ron2k_1

For the past couple months I've been noticing that my rear cylinder is more noisy than the front one. When I start the machine the valves (I cannot catch whether it comes from the intake or ex) sound like you're hitting the exhaust pipe with a 3 inch nail from 1" distance repeatedly at the same RPMs the engines is running on (meaning that you'd hit that nail on my exhaust at 800 or so RPMs per min). After its warmed it kinda quiets down, strange huh?!. My ticking noise is kinda acute and not necessarily really loud but acute.

Having a description that the engine should sound like a sewing machine is kinda hard to go by. This is the only bike like it around, so I cannot really compare. The thing is that I don't really get the same sound from the front cylinder - it is more quite and the ticking is kinda relaxed and mild, the ticking on the rear one is aggressive and at warm up the ticking is more like mild clanking (hence the nail on exhaust analogy).

Here is a video
Valve Noise
Notice the difference on going from rear to front cylinder.

I've adjusted my valves twice during the last 10 months. The bike only has like 6K miles since new (when I got it).

Is it normal to have that kind of noice when warming up and then quite down once warm?

Ron

__________________
Ron
----------------------------------------------------------
Friendship is like peeing yourself - everybody else
can see it but only you can feel its warmth
----------------------------------------------------------

DrBLVD

Linky no worky....

These motors sound like rabid sewing machines, if that helps.

With the bike idling, stand on the left side as not to let the exhaust noise interfere with your diagnosis.

If you don't have an automotive stethoscope, you can put a cut-off broom stick or dowel on the top of the head and put your ear on your cupped hand to the other end of the dowel and listen to see if both heads 'click' the same.

__________________
Why use a big word when a diminutive utterance would suffice?

ron2k_1

I've really made sure on my lat two tried of valve adjustment that I adjust on the right TDC. I'm pretty sure that the noise comes from the ex valves of the rear cylinder, the in valve sound ok.

Oh, I've fixed the link, so please try again.

Thanks

Ron

__________________
Ron
----------------------------------------------------------
Friendship is like peeing yourself - everybody else
can see it but only you can feel its warmth
----------------------------------------------------------

DrBLVD

I listened to it. Hmmmm, I've heard that before from others posting there motor's sound.
I am kinda suspicion of the valve adjust. Did it make that noise before the adjust? Could the gap be too big? Kinda sounds like the rocker slapping on the valve.

Try to record it again from the other side, to minimize the exhaust.

Maybe someone who had this noise will chime in. Hard to diagnose a problem via Youtube and a Forum.

Since it's coming from the head, got to be valve/rocker related. You don't hear it from below, like a connecting rod slap?

How many miles on the bike? Maybe a cam chain out of adjust? Try the dowel/broomstick technique on the back and front of the rear head, may be able to tell what set of valves (in or out) before disassembly.

__________________
Why use a big word when a diminutive utterance would suffice?

Harpy350

My bike is doing the same thing and I just had the dealership adj the valves. It's like 1600 bucks to have a new cam chain put in without the price of parts. I'm really disappointed in the fact that I just bought the friggin thing this past Thursday. Can anyone help me out with pointers on how to fix this


Sent from my iPhone using MO Free

Logan

I'm the exact same boat as Harpy. I adjusted my valves and got the same noise as the original poster of this thread, so I took it to the stealership. They said my valve job was perfect, but that my top-end noise was way too loud...probably the "hard faces" worn off the cam and rockers of the rear exhaust cylinder. They even said it was potentially dangerous to ride the bike that way, though I don't see how.

Sorry to re-awaken this thread, but before I tear my engine apart, is this considered normal?? the bike's got 20,000 or so on it so I have a hard time understanding how the hardness of the metal goes away. The dealer said my valves were adjusted right. The whole 'sewing machine' analogy is a little confusing; does anyone have a good sound bite of what a healthy M50 engine should sound like??


Thanks

Logan

peprice

Mine is the same way, I keep the oil level right , adjust valves every 7000 miles. I just got tired of worrying about it I guess

cavie

You can not diognose a valve problem over a computer sound bite. Get a second opinion from an independant machanic. Prefribly a metric mechanic. These bikes should make noise. If it doesn't, turn it off.

__________________
'03 Volusia Intruder, Cobra Drag Pipes, K&N air filter, Fatty Knees Bars, Mustang seat, Grasshopper backrest, Wolo horn. Gold wing floor boards and a few other goodies.

kerf

There is a reason that the engine is noisier when first started and it has to do with the reason that there is valve lash in the first place. The one thing that will destroy valves is for them not to be fully seated during firing, as hot combustion gas will cut the valve face just like a cutting torch. Valve lash is introduced with the engine cold, so that when it warms to operating temperature and parts expand, the valve will not be held off its seat.

The cold valve lash will be reduced as the engine warms and there will be less tapping. This of course says nothing as to excessive wear in the valve train. I have had automotive cams wear out but only with high mileage, provided the cam is properly broken in, which should have occurred at the factory.

Againstallodds

Hey Ron, same sound as my bike. Any update as to how u fixed it?