Scary Noise Or No Big Deal?

S

SR-71

Registered
Hi everyone,

I'm new to the board and I'm working on getting my blackbird up and running

Changed all the fluids, spark plugs, started up… Now there's a noise I'm not sure exactly what it is… But I'm hoping it's some type of exhaust lea… Maybe a few of you can chime in …




Thank you in advance

Yours truly,

SR 71
 
Never heard a noise quite like that other than a valve floating around that had broken loose. Pulling the plugs would be your next step to see if or which one of them shows a flaw. Simply changing fluids and plugs, (if) you used the correct length plugs, would not cause any noise. Was it quiet before the plug change?
 
hi CBX,

When I first bought the bike it would not run very bad load of fuel… I removed and cleaned the pump and the pickup… Fuel pressure back to normal… Fuel running clear… Then I removed all the injectors clean the screens and started the bike

prior to starting the plugs that I removed were new But fouled because of the bad load of fuel… and previous attempted starts

the new plugs I installed are the CR9EHI-9 Iridium

I'm not sure the video I took accurately represents the noise… I can't tell if it sounds metallic or an exhaust leak…

How would I check if I have a bent valve…

Any suggestions or helpful hints would be greatly appreciated

Thank you

SR 71
 
Last edited:
Dude, make sure all the plugs are in tight and that the coil packs are pressed on hard, sounds like an arch to me ...........
 
A plug check might tell you if you have a valve problem as that cylinder won't be getting the right air/fuel mixture. The tip will look different than the others. To check for exhaust leaks get a bottle of windex or something similar, start it up and then squirt it around the head to pipe connectors and anywhere there's a junction...BUT if that sound came out of my motor I wouldn't start it again.
 
Totally sounds like an electrical arc in one lead. Turn the kigbts out in the garage and you might be able to see where the arc is coming from if the tank is up. Its probably a coil pack. I forget if the plugs need the little nubs or not? Maybe that's the problem?
 
Hi everyone,

I pretty much confirmed it's not an electrical arc I replaced all the coils… Started the bike and that awful sound is still there

I'm going to have to bring it to a shop next week I will keep everybody advised

Thanks again everybody for the helpful hints and tips… I'm sure I will need some more guidance in the future

Yours truly,

SR 71
 
SR-71 said:
Hi everyone,

I pretty much confirmed it's not an electrical arc I replaced all the coils… Started the bike and that awful sound is still there

I'm going to have to bring it to a shop next week I will keep everybody advised

Thanks again everybody for the helpful hints and tips… I'm sure I will need some more guidance in the future

Yours truly,

SR 71
Click to expand...
take a compression check, that is the quick way to find out if you dropped a valve or jumped timing , could also be bad timing chain guides also see if the noise is still there while pulling in clutch, a bad clutch basket can make a lot of noise , , if it were a leaking exhaust gasket you could hold your hand around the exhaust flange and the head and feel the air coming out, could be a broken piston skirt, you could pull the valve cover off and rotate the motor over and look to see if all the valves are coming back up once the came lob is off the came bucket
 
Hello, to all and a very Happy and Safe New Year:

I have not done a compression check:… I guess that's next on my list

I start the bike with the fast idle (No miss or misfire)… Give it a few minutes to warm up… then return to normal idle… Runs very smooth… occasionally and cautiously I will rev the throttle up but there is no hint of a misfire

As was previously suggested I put the front tire up against a wall… And let out the clutch does not seem to be any difference in the strange noise which is driving me CRAZY

And no I have not driven the bike for fear of causing any additional damage

I want to try and tackle a few more things today since I have some time off but I'm very perplexed as to what to try next

Thanks again, everyone for the suggestions and helpful tips…

SR 71
 
AHAH! So this noise began after the plug swap. Perhaps one of the plugs has a broken or bad insulator. This could create that sound and the bike would still run just about the same. A valve drop woyld sound and behave differently. An exhaust leak wouldn't show up that suddely and you would be able to see an arc elsewhere on the bike (if you did the test I recommded). You won't be able to see arcing on the plug because the coil pack and rubber insulator will seal off the plug area.
Put on some thick gloves and pull one coil pack at a time off while its running. See which one is the culprit.
 
hi turboJohnny,

The reason I initially change the plugs is that the bike would not start they were quite fouled… But that may have been, what I thought to be a blessing in disguise at the time… Pumping fresh new oil in the system without starting…

Further, I have removed the plugs 3 times thoroughly inspected them no damage, and no hint of hitting the piston or the valve

Additionally, I replaced all the coil packs brand-new … No appreciable difference maybe a little bit easier to start but that's it

Now, I'm going to follow your suggestion … ( "BECAUSEI I DON'T MISS A MUDDY PUDDLE"… LOL…) and pull each one of the coil pack wires looking for a culprit… But with my luck I'll be standing in pool of gas waiting for the spark to travel from my fingers down to my toes sitting me on fire… Ha ha

Of course I'm very very upset just try to keep a smile on my face

Thanks for your reply… Any other suggestions will be greatly appreciated and welcome

SR 71
 
Wouldn't a dodgy coil pack throw up a 'C' code ? ... That noise sounds to me like a timing chain slapping against the cover. Seems too loud to be an arc.

Or worst case scenario ... You dropped a bolt into the hole when changing a spark plug and its bouncing around in there !!
 
Darn. If youve pulled the plugs already and swapped them then thats probably not it. Harbor Freight sells a mechanics stethascope for pretty cheap. You could listen for the cam chain. Also, you could get one of those little bore scopes from HF for 70 bucks a take a peak inside the cylinders.
I am so curious to see what this is.
 
See if anyone you know has a bore scope. Take a look for debris in a cylinder with a plug out. I should have read the last post. Lol. Where you located?
 
hi Mike 04 Buser,

I'm in Los Angeles… I bought mechanic stethoscope … Trying to locate borescope that hooks up to the android phone so I can save a few dollars…

I have a little time today so I will try and use the stethoscope to pinpoint the cylinder or offending location

Thanks for your time and consideration… I'll keep everybody advised

SR 71
 
hi everyone,

I borescoped all 4 cylinders… Couldn't find anything inside I made a video but for some reason didn't record or I just can't find it on my phone… the boresocape indicated it was recording but I can't seem to find it… However I did a thorough inspection and it was nothing in the cylinders

I made a few more videos hopefully this will help with the diagnosis… One is with plugs removed engine turning over… Then I made to others with the engine running hopefully there will be a little better audio to help with the diagnosis




Thanks everyone in advance

Thank you


 
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