Lash continues to increase...?

Jeff.Saunders wrote:

Kraz1 wrote:

...but all the aftermarket valves are radius keeper grooves.

Not true at all. There are several companies making the earlier Z1 style valves. We stock 2 different brands.
www.z1enterprises.com/SearchResult.aspx?...&KeyWords=z1%20valve
www.z1enterprises.com/detail.aspx?ID=321

As to the valve clearances INCREASING.

I've only seen this with engines burning oil - the valves/seats get a layer of carbon on them.

Bingo. Had mine do that both times the valve seals were failing. Oil would seep down through the valve openings and build up a burned on layer of crud on the valve seat

The more I think about this, it can't be retainer or keeper related.

OK, sorry was away for a bit there.

Its an 80 Suzuki GS 1000 G.

The head was removed 2 seasons ago and all valves/seats cut/cleaned etc. Springs/keepers/other hardware was all retained due to low origional miles. Not much really needed to be done as the bike had only 18000 origional.
New OEM seals were installed and the guides were very good.
New Head gasket and nuts + torqued to 36ft - no problems/leaks.

Compression is in the 140-145 range all across with hone and new rings everything spec'd, and balance is excellent when running. Mixtures have exact same flamefront color at same number of turns out @idle (1 3/4). Dynamic balance stays uniform across entire rpm range and of course makes nice HP and torque smooth througout.

The bike is rode fairly normal I guess. Daily traffic with a few good blasts here and there. I asked him this before. It sees about 6-7000 miles a season, so were up to 34k+ on the odo now.

I have had to change 3 shims on two different intervals for tighter clearance.

The plugs are good, and the valves look uniform/clean thru the intake and exhaust ports.

Cams and shims look ok. There are some wear marks but all is good for the most part.

I askes the owner if it seemed to make a difference in power over the season, but he reall says there isnt. Maybe he just cant tell.

I havn't encountered valves stretching before in this type of application. Is it far fetched? I dont see where.

Bike is gone now with clearances all checked and rechecked again, and runs hard like new.

I just dont know. Havnt encountered this with any other.

?? :huh:

Jeff.Saunders wrote:

Kraz1 wrote:

...but all the aftermarket valves are radius keeper grooves.

I actually didn't write that, it was excerpted from the LINK I provided in my reply, which was lifted from the "Schnitz" website. As far as KEEPERS go, there is only Radius or Square Groove..

That was a good opportunity to show your product, however I'm sure you sell more "Radius Groove Valves" than Square.

larrycavan wrote:

The more I think about this, it can't be retainer or keeper related.

i thought sukis used rocker arms? :S

PLUMMEN wrote:

larrycavan wrote:

The more I think about this, it can't be retainer or keeper related.

i thought sukis used rocker arms? :S

82GS1000 has SOT setup and runs a tight lash. .0015" - .003".

Just because some of the valves get loose doesn't mean it's a problem. I don't know who started this nonsense that valve lash only gets tighter but I can assure you it's not true.

Suzuki cams run in the aluminum head w/o bearing inserts.

No matter what happens with the retainers & keepers, all that's going to affect is spring height.

2 valve GS motors often have that sewing machine noise in the top end as miles rack up.

I tuned & serviced those bikes when they were new in 82. Not unrealistic to have some valves be loose at 600 mile service....


PS....that Suzuki shim tool is pretty nice to use..hey

the only time i have ever seen something like this happen was when the keepers were pulling through the retainers.

larrycavan wrote:

PLUMMEN wrote:

larrycavan wrote:

The more I think about this, it can't be retainer or keeper related.

i thought sukis used rocker arms? :S

82GS1000 has SOT setup and runs a tight lash. .0015" - .003".

Just because some of the valves get loose doesn't mean it's a problem. I don't know who started this nonsense that valve lash only gets tighter but I can assure you it's not true.

Suzuki cams run in the aluminum head w/o bearing inserts.

No matter what happens with the retainers & keepers, all that's going to affect is spring height.

2 valve GS motors often have that sewing machine noise in the top end as miles rack up.

I tuned & serviced those bikes when they were new in 82. Not unrealistic to have some valves be loose at 600 mile service....


PS....that Suzuki shim tool is pretty nice to use..hey

The info we had for the 80 is 1-3 thou, so we set intakes 2, and exhausts 3 or just under, trying to get everything as close as possible measuring with micrometer.

In my last post I said i havnt encountered valves stretching? Of course they can, I meant shrink obviously. (increasing gap).

You're right, the cams ride in the head, no bearings. I think i said bearings before, my bad.. everything is square and tight to spec. No problems with retainers/keeper either at all.

Valves loose as soon as 600 I've seen. Seating of the shim and bucket components, caps, etc.Oil in between parts... opens things a thou or more. But these seemingly keep getting bigger... :dry:

The bike deffinately has that tell whirry tic-ticka like a sewing machine :laugh:

We don't have the suzuki shim tool. We have been using an old home-made tool that some old guy that looks like a bent fingered fork with a long moveable middlefinger that stops the bucket while the thing holds the cam. :silly: Works great!

I doubt its of any issue, considering the condition of the bike, and I have pummelled that motor in testing with no issues.

Really, I'm just trying to extract more possiblilities for this here... thanks all for input thus far!

Next time it's in the shop, pull the plugs, open the valves all the way and look at the seating surface of the valves through the plug holes.

Most likely.....

Either carbon is building on the seats or there's wear of the journals in the head. If you go by the Suzuki marks on the cams when checking lash, it loads the cam in a way that pushes up the end of the cam you're checking. Any journal wear will show up for sure and make lash looser.

In other words if you were checking 1 & 2 intakes, then 3 is pushing the intake valve open while 1 & 2 have no load on that end of the cam...so that end will be pushed up hard against the cap by #3 lobe being loaded....any wear in the journals will be amplified and show up in lash measurements of 1 & 2...

i got the suzuki education from the head master himself this morning on my way to work! :laugh:

larrycavan wrote:

Next time it's in the shop, pull the plugs, open the valves all the way and look at the seating surface of the valves through the plug holes.

Most likely.....

Either carbon is building on the seats or there's wear of the journals in the head. If you go by the Suzuki marks on the cams when checking lash, it loads the cam in a way that pushes up the end of the cam you're checking. Any journal wear will show up for sure and make lash looser.

In other words if you were checking 1 & 2 intakes, then 3 is pushing the intake valve open while 1 & 2 have no load on that end of the cam...so that end will be pushed up hard against the cap by #3 lobe being loaded....any wear in the journals will be amplified and show up in lash measurements of 1 & 2...

Makes good sense to me... nice call.

Likely a combination of both being missed...