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Author Topic: Is rod knock impossible on these bikes or something?  (Read 830 times)

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Offline HondaOwnerLOL

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Is rod knock impossible on these bikes or something?
« on: February 18, 2023, 05:15:52 PM »
I have never found a single person with a SOHC/4 experiencing rod knock. Is it super rare? Is there some design quirk that prevents it from happening on these engines? Do people just not talk about it when it happens? Does that just not happen on engines of this size or age? What's the deal with that?
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Offline Tracksnblades1

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Re: Is rod knock impossible on these bikes or something?
« Reply #1 on: February 18, 2023, 05:22:47 PM »
It’s just a good drysump design. Drag car airplane stuff except no extended upside down operation.

I assure you the rods will knock and they will fly out and picture window cases like all engine.
Clearance, oil, and rpm. Any one wrong as well as poor maintenance and she’ll tell you before see blows.
« Last Edit: February 18, 2023, 05:33:08 PM by Tracksnblades1 »
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Offline newday777

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Re: Is rod knock impossible on these bikes or something?
« Reply #2 on: February 18, 2023, 05:31:27 PM »
Back 1983 when I still had my K6 from new, with 45,000 miles of hard riding, I was thinking it was making bottom end noise, so that was part of the decision to sell it and stop riding because of my new growing family. I didn't want to leave them fatherless if anything happened nor did we have extra money to spend on tearing it down either.
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Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline HondaOwnerLOL

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Re: Is rod knock impossible on these bikes or something?
« Reply #3 on: February 18, 2023, 05:42:30 PM »
Quote from: newday777 on February 18, 2023, 05:31:27 PM
Back 1983 when I still had my K6 from new, with 45,000 miles of hard riding, I was thinking it was making bottom end noise, so that was part of the decision to sell it and stop riding because of my new growing family. I didn't want to leave them fatherless if anything happened nor did we have extra money to spend on tearing it down either.

Sorry to hear about that mate that sounds like it sucked. You must be a great father. Glad you're back in the game!
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Offline RAFster122s

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Re: Is rod knock impossible on these bikes or something?
« Reply #4 on: February 18, 2023, 07:09:47 PM »
Stev-O had a big bang bike, it windowed the cases… he rebuilt it has a thread with pictures of the carnage. New cases of course, as well as lots of other parts…
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Online Don R

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Re: Is rod knock impossible on these bikes or something?
« Reply #5 on: February 18, 2023, 07:10:19 PM »
 I hauled home a few ventilated crankcases with large purchases of 750 stuff. They do withstand a lot of abuse before giving up.
 
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Offline MRieck

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Re: Is rod knock impossible on these bikes or something?
« Reply #6 on: February 19, 2023, 03:48:07 PM »
I have seen.....and heard it.
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Offline Stev-o

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Re: Is rod knock impossible on these bikes or something?
« Reply #7 on: February 20, 2023, 11:19:43 AM »
"Rod knock" is very common on worn automotive engines when the rod bushings wear out and allow slop where connected at the crankshaft.

My "Big Bang" bike suffered a catastrophic engine failure when a connecting rod nut came loose at high speed and blew a 3" hole in the case! [previous owner had installed an 836 kit years before]



Believe it or not, the motor still ran like this! Can you say bulletproof?!!
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Offline ekpent

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Re: Is rod knock impossible on these bikes or something?
« Reply #8 on: February 20, 2023, 12:16:20 PM »
 I was waiting for that picture Steve, what took so dang long ?  Must be playin' with those race cars again !!  :)
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Offline MauiK3

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Re: Is rod knock impossible on these bikes or something?
« Reply #9 on: February 20, 2023, 01:29:30 PM »
There just isn’t much that compares to these Sohc machines, at least the early ones.
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Offline robvangulik

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Re: Is rod knock impossible on these bikes or something?
« Reply #10 on: February 20, 2023, 01:36:49 PM »
Quote
Can you say bulletproof?!!
So long as oil is pumped it will run ;)
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Offline mad mike

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Re: Is rod knock impossible on these bikes or something?
« Reply #11 on: March 13, 2023, 09:05:40 AM »
It can and does happen, ..... in 1977 my k2  900cc race bike shot the Number 2 big end while i was leading a race, .... lost me a club championship by ONE POINT !!!
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Offline Slow2

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Re: Is rod knock impossible on these bikes or something?
« Reply #12 on: March 14, 2023, 05:41:27 AM »
Oh, they will definitely knock. I drove 300 miles to look at a k4 that supposedly “ran great”. The bike was a mess with not much salvageable but the guy insisted on cranking it up. The poor bike knocked so loud I backed away to keep from getting hit with shrapnel!! Even my wife, who knows nothing about engines, asked me what that loud knocking was, lol. The guy wanted $1500 and wouldn’t budge. Needless to say, I left it there. So yes, they will knock!!!

Ed
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Offline dave500

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Re: Is rod knock impossible on these bikes or something?
« Reply #13 on: March 14, 2023, 11:50:58 PM »
shouldve asked if you could rev it up without riding it,let it grenade then walk away.
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