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Discussion Starter · #1 ·
I know this subject has been covered with many posts over the yrs but I thought I would give those a heads up who think this can be put off. I have a 2017 dl 650 I bought used with 8400 miles in July.I now have 15,500 on it. I was planning on doing it a 14,500 ( 24k) but I am doing a few other things to it and wanted to do it all at once ,and had to get a few things together. And the riding weather in Md has been pretty nice so far this winter).
So here is what I found
Front cylinder. Both Exhaust were .18mm .Thats .02 under minimums.
Intake- One at .15mm ,and one at .12
Rear Cylinder- Exhaust- both at .20mm (min)
Intake- both at .12mm
So out of 8 valves I am changing 7 of them, The bike has been running great, plugs looked good although gaps were at .040. I have new ones although they certainly could be used after re gapping. So the lesson here is, the factory interval should not be ignored unless you are the gambling type. I cannot imagine going thousands of miles more with under min exhaust valves.
 

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What is the downside of riding with "under minimum" exhaust valves? In other words, what is the impact on riding? Poor performance? Poor gas mileage? Potential catastrophic breakdown?
In the OPs case, nothing.

If the clearance goes to zero, the valve won’t shed heat to the valve seat and you can “burn” a valve. However, when the clearance goes to zero, the engine is harder to start when hot.
 

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I let the valve clearences go on my '80 Kawasaki KZ 750. They are also a shim under bucket type. The bike got very hard to start, and would backfire up through the carbs during starts. I think it got bad enough that at least one or more intake valves were closing late, and probably the same for exhaust valves. I hadn't noticed how performance loss much until I did a carb rebuild, valve shims, and new plugs, then wot a difference! I don't know how much could be attributed to the carbs and plugs but she started on the 2nd or third revolution, idled smoothly and revved clean.
 

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...So out of 8 valves I am changing 7 of them...
I agree that checking the valves on a new-to-you bike is a good idea. I bought my 2020 DL650 XTA with 8400 miles. But every one of my valves was set right where I would have done it myself -- just a bit looser than the minimum spec. So, I was left thinking that the factory did a great job. Maybe your bike was made on a Monday? or is that Friday? :)
 

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Valve adjustment paranoia makes me smile. I assume that @Motorpsychology Kawasaki above did not blow up.

As a matter of fact. It is extremely rare to hear or read about burnt valves outside of the racing community.

Does anyone have a burnt valve story?
STCorndog, likely the first to fail would be any rubber type oil seal or oil film as heat goes up the stem. with the expected outcomes. Tappet wear from constant contact would increase. These would be degredation.

I do know of a Pontiac 455 Ram Air IV that dropped an exhaust valve at idle.😪
 

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STCorndog, likely the first to fail would be any rubber type oil seal or oil film as heat goes up the stem. with the expected outcomes. Tappet wear from constant contact would increase. These would be degredation.

I do know of a Pontiac 455 Ram Air IV that dropped an exhaust valve at idle.😪
If the tappets (really the cam and followers in our case) wear, clearance increases and it heals itself.

However, you touched on a point I posted about previously. When an engine is new, the clearances going away can be caused by several things.

  • cylinder head bolts relax from heat cycling
  • valve stem stretch
  • valve seat recession

The first on the list, in my estimation occurs quickly and then stabilizes. The other 2 on the list take time to occur, if at all.
 

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Valve adjustment paranoia makes me smile. I assume that @Motorpsychology Kawasaki above did not blow up.

As a matter of fact. It is extremely rare to hear or read about burnt valves outside of the racing community.

Does anyone have a burnt valve story?
Burnt enough for you?
Wood Flooring Floor Gas Tints and shades


Bad things can and do happen to valves. This one is out of my old Toyota minivan. Hardly a racing vehicle.

Do the valve clearance checks on schedule, people. They're not difficult and will let you know well in advance if something is going on with your engine. Chances are you won't need to change shims very often in Strom engines, but if you don't check you'll never know until there's a problem.
 

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Discussion Starter · #11 ·
Its all about piece of mind. And just for the record ,I was expecting the worst with the rear cam chain tensioner after reading how much of a PIA it is. But I needed to check my rear pads closer so I removed the rear wheel. This is THE way to go. It was very easy to get out and just mildly fussy to get back in.
 

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Discussion Starter · #13 ·
I agree that checking the valves on a new-to-you bike is a good idea. I bought my 2020 DL650 XTA with 8400 miles. But every one of my valves was set right where I would have done it myself -- just a bit looser than the minimum spec. So, I was left thinking that the factory did a great job. Maybe your bike was made on a Monday? or is that Friday? :)
Who knows ? But I am glad
What is the downside of riding with "under minimum" exhaust valves? In other words, what is the impact on riding? Poor performance? Poor gas mileage? Potential catastrophic breakdown?
Supposing , exhaust valves can get burnt and intake valves would affect fuel intake, but I am no mechanic, or valve expert. But suzuki made it and they seem to know what they are doing ,so I will stick with factory recommendations.
 

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Discussion Starter · #14 ·
And most of all I am looking forward to the "placebo" effect which means my wee is going to run better, go faster, and.even get better gas miliage regardless of whether the engine knows it had a valve adjustment. I usually notice this even after washing. :)
 

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@Dark Angel

I didn’t think I needed to clarify I was asking about motorcycle engines.

Out of curiosity, what was your mileage on your van? Was the engine a 3.0. L V-6?
Original, yes. Maybe 180,000km 2.0l inline four. I'm in Australia. We didn't have V6 engines in Taragos in the 1980s.
 

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Discussion Starter · #16 ·
If the tappets (really the cam and followers in our case) wear, clearance increases and it heals itself.

However, you touched on a point I posted about previously. When an engine is new, the clearances going away can be caused by several things.

  • cylinder head bolts relax from heat cycling
  • valve stem stretch
  • valve seat recession

The first on the list, in my estimation occurs quickly and then stabilizes. The other 2 on the list take time to occur, if at all.
Good point. I think Suzuki gives its 14,500 interval because they know that there are variations which may affect clearances as you stated.
 

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Valve adjustment paranoia makes me smile. I assume that @Motorpsychology Kawasaki above did not blow up.

As a matter of fact. It is extremely rare to hear or read about burnt valves outside of the racing community.

Does anyone have a burnt valve story?
a couple, my first was on a '67 Honda Super90, I was going rather fast whe suddenly no power and the engine clattered till I came to a stop (within short walk home) I tore the engine down, I found the head of the valve in the crankcase a hole in the piston, and a very burnt valve stem
my second experience, was the infamous burnt valve in #3 cylinder of a VW beetle syndrome, it is common, because the position of the oil cooler within the fan shroud, restricts air from #3 and it runs hotter. The WV engineers have #3 on the distributor cap retarded 3° to compensate, but it still runs a bit hotter and burnt valve is common, same thing happened on my Beetle, exhaust valve head broke off and went thru the piston. scarring up the cylinder walls pretty good too
 

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Another over 40 year old story. A friend of mine worked in a a bike shop after school,& on Saturday mornings. When a newer bike came in for the first valve inspection he was told to take it for a rip.
”seem OK to you?” Yep. Clean valve cover area.Put in a set of spark plugs,and Bobs your uncle.!
Many customers said their bike never ran better.
 
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