sledneck666
New member
hey guys i got a question , i have a 98 vmax xt 600 twin and i noticed today when it was running and warm it had a pretty good rattle at idle but as soon as you bring it off idle it goes away , let it come back down on to idle and it comes back , i took it around the yard and did not hear it has lots of power plugs are burning black ( rich ) , has 125psi both sides it sounds like its comming from the motor is it something to worry about or just drive it ? ive read a few things and some people say its piston skirts are slapping ? is it going to do much harm ? any answers would be great thanks !
Devilin AblueDress!
New member
Not to hip on twins but when you say "off idle" do you mean slighlty raising idle but less than clutch engagement or as soon as clutch engages it goes away? If its after clutch engagement I would be taking a good look at the primary. Worn rollers,bushings or cracked/broken parts will rattle until clutch is under load. COULD be very bad if it fails at 5-6 grand RPM while running down the trail 20 miles from a road!
sledneck666
New member
Devilin AblueDress! said:
ya its slighlty off idle but less than clutch engagement , i was just looking on youtube of videos of other 600s running and there is lots of them with the same sound
http://www.youtube.com/watch?v=x6krTKDUOAU
if you listen to that video my sled makes the same sound you can really hear it at 1.17 to 1.20 you can hear it when the sled comes down on idle the rattling appears but as soon as you bring it up its gone
yami1
Member
This may sound dumb but had a 98 once with the heated carbs. Believe there is a petcock attached to the airbox for the coolant??? This came off and was rattling against airbox. Terrible sound simple fix. Look for loose parts, might be something dumb.
sledneck666
New member
i did check around the engine , im pretty sure its comming from inside , i might just adjust the idle up another hundred rpm so its gone and do a rebuild in the summer
It sounds like the exhaust has a leak in that video. Check all the exhaust gaskets. An exhaust leak can have a very sharp sound at idle that sounds like a rattle
sledneck666
New member
stein700sx said:
all gaskets have been just replaced last month because there was an exhaust leak on the main pipe and i also put a mbrp can on it , i have found that if the pistons are worn very slightly at idle the skirts will rattle up against the cylinders causing the sound , and it only happens at idle im worried that its a little noisy but theres lots of them out there that does this and most of them drive forever like that , at the end of the season ill put new pistons and rings and a set of gaskets all oem from yamaha , we just got a huge amount of snow down here so the sleds not staying in the garage any longer lol
heres a little video of what she sounds like
http://www.facebook.com/photo.php?v=506701166027535&set=vb.100000629685169&type=2&theater
