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You can the entire collection of Safety Tip articles in a 33 Megabyte PDF Portfolio

 All Forums
 Motorcycle Safety
 Technical/Maintenance
 Initial Valve Clearance Inspection / Adjustment
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kilodelta
Male Junior Member
54 Posts


Stafford, VA
USA

Suzuki

SFV-650

Posted - 07/03/2014 :  7:23 PM                       Like
I'm looking for some advice.

Current stats:
1. New Suzuki SFV-650 (2-months old)
2. 900 miles (with 600 being the recommend initial maintenance)

I have done the basic inspections, chain cleaning and lubrication, and the oil change. But, I don't have the skill / knowledge to inspect or adjust the valve clearance as recommended by the dealership. I checked the owner's manual and it says to inspect the valve clearance at 4 years or 14,500 miles.

My question is about the valve clearance and the conflicting guidance from the dealer and the manual. Should I:

1. Shell out the cash for the valve adjustment as recommended by the dealership. (I'll call around for prices.)

2. Wait for the valve clearance inspection as stated in the owner's manual.

3. Other?


Thank you in advance.

scottrnelson
Advanced Member
6890 Posts
[Mentor]


Pleasanton, CA
USA

KTM

990 Adv, XR650L

Posted - 07/03/2014 :  8:09 PM
Checking the valve clearance and adjusting the valves are two different things. Typically, you check the valve clearance at 600 miles to make sure all is good, but it is rare that they actually need adjustment. Modern bikes should have good enough quality control to actually last 10-15,000 miles before valves need adjusting.

Valves that use shims to adjust the clearance are easier to check than to adjust. You have to switch shims to change the clearance which might even involve taking the camshaft out.

Valves with screw-type adjusters like on my Honda XR650L, are actually easier to adjust than to check. So when I do the valves on that bike I stick the feeler gauge in place and set them exactly where they should be. It's easier to get the adjustment exactly right than to verify that the clearance is correct on that particular engine.

If you're really concerned about the valve clearance, you should be able to learn how to check if you can handle something like an oil change.
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kilodelta
Male Junior Member
54 Posts


Stafford, VA
USA

Suzuki

SFV-650

Posted - 07/03/2014 :  9:14 PM
Thank you. I found an excerpt from the service manual that describes the process to check the clearances. I just need to purchase a thickness gauge.

Academic question: What's the downside of having the clearances out of spec? Engine damage? Decreased performance?
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greywolf
Male Moderator
1495 Posts
[Mentor]


Evanston, IL
USA

Suzuki

DL650AL2

Posted - 07/03/2014 :  9:41 PM
Your engine uses shim under bucket valves. You're fine waiting for the 14,500 mile check. I'm a moderator for a DL650 site and my bike uses basically the same engine. Valve clearances on those engines change very little and, almost always, the exhaust clearances are the ones that may close up very slowly over many thousands of miles.

The first check is the most important. If none of the clearances are on the narrow end of the range on the first check or have been changed away from the narrow end, you can go another 50,000 miles until the next check safely. It is uncommon to need an adjustment on the first check but it has happened. Make sure the tech gives you a sheet with the clearances marked.

The first check is the most important as you don't know what the clearances are before that. It takes about twice as long to change clearances as it does to check them. If the clearance is much below minimum, especially on an exhaust valve, the valve won't seat and that allows combustion gasses to work like a cutting torch on valves and seats.

Those engines rarely need adjustment. Put a mark across the valve cover gasket with chalk or nail polish in an unobtrusive place before taking it in. Some dealers will charge a few hundred bucks for a valve clearance inspection and never take the valve cover off.
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scottrnelson
Advanced Member
6890 Posts
[Mentor]


Pleasanton, CA
USA

KTM

990 Adv, XR650L

Posted - 07/04/2014 :  9:29 AM
quote:
Originally posted by kilodelta

Academic question: What's the downside of having the clearances out of spec? Engine damage? Decreased performance?

If the clearance is too small, the valve won't close properly. At a minimum, the bike will be harder to start. Worst case is a burned valve and having to replace both the valve and the valve seat.

If the clearance is too big it will be noisy and you'll have added wear everywhere metal is striking metal.

And if it's a Ducati with desmodromic valve actuation there are addition possible problems depending on whether the opening of closing clearance is out of spec.
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