MM700 Engine busted

Kris MM700

Kris MM700

New member
Joined
Nov 13, 2004
Messages
45
Age
44
Location
Greenland
Website
www.pbase.com
I was out with my brother and a friend thursday after work for a quick ride chasing the remaining light and we got about 15 min out in the backcountry before it happened. We just arrived at a small lake when we opened up the throttles. I got up to around 90 Km/h when the rpm suddenly dropped and a missound from the engine in form of metal scrithcing started. I immediatly pulled the brake and blocked the track and hit the killswitch, to minimize damages. I started checking from an end, pulled the startrope to see if the engine would turn smoothly. Initially the engine turned, but with a sound of metal rubbing against metal. It would then lock up pretty hard, actually so hard that I pulled the entire sled, when I tried pulling the startrope again. First I thought the engine wasn't getting oil and had blown a cylinder ring, but the oil tank was pretty much full. So I removed the spark plugs and poured a little oil in each cylinder to make sure that there was oil there. With the spark plugs still removed, I then started to turn on the primary to see how smooth the engineparts were running. The metal to metal sound was still there and when I kept turning on the primary, the engine would at some point lock up and stop turning. And the sound came from somewhere near the bottom of the engine, on the magside. So I got the feeling that it was a bearing that was blown, somewhere in the bottom of the engine. We concluded that we couldn't do anything else but to get the sled home, so my brother went off and got some heavy duty rope and we got the sled pulled home.
Now, I've worked some hours on engines in general, but I have never pulled an engine apart on my own. I would like to fix the sled myself, but I'm figuring that I can't do it without help. I have the facilities and pretty much all the tools to pull the engine apart. But first I would like to hear if anybody has any suggestions to my problem and might be able to help me and guide me through some parts of the process of pulling an enginge apart. Any inputs are greatly appreciated.
 
You got a bad crank bearing...probably PTO. Been der dun dat exactly the same on my 97 700 MM.
 
Crank Bearings!!!!!!!!!!!!!!! Dam 97 700's. Find a bottom to a 98 in good shape.(cases and crank) Much cheaper and easier than replacing the old 97 bearings.
 
Alright, so I need to take the entire engine out right? How much do I need to take apart to get to the crankshaft and the bearing? I don't think I can get used parts for my model here in Greenland. The easiest way for me is to order parts from either Canada or the states. But that new parts. Is their an easier way to get used parts from Canada or the states?
 
you gotta split the cases for that one man, you'll have to pull the motor out, get it on the bench, pull head, cylinders, pistons, then flip it upside down, there's bolts in the bottom of the case that you'll need to pull then the cases should come apart, but the often stick, might have to gently tap it with a hammer to get it apart, cases fall in half (try not the let them drop, I usually end up throwing the hammer to catch the cases)

then the crank will be still in one of them and can just lift out, but again, they like to stick, might have to get the hammer out again, I try to hit the key so as to not make it out of round, but you'll likely need the shock to loosen things up

once it's out you'll be able to check the bearings one by one, just spinning them, to see which one is wrecked.

if you get it that far apart and confirm that it is a bad bearing, your options are to scrap those cases and crank and go with a 98 botom end, or to send the crank out to be rebuilt, atelier bedard in canada does it, as does I beleive PSI in the US, but you're talking pretty big money at this point, unfortunatly, it's not the kinda thing you can do yourself.

any questions feel free to PM me
 
I'm not to sure that you can't do it your self. Just depends on your mechanical limitations. I did mine on my 97 myself with out any problems. However if you can find a 98 or newer 700 bottom you'd be better off. I have seen them in the states sell for as little as 300 USD. One of the larger bearings will cost you this much.
 
my '97 700 acted the same way but i broke a piston skirt, and the pieces fell down into the bottom end, got under the connecting rod, and the crank smashed the pieces through the bottom end, left a nice hole. most likely it is a bearing however, piston skirt failures aren't too common on these. yea definately get the updated 98 or newer bottom end, BETHEVIPER may have one for a decent price.
 
I have a 97 700 as well. What I'm wondering is there any way to update the 97 crank and cases. I'm sure someone once told me they put the wider bearing in their 97 case, but mabey, I'm wrong. Anybody know for sure?
 
Yes, you can update. You need the machining specs for the case modification. Then you need to find someone to machine the 97 cases to make the updated bearings fit.
 
Can I get away with just changing the bearing or is just standard procedure to change the crankshaft along with the bearings, when something like happens?
The thing is that, it's extremely expensive to send heavy stuff to either the states or canada from greenland, because i can only send it with ups. Sending the parts by sea would take months because there's no direct line of shipping between greenland and north america. Also, which parts would be good to order in advance, before I start pulling engine apart? I mean besides the bearings atleast.
Any inputs are greatly appreciated, i'm quite a newbie to pulling engines apart and putting them back together, so i'm trying to get as much knowledge here in the forum before i start taking this baby apart.
 
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you can just change the bearing but like everyone says you're better off to just find another bottom end- cheaper and easier. if you had one go bad now how far along are the rest? by the time you spend all the money for bearings to replace the set up you have you'll be in four times or more than what you can get a used bottom end for with the bigger updated bearings (1998+).
 
Yeah, I'll go for a newer used bottom then. Any suggestions to where a used bottom from a 98+ can be found in canada or the states? Thanks for the inputs, it's been really great help for a newbie!
 
Try BETHEVIPER. He has a parts list as a sticky in the classifieds. Email him if there is nothing posted there.
 
you can also use a bottom end from a 600sxr triple, they are the same. btv sold me one from a 2002 this fall. the 700 top end bolts right on and it has all the updated bearings! put this in my 97 700sx when i found most of the bearings were shot when i rebuilt the top end! NICKSXR might also have one, i saw he had a 600sxr complete engine for sale on here

nicksxr engine:
http://www.totallyamaha.com/forums/showthread.php?t=4784
 
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buy used

I just seen a red head 700 triple on ebay , I've seen several on there and for a decent price . I would buy another motor , just make sure the seller has excellent feedback . Good luck :rockon:
 
the bearings in it are ball bearings, integral to the crank, it's not a journal bearing like you would find in a regular automotive engine, this means you'll have to split the crankshaft to replace the bearing, split crank, press old bearing off, press new bearing on, press crank back together.

doable forsure, but for the costs I find it easier to just ship off your crank and get a reman one sent to you.
 
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