Life span timing chain
 

My bike makes more sound than it did in the beginning. It sounds like some metal balls at low rpm. First I thought about the big end, but there is no metal in the oil nor in the oilfilter. Adjusted the valves and the cam looks normal. Now I am thinking of the timing chain. What is the life span of it, can it make a knocking sound at low rpm, I always thought it was more of a rattle sound.

BTW it has 60.000km on it.

Interested in the out come of this, my XTR's got 42kmiles and has similar rougher sounding. Seemed to be a bit quieter when it had a service including values checked about 4k miles ago, which seems wierd to me.

Nobody? I will also post it in XT660R.

I'm still on original camchain at 57,000+ miles but it seemed tight enough when I checked at the weekend.

Problem I always had with previous bikes (all big singles) was the clutch basket damping springs going slack causing major clutch rattle and clatter on take up.

Listening to some comments, do the following test:

Listen to the noise with the clutch out in neutral, and with the clutch in, see if there's a difference

I would expect a XT's timing chain to last more than 80K miles, depending on how the bike is serviced & ridden.

Oke, that was the more or less what I expected.

No change in sound with or without the clutch engaged.

I will make a movie and post it.

Here are my video:
http://www.youtube.com/watch?v=rjYYt1DstIU
http://www.youtube.com/watch?v=JegGVCO36lo

That doesn't sound ... uh. . . . . 'healthy'.

What about oil consumption? Tilting piston???? Wouldn't expect it though... not at that mileage...

... but still better then ... indeed ... your big end.... wouldn't expect that either ...

Use a screwdriver as a stethoscope to localize the source of that sound more accurate.

HJ

If your bike is still under warranty take it straight back to Yamaha for repairs. Otherwise you best strip the motor to find the problem, I would not be riding it.
:Suspicious_DXD5FP:

Jip, still under warranty. I will visit the dealer on Saturday. Curious what it is.

mmmm
 

doesn't sound healthy does it....

(that is an official diagnosis)

will she make it... http://img151.imageshack.us/img151/1...nicyj81uh9.gif

doctor ???

Ouch - sounds very poorly.. Could be a combination of all sorts of sloppy mechanical bits..

I've got my bike back. It was the nut of the crackshaft. It is a known problem for the older XTZ 660's and also on some 600. A pitty Yamaha did not find a solution.

Which side?

Hi Neik, I assume you mean the clutch basket/primary gear nut? Just did a quick google on it - something else to watch out for!

Cheers,
Rick

I know about the clutch hub nut coming loose, but have never heard of the crank nut coming loose on a XT before.

I assume it's the nut that holds the magneto/flywheel in place.

http://home.planet.nl/~scho3025/Tene...tchMagneto.jpg

I remember in my early days of (low budget) motorcycling I had an similar experience when I didn't put things together properly after replacing a faulty AC-generator on my worn Honda CB400N. After 40km's the engine started to sound and feel like it would fall apart.... flywheel had come loose...

HJ

I think it was the nut holding the balancer drive gear, have to check it at home.

Found it, lock washer 90215-20X00 has been replaced which is from the nut on the right side of the primary drive. figure 16 part no 4 of the parts list.
http://i53.tinypic.com/9vcahu.jpg

Here's another patient: mine has covered 70.000km's and hasn't had an easy life. Noticed a rather irregular rattle that distorted the idle run speed. My mechanic demonstrated how it disappeared when he put it in first gear, loaded up the drive by engaging the clutch while keeping the engine at low rev speed and brakes on => sound disappeared, so nothing wrong with piston, rod, big-end or crank or gearbox. Clutch dis-engaged: rattle returned => some sort of play in clutch (drive)

Took it out to find out it's exact the same problem as with Niek's bike.

HJ

If it is a loose right side primary drive nut then I suspect the r/h main bearing is worn.
As the bearing wears it not only develops radial play - it develops axial play. It's the axial play that unloads the nut.
Just retightening the nut helps to eliminate the play. I've been riding about 25k miles with another worn r/h main bearing by just tightening this nut (slightly over torqued).

Yeah, I've just been reading about rolling element bearings in main bearing applications, and it seems that any excessive radial play (from new) is adjusted by axial preloading of said bearings.

So RickM is right, according to guru type people. Retorqueing a loose crank nut should quieten a bearing if it hasn't been left too long.

I think I need to get a life...:005::gsmile:

Who was it that said a small amount of knowledge is a dangerous thing?

thanks for that guys. Briefed this on to my mechanic and he confirmed this (rather skilled/experienced guy).

HJ