Hi, I’m Troy McClure, (not really), and you may remember me from such posts as “pulling cylinder head, advice?” or “15000 Km service, valve clearances, engine noise” I checked valves and timing chain over the winter. This spring, it didn’t sound any better. After a couple short rides, the noise is now much worse. Here’s the video. https://youtu.be/_grmfyYbVxg It now sporadically makes loud knocking under decel too. She’s coming apart. I suspect crank or rod bearing, or a busted ring or piston. Going to document the tear down here for future reference and to help me remember how it all goes back together. Certainly going to have some questions as I get into it. First, drained the oil. Hmm. This does not look good. Pulled the clutch side cover to get as much out as possible. Also removed the clutch at this point. Have a new bushing. Spring washers were done last fall. While the basket had lots of movement, no indication that it was hitting anything else in there. Right side screen was intact, and clean. Pulled the oil pump apart. This does not look good either. Manual states I should have 0.1mm side clearance, this look like there was no clearance, or, the metal in the oil that was small enough to pass the pickup screens has done a number on it. The outter plate was nicley scored up too. Next step, engine is coming out. Tank is off. Hint, it’s easier to disconnect the fuel hose from the throttle body than it is the tank/pump connection. I started reading ahead in the repair manual. Looks like I should be able to get the engine out, head and cylinder off, with little effort. I’ll get a good look at the bore, piston, rings, piston pin, and a feel for the crank/rod bearing. Then it’s on to splitting the cases. Going to be done so I can give everything inside a good cleanup and inspection. Given that the crank is a 3 piece press fit, I’ll have to enlist some professional help to dismantle and replace the rod bearing. I’ll post up pics and progress as I go. I’m hoping that whatever the problem is, is not terminal. Plan B, I wonder if SWM has the Super Dual in production, and, what they would want for a new motor. Lol. Look forward to advise, criticism, suggestions, or comments as I go.
I applaud what you're doing and appreciate you posting up a progress thread. I'll be watching with great interest. I was tempted to tear into mine when I went through my issue but had to be honest with myself- just don't have the experience/expertise to have confidence in the job and since this is my only bike that gets used with great regularity I didn't wanna botch anything (had rebuilt two-strokes wayyyy back in the day, but have never tried anything more challenging.)
Thanks for the encouragement. I've done a couple 4 strokes, from the cases up, but never as far as splitting the cases. Not much progress tonight, just got the airbox and coolant tank off.
Thanks man. Plan is to get it apart and do up a parts list. I might take u up on the offer pending price or availability of the new parts. I should be able to at least get the engine out and head off this weekend. Tied up the past couple evenings helping a friend move and another mount some tires.
G'day, I'm doing the same with my 07 610. It's all relatively easy getting to the case split except for removing the primary gears near the clutch basket. I used a brass angle as a lever. You'll have to leave a little, rotate 180 degrees lever a little and repeat many many times. It took me over an hour. A lesson in patience it was for sure. Ps if you go down this road don't use anything but brass it will damage the gears. I've gotta go but I will keep an eye on this thread very keen to see how you get on. Good luck and cheers PHIL.
Thanks for the tip Phil. Have everything disconnected and out of the way, ready to come out. Left everything on the throttle body and just undid the one clamp on the intake boot. Loosened the right rad too to get room to wiggle the ignintion connectors out. Swing arm pivot out and the other engine mounts loose. The manual has been pretty good so far. Find out this evening how much this lump weighs. Waiting for a buddy to drop by to help wrestle it out.
Engine out. Left the exhaust mostly on, just removed the head pipes. On the bench. Now to clean it up and start the investigation.
Not too bad. With the right rad out of the way there was enough room to slide it forward, then rotate the ass end out first, then pick it up. Extra set of hands helped. Got the stator cover off. More bad news. Oil shouldn't be this shiney. My finger after whiping the threads on end of the crank. The bearing in the cover is rough, and looks like the id of the rotor has hit the stator. I'm guessing the crank bearings are toast to allow the crank enough movement to allow the rotor to contact the stator.
This is an interesting thread. Thanks for taking the time to make it. I will watch as you update it. Poor luck with your motor, i hope you get it sorted easily.
First of all, sorry for this useless piece of information: I took it for granted that you have a 610, like me; I was wrong. Anyhow, IMHO you shouldn't worry about this: My flywheel (it's magnetized on the 610, too, so this should be helpful ) is covered by a grey layer of oily powder like yours. On the manual, they state: «Every engine ovehaul, clean the flywheel rotor removing any debris gathered in centrifugated oil and attracted to the magnets.». So, it should be normal.
Cool. Good to know that's normal. Got a little further in today. Cams out. Top end looks pretty good. Cam bearings roll smooth and no play in them I can feel. Little slop between the gears on the cam and the drive gear, but I have a new drive gear to drop in anyway as part of the cam chain service. Flywheel off. Air tools and the motion pro puller did the trick. Nothing out of the ordinary with the flywheel that I could see. Couldn't feel any play in the end of the crank either. Didn't put a dial indicator on it but may set one up when I get the cylinder off and can get a good pull on the rod. Also got the water pump out, it and it's bearing look and feel good. Now here's where I'm stuck. The 2 13mm nuts under the head. The are fn tight! Can't get a good bite on them with open end 13mm wrench, and can't get a socket on them, and I have a headache so I gave up for the night.
You might want to switch the 2 front rockers around. The one under the auto-decompressor (right one when riding the bike) looks a little worn. Mine was like that and eventually couldn't hold the valve open. There is so much compression on this engine that the starter couldn't turn the engine with the valves closed. You can see my saga here: http://www.cafehusky.com/threads/auto-decompressor-on-a-630.45551/
Great thread! Nuda and 630 owner over here that is very interested in the progress of your rebuild! Erik Italhusky.com
Check your Cs spline for wear. If it's worn the only way to replace is to split the case. Just sayin.
Yea, I'm going to price it out. It's not visibly worn, but the new sprocket I just mounted has a very small amount of rotational play on the shaft. On to the main event. Got the head off. Piston has lots of carbon buildup. Could be a little rich. Got the cylinder out. Cross hatching still visible. Also, can see where the piston skirt has been rubbing the bore on the front and back, but, you can still see cross hatching in the rub area so I don't think it's too bad. I'll measure for out of round and piston to cylinder clearance when I get every thing cleaned up. Might get away with new rings only. I'll check the gap on those too before deciding. Piston has some good /bad scuffs. These you can feel. Won't get away without replacing the big end connecting rod bearing. It's DONE. Lots of play up and down and all around. View: https://youtu.be/xEvi2GPXkG8
