Boys...I've Got Me A Rattle

[Jason2tpa]

Curious.....during operation the flywheel turns clockwise. When not operating, does the flywheel turn counterclockwise if manually manipulated? If it doesn't, what's the purpose of using the universal holder while removing the nut?

[DennisG01]

With enough leverage (socket on a long bar) you could turn the engine backwards. The holder is to keep the flywheel from turning so you can unscrew the nut. Which is why an air gun is nice - goes quickly enough that you don't need anything to hold back the flywheel. And... of course there's the "easy" factor.... you know, like needing a power driver to remove those little intake silencer bolts?

[99yam40]

Curious.....during operation the flywheel turns clockwise. When not operating, does the flywheel turn counterclockwise if manually manipulated? If it doesn't, what's the purpose of using the universal holder while removing the nut?

think about it,
what would keep it from turning any direction you wish to turn it?

[pstephens46]

Curious.....during operation the flywheel turns clockwise. When not operating, does the flywheel turn counterclockwise if manually manipulated? If it doesn't, what's the purpose of using the universal holder while removing the nut?

Go old school. Put it in gear and use a piece of wood to block the prop against the anti cav plate.

[panasonic]

Go old school. Put it in gear and use a piece of wood to block the prop against the anti cav plate.

Old school method #2 for locking up a two stroke engine to remove a flywheel nut or clutch nut. All that is required is a spark plug socket and a small piece of rope. That's the clues...will let you all figure it out for yourselves...lol

[pstephens46]

Old school method #2 for locking up a two stroke engine to remove a flywheel nut or clutch nut. All that is required is a spark plug socket and a small piece of rope. That's the clues...will let you all figure it out for yourselves...lol

Used that one on a weed eater a couple times.

[Jason2tpa]

think about it,
what would keep it from turning any direction you wish to turn it?

I'm sure it's remedial for some but I don't know, that's why I asked. Isn't that what this forums purpose is for bud?

[Jason2tpa]

With enough leverage (socket on a long bar) you could turn the engine backwards. The holder is to keep the flywheel from turning so you can unscrew the nut. Which is why an air gun is nice - goes quickly enough that you don't need anything to hold back the flywheel. And... of course there's the "easy" factor.... you know, like needing a power driver to remove those little intake silencer bolts?

Appreciate the insight, and the old school methods suggested by pstephens and pano.

[99yam40]

I'm sure it's remedial for some but I don't know, that's why I asked. Isn't that what this forums purpose is for bud?

very true.
but I have never found a motor that you could not turn either direction by hand.

they do not have one way clutches/bearings or anything else that I can think of that would prohibit it

I have even seen diesel motors run backward blowing exhaust out the air filter

even some of the old outboards got reverse by starting them in the opposite direction

[zenoahphobic]

very true.
but I have never found a motor that you could not turn either direction by hand.

they do not have one way clutches/bearings or anything else that I can think of that would prohibit it

I have even seen diesel motors run backward blowing exhaust out the air filter

even some of the old outboards got reverse by starting them in the opposite direction

Only true for a short while (turning backwards) for all motors.
Commonly a lot of overhead cam interference engines get jammed in reverse.
This is when they are turned in reverse the cam chain or belt loosens as the cam chain or belt tensioner compresses often enough to alter the cam timing enough so that the piston jams on a valve;
or the timing completely changes with the subsequent sag of the belt or chain dropping it from the lower sprocket or crankshaft gear.
Also depending on the room available particularly with a chain it can pile up and jam the crankshaft.
I also had a Laverda motorcycle that had a reverse locking bearing from the chain drive from the starter motor. It turned backwards with a lot of force forcing the starter motor to engage.
I guess it generally accepted good practice to prevent reverse rotation.

[zenoahphobic]

Saying some engines suffer damage when turned in reverse.
Two strokes can run in reverse when ignition retarded. My Bultaco (unadjustable timing ) did. Used to try to ride it when that happened even siting backwards on the tank. Stupid things I used to do, but I never tried changing gears when this happened!

[panasonic]

Bombardier has some snowmobiles, two stroke, that have reverse with no gear box. When you select reverse the engine slows down to almost a dead stop and then runs in reverse...pretty slick system...

But as Zen says most Four strokes with timing belts and/or chains are not meant to be turned backwards...even when doing maintenance on them.

[Jason2tpa]

Finally had some time today to remove silencer, in hopes of pinpointing the rattle. With silencer off I had my ear just about inside the carb throat lol. Still no luck. It can be best heard in between carbs and starter, so it could very well be coming from under the flywheel. I think it was 99yam whom mentioned it could be a bearing.

My service manual parts blow-out for parts under the flywheel is as you see below. The bearing housing is circled in red. My question is, how will I know a bearing is bad? Will this be obvious once I'm looking at the bearings in the housing? Next question, let's say there is a bad bearing. Are individual bearings replaceable, or does the entire bearing housing need replacing? Also, the 2 blue arrows. Are these rubber gaskets?

Auto parts stores like Ace, Autozone, etc., have tools that can be loaned. They offer a universal puller. Same puller required by Yam?





Yam.jpg

[99yam40]

My used C40 had a strange noise to it when I 1st got it.
after several years it just kept getting louder, so I took it apart to find 3 of the 4 main crank (ball) bearings were rough when turned by hand.
If you cannot see the bearings feeling then when turning may help.

I still think you need to get a stethoscope to listen to your motor

[panasonic]

[QUOTE=99yam40;n204074]My used C40 had a strange noise to it when I 1st got it.
after several years it just kept getting louder, so I took it apart to find 3 of the 4 main crank (ball) bearings were rough when turned by hand.
If you cannot see the bearings feeling then when turning may help.

I still think you need to get a stethoscope to listen to your motor[/QUOTE]

Di you get a stethoscope Jason? One thing at a time buddy. Narrow down the place, you might not have to pull that flywheel or you might, cross that bridge when you come to it.