Valve wear bet between Doc and Forest who is corect?

[Blinc]

This was video evidence taken during Spyderfest in Cuba 2011
Looking for some educational input here :helpsmilie:
Someone has to loose $100, but I think I should get 20% brokers fee on this....

 

[bullant12]

Good thing you filmed it... otherwise Forrest might deny the whole thing!! (blame it on old age syndrome?!?!):roflblack::roflblack::roflblack:

 

[jedd]

Doc, gonna use the $100 to get a oil change after those hard miles to Cuba???

Jim:thumbup:

 

[Firefly]

Hate to see doc take advantage of a senior citizen like that----:roflblack:

I think Forest is thinking old school lifters --- the Rotax is Dual overhead cams.....

 

[ataDude]

Sorry, Forrest, but you lose on the Spyder. The valves/valve seats wear more quickly thereby tightening up the clearance.

In other words, the damage can be done when you DON'T hear clattering.

.

 

[Spyder Cat]

You know don't ya, that in this age with all this new fangled technology allowing folks to record conversations such as this,
before long, it's gonna be hard to find somebody to go fishin' with! :roflblack::roflblack::roflblack:

 

[Lamonster]

:lecturef_smilie:

 

[NancysToy]

Sorry, Forrest, but you lose on the Spyder. The valves/valve seats wear more quickly thereby tightening up the clearance.

In other words, the damage can be done when you DON'T hear clattering.

.

:agree: (Don't shoot the messenger!) If the valve wear was at the cam followers or on the cam lobes, the valves would open up, but most commonly the valves recess in the seats, or harder seats wear them down, closing the gap. You can thank unleaded gas for that.

 

[dave01]

Now I know what that phone call was all about...

100.00 goes to doc on this one. That's gonna buy you a lot of hot chocolate when we stop for Forrest.......

Sent from my Xoom using Tapatalk

 

[pauly1]

If the cam-to-lifter bucket were worn, it would increase the clearance. However, if the clearance were measurable, the surfaces would likely be very scored and damaged, making lots of noise.

I've checked the clearance at 6k and 30K miles and recorded the clearances: there was no measurable difference between the two readings. As the Professor stated, the wear would likely be at the valve face/valve seat interface. I was pleasantly surprised to see no difference in the readings, nice and stable!

The first bike I worked on with direct OH cams was the 1973 Kawasaki Z1 900. One would regularly have to make adjustments as the valve seat and face would wear. The shims would be swapped out and recycled (before recycling was cool).

Wayne

 

[groundeffect]

Hey guys. Ah, someone is losing $100, .

I've checked the clearance at 6k and 30K miles and recorded the clearances: there was no measurable difference between the two readings. As the Professor stated, the wear would likely be at the valve face/valve seat interface. I was pleasantly surprised to see no difference in the readings, nice and stable!

This on your RS/GS?


So - what is the 'normal' mileage when the Spyder RS/GS valves need to be adjusted? I've read 40k+ miles?

Cheers guys.

 

[docdoru]

Hey guys. Ah, someone is losing $100, .


This on your RS/GS?


So - what is the 'normal' mileage when the Spyder RS/GS valves need to be adjusted? I've read 40k+ miles?

Cheers guys.

1. To keep your warranty: every 12K (in 2008 was 6K and every 12K after)
2. Normal wear: I'll check first at 12K and every 24K after (ex 12, 36, 60, 84 and 108)
3. New guiding principle from BRP: to be announced soon

 

[NancysToy]

.....12K and every 24K after...New guiding principle from BRP: to be announced soon.

:thumbup::thumbup::thumbup:

 

[jedd]

Bump:roflblack::roflblack::roflblack:

 

[jedd]

Hey Forrest I am using your advise!!:welcome:

Jim:thumbup:

 

[jedd]

Oh I forgot this too


HEY Doc! Funny stuff huh??


Good times

Jim:thumbup:

 

[jedd]

Oh what the heck

HEY Bump......

Ok this is the last one hyea:hyea:hyea:

Jim:thumbup:

 

[effgjamis]

I can understand that as the valve face and seat wears that damage has occurred.
However, I think that wear of the lifter, for whatever you call it, has wear then the valve travel has been reduced thereby the valve does not open fully and thereby valve damage, Burn, will occur, as well as performance.
the valve itself does not, in my thought, get tighter, as the spring tension is basically the same from the time it was new to the time of wear of the lifters, only the gap of clearence between the stem of the valve and lifter has changed and allowed the valve and seat to be damaged due to the gap clearence thus by reducing the opening, travel, of the valve.
I guess I am from the old school, and I still say wear don't make it tighter.
Just an after thought, if the valve adjustment was tight, no gap between lifter and valve stem, then the valve itself would not seat and thereby also damage the valve and seat via burn.

Just another senior monent.:roflblack:

 

[NancysToy]

I can understand that as the valve face and seat wears that damage has occurred.
However, I think that wear of the lifter, for whatever you call it, has wear then the valve travel has been reduced thereby the valve does not open fully and thereby valve damage, Burn, will occur, as well as performance.
the valve itself does not, in my thought, get tighter, as the spring tension is basically the same from the time it was new to the time of wear of the lifters, only the gap of clearence between the stem of the valve and lifter has changed and allowed the valve and seat to be damaged due to the gap clearence thus by reducing the opening, travel, of the valve.
I guess I am from the old school, and I still say wear don't make it tighter.
Just an after thought, if the valve adjustment was tight, no gap between lifter and valve stem, then the valve itself would not seat and thereby also damage the valve and seat via burn.

Just another senior monent.:roflblack:

Your thinking is right, but circumstances affect the outcome. As I said, wear of the cam or follower will increase valve lash. Wear of the valve or seat will decrease valve lash. (Hopefully it will never come down to zero lash, making a valve stay open, BTW.) What it boils down to is which occurs at a faster rate. For the follower and camshaft, good lubrication and good metallurgy usually keep wear to a minimum...provided the design is sound. The valves, however, are thin on the edges, and bang against the seats several times each second. Even the best metallury sometimes isn't enough. The effects of this are accelerated due to the lack of lubrication, caused by removing the lead from gasoline. Heat is also damaging, especially for the exhaust valve. Something has to give, and it is normally the valve edge or the valve seat. As a result, the valve sinks into the head ever so slightly over time, and the valve lash closes up. In effect, the height of the valve has increased because it sunk a little deeper.

Which area of wear will show up first depends on a lot of things...oil, design, metallurgy, fuel additives, and operating temperatures. For most modern engines, the valve wear shows first, reducing clearances. Sort of a chicken & egg sort of thing.

 

[docdoru]