Raptor guru's, here's the problem, or maybe it's not ?

On initial cold start up my rpator makes a noticeable whizzing noise from the low end on the flywheel side of the engine for about 20 seconds then shuts up ?

I've just had to replace my starter clutch (slipping badly) and I thought the noise was associated with the worn clutch unit.

IS this a sign that the timing chain is knackered, seems strange that it goes quite after a short period of running and thereafter the engine noise is gone ? I would have thought that a b-uggered chain would be very noisy when hot ?

Is this a lubrication problem, cold start taking a while to get the oil into some part in the low end, do these engines use oil pressure to assist in cam chain tensioning like alot of automotive engines ?

The problem is annoying, I know it shouldn't be making this noise, it only does ot on cold start and usually excess mechanical noise means problems are just around the corner......................

Kiwi

 

mine has done it since the day i bought it, when i questioned my dealer about it, he told me "you've never owned a Yamaha before have you" mine goes away after warm up too, must just be a rap thing

 

Mine does it too.....sounds like the crankshaft counterweight. 400ex's do this all the time...even efter warmup....normal stuff.

 

same here . does it only on the cold start up ... so does my buddy's 02

 

Mine did the same thing on cold startup and then after about 20 seconds the noise went away.

 

Thanks guys, just bugs me that initially it did not make this noise, it's just recently developed hence the concern. I've tried all different oil's, I was using a blend of castrol GP50 monograde and 10-40 and thought that was the problem and dumped it straight back out again, tried PJ1 10-40 and Yamalube 20-40, no different. I was keen on using the heavier weight oils as this most definately adds in shock loading protection of gears, certainly didn't make any difference to gear selection. NZ temps are very mild, we don't get much below 60 F typical 70's. Our 2002 doesn't make this whizz noise either so Hmmmmmmmm maybe it just time to ditch old number 0000016....

Kiwi