Slight knocking at cold start up - Motorcycle-Journal Forums

Jerryzuki · 11-17-2005, 07:02 PM

Anyone else notice a slight knock from the left side of the engine when reving to pull out the first time with a cold engine? I can hear mine; it doesn't sound that bad and goes away when the engine is up to full operating temp.

jkulysses · 11-17-2005, 07:43 PM

Mine is noisy when it is cold but I just figured that was normal.

Rickster · 11-17-2005, 09:02 PM

Didn't notice any knocking, but it does clunk prety loud when I put her in gear after a cold start.

QuacktheDuck · 11-17-2005, 09:07 PM

No real fuss from my engine...depending on how cold it is outside it seems like it starts very sharply but it runs fine right after. Definitely did not hear any knocking so far.

moccasin · 11-17-2005, 09:32 PM

If the C50 has hydraulic valves, yours just has a slightly looser fit between the plunger and barrel on one or more of its lifters. Nothing to worry about as long as it pumps itself up after a short warm up. If the engine stops with tension on that particular valve, it will "deflate" the lifter over a period of sitting time. This is not an indication of a problem. Its just the nature of hydraulic valves, and no harm is being done while its knocking.

Incidentally, trailering a bike will often cause deflation of lifters even on bikes that don't normally do that. The combination of road and trailer vibrations, and LACK of a running engine's oil pressure will cause the lifters under tension to collapse. Scares the crap out of people who trailer a bike for the first time and then crank it up! HAHA!!

Danr · 11-18-2005, 05:56 AM

The C50 does not have hydraulic lifters (good info on tailering BTW).

Question that need to asked are:

How many miles on the bike?

Did it do it when it was new?

What weight oil are you running?

What is the air temperature?

The only thing hanging out the left side is the Pair Valve, that could be the source. It is controlled by the bikes ECM

blackie1491 · 11-18-2005, 11:24 AM

I have not noticed anything. I always start my bike and let it warm up as I put my helmet and gloves on. Warm up about a minute or 2.
This bike is more noisier than my wing was, but nothing extreme.

11-17-2005, 09:32 PM	#5 (permalink)
moccasin Where Am I ? Joined: Jul 2005 Posts: 47	If the C50 has hydraulic valves, yours just has a slightly looser fit between the plunger and barrel on one or more of its lifters. Nothing to worry about as long as it pumps itself up after a short warm up. If the engine stops with tension on that particular valve, it will "deflate" the lifter over a period of sitting time. This is not an indication of a problem. Its just the nature of hydraulic valves, and no harm is being done while its knocking. Incidentally, trailering a bike will often cause deflation of lifters even on bikes that don't normally do that. The combination of road and trailer vibrations, and LACK of a running engine's oil pressure will cause the lifters under tension to collapse. Scares the crap out of people who trailer a bike for the first time and then crank it up! HAHA!! __________________ Mocc's Place Snake Mail Intruder Stuff ~ Tech Stuff ~ Pair Valve Removal Kits Polish the Bell

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11-17-2005, 07:43 PM	#2 (permalink)
jkulysses Sprocket Pilot Joined: Sep 2005 Bike: 2006 Blue M50 Location: Oregon Posts: 832	Mine is noisy when it is cold but I just figured that was normal.

11-17-2005, 09:02 PM	#3 (permalink)
Rickster Throttle Jockey Joined: Oct 2005 Location: St Paul Mn Posts: 3,137	Didn't notice any knocking, but it does clunk prety loud when I put her in gear after a cold start.

11-17-2005, 09:07 PM	#4 (permalink)
QuacktheDuck Sprocket Pilot Joined: May 2005 Bike: 2004 FZ6 Location: Torrance, CA Posts: 858	No real fuss from my engine...depending on how cold it is outside it seems like it starts very sharply but it runs fine right after. Definitely did not hear any knocking so far.

11-18-2005, 05:56 AM	#6 (permalink)
Danr Sit speling cheker Joined: May 2005 Posts: 1,616	The C50 does not have hydraulic lifters (good info on tailering BTW). Question that need to asked are: How many miles on the bike? Did it do it when it was new? What weight oil are you running? What is the air temperature? The only thing hanging out the left side is the Pair Valve, that could be the source. It is controlled by the bikes ECM

11-18-2005, 11:24 AM	#7 (permalink)
blackie1491 I took the All Bran Challenge Joined: Jun 2005 Bike: C50SE Location: Aldergrove, B.C., Canada Posts: 7,333	I have not noticed anything. I always start my bike and let it warm up as I put my helmet and gloves on. Warm up about a minute or 2. This bike is more noisier than my wing was, but nothing extreme.

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