Author Topic: wiggly rods?  (Read 2876 times)

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Offline Tobias

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wiggly rods?
« on: February 18, 2010, 08:24:07 AM »
Should there be any wiggle or play when the rods are on the crankshaft? I have my head and cylinders off and the rods with the pistons sticking out and they seem to wiggle a bit left and right....is this normal? Or do I have to take this all apart?

Offline MCRider

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Re: wiggly rods?
« Reply #1 on: February 18, 2010, 08:36:15 AM »
Should there be any wiggle or play when the rods are on the crankshaft? I have my head and cylinders off and the rods with the pistons sticking out and they seem to wiggle a bit left and right....is this normal? Or do I have to take this all apart?
To a large extent some wiggle is normal. But you have to have felt a good one to know.

There are 2 things: the rods are sliding side to side on the journal. That's OK.

Then there is the rod is cocking on the journal. That should be nearly 0. And again, hard to describe unless you've felt a good one to compare it to.

But if you had no symptoms, like a rod knock noise while running, and no indications like it is real high mileage with abuse, then its probably OK.

Need to hear from an expert though. I'm just flinging it into the air.
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1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
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Offline Tobias

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Re: wiggly rods?
« Reply #2 on: February 18, 2010, 08:52:46 AM »
Well the bike has 12k+ miles on it...F2 model grenaded the head cylinder 4 and piston. So I have an F1 and cylinders and pistons to replace it but I really don't want to end up somewhere worse after all this effort. I don't think it knocked before it died...I also have the fried piston still stuck on the rod...havn't figured out how to get it off yet.

Offline turboguzzi

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Re: wiggly rods?
« Reply #3 on: February 18, 2010, 09:04:16 AM »
a picture is worth a thousand words....

Offline Tobias

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Re: wiggly rods?
« Reply #4 on: February 18, 2010, 09:16:20 AM »
heres a pic

Offline ekpent

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Re: wiggly rods?
« Reply #5 on: February 18, 2010, 09:31:16 AM »
Wonder where all that metal went to  :o You may have to take a peek inside there anyway.

Offline domer

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Re: wiggly rods?
« Reply #6 on: February 18, 2010, 09:32:04 AM »
holy #$%*...  :o

Offline Turbogrimace

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Re: wiggly rods?
« Reply #7 on: February 18, 2010, 09:33:10 AM »
Lordy me!  If that's what went on at the top, what the hell happened to the bearing under that rod!  Good LAWWWD!


Offline Tobias

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Re: wiggly rods?
« Reply #8 on: February 18, 2010, 09:39:28 AM »
ya thats what i wonder...maybe I should just crack it all open and make it "new" so I have no worries about all these new top end parts.

Offline domer

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Re: wiggly rods?
« Reply #9 on: February 18, 2010, 09:44:31 AM »
if it were me... with spring coming, id hunt for a used motor to get through while you spend an undetermined amount of money and time on what you've got... and turn that piston into the coolest ashtray ever! but thats just me...

Offline fastbroshi

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Re: wiggly rods?
« Reply #10 on: February 18, 2010, 09:46:31 AM »
  Seriously though, you just wrapped a bunch of aluminum foil around the piston, right?
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Offline MCRider

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Re: wiggly rods?
« Reply #11 on: February 18, 2010, 09:50:03 AM »
ya thats what i wonder...maybe I should just crack it all open and make it "new" so I have no worries about all these new top end parts.
Wow. So even if it were shut off before it spun a lower end bearing, you probably pumped some metal through the bearings and scored them up pretty bad. Which needn't show up in your wiggle test but nonetheless, they'd be shot.

Can't see anyway around it from that damage, you gotta take it apart.
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Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline 754

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Re: wiggly rods?
« Reply #12 on: February 18, 2010, 10:12:50 AM »
Split the cases now, or you might be sooner than you want..

 I would be honoured to have that piston on my "Offerings to the God of Speed wall"

 What do you want to trade for it..?
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Offline Deceptibong

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Re: wiggly rods?
« Reply #13 on: February 18, 2010, 10:24:34 AM »
oooooo....very gnarly!   :o  how might something like that happen??
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Offline Tobias

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Re: wiggly rods?
« Reply #14 on: February 18, 2010, 10:25:19 AM »
haha...it would be cool to have it honored...80mph POW! Ahh whenever I get it off the rod you pay the shipping you can have it if I can have a pic of your cool wall with my piston in the collection??? Send me your email in a private msg.

Offline Tobias

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Re: wiggly rods?
« Reply #15 on: February 18, 2010, 10:28:09 AM »
I think it dropped a valve...the retainer was broke. The valve looked like a well trashed nickle...no stem left! The other valve stem is in place the valve is MIA...ya I need to take it apart...grumble...ahwell the bike was nasty dirty and needed lotsa little things.

Offline Deceptibong

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Re: wiggly rods?
« Reply #16 on: February 18, 2010, 10:32:19 AM »
I bet that bang was loud!  Yeah i would look for a new motor for the time being.  I mean...its almost spring!  Everyone wants to be on the road by then ;)
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Offline Tobias

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Re: wiggly rods?
« Reply #17 on: February 18, 2010, 10:36:55 AM »
Engines in TX. seem to be hard to find without spending a ton or getting something else junky...it wasn't loud it just lost power died and a bit of smoke from the 4th carb. I'll keep an eye out for a useable engine for sure while I fix up what I got going here.

Offline lone*X

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Re: wiggly rods?
« Reply #18 on: February 18, 2010, 06:56:12 PM »
Engines in TX. seem to be hard to find without spending a ton or getting something else junky...

There is a distinct shortage of 550 parts/parts bikes in Texas, that's for sure.  Where are you located?
Lone*X  ( Don )

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wdhewson

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Re: wiggly rods?
« Reply #19 on: February 18, 2010, 07:24:32 PM »
That amount of catastrophic damage requires an every nut and bolt teardown, surgical cleaning of everything, and reassembly.  No choice in the matter if you want a decent engine with expected longevity.

Offline 754

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Re: wiggly rods?
« Reply #20 on: February 18, 2010, 09:49:53 PM »
I will PM my info in next day or so.. I think it wont be out of the engine by the weekend.. ;).. bet the head looks the same..

...........................................................................

 Let me tell you about a former roomates, big bore Suzuki GS 1000. He was riding with a few other bikes north of Seattle on a Sat morning or afternoon in fairly heavy traffic. There were 3 or 4 lanes in each direction, and I think he was about 3rd lane from the shoulder. suddenly the motor blew, billowing smoke and clattering away, and he luckily got over to the shoulder, without getting run over.. Probably the smokescreen made drivers back off..
 
 Engine was toast, he left the bike there.. Not sure if he ever picked it up.. ??? Anyway he  gave me a souvenier from the engine.. a chunk of the piston, about 1 or 1 1/8 long, with part of the ring lands. not sure but I think it came out of the exhaust... :o   :o   :o
Maker of the WELDLESS 750 Frame Kit
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My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline faux fiddy

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Re: wiggly rods?
« Reply #21 on: February 19, 2010, 12:44:47 AM »
heres a pic

Technical term for that is catastrophic existence failure.

I agree with a teardown and thorough cleanup. Look and see what's in the oil filter and pan already. That must have been hammering in there for a while.
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Offline BLUE71TURBO

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Re: wiggly rods?
« Reply #22 on: February 19, 2010, 12:58:36 AM »
heres a pic


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Offline dave500

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Re: wiggly rods?
« Reply #23 on: February 19, 2010, 02:08:44 AM »
dont just drop a new top end on that!!its a full rebuild,or used engine.,there will be debris all though that motor,try removing the oil filter and cutting it open just to see what it trapped,anything trapped has been through the oil pump.!!drop the pan (open a beer first).

Offline faux fiddy

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Re: wiggly rods?
« Reply #24 on: February 19, 2010, 02:30:15 AM »
+1 beer

Disassemble compressed air, scrub with solvent or deisel rinse, compressrd air, repeat, repeat again and again..
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