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My 89 trx 350 has a tick, I first figured it was the timing chain the bike seems to rev fine although I haven't ever drove it before, I know for sure it has an exhaust leak due to residue around the exhaust mandifold/gasket area, good the leaking exhaust be causing my tick? Thanks in advance!
 

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It would enhance the sound of a tick and can sometimes give the illusion that something serious is wrong.
I'd have a look at the chain to see just how much slack there is. The exhaust is an easy fix too.
 

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SamUK has got ya covered. An exhaust leak will make a ticking/knocking noise and fool ya...

You can check the condition of the timing chain by first taking the small plug (8mm socket fits it) out of the end of the chain tensioner (chain tensioner is attached to the lower-right of the cylinder just above the base gasket), then remove the two tensioner mounting bolts with your 8mm socket.

It is good practice to first rotate the crankshaft until the piston is into the compression stroke, just in case an approaching cam lobe ramp (beginning to open valves)... causes the camshaft to rotate backwards when you take the chain tensioner out.

Once the two tensioner mounting bolts are out, pull the tensioner out and inspect the end of it. It should be clean and smooth with no visible damage. Next you'll push the chain tensioner back into place until it stops. At this point there should be a gap between the mounting ears of the tensioner and the cylinder. Hold the tensioner straight... as if the mounting bolts were in it but backed way out... Note the distance of the gap you'll see there between the tensioner and the cylinder.

If that gap is as little as 3/16" or less the chain is stretched badly and needs an immediate replacement. If the gap is 1/4" or more you have just a bit more time. If the gap is larger than 3/8" then you can probably put off replacing the chain for quite a while if you wish, but should recheck it every so often. Once its worn out it may jump time and bend valves.

I personally won't allow them to stretch out until they are junk because they can take out the sprockets a lot faster, costing more to fix it than if it is caught early.

Anyway, once you have determined the chain wear put a narrow flat-blade screwdriver into the hole in the end of the tensioner (where you removed the plug earlier) and rotate the spring loaded screw counter-clockwise so that you can bolt the tensioner back in where it belongs. Once both bolts are tight, release your narrow screwdriver to allow the tensioner to self-adjust back against the chain guide where it was when you took it apart.

Again, it is good practice to slowly rotate the crankshaft one full revolution in the direction of normal travel to insure that the tensioner has taken up all slack in the chain before starting the motor.

And its good practice to enjoy your work and have fun. Celebrate it. :)
 
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