. If you are sure you can completely trust the guy, it may be time for a motor change.

Generic response to this subject, from a guy who owns the equipment to properly weld aluminum.

Any more I take this approach. If it isn't a stressed area, it can probably be epoxied. If it is a stressed area, chances are it's not worth welding because the work required to do it right will be offset by the cost to do that much work. Due to the alloys and heat treating of some of these castings, some parts are near impossible to repair properly even using good welding procedure and technique. Bottom line is, I might weld an easily removed part such as a cover damaged in a crash. Anything not stressed on a main case, I would probably epoxy using very careful preparation and strictly following the manufacturer's directions. If it was an antique using sand castings, I'd preheat and weld it all day, every day, and remachine if needed. Hope that helps.

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Last edited by Dad; 11-11-2003 at 12:19 PM.
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post #6 of 8 (permalink) Old 11-11-2003, 12:20 PM
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in this case you gotta consider the worst case scenario. you weld it put it together, it works, you drive for a while and one day it leaks again while your riding, putting a nice stream of oil on your rear wheel, you know what happens next right.

or your going down the street when the weak point causes your engine to granade and you get highsided at speed.

if it was a dirtbike I'd say try it cause of the slower speeds and oil on dirt isn't to terrible, its not good, but you have more control. oil on streets is like riding on ice.

I say hit ebay and get another engine.
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post #7 of 8 (permalink) Old 11-12-2003, 06:10 AM
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I have to point out that when folks used to weld cracked engine cases, those cases were made from steel. Not Aluminum.

I wouldn't trust it.

If you want a reliable second opinion, eMail a Yamaha~specific tuner. Between Damon Buckmaster, Jamie Hacking, Aaron Gobert and Jason DiSalvo I am sure there has been a cracked case or three... So they would know if you can weld or not. But if you ask me, it's New Motor Time.

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post #8 of 8 (permalink) Old 11-12-2003, 07:07 AM Thread Starter
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Thanks for the replies, I was leaning toward trying a weld and if it didnt hold, what the hell.. But Silentneko reminded me of a good point. I almost S##t myself when I saw all of the oil on my rear tire when this happened, it was comletely covered and I could trace my tiremarks back to were it cracked , thats how fast the oil was running out. If I had not stopped immidiately I know I would have lost it on the next corner, this section of road is very hilly,twisty, with absolutely no houses, traffic and I was doing atleast 90mph when it went. And I dont need that in the back of my mind while trying to enjoy a ride (the police are worry enough!!). Im going to give ebay a try, keep the info coming please!!!!!
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