Engine Knock?
08-05-2008 | 10:22 AM
#1
Thread Starter
Junior Member
Squid
Joined: Jul 2008
Posts: 2
Engine Knock?
Well i just bought this beautiful '98 superhawk with 40,000 miles. I had to go out of town shortly after and I wasn't able to ride it for to long. Well i'm back and i took it out yesterday and today and noticed something very disturbing. It sounds like a knock coming from the engine. It happens between 2500 rpm and 3300-3400 rpm. I've tried 1,2, and 3rd gear and they all produce the same knock at the same rpm range. When this knock occurs if feels like there is a loss of power for a split second and then the bike seems to run fine until the next knock occurs. Once i'm above 3500 rpm the bike runs great and i can't hear/notice the knock anymore. I was wondering if anyone knows what is going on b/c i have no clue. Please help!
08-05-2008 | 01:32 PM
#3
AZ RIDER
Superstock
Joined: Jul 2008
Posts: 294
From: Arizona
could be your slide carb making noise.. thats very common.. did you check to see that you dont have any missing or loos bolts on the headers.. that happened to me 3 days ago.. couldnt figure out why i had a terrible exhaust leak sound and sudden backfire and come to find out the bolts were gone on the rear exaust flange.. had to go find similar M7 Metric bolt for it... i have also heard you can get manual cam chain tensioners for fairly cheap if that is your knocking..
08-05-2008 | 04:25 PM
#6
Senior Member
SuperSport
SuperSport
Joined: Dec 2006
Posts: 880
From: Victoriaville, Quebec, Canada
This is no knock, it's more like a fart, intake fart.
This means that your needles are lean, if you have a DJ kit installed, pull the needles one notch, or shim the stock needles.
Or put that stock exhaust and air filter back.
This means that your needles are lean, if you have a DJ kit installed, pull the needles one notch, or shim the stock needles.
Or put that stock exhaust and air filter back.
08-06-2008 | 12:21 AM
#7
Junior Member
Squid
Joined: Jul 2006
Posts: 17
From: Finland
+1 to intake backfire caused by lean condition. If bike used to run fine with the exactly same setup then there is a new air leak somewhere or you need to clean the carbs. Otherwise just get the mixture corrected as gboezio suggested.
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