I Blew Up My Maxim

I just want to get the main points up and hopefully follow with pictures and mechanical background tomorrow.

1) 70 mph on Highway 316 at night, 10 miles from the end of a ride from Nashville, TN to Athens, GA - I feel a drop in power, almost like it was starting to run out of gas (it had half a tank). I gave it a little more throttle to see if it acted like it really was running out of gas.

2) BOOM! I see three pieces of metal, the largest the size of a ping pong ball, go skipping down the road in front of me at high speed. At first I thought something had come off the front wheel but I immediately realized it was the engine.

3) Thankfully I instantly pulled the clutch and did not hit either brake. I coasted to a stop just off the road and got off the bike. There was a fist sized chunk missing from the engine casing below the exhaust headers, several pieces of shrapnel stuck in the pipes, and no oil in the case.

4) The rear wheel was dripping and smoking with engine oil.

I'm going to try and get some photos in the daylight. I plan on totally replacing the engine and doing a lot of other needed mods over the winter. What engines can fit in the frame?

 

Sounds to me like a rod cap came off. My sincerest condoleces on the loss of your engine. I too am an owner of an 82 750 Maxim, so I am always concerned when I hear of anything regarding our bikes. Was the engine recently apart? for bottom end work? If so you may be able to get compensation from the mechanic responsible for this unfortunate incident. Good luck and please be forthcoming with the gory pics.

 

sorry to hear about your motor with only 31000 on it, thank god you were quick on the clutch and rolled to a nice soft stop

 

Well the motor crossed 33333 while I was riding back so I put a few more miles on it since I made the sigline. And yeah, shining my flashlight on the smoking wet tire I had the ultimate "pucker moment" . . . I don't know if I'm lucky or good but I'll take it either way.

That part of the engine had not been messed with by me since I owned the bike. I did take off and re-gasket the left side clutch cover several months ago, but I was pretty meticulous about making sure no foreign debris or contaminants got into the oil reservoir. I'm embarrassed to say I don't know what a rod cap is yet. I'll get some photos and maybe you can tell me.

The left front engine mount completely shattered. I think I'll pull the exhaust tomorrow to get a better view.

 

That's sad but at least you weren't injured. Motors can always be replaced. It seems strange that your oil was all gone so quickly. Your oil pump might have failed, oil overheated and began to escape, engine overheated and went pop! Of course might have just been a mechanical failure in a piston assembly. Recently a Hog rider had a rear tire lock up on him on one of our not-busy highways and simply slammed into the road with no helmet and died. You gotta be safe.

 

I just re-read what metabolic said, "I feel a drop in power", this could indicate a bearing seizure, and with the engine revs high enough to go 70, so there's a lot of energy that has to go somewhere. Check to see if your oil pump chain is broken. Not having an oil pressure light/gauge is about the only thing I don't like about Yamaha.

 

Sorry, I had a long work day and missed daylight for picture taking.

It really looks like a mechanical failure that massively shattered the engine block. It looks like one of the piston arms whipped against the wall and blew it out around 7-8k RPM. I haven't seen any signs of leaks anywhere else on the bike, and considering how bad the summer's oil leak was I've always been a hawk about checking for it on rest stops.

And on a related note I was riding my other bike (BMW R1200C) on Sunday night and a full grown whitetail buck jumped across my front fender, missing me by about 18 inches. I usually watch for deer, I just wasn't expecting it at the second busiest intersection in Athens. I swear I pissed one of the gods off . . .

 

MMMM THINGS HAPPEN IN THREES?

 

Hey Hey metabolic, I owned a 1971 R75/5 and a 1974 R90s. I wish I still had them. Did you ever own an older Beemer?

 

Considering that these, are high reving motors. Any oil leak puts a lot of stress on the bearings, and lower end. Very possibly the cause of your bottom end failure. The boggin down sounds exactly like a bearing getting hot, and seizing on the crank. Were you able to hear any kind of a ticking/knocking noise just prior?

Glad to hear that you did not get hurt. It could have been very bad, very fast with all that oil making the rear tire slick.

Ghost

 

Where was that oil leak?

 

Summer's oil leak was coming from the bottom of the left crankcase cover. It pooled on top of the exhaust collector and concealed the extent of the problem . . . on one occasion I was probably down to < 500ml of oil without realizing it. I'd wager the damage was done then and that it was just a matter of time.

I *did* hear what could have been ticking or knocking on the trip up to Nashville that weekend but it was very infrequent and was mixed in with the amalgamation of sharp small potholes on I-75 North. Though now I think I know the difference.

No older Beemers, just an old dad with two newer Beemers.

 

It's just as well, an old Beemer would probably feel quite primitive. Back on subject; Do you plan on a total engine replacement? I saw some fairly inexpensive ones on Ebay.

 

Yeah, total engine replacement. Keep the old one for cannibalization. Most of the ones I see are in much better condition than mine was.

Can I fit any other engines in that frame size?

 

Sorry to hear about your luck. I can certainly sympathize being that the EXACT same thing happened to me on my 1980 XJ650 Maxim. I was out riding with a buddy, going on about 100 miles of the ride. I had just started up from a stop light and was only going about 30mph when I heard a faint rattling coming from the engine, followed by a sudden drop in rpm and no throttle response, followed shortly thereafter by a POP sending several pieces of the front engine wall bouncing across the median and locking up my back wheel. Unlike you I was not so quick to grab the clutch so I skidded to a halt - safely fortunately - on the side of the road without laying it down. There was a 2" inch diameter hole just below the headers, with a rod sticking out.

I still have no idea what caused it. I had just replaced the oil the day before, replaced the plugs, retuned, and the engine seemed to be running fine other than some idling issues. The engine had 38,000 miles on it so I'm attributing it to a bearing or seal failure somewhere. I looked into swapping in an XJ750 engine, which can be done fairly painlessly, but found a great deal on a 650 with relatively low miles so that's what I'm doing. If you opt for a 750 and need a CDI, let me know - I bought one that I no longer need (1982 XJ750 Maxim). Also, see the link below for general engine swap info (about 15% down the page). Best of luck to you!

http://xjbikes.com/Forums/viewtopic/t=27544.html