To make a story short, this is my friend's '06 700R with probably under 30hrs that was stored at someone's house who lent it out and now we have a few problems. When we got it back, there was a bad tapping in the motor, sort of like the cam chain noise my Z had. I listened closely and it seemed to be loudest in the cylinder. I haven't looked at it much closer because the lower rad house was also busted and it won't hold fluid. Could we get universal hose from Discount or something, or just order from the dealer? Anyways, so I checked the compression (cold) and it read about 80psi. I thought that was low, but the motor is completely cold, not sure if that affects the reading, and I'm not sure what fact specs are. What else can I check that could be making that noise? Figuring this out to know if anyone owes my friend money or not for repairs. Thanks in advance...

 

it could be the lifters.... I heard a rumor not sure if it is true but they said since the gas is having ethanol in it that the lifters are starting to make a tapping sound.. i got the same thing from my beartracker and not worried about it... I would try putting some mystery oil in with the gas.. This should help to lube them and that might help to determine the problem... Hope this helps

 

Do a leak-down check on the motor.

Then, adjust valves if necessary.

Then, check cam chain and the tensioner. [img]i/expressions/face-icon-small-smile.gif[/img]

 

take the engine mods off and make it stock and take it back to yamaha. warrentee

 

The 700R does not have lifters per say, it has roller wheels on the end of the rocker arm that ride on the camshaft.
I would call them cam followers. From what I have seen on my 700R after the initial adjustment the valve clearance stays dead nuts on. I have 200 hrs on mine and it's still in spec.


I would be more inclined to think it's possibly hung a valve in a guide, especially if they got it hot and **** wound it . That would account for the noise and the low compression reading. It should give you a comp reading of around 150 but like Headsup said a leak down test is your best bet to isolate the problem.

 

Good info guys. Yeah apparently he didn't get the extended warranty and it was up after 6 months? (He seriously has only like 30hrs in 8 months...) Yeah, I thought that was a low reading, it did still feel ballzy. Another thing I noticed was the throttle sticking, or it not wanting to come down to idle sometimes. But I thought that was a separate problem. I'm going to tell him to get a manual before I mess with it too much, but we'll do the leakdown and see if we come up with something. Anything else?

 

80psi, That sounds right... There is a decompresion unit on the cam.

 

I just checked the compression spec and it's 64 PSI at sea level. So 80 PSI cold is not bad at all.