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Terrifying clack noise..

Old 01-29-2018, 12:57 PM
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Terrifying clack noise..

So this happened once or twice with long periods of time in between then became once every few start ups now and happened many times on one startup attempt this fall during winterization..

While the bike was starting up it almost sounds like the bike cuts out and puts out a loud CLACK! Like i struck the engine casing with a wrench or something then comes back to life. It also started doing it when in nuetral/while holding the clutch in if you burp the throttle. If its running and does this the engine cuts out to dead silence, clack, then roars back to life. It has never happened while putting power to the tire. And last but not least during an attempt to start up to run fuel stabilizer it turned over,clacked, turned over again, then staryed making the noise 2 or 3 times repetitively to the point where I'd rather tear apart and clean my carbs then try starting it any further. I tried searching what I could but no luck... Any input would be appreciated. This is my first bike/first season riding and I have a bunch of time and money in trying to get her going good. (Bought her as is with bad road rash and no plastics, now looks mint, new factory carb setup, all the basics covered) Thanks in advance for looking this over.
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Old 01-29-2018, 01:36 PM
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Sounds to me like several things potentially, you will need to give us details as we go with questions.
The clack noise is most likely just from abrupt shutoff, the reasons is usually the carbs set up for burping as such.
What is the RPM on your bike at working temperature in idle?
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Old 01-29-2018, 02:15 PM
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Around 900-1k ish
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Old 01-29-2018, 02:40 PM
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Ok, that is a bit low, that may explain it, it should be running around 1200 to 1250
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Old 01-29-2018, 04:18 PM
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"Clack "or fart?

As mentioned up the idle to help lessen the chance it stalling esp in low speed turns...
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Old 01-29-2018, 10:09 PM
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Old 01-30-2018, 06:18 AM
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Would carb darts occur while starting the bike? It was cold so it turn over without actually firing nust cranked and cracked. And i'll definetly turn up the idle on it. I did a spocket and chain replacement in the fall before this happened (I hang my head in shame as my lack of knowledge is going to shine through) and I can't remember if i dropped a tooth or gain a tooth in the rear (geared it towards low end a tad more) and I still have just enough power to barely keep up with my buddies stock superhawk. So maybe I do need to do another carb calibration, and maybe put some low strength thread lock on the screw?

Also I just thought of this but I developed a slight ticking that sounds like its coming out from under tthe front of the gas tank so i tried adjusting my cct's and accidently loosened em up a tad before I realized what was going and then tightened them back up. Is there a chance it could have jumped a single tooth or something? I thought if it jumped one tooth at all it would have issues running but this happeed and didn't result in any immediate immediately noticeable issues.
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Old 02-15-2018, 05:45 AM
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I also occasionally experience the noise you're describing on cold starts. I find its usually if I let off the starter before the engine gets going... Was alarmed at first but while it runs I have no issues, and seems to be just fine on power (have ridden a friends superhawk as well for comparison).
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Old 02-24-2018, 12:51 PM
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its your sprag clutch gear. the noise your hearing is it hitting its backlash.. they can fail as they are a kinda press fit and only rotate one way, what you are hearing is it trying to rotate the other way.

always keep a tip top battery as this helps stop this happening
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Old 05-26-2018, 06:40 AM
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So I tore the top of the bike apart and found a couple things, first: battery has a lose terminal, so fabiostar could have very well been right about the noise, Second: My loss of power i think can be explained by my front intake being out of time one tooth. Me and my buddy were able to loosen the CCT so we could jump the chain back one tooth to proper timing and i've started reassembling the bike. I'm hoping it starts and runs proper and I dont have to do any major repairs to the tops end. Thanks everyone for the input, hopefully this question has been solved!
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Old 05-26-2018, 09:10 AM
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Originally Posted by fabiostar View Post
its your sprag clutch gear. the noise your hearing is it hitting its backlash.. they can fail as they are a kinda press fit and only rotate one way, what you are hearing is it trying to rotate the other way.

always keep a tip top battery as this helps stop this happening
I agree this is the most likely issue.
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Old 05-26-2018, 11:43 AM
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test ride was a success! Drives like a dream. putting all the plastics back on it now.
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Old 05-27-2018, 07:16 AM
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I'll add some final notes to this for anyone looking at this thread who'd like a little more info. Last summer my buddy "MwCrf450R" bought a superhawk in rough shape. We changed fluids, returned air box and carbs to stock (hawks carb setup) and balanced carbs. the bike ran great all summer and in the fall he was telling me he had these loud "clacking" sounds. I thought the problem was carb farts too. My bike will occasionally let out a carb fart but the sound is more like a "poof" or "pow" and then the engine speed will drop. "MwCrf450R's" bike was making a VERY loud "CLACK!" and engine would almost completely die. This sound was coming from the top of the front cylinder, so my recommendation was for him to try tightening the front cam chain tensioner (APE manual). I think he loosened 1/4 turn instead of tightened 1/4 turn. As soon as we got the cover off the front cylinder it was clear that the cam chain was very loose and some very light scratches and scoring on the inside of the motor casing where the cam chain had been slapping back and forth. Following the factory Honda service manual we checked timing on the rear cylinder (spot on) then moved to the front cylinder and found the intake cam sprocket had slipped and was now off time by 1 tooth. Zip tied the exhaust cam in place, loosened the cam chain, slipped the intake cam back 1 tooth, tightened the chain back up and using a straight edge everything was lined up PERFECTLY ! Put the motor back together and it's purring like a kitten again !
So, to make a long story short. Anyone with a "clack and die" problem on thier bike should probably think about carb issues but should also consider loose cam chains or timing being off slightly. My thought is my buddy just got really, really, really lucky the motor didnt "grenade" itself !
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