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Author Topic: Is it a rod knocking  (Read 1287 times)

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Offline ekim98

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Is it a rod knocking
« on: July 28, 2008, 09:33:39 AM »
 Ok, I got to low on oil and now I have a loud tapping/knock when I rev up! If I put it in gear and "put presure on the engine" engage first gear and start to move the knock goes away. I've triple checked the valve adjustment and the cam chain tensioner. The engine starts right up and seems to have good power, but god that knock sounds horrible. I put a big screw driver on the cases and it sounds like its in the lower half by the # 2 cylinder. Are we talking a rod bearing?? Say it isn't so. :'( :'(   Any other possiblities!!!  ::) ::) I just started to make room for the big tear down, but am waiting for someone to tell me I don't have to. ;D ;D ;D
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Offline markjenn

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Re: Is it a rod knocking
« Reply #1 on: July 28, 2008, 10:43:27 AM »
In my experience, rod bearing knock has a "deep down" sort of "wow, that sounds nasty" sound and gets worse with revs and loads.  I tinnier sound would lead me to the top end - either cam chain problems or cam bearings.  I'd check valve clearances and adjust your cam chain and see if this changes things.

- Mark
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Offline ekim98

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Re: Is it a rod knocking
« Reply #2 on: July 28, 2008, 06:32:37 PM »
Well, unless they started making metal flake oil I guess I know what the problem is. Good thing I made extra room to spread out parts and got that other fan put in the work shed.
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martino1972

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Re: Is it a rod knocking
« Reply #3 on: July 28, 2008, 08:16:14 PM »
sorry to hear that,keep us posted
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Offline 754

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Re: Is it a rod knocking
« Reply #4 on: July 28, 2008, 08:21:58 PM »
Stop using it, may save the crank.. but if you got flake it maybe too late.

Cranks are still reasonable or get a parts motor.
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Offline bryanj

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Re: Is it a rod knocking
« Reply #5 on: July 28, 2008, 08:47:32 PM »
If you can hear the knock you need a new crank and rod plus all the shells.

Check the oil hoses, long time ago there was a bad batch that collapsed and starved the engine
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Offline ekim98

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Re: Is it a rod knocking
« Reply #6 on: July 28, 2008, 09:12:02 PM »
Quote from: bryanj on July 28, 2008, 08:47:32 PM
If you can hear the knock you need a new crank and rod plus all the shells.

Check the oil hoses, long time ago there was a bad batch that collapsed and starved the engine

It was 100% my fault. I knew I had a "small" oil leak - bad stator cover, and was fly low on the highway for about 2 hours going home and looked down and saw oil all over my left boot. To late.
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Offline bryanj

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Re: Is it a rod knocking
« Reply #7 on: July 29, 2008, 09:14:37 AM »
Oh dear, like I said if you can here it knocking your best bet is a used crank and rod set from another motor
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Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline ekim98

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Re: Is it a rod knocking
« Reply #8 on: July 29, 2008, 02:36:26 PM »
I'm slowly tearing it down now and will see what it looks like soon. I've never split the cases before so I'm going slow (and it's really hot out there, 100 degrees by my thermometer in the shade). Can't I just replace rod and crank bearings if the journals and stuff aren't scored?  :-\  The cam journals and bearing housing look good! I'm not sure how much more $$ I want to put into this thing now. I didn't buy it to make money, but your talking some $$ even for a used crank,rods and then bearings etc. plus I was hopping to get a mild cam and have the head port & polished as long as it's down. It's getting good oil to the head! I'm really tick at myself now and really just want to go for a nice ride, dammit all. Sorry, had to rant a little.
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martino1972

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Re: Is it a rod knocking
« Reply #9 on: July 29, 2008, 02:50:54 PM »
i'm not 100% sure.but i dont think you have to take the head off to split the bottom halve...
now running out of oil could very well have damaged the rings/pistons,but if you say it runs good still,then ur probably oke there...
maybe read up on splitting the bottom without taking the top-end apart,will safe you some gaskets etc..
might be when you take a peek at the crank and rods that you can get away with just some bearing shells..
but dont get your hopes up too  high for that..
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Offline ekim98

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Re: Is it a rod knocking
« Reply #10 on: July 29, 2008, 03:13:29 PM »
Quote from: martino1972 on July 29, 2008, 02:50:54 PM
i'm not 100% sure.but i dont think you have to take the head off to split the bottom halve...
now running out of oil could very well have damaged the rings/pistons,but if you say it runs good still,then ur probably oke there...
maybe read up on splitting the bottom without taking the top-end apart,will safe you some gaskets etc..
might be when you take a peek at the crank and rods that you can get away with just some bearing shells..
but dont get your hopes up too  high for that..

I already pull the cam out(wanted to make sure it was ok). As I said I never split the cases before but I"ll try that next and hope for the best
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Offline bryanj

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Re: Is it a rod knocking
« Reply #11 on: July 30, 2008, 08:08:16 AM »
Having 30+ years on these i assure that if you can here the knock the rod is oval and any scoring on the pin makes it scrap.
Now shells are $10 ish each HALF and a rod $100 plus you need the correct weight code so a complete crank with pods from a running motor will be cheaper although you will still need 10 main shells unless you are incredinbly lucky to get a used crank with the same codes
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Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline Tower

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Re: Is it a rod knocking
« Reply #12 on: July 30, 2008, 10:12:36 AM »
When the rods go a knocking
The cost may be quite shocking
Major engine work
That you shouldn't shirk
Is in your Christmas stocking ;D
« Last Edit: July 30, 2008, 10:14:19 AM by Tower »
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