I have a Yamaha TDR 2001. About 500km ago I had my engine rebuilt (new piston, rebuilt crankshaft, new bearings,..). The engine runs smoothly, but between 6000-7000rpm there is a rattling noise coming from it. My mechanic told me, that it must be a YPVS, but there is nothing wrong with this noise.
Have anybody had a similar problem? How do you fixed it?
Take the YPVS cover off that you can see at 0:41 in the video. Make sure the pulley wheel hole is lined up with the hole behind. Then dissconnect the servo motor ( both the connector block and the single bullet connector).
Then run the engine again and listen for the sound to check if it is the piston hitting the powervalve. Has the barrel had a re bore?
I don't think it will be the powervalve because by the time the engine gets to 6-7krpm the powervalve should be fully open and not interfering with the piston.
The cylinder liner had been replaced with a new one by a previous owner. But the work wasn't done very well, because the new liner wasn't pushed into the cylinder to the end and a new piston had too much tolerance. Then my mechanic pushed a liner to the right position, re-bore cylinder and inserted new piston. Crankshaft had also been repaired.
Mechanic told me, that he had been repairing TDRs before (so he has some knowledge about this engines). He had also checked my YPVS and it seems, that there is nothing wrong .
What means piston slap? That the piston is hitting cylinder's wall? But why isn't it hitting at higher RPMs? The new piston has about 0.07 tolerance.
Yeah piston slap would be where the piston is hitting the walls but your right, it should only really occur when you've just started the engine and as the engine heats up it would stop. Really don't know. If you are good with mechanics then I'd advise taking the barrel off and having a look at everything to check for play.
For the cost of a new head and base gasket and coolant, it has to be worth it.
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