Just curious, why do we adjust valves?

[joevano]

Since hydraulic lifters were introduced in the '30's by Pierce Arrow, there have been millions of valves working for billions of miles. So, why have they not been integrated into motorcycles?

Just something that kept me awake last night :sleep:

[DaveDragon]

Since hydraulic lifters were introduced in the '30's by Pierce Arrow, there have been millions of valves working for billions of miles. So, why have they not been integrated into motorcycles?

Just something that kept me awake last night :sleep:

They have, just not in the K engine.
I adjust the valves in my R1200GS regularly.

[dukey33]

There are plenty of bikes with hydraulic lifters (including GL1500 wings), but hydraulic lifters are inaccurate relatively speaking in terms of valve timing. Because there is oil used to cushion the lash; the timing, duration and lift of valve opening varies somewhat and is less precise than "solid" lifters. If you ever played with cars, you recall that race cams are almost all solid or roller tappet (at least they used to be). Since motorcycle engines are usually designed to extract the maximum output, the omission of hydraulic lifters avoid compromise in this area.

edit: I should have also included that hydraulic lifters are more suited for low-rpm operation. At higher engine speeds, they can "pump up" and prevent valves from closing completely which could quickly lead to a burned valve.

[NRuest]

. . . . I adjust the valves in my R1200GS regularly.

Doing it often, do you find that they are out of adjustment often? Or are you verifying that they are still good?

[NRuest]

Doing it often, do you find that they are out of adjustment often? Or are you verifying that they are still good?

I don't know but I thought this was a valid question.

[grifscoots]

Since hydraulic lifters were introduced in the '30's by Pierce Arrow, there have been millions of valves working for billions of miles. So, why have they not been integrated into motorcycles?

Just something that kept me awake last night :sleep:The shim under bucket arrangement allows for more rev's. Basically, the valve follower is almost touching the cam- except for the shim under, which allows for adjustment.

[lovetomotor]

The reason we check the valve clearances is because on the LT's K engine uses a shim under bucket design and as parts wear, the clearance is minimized. Run it too long like that and you will burn a valve.

The reason BMW and lots of other motorcycle manufactures use this design and others similar is for better performance at higher rpms. It's one the reasons the LT's engine is sooooo sweet!

[NRuest]

OK. Thanks for the great answers. You guys are the best. So maybe it was a good question just not very clear. :confused:

This was the first statement:

. . . . I adjust the valves in my R1200GS regularly.

To which I asked:
Doing it often, do you find that they are out of adjustment often? Or are you verifying that they are still good?

Now I understand the need for proper valve adjustment but I guess, since DaveDragon "adjusts his valves regularly", then I was wondering' if he found them to be out of adjustment every time he checks them or do they stay within tolerence. Of course I can't know the frequency that he checks them and it could be every 5K or every 60K but "regularly" suggests maybe shorter intervals than recommeded.

:deadhorse
So then the question remains, doing (or checking) the adustment often, do you find that they are usually OUT of adjustment or are you verifying that the tolerence still within acceptable limits?

:crybaby:
Or... Your Honor. I'd like to withdraw my question at this time if it pleases the court. And let's just ride!!! :lol8: (or maybe I should get to adjustin my valves)

.

[bblalock]

So far 59,500 miles and all I have done is check, not adjust, the valves. Just ride it!

[loansumrider]

to get us out of the house and away from the honey-doo's. with the greese on our hands, who would want you to fold clothes, make beds, wash dishes,
go shopping...

[ibbones]

:rotf::rotf::rotf:to get us out of the house and away from the honey-doo's. with the greese on our hands, who would want you to fold clothes, make beds, wash dishes,
go shopping...

[NRuest]

Thanks for the response. Of course. why didn't I think of that. Greasy hands... folding clothes.. Hmmm. I like the way you think. lol