Puzzled by locked up 74

1ironhead · Posted: August 12, 2009, 5:32 pm Post subject: Puzzled by locked up 74

I bought my 74 with what I thought was a locked up motor due to sitting for years.What I discovered has me wondering now.When in nuetral,the kicker won't budge,as if the motor is locked up so I've been dowsing the cylinders w/marvel mystery oil and diesel and rocking it in 2nd or 3rd.I stood on the kicker in 3rd.Didn't budge.Pulled in the clutch and stood on the kicker and it walked right across the floor.When I pull the clutch in in nuetral,the kicker free wheels(for lack of a better explanation).Should I also fill the case with diesel for a while or what ????

jayel · Posted: August 12, 2009, 6:13 pm Post subject: Re: Puzzled by locked up 74

no the kicker drives the outer clutch basket which drives the motor pinion gear (crankshaft) with clutch engaged,..... with clutch dis-engaged it's no longer trying to turn the motor, and turns the transmision (walks acrossed the floor)

1ironhead · Posted: August 12, 2009, 10:21 pm Post subject: Re: Puzzled by locked up 74

Thanks Jayel.So what you're saying is the motor IS still locked up and I should continue the process of soakin' n rockin' ?

pumps · Posted: August 16, 2009, 8:16 pm Post subject: Re: Puzzled by locked up 74

Ironhead, how's this coming along? Any progress to speak of?

jayel · Posted: August 16, 2009, 9:02 pm Post subject: Re: Puzzled by locked up 74

1ironhead wrote:

Thanks Jayel.So what you're saying is the motor IS still locked up and I should continue the process of soakin' n rockin' ?

yes, remove plugs (already done I suppose) put it low gear and rock the rear wheel back and forth, don't slam it just try to bump it

pumps · Posted: August 17, 2009, 11:24 am Post subject: Re: Puzzled by locked up 74

Will these usually come loose? And if not then what's next? Take it apart and knock the pistons out?

Xumi · Posted: August 17, 2009, 12:31 pm Post subject: Re: Puzzled by locked up 74

You can make a grease fitting with a hollowed out spark plug, and then pump grease into the cyl. Hydrolic pressure will force it to break loose, as it will put 1000's of lbs of pressure on the stuck piston.

Of course you'll have to do a top end rebuild after at the minimum... but it's smelling like you'll likely have to do that anyway.

I have a link somewheres (gotta find it) that details how to do the grease method. Let me know if you want it.

pumps · Posted: August 17, 2009, 1:48 pm Post subject: Re: Puzzled by locked up 74

Here it is right here.
www.cyclepsycho.com/gr...eplug.html

Last thing he says is: Remember, if you plan to do this, make sure that both the valves on the cylinder are CLOSED. Otherwise,
you will have an even bigger mess on your hands!

I guess you could adjust them closed by backing off the adjusters letting the springs pull them closed into their seats?

Xumi · Posted: August 17, 2009, 1:59 pm Post subject: Re: Puzzled by locked up 74

The article I read talks about pulling the cam to make sure the valves are all closed.. where is that thing...

Here it is:
www.dansmc.com/stuck_engine.htm
(love that site.. tons of good stuff there)

Good luck!

1ironhead · Posted: August 18, 2009, 3:57 am Post subject: Re: Puzzled by locked up 74

Thanks Xumi,that looks like vault material to me.It look's like I may have my work cut out for me.One thing:Doing the sparkplug/grease fitting thing,can I use a manual grease gun or do I have to take it somewhere that has one that run on air or whatever they run on? I picked up another 74.That one has no title.The stuck one has a recustructed title(old type w/rivet ID plate).The one w/no title was said to have ran when parked a few years ago,but had a charging issue.I was thinking about getting creative with the titles and try to get the untitled one on the road(possibly for my son).

jayel · Posted: August 18, 2009, 7:01 am Post subject: Re: Puzzled by locked up 74

pumps wrote:

Will these usually come loose? And if not then what's next? Take it apart and knock the pistons out?

that depends on how and why it's locked up, a cyl/piston seized by a damaged engine is different than one seized that just sat and locked up over time, if it won't close the valves you're looking at a tear down anyway

xsleo · Posted: August 18, 2009, 11:11 am Post subject: Re: Puzzled by locked up 74

Put the good engine into the frame with the good title. Rebuild the bad engine. Go to your DMV, see what they say about getting a title for the one without, it may be easy.

ayrhen · Posted: August 18, 2009, 2:35 pm Post subject: Re: Puzzled by locked up 74

The engine on my CB750 got stuck after I let it sit for too long. I tried rocking the bike as described above and it did not work. I also pushed the bike in neutral and had a buddy ride it and shift into gear to try to break it loose and it did not work either. The same friend then helped me free it using the following procedure (he is much more mechanically savy than I and this is the best of my recollection): Lubricate cylinder walls with Marvels Mystery Oil. Remove side cover from engine to reveal nut on end of crankshaft. Put socket on this nut and rotate crankshaft manually using socket wrench. You may need a cheater bar on your socket wrench for increased leverage. Mine broke free relatively easily and with little effort using this procedure.

1ironhead · Posted: August 18, 2009, 5:29 pm Post subject: Re: Puzzled by locked up 74

Pumps,progress ??? has been slow.It makes a little more noise rocking than when I first started,but I haven't been at the garage much the past 2 or 3 weeks so it doesn't get rocked much or MMO/diesel dumped into it either.The thing with my kid has me psyched though and wanting to MAKE time.
Jayel,it is locked supposidly from sitting for some time.Hopefully that's the case.

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