660 Check it before it goes BANG!!!

[duncmac]

Thanks from me as well, keep it up!

[Mastiff660]

I must ask how common this issue really is? I have asked 3 Yamaha dealers and they have never heard of this problem on the Yamaha models. Is it on 1 engine this have occured or is it "many"?

I wont open a good "sounding" and working engine cause of a very rare issue.

[den]

as i understand it , its down to the way you ride the bike , nice and gentle , not a problem,,race tune it and go like a bat out of hell,,problem,,
like in my video,, there was no reason for me to do mine but i collected all the bits anyway, so i did it ,,was a good opportunity to inspect the clutch and gears ..one thing i did notice,, the vibration in the handlebars almost disappeared,,

[DAVID THOMPSON]

one thing i did notice,, the vibration in the handlebars almost disappeared,,

its worth it for the above

my traveller is very ruff at speed
i can almost get there as fast on the rt125cc
the traveller beats the crap out of me and does about 100 miles on a tank of fuel
the rt is smooth and goes 150 m on a tank
so a 250 mile trip is often faster on the 125
one factor that helps the rt125 is max speed on most of the roads is 55 to 60 mph
and mine loves a flat road at 55 to 60

[Skorpion]

one thing i did notice,, the vibration in the handlebars almost disappeared,,

its worth it for the above

my traveller is very ruff at speed
i can almost get there as fast on the rt125cc
the traveller beats the crap out of me and does about 100 miles on a tank of fuel
the rt is smooth and goes 150 m on a tank
so a 250 mile trip is often faster on the 125
one factor that helps the rt125 is max speed on most of the roads is 55 to 60 mph
and mine loves a flat road at 55 to 60

David I must say your Traveller has a problem.

In my 13 years of Skorpion Traveller ownership I found the engine got smoother with more rev's, I also once rode down the country at 50-60 mph and got 190 miles to reserve, at my normal riding speed 70-85 mph 130-140 to reserve.

[DAVID THOMPSON]

now that i am retired i hope to get into the carb and see if the past owners
did the jets for a aftermarket pipe and also give it a good cleaning
its been changed back to a stock MZ pipe...
here is its picture just befor i got it
gallery/menu.php?gallery=members&album_id=9#

and i have the parts to fix the balance gear
so that will also get fixed

also things under the seat have been moved around a bit allowing for a bigger battery to fit
need to get that finished
dave

[Chalks]

I haven't been using the Bagggy for a while due to work commitments but I've finally managed to check the nut on my balance shaft,

The lock washer locating tab had sheared off and the nut was finger tight.

I think I've caught it just in time, I reckon the hour spent sorting it might have saved me some serious crank case damage!

That's Three out of Four of these engines I've had apart with the same issue.

[handsomejackuk]

checked mine today as fed up of rough running and wanted to rule this out had a few hours to kill and glad i did, as the nut was hand tight and only held on with the tab washer....

[DAVID THOMPSON]

oops something else to check before my Ttravller goes out for a hard run

[handsomejackuk]

well its all back together... and i have a whirring noise... sounds like a gear noise i thought at first it was the clutch plates screeching as i didnt oil them when i put them back anyway i have take the cover off again and double checked eveything and slackened off the balance gear nut a bit as i thought i may have overtightened it... i did mark the original position. so if all else fails i can return it to the original position...

anyone got any idea what the whirring noise could be is there any other timing going on in the casing i should have been aware of ?

the water pump and oil pump are free and the whirring doesnt seem to be from there...

whats the mechanism on the bottom left of the casings ?

i have not touched any of those...

i beginning to wish i hadnt even took the cover off now and left it as it was...

i just hope i not done any damage to anything...

[handsomejackuk]

can anyone tell me what is the idea of this part as on some other videos i dont see it shown ..? I suspect that when I bent over the tab washer i may have slightly distorted this part i wondering if its ringing like a bell type of noise... is it critical..?

the part is at 9:11 on this video



https://www.youtube.com/watch?v=HX2EjjE ... oseOnorati

also when i put the keyway in when put in the original position i can see the mark on there where the key way as marked the key there is a small amount of movement between the keyway and the balance shaft gear.. if i rotate the key 90 degrees its a tighter fit and slightly less movement between the key balance shaft and balance gear...

[DAVID THOMPSON]

this link is for the English speakers
https://www.youtube.com/watch?v=T8M-m0i3uWI

balance gear change viedo

[handsomejackuk]

I watched that video a few times have since taken cover off again and replaced and still have the whining noise only thing i can think to do is replace oil and filter although its been changed only 500 miles ago and hope the noise goes away

[breakwellmz]

I was wondering what that that strange shaped piece was as well when i first saw it to be honest, very odd.
The gear went on the same way round did it? (Assuming it`s possible to fit it either way round)
Perhaps turning the key around is making the two gears mesh slightly differently causing whining? Maybe put it back the way it was, check noise. Re-assemble keyway/key with Loctite 638 or similar.

[handsomejackuk]

yeah the gear can only fit one way around as there are no timing marks on the other side and its slightly raised on one side.

I beginning to wonder whether that slack was there for a reason on that balancer shaft, it was barely hand tight, my bike has done over 30,000 miles in this condition, bought the bike with 2,000 miles so i am fairly confident no one else has been inside this engine since it left yamaha

I note on one of the russian videos that piece is not shown and i do wonder what it does ? it would certainly help to allow more of that tang on that tab washer to go in to the keyway and help lock that key and gear together...

I was wondering if that piece allows oil to build up and fling out maybe to splash coat the gears.. I really cant see what else i could have done to make that noise other than remove the gear off the shaft and put it back on... i wonderered if there was a washer I was missing or if something is touching somewhere but i have taken it apart 3 times now and i still get this whining noise..

i going to put it all back together in a minute and drain oil and put fresh oil in see if that makes any difference.. i suspect its not going to though...

If not i be sorning bike and putting up garage for a few months, i really cant be bothered anymore with it