xt660 crankcase knock diagnostic vids and fix!
 

ok so i thought i would share my personal fix and problem with my 09 xt660x as there is very little info on the net about this exact problem. the way it happened for me ....... ok so i bought my baby with 10500 miles on it a few months back and i took it for a long hard ride and came back with a knock under acceleration
i instantly thought the worst thinking i had killed the big end bearings as that was wear the sound seemed to be coming from. so i rode it for a few days to check it wasn't my imagination and there was still a knock there that was bothering me so i took it to 3 different local bike mechanics they all agreed it sounded "corse" but said its "just a big single and that's all the noise is keep riding it and see if it gets worse" so my mechanic instincts kicked in (car mechanic) and i new something was wrong as the sound had changed and sounded very metallic when accelerating / decelerating the engine from a fixed speed . i also realized that if i put it in gear and hold the front brake and try and drive (take up any slack in transmission ) it would sound just like hitting a hammer on the top of a vice. which cant be good so i did some research and found very little info on it so i decided i would strip the oil filter, water pump, clutch cover and arm, and the right hand side foot peg off so i could take the crank cover off. when i looked close i could see that the primary gears on the end of the crank shaft could be rotated a fair way either way before the shaft stopped it from rotating freely so i un folded the lock tab which had no signs of allowing the nut to spin and found once this was out the way i could rotate the nut off the end of the shaft by hand .... obviously this wasn't right so i tried some more research and found something to do with on the newer models the torque settings had been reduced even tho its the same components they just deiced to fit the newer engines with a lower torque measurement . so i found some were on the web which stated the older torque measurement was 110nm so i went and bought a new lock tab washer and some permanent lock tight and resembled the nut back onto the crankshaft (luckily they was no signs of wear or damage)

so with the lock tight and new tab washer i torques it up to 110nm which was rather tricky because of having to take up the transmission slack while on a paddock stand but i managed it in the end then i bent the tab washer over one of the flat sides of the washer and also manged to bend the other side of the washer into a triangle over the top corner of the nut i then rebuilt the bike put it all back together and have done 1300 hard miles since and there's still no knock :) all this cost me about 4 hours of my time laid infront of a heater and about �10 for the new washed and loctite .

just thought i would share my story as i think it might be pretty helpfull for others cos when it first started i was prety worried thinking that sounds expensive lol
below you will see three youtube links of the knock and also of the fix

any questions just message me or comment below.ash
happy riding

vid 1 of knock http://www.youtube.com/watch?v=1yOV3...ature=youtu.be

vid 2 of more knocking noise http://www.youtube.com/watch?v=bEggx...ature=youtu.be

vid 3 the problem and fix http://youtu.be/Nyk4PWGVQgw


(i hope i have posted all this in the correct location)

Nice work mate, we are seeing more & more of these loose nuts, first one was back in 2007.

cheers i just thought i would make that thread due to been very little info on the web about it (or what i could find anyway)

Like the videos, I am sure it will help other guys out.

hi bikemad195,

thanks so much for the videos! it helps a lot. yesterday I went to a yamaha mechanic who said that the noise from my engine was perfectly fine.....will check the third opinion and will show your video.

cheers,
davide

from my mechanical passed i find that if a customer or owner of a vehicle who uses it day in day out from cold and through all the variables and the say that something is different 99% of the time they are correct. in my case i rode it hard and it made the noise more obvious to me so i knew there was defiantly something wrong lol

I had the same problem on my 2007 XTX. The knock started on at 64000 km. I went to a Yamaha dealer and the problem solved. He told me that the crank nut was loose. I believe it was the same as yours. The mechanic also replaced the piston springs, oil, oil filter, antifreeze and checked valve clearence. For about 1000 km I rode it soft, then I replaced the oil and oil filter. At 65000 km the bike felt like new. Now (66500 km) I hear a strange metallic noise from the engine when braking, like two metal sheets hitting each other. I can't figure out what it is, I have to get the bike back to the dealer...

I just got back form the dealer..There's no problem at all with the engine. He said the engine sounds and is healthy. This sound might be from the brake pads. He suggest to clean the brake pads, disk and caliper. That's all....relief!...

engine noise been the brake pads .... ? wtf?

It was my mistake that the noise comes from the engine. He said it's the pads. First time I hear this noise, so I can't tell...

BM, thanks for the post. I have 96 Ten which developed a death rattle that I was sure were the Big Ends. But sure enough, upon having a look after having read your post it was a loose nut ( no not the one behind the handlebars:toothy9:). A tighten up with a shifter to the recommended tension ( dead tight plus half a turn) and all is well. The old girl purrs like the proverbial kitten.
Thanks again

H.

Thanks for the info, well written and really clear, thanks!!!

Bike mad,, theres no sound in your youtube vids,,, but in vid 3 is that the nut that needs tightened,,,??? as this is my exact noise heard from the site in another vid.... cheers.

subscribed

its there it sounds like a hammer on the back of a vice if you hold the fron brake on and bang it into gear and apply power trying to move forward it knocks its head off same as on deceleration and yes it needs that nut taking off and apply some premanent loctite and a new tab washer . u used the same washer but did one tab over a entire flat side and then the other unused tab i folded into a trinagle over the corner hexagon of the nut

Two things I need help with, the first is what is the part number for lock washer I have the parts manual but cannot determine which washer it is. Secondly what size socket will fit the nut

Yammy XT's aren't the only motors that this problem occurs in. My Ducati 900 two valve had the same prob up around the 50 or 60k km mark. A cheap fix for something you initially believe could be big $$'s is always a welcome relief.

Sent from my MB526 using Tapatalk 2

I went out and bought a socekt for the job which was a 38mm turns out it was the size below but due to it been a impact socket it still drove the mashousive flat sides without a problem . As for the lock washer I was naughty and used the other side as only one side had been used then I folded the other side into a tringle onto the peak of 2 flat sides and also used lock tight but YOU SHOULD REPLACE THE LOCK WASHER to do it correctly. Ash

Sorry for the ignorance. Would the correct fit be a 37mm socket. It's just I can only find 36 or 38 in the store

Anyone got a part number for the lock wAsher as I am not feeling save riding around at the moment especially when I have no idea if it's correctly torqued or not!
Probably wait to another 5000k has passed. Price of changing oil is ridiculous.

If you put it in gear with the front break on and try to drive foward and its knocks its head off then dont use it untill its done as it could write the crankshaft off .... as for socket size all I can say is a mesured with a rule and bought what I thought was the correct size but it did feal amsize 2 big so 37 would be better but like I say I used a flat sided deep imact socket and made usre I kept it pushed all the way home and applied the force squire and it was fine did it at 120 nm and no sign of slipping or damging the nut BUT one of the gurus on here will be here shorty im sure and will tell u the exact size and part numbers of everything

+1...Have a WR450 that owes me plenty after H/C JE, re-plated cyl, cams, powerbowl, ECU, rims etc etc. Had a couple of flat track outings and now I hear this noise??? Seems there is still hope :hcrap: Off to the shed!!

Besides my XT660Z I also own a XTZ660 from 1991. I recently changed the piston. After the rebuild I hear this clicking noise. To me it sounds similar as the vid from the topic starter.

What do you think?

https://www.youtube.com/watch?v=Fh-C...ngq_JV0ob4sLPA

Valve clearance must be OK. I also checked the automatic chain tensioner which is OK. The sound doesn't really speed up when I rev the engine.