Yamaha Grizzly ATV Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
I have a 2002 660 grizzly and I ran it low on oil while going past normal speeds. It has a lose of power and there's a constant knocking noise while the bike is on and running. It still drives but I broke down into it thinking it was a loose valve but I adjusted them and the noise is still there. Need help
 

·
Grizzled
2014 Yamaha Grizzly 700 EPS
Joined
·
3,659 Posts
Welcome to GC!

It might help others if you could post a video on youtube of the knocking and link it in this thread. Is the knocking continuous or does it only happen initially once you apply throttle?
 

·
Registered
Joined
·
5,537 Posts
A video would be helpful so we can hear the sound.
But when you run a 660 low on oil, the piston/cylinder wear is common, and the connecting rod bearings usually fail. When the connecting rod bearings fail, you'll get a knock in the engine.

Basically, if you run a 660 low on oil, your looking at new crank, new cylinder/piston (or re-bored cylinder with oversize piston). Most replace the entire engine if the connecting rod crank bearings are shot.
 

·
Registered
Joined
·
7 Posts
If I ran my Quad low on oil and it started knocking, I would definitely pull it down for a full inspection/rebuild before it detonates! Dont waste time on videos, start wrenching!
 

·
Premium Member
Joined
·
10,621 Posts
Welcome from Colorado.
I'm betting you need a rebuild, both top and bottom ends.
I bet the knock is from the rod bearings and hopefully only on the piston end.
Running the engine after this sound showed up is causing more damage, and you may have to split the case or buy a rebuilt engine from our site sponsor.
 
  • Like
Reactions: Kainen12

·
Registered
Joined
·
8 Posts
Discussion Starter #7
I'm 15. I don't know to much about engines. I learn quick so if i have to tear my engine down completely to find the problem I will
 

·
Registered
Joined
·
2,099 Posts
Is a rod bearing somewhat simple?
The small end connecting rod bearing (the one connected to piston) Can be done with the engine in place and in a reasonable amount of time and work.

The big end connected rod bearing, (the one on the crank) Needs to have the engine removed and completely dissassemble ( split crankcase) .

If the final verdict is the big end bearing is damaged, a good used engine ( if available near you ofcourse ) would save alot of time and work and get you back on the trail quicker.
 

·
Premium Member
Joined
·
10,621 Posts
You stated the problem correctly, a guess.
The 'splitting the cases' situation is difficult and time consuming because of the transmission after getting the engine out of the bike. And you will need some special tools you probably do not have now.
You can get a f.s.m. on line from trade-bit for a few bucks u.S. and read the tear down, re assemble procedure to understand all that will happen.
I wouldn't have a problem, but some not wanting a big project would sell the bike and get another bike.
If I had to tear into mine, I would try going for a 1000 cc monster if not a smaller 3 liter V-6 from an S.H.O.
 

·
Registered
Joined
·
370 Posts
Welcome to GC. I just finished rebuilding my 02 660 a couple of weeks ago. It took me almost 4 months at a couple of hours a day and most weekends (I took my time, was in no rush). I had never taken an engine apart before. At age 15 that would be an awesome project for you if you have the funds. I'm sure that with a service manual, torque wrenches, and the proper tools you could get it done. You just have to be well organized, take your time, go through the service manual a few times, watch some videos on YouTube and make friends with the Google search bar. And of course, if you get stuck, you come here to get loads of help.

Or you could buy a rebuilt engine. It'll cost about the same. Maybe a bit less because you wouldn't need to buy a bunch of tools. But if you do it yourself, you'll know your Grizzly inside out.
 

·
Just wanna ride!!
Joined
·
5,517 Posts
Welcome to GC. A service manual from tradebit.com is a great idea. It will be an electronic version but you can print it and put it in a binder which is what I did. This is a pretty good sized project in $$$ and in time. Another option to consider is to sell it as a project bike and put that dough into another machine. But keep an eye on the oil level this time. lol. Whatever route you decide to go, we’re always here to bounce problems and / or questions off of. We have a very knowledgeable membership that are always willing to help. Just be aware of what you are biting off before you go the rebuild route.
 
1 - 14 of 14 Posts
Top