Valve Adjustment - Yamaha XS400

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Eberley
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Valve Adjustment - Yamaha XS400

#1 Unread post by Eberley »

Hi, I recently bought a new 2004 Katana 600, and the costly valve adjustment procedure for this bike at is 600 mile service visit got me to thinking about the older bike I have. Its a 1981 Yamaha XS400 Special 11. I bought it new in 1982, and it now has 7400 miles on it. My records say it had a valve adjustment check in 1982 at 600 miles and then again in 1987 at 3,000 miles, and in 1997 at 6,700 miles. The manual specified valve clearance checks at 600 and 3,000 miles, and every 5,000 miles or 12 months thereafter.

I took the bike out of winter storage for the first time this evening and it runs just fine, with great thumping power from the "little" twin.

The valve adjustment ordeal with the Katana got me to thinking about my XS400. I don't even recall any significant charge from the Yamaha dealer for the valve check. I was under the impression that there was some handy cover that they just pulled off of the upper part of the engine and did a quick chect with a feeler gage.

But from my research I find that there is never an easy way to check valve clearance. It alway requires getting at the upper part of the engine. Granted, the XS400 is easier to get at then the Katana.

Does anyone know or remember a ball park figure for what a valve clearance check should cost on an XS400?

Also, if my bike is running as strong now as it did 20 plus years ago, should I conclude that a valve check/adjustment is not necessary? As I understand things, its the checking thats costly and time consuming, the actual adjustment if needed, is quite simple.

What is the danger of now checking the valve clearance if the bike is running fine? How can valve adjustment go "off" in just 12 months regardless of miles driven, as the service interval suggests?

Thanks in advance for any input?

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honda599
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#2 Unread post by honda599 »

I don't know the cost but it shouldn't be that much. Now that you have it running I would continue to use it, and depending how much you ride this year check them next winter when your bike is stored.

Valve clearances normally get loose through use, tight valves however can cause damage over a period of time. You have already had them adjusted 3 times in the past so don't worry. Are you going to try yourself to adjust? Pick up a shop manual(borrow from library) and follow procedures to check adjustment(when engine cold). It's not really that hard-however adjustment can be a little tricky-if needed.

Eberley
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#3 Unread post by Eberley »

Honda599, thanks for the reply. I was beginning to think that my question would just drop further and further down the list with zero replys.

So you are saying that a person can't always tell whether or not a bike engine needs valve adjustment by how the engine sounds or runs. Out of adjustment valves might cause backfiring or the engine might make a "tick,tick, tick", or "tinck, tinck, tinck" sound? But absent these indicators, there is no way to tell? I guess if the bike runs great, most people would leave it alone.

Getting the manual makes sense, since even if I can't do the valve adjustment myself (after reviewing the manual), there are other procedures that I should be able to do, and that are or will be needed on a bike this old.

I got a quote of about $90 for valve adjustment and carb sync. After the valves are adjusted, I am going to remember how the engine is supposed to sound (there is a little ticking at idle right now), and I don't know if that is normal.

I appreciate my XS400 now that I have a "modern" 600 Katana. The 400 feels so light and manuverable, while the Kat is long and top heavy.

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#4 Unread post by honda599 »

Not backfiring but loose ones can cause ticking noise. Wouldn't worry, just ride for this season and look after in fall...maybe a winter project for you to try. Too bad your so far away or I could show you how, also have carb sticks or carb sync.

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#5 Unread post by Eberley »

I don't have a heated garage, and it gets very cold here in the winter, so I will gladly address this project when I do not have to keep a bucket of hot water in the garage to dip my hands into.

Its good to know that loose valves make the ticking sound.

At 24.5 years since its manufacture, my XS400 is in the vintage category in my mind, so a little riding is good for me and the bike, but preservation of the bike is my main objective.

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