Some questions about servo cable & tie rods

snomofo said:
It depends on how they aren't operating. If stuck closed (cables disconnected) you won't reach peak power at WOT. If stuck open, you won't have the same throttle response down low. Some will mechanically hold them open for drag racing.

Either way the sled is still rideable but if the cables are disconnected and run long enough you may end up with the valve making contact with the piston... or so I've read.
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Makes sense, I was afraid to hear that. hopefully the pistons are ok.
 

Ok so heres some pics of the valves and dowels im not sure if I really need or not.
http://i1129.photobucket.com/albums/m504/thiessen1/DSC03759.jpg?t=1355940966
Do I need to have these dowels? if so, I need 2. anybody know where I can get some?
http://i1129.photobucket.com/albums/m504/thiessen1/DSC03758.jpg?t=1355940965
http://i1129.photobucket.com/albums/m504/thiessen1/DSC03756.jpg?t=1355940964
http://i1129.photobucket.com/albums/m504/thiessen1/DSC03755.jpg?t=1355940964

All this just in time for 20-30cm next week we probably wont get anyways! :o|
 
Cooper0809 said:
Ok so heres some pics of the valves and dowels im not sure if I really need or not.snip
All this just in time for 20-30cm next week we probably wont get anyways! :o|
Click to expand...

The dowl pins are locators to ensure the housing is lined up with the valve/cylinder. As you can probably see, there is enough room in the screw holes to allow for movment. Not much, but enough to cause binding and or/taking out the seal.

I suppose you could put it together without them then cycle the cable to ensure the valve moves freely (when cold). Since you're sending the valves out for repairs, get some dowel pins. Perhaps Yamahead has some.
 
snomofo said:
The dowl pins are locators to ensure the housing is lined up with the valve/cylinder. As you can probably see, there is enough room in the screw holes to allow for movment. Not much, but enough to cause binding and or/taking out the seal.

I suppose you could put it together without them then cycle the cable to ensure the valve moves freely (when cold). Since you're sending the valves out for repairs, get some dowel pins. Perhaps Yamahead has some.
Click to expand...

Ya I'll ask Rich if he has any kickin around. As always, Thanks a lot!!!
 
X2 on the dowels...better to have them than not have them. If there was any damge to pistons/cylinders you would be able to tell on thenon cable end, would be beat up mis-shapen. Pics look okay but not really taken from that end of valve.
 
that is the worse valves I have ever seen.I guess they weren't maintained properly over time.I think Yamaha did blow it on these valves,very weak materials and high replacement costs for new=money in the Bank for Yamaha.They could of done better I believe.Seems like PV's are just a high maintenance problem for a lot of people.Wish they did not have to have PV's in these motors.Look at the Redheads..they can be made to make HP without valves.
 
bluemonster1 said:
that is the worse valves I have ever seen.I guess they weren't maintained properly over time.I think Yamaha did blow it on these valves,very weak materials and high replacement costs for new=money in the Bank for Yamaha.They could of done better I believe.Seems like PV's are just a high maintenance problem for a lot of people.Wish they did not have to have PV's in these motors.Look at the Redheads..they can be made to make HP without valves.
Click to expand...

Ya out of all the pics I've seen on here on valves, I think mine are the worst!
They are BLACK and caked. Lots of dry crusty crap too. I shined a light inside and it looks smooth. But I know I'll never be able to tell if there ok without taking it apart more. Not something I feel like doing right now. Just want to get the brakes replaced and the valves back together and get riding.
 
Devilin AblueDress! said:
X2 on the dowels...better to have them than not have them. If there was any damge to pistons/cylinders you would be able to tell on thenon cable end, would be beat up mis-shapen. Pics look okay but not really taken from that end of valve.
Click to expand...

Just went out to look at the "non cable end". They look ok, 1 tiny ding on one tip. I do plan on re-building come spring, so i'm hoping this would be ok for this season. I guess Yamahead will let me know for sure how bad/good they are once he receives them in the mail.
 
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