Engine, carbs, valves... not sure what is up. But something is up for sure

rattpunk

rattpunk

Been Around the Block
Edit for brevity and bump:
So the bike is an 82 cm450c. Mechanically stock. I replaced the stock exhaust with shorties clamped right onto the headers. What's troubling me is that after I got the pipes back on, there was a really loud ticka-ticka-ticka-ticka-ticka-ticka-ticka-ticka sound coming from the right side of the engine. I figured it was the valves needing an adjustment?? But thought it strange that I didn't remember that sound from before. And it only seemed to be coming from the right side.

Bike ran out of gas when a buddy was riding it around the block (petcock not turned on...), started it back up and the ticka-ticka was gone and I swear the exhaust overall was about half as loud as it was before the gas ran out. I took it around the block once more and it seemed to run fine. So if anything, maybe whatever was wrong, causing the noise is better, but I don't like drastic changes that I don't understand :eek:

Another thing I noticed was that, especially when the noise was present, the left exhaust was puffing faster and harder than the right. I would put my hands a few inches away and you could definitely tell the difference. There is still a difference, but I'm sure it's been ages since carbs were synced.

Any thoughts on the below question, please:
So, what the hell was that noise? -valves?
Why did it go away after the gas ran out?
And why would it be quieter?
Why would the right side exhaust be weaker? -carb sync issue?
 
Re: Engine, carbs, valves... Noise stopped??

I'll check the valves this weekend if I get time, but has any had similar experience where their bike/car/whatever was making noise and then something happened and the noise stopped?


Could some bad gas (rust) have fouled something up in there somewhere causing the noise and then it cleared?


Am I just chasing my tail and should just assume it's all good now and move on 8)
 
Maybe when the noise was present the right side wasn't actually firing, or not consistently like the left side. Only a guess though. If it was me, I'd check valve clearances, adjust both the cam chain tensioner and balancer and have a look at the plugs. Check compression in both if you have a gauge.

Could also be the exhaust on the right side wasn't completely tight and was rattling, only to stop rattling when the heat expanded it. If it happens again, spray some water on the headers to see if both are hot.
 
Valves is a good idea for sure. That being said, the shorty pipes will amplify your valve noise on these motors and they are supposed to have some. Also there is a balancer Chain, on the right, that has a tensioner that can slip. The big silver button with the slot is how you access it, the manual explains it. Also your cam chain tensioner can loosen up and then go tight so you should check that as well while you are at it. All 3 of those things need to be done, valves, balancer and cam chain tension, around once a season or every other, or sometimes 2 times depending on how often and how hard you ride. And if you never do them, you can wear a hole in the cases in places if the chains get too slack or they can slip. My 450 with shorties was loud (Clicky clackety) and if you were in an ally it sounded like it was falling apart. when I baffled it a bit, it got alot better.
 
Thank guys!


I'll go through the manual and see what I can do with the tools I have and what will have to wait until I can borrow the others (like the compression gauges).


Definitely wasn't a rattle. You could have timed a watch to it. Also, the noise wan't audible from the muffler end, it was coming straight from the case. I even got one of those mechanic's stethoscopes from Auto-zone a month ago when I first heard the noise but broke the thing before I even got it home ::)

So:
Valve clearance check/adjust
Cam chain tension check/adjust
Cam chain balance check/adjust

btw- Maritime, how did you baffle your shorties?
 
3.00 lawnmower mufflers from tractor supply, I screwed them in with self tapping ss screws. Ghetto but helped with the volume, I then used a step drill to drill the plate in them until I got the flow to sound ratio just right. I think I posted it here but not sure.

Cheers,
 
rattpunk said:
So:
Valve clearance check/adjust
Cam chain tension check/adjust
Cam chain balance check/adjust
Click to expand...

Just a note, the last one is just a balancer chain adjustment, not a cam chain balancer. Its just a balancer to reduce the vibrations common in an inline twin.

You probably already know this but thought I'd correct for anyone reading at a later date and getting confused.
 
Deacon, Thanks man. I hadn't gotten to that part of my manual yet. I'm sure you just saved me a few minutes of confused searching through the pages looking for the wrong info.

That's why I put the list there so you guys could set me straight. I've only ever adjusted valves, those other two are new to me, as will be checking compression. Didn't even know people did that till I saw it mentioned in threads here.

Maritime, the lawnmower ghetto-rigging sounds familiar, think I read that post a while back.
 
Plug cap wasn't fitted right and arcing to head? (it's what it sounds like to me)
 
I got a chance to pull out the manual and check out the bike. Not enough to get the tools out, just surveying the scene, if you will. Looks like I should be able to adjust the balancer and cam chain tensioner tomorrow (weather permitting). Have to pick up the feelers to adjust the valves though sold my set in CA a few years back ???


I pulled the spark plug and snapped a couple pics. It's got a solid black coat by the gap. Other than that, the plug and the cap both seemed as tight as they could be. Crazy, is there a way to know if your thoughts were actually what was wrong?


IMG_20121013_160014.jpg



and a pic of the bike so you can see the mess I'm working with ;)
IMG_20121007_123116.jpg
 
It's probably just the exhaust nut you dropped into the cylinder, sounds like its gone now... Its probably wedged in the valve which is the chuffing noise? :)
Sorry couldn't resist!
 
Not really any way to check, maybe turning on fuel moved something?
Check plug wire where it goes into coil, if needed, they can be changed on CM400/450
The balancer chain almost always needs clutch cover pulled off to re-set the tensioner quadrant (it's on splines)
 
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