[TJohn]

So i bought a used 07 450r late last summer, and it ran great the rest of the year but the valves kept tightening up so i figured it was time for a top end. When i tore into it i found that the wrist pin was worn weird on one side, so i kept digging. To make a long story short the bike now has new main bearings and seals, balancer bearings and seal, waterpump, piston rings wrist pin, and intake valves. The only thing i didn't replace was the crank because it had no play at all up and down, and very little (in spec) side to side. The only reason for replacing the mains was because the flywheel side of the crank had a very small amount of play... which is still there with the new bearings, and i believe its because of the tapered bearing.

So when i finally started it for the first time it fired right up and ran excellent, but it has a slight knock that i don't remember from before. I checked the valves and there perfectly in spec and all fluids are good. I haven't pulled the oil filter yet to look for metal though. Should i be worried about the noise or not?

[JimDirt]

There was no knock when it ran prior to the rebuild correct ??

When you hear the noise is it a tinny sound or more of a heavy thump sound ?

Does it sound like its in the top end or bottom end ??

If you rest your hand on the head ,cylinder or case does it feel like it is in one of those areas only ?

Did you replace the timing chain ?

Have you tried using a long screwdriver , and holding it to your ear at the handle with your thumb over the top of the handle ,pressed up against your ear to act as a stethoscope , and listened to each area to locate the source of the noise ??

Does the noise go away when you rev the motor beyond idle ?

[TJohn]

-No it didn't knock before it i rebuilt it

-Its not a hard thumping sound but it doesn't sound like a ticking valve sound either it is somewhat tinny

-listening to it you cannot tell a difference if its top or bottom end, not even with a screw driver on the cylinder bolt or a case bolt or a head bolt. it all sounds the same. the engine sounds very smooth but just has this odd knock.

-I for got to say it has a new timing chain and oem tensioner also. the chain had tension on it when i checked the valves so that should be fine.

-and it seems to be more noticeable when its idling than when you rev it.

I pulled the oil filter and it didn't have a spec of metal in it.

[crfsonly]

could be the decomp if it's a ticking sound at idle or just off idle. remove the decomp mechanism from cam and inspect all parts and reinstall making sure the spring is installed correctly. before reinstalling apply oil/light film of assembly lube on all moving parts of the decomp.

[TJohn]

I thought about the decomp but it seems ok. Although i dont have a book for the 07, it seemed like it could only go on one way to work properly and it isnt overly hard to kick. the weight seems to move the pin up and down on the lobe so I assumed it was ok. could the spring be weak?

[crfsonly]

yeah, if it's a knocking sound it won't be teh decomp. if it's more of a ticking sound check the decomp spring is installed correctly.

[TJohn]

The decomp seems fine, i dont think its the problem. The motors not broke in yet, i'm wondering if it could go away once it is broke in, maybe i'm worrying too much...