Engine Noise, any idea?

Everything_To_Xs · Posted: May 5, 2009, 5:49 am Post subject: Engine Noise, any idea?

I have virtually undone the cam tensioner so that it is not touching the rod but as you can see it appears to still be too much tension! wierd...

Well watch this video please and see if you can tell me what you think the noise is.

just follow the link

s22.photobucket.com/al...deo021.flv

Everything_To_Xs · Posted: May 5, 2009, 6:45 am Post subject: Re: Engine Noise, any idea?

i have reason to believe that the sound may suggest that the chain is not on correctly? but i dont see how :-/

Everything_To_Xs · Posted: May 5, 2009, 6:46 am Post subject: Re: Engine Noise, any idea?

i cannot kick the bike over unless i turn the crank a few times first, then i have the ability to kick it. and then after 1 or 2 kicks it locks up again, All the time with that exact same noise though

Everything_To_Xs · Posted: May 5, 2009, 8:30 am Post subject: Re: Engine Noise, any idea?

I have takjen the bottom crankcase half off to find no obvious problems at all.

The gears are all located, the gearbox is doing what it should do, the selector forks are in perfect condition and are in the correct position.

Only place i can see and hear it coming from is the cam tensioner

I have taken the cam tension spring and arm out and it stops making the noise

Soon as you put it back in it just doesnt wanna know.

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

Looks like in the vid that the spring is getting stuck and when it snaps back it clicks. Try and lube it? Let us know how you make out. Have you had the cam chain adjuster out since this started?

xsjohn · Posted: May 5, 2009, 8:33 am Post subject: Re: Engine Noise, any idea?

You are lucky it won't start..........the chain tightens as the cam passes a lobe then the spring snaps the adjuster.........this would be just a wild ass guess but when you put the new chain in there it acts like an extra link judging on how much adjustment you have and how far it would require the adjuster to be turned in to make a correct cam chain adjustment.....something wrong with the adjuster....?.....time to take it back down and find out what you did wrong....

xsjohn

Everything_To_Xs · Posted: May 5, 2009, 8:42 am Post subject: Re: Engine Noise, any idea?

Oh god thats exactly what i did not want to do lol.

In the end i didnt actually replace the chain, I seperated it and then replaced the link using the old chain again.

Same ammount of links, same chain just different link.

I did however though replace the the cam tensioner pivot arm assembly, the entire lot, as mine was worn well beyond tolerance.

Thinking about it, is it possible that because the chain tensioner was worn that the chain may have been worn to and then putting the new arm just means time for a new chain to go along with it?

Any help any ideas will be greatly appreciated.

Xsjohn thanks for the info i guess the strip down starts again now Sad

xsjohn · Posted: May 5, 2009, 8:54 am Post subject: Re: Engine Noise, any idea?

Replacing a worn adjuster should have improved the amount of spare adjustment tension in the adjuster at the back of the cylinder...........something tells me there is something else at play here too..........

xsjohn

Retiredgentleman · Posted: May 5, 2009, 11:12 am Post subject: Re: Engine Noise, any idea?

If your camchain is not stretched (worn out), then you should be able to tighten the chain adjuster nut until there is no bobble (and no clicking), when cranking the engine by hand.

If you tighten the adjuster all the way inward and still have the huge amount of slack that gives that click, then the chain is toast and time to replace the chain.

Everything_To_Xs · Posted: May 5, 2009, 3:51 pm Post subject: Re: Engine Noise, any idea?

Ok so we have figured that a replacement chain is due but why is it that sometimes it will kick over and other times it wont?

xsjohn · Posted: May 5, 2009, 4:07 pm Post subject: Re: Engine Noise, any idea?

If that thing managed to start it may just lunch itself......... xsjohn

jayel · Posted: May 5, 2009, 4:38 pm Post subject: Re: Engine Noise, any idea?

yeah I'd be checking, almost sounds like the valves are hitting the tops of the pistons, entirely possible if the chain has jumped a tooth or two

gordo · Posted: May 5, 2009, 4:53 pm Post subject: Re: Engine Noise, any idea?

It look's like the tensioner wheel is sticking in the chain as the engine is rotated. I wouldn't run it till you check the cam timing again. I'd say a new chain & rivit link are in order, sorry to say. Surprised

Oh, no wheel, chain getting caught under the new tensioner assy. When you get it apart, look at the bottom of the tensioner for sign's of that. The chain should run near the center .

Everything_To_Xs · Posted: May 6, 2009, 10:11 am Post subject: Re: Engine Noise, any idea?

Jayel you are correct, I have since looked inside the plug holes and i noticed that the valve was hitting the top of the piston.

I have taken the rocker cover off and the cam is in perfect allignment just as it should be.

yamaman · Posted: May 6, 2009, 10:39 am Post subject: Re: Engine Noise, any idea?

180* out?

Mofokker · Full Member Joined: Oct 22, 2008 Posts: 46

sound like a piston hitting a valve. Your timing must be off a tooth or so. Which mark did you use on the camshaft to line it up? If you used the one on the right hand side of the cam, you will be 90* off (ouch) The mark is on the left side (same side as points)

Mofokker · Full Member Joined: Oct 22, 2008 Posts: 46

Yamaman says "180* out?" Not possible on a engine where both pistons are at TDC at the same time. I know they will be on different strokes but all you have to do is turn the crankshaft once and the cam will turn 180* opposite. Putting it where you want it.

Everything_To_Xs · Posted: May 6, 2009, 12:15 pm Post subject: Re: Engine Noise, any idea?

i have sorted the problem with the valve hitting the piston. but still got the problem with clicking, it doesnt make sence because its the same chain i used before and then it was fine , how can it suddenly be no good no anymore?.

That tensioner bar that you adjust for the cam chain, well that is supposed to sit flush with the nut on the tensioner when it is at correct tension.

Well no matter how far out you turn it, the bar still comes past the nut just like in that video, i had the tensioner allmost out just and its still doing the same thing.... Spooky lol?

yamaman · Posted: May 6, 2009, 12:19 pm Post subject: Re: Engine Noise, any idea?

Everything_To_Xs wrote:

i have sorted the problem with the valve hitting the piston.

How?

Yep, good point Mofo, I guess I didn't really think that one through, cheers!

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

the Tensioner is way to slack.

It sounds to me like the chain has stretched so much that the tensioner is no longer working properly, that rod should only move in and out about a mm when the engine is being spun over..

It sounds to me like the chain is jumping and thats whats creating sudden slack..

The noise you are hearing doesnt appear to be the piston hitting a valve because the noise is synced with the tensioner rod.

Either way dude. Top end off, new chain, new link, check the guide and tensioner blades. Dont try running it without do this!

xsjohn · Posted: May 6, 2009, 7:00 pm Post subject: Re: Engine Noise, any idea?

Jake here is what everything said in his first post .........not sure what this test was supposed to find...........the clicking was the cam lobe passing the lifter on a loosened adjuster and probably a worn chain .........snap...and loosening the chain that much would put the cam way out of adjustment and maybe a valve could hit a piston being so far out of time........

""""""I have virtually undone the cam tensioner so that it is not touching the rod but as you can see it appears to still be too much tension! wierd...""""""

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

WTF?

? LOL

Hey "everything" dude..where in the UK are you?

aybe its close enough for me to come round and help you with / fix it for ya? Smile

With the clearence wound right out, the valve spring would just be a method of firing the cam around, especially with the chain that loose...

Should be easy to fix is the chain and associated guide and tensioner arent too f_cked. Probably even without a new gasket..

xsleo · Posted: May 7, 2009, 3:02 am Post subject: Re: Engine Noise, any idea?

I had a noise like that in my 75 engine. It was the cam chain adjuster plunger hitting the adjuster screw. I put it together with out the damper on the plunger rod. If you tighten the adjuster up the noise will still be there.
The noise comes from the cam going over center and pulling the slack out the chain very fast and the plunger getting thrown against the screw. it only happens at one place as you turn the crank.
I think the reason you can turn it over but can't kick it is with the chain so loose it piles up on top off the crank sprocket enough to bind the engine, when you turn it by hand you take up the slack so the engine will kick over a time or two then the loose chain binds up again.
Try putting a damper on the plunger rod and adjust the chain properly. Check the cam timing by setting the timing marks to tdc and check the pin in the points cam to see if it pouints straight up or straight down. If not the chain may have jumped a tooth or two. I had to reset the cam two teeth to get it back to where the point cam pin pointed straight up. Once I did this the noise went away.

Everything_To_Xs · Posted: May 7, 2009, 5:03 am Post subject: Re: Engine Noise, any idea?

All valid points my friends but i think i have found the problem. Appears to be that the New pivot assembly i put in is too big, it gets jammed half way as it passes through the channel cut out for it in between the head and the barrels.

So when i screw in the adjuster it pushes the Pivot arm plastic tensioner into the chain right? but then it gets stuck, its jammed solid and i mean solid! i couldnt move it at all without taking the head off.

I have 5 of these tensioners i have now tried another one in it and all seems to be fine.

If i do come across the problem again or anything simillar as i am going through the yet again engine rebuild stages then i will surely let you know. Thanks For the insight guys youve been a massive help!

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