I have 36K miles on my '96. About 10K of these are mine. I have never checked the valve clearances, and see no evidence that anyone else has either. According to the shop manual, this should happen every 16K miles. This might have been performed by the previous owner, who bought the bike new, but it was "declined by owner" at 21K miles.
So, what experiences do others have? This looks like a simple procedure that would probably take an afternoon for a slowpoke like me. Should I start with a set of shims in hand, assuming adjustment will be required? Should I have a new set of valve cover gaskets? There may be a minuscule leak from mine, but it is not significant -- yet.
I asked this question before, you may want to search for the responses..
But the summery is.. Several people have taken in their bikes for this, or done it themselves and usually everything is within tolerance or VERY close to tolerances..
Because of this discussion, (and I'm cheap) I did NOT have mine done and I've got 60+K on mine..
It's your decision..
The only reason I posed the question was that I plan to ride out to Ken's place in Hutto tomorrow. His CB900 has a soft cylinder, and we think it is because of a bad valve. Apparently they are sensitive to adjustment and the PO was lax in this regard. (I have an "optical snake" that we hope to examine the cylinder walls with before deciding what to do about his one low compression cylinder.)
Thanks for your response. I am much relieved, and will probably just change the oil on schedule and ride on.
Lawrence, has your fuel economy dropped? Power dropped? Any changes over the average??? SAVE YOUR MONEY and just ride.
I have only seen 2 yep 2 third gen Magna's that had the valve clearance checked and were off, and I have been around a couple :lol: :cool:
They just dont tend to go out of adjustment like other designs.. The shim under bucket is good for this....
I'd check 'em at 50k.
For those who don't know, here's how it works with solid lifters. There are two general areas of wear that will change valve clearance. The valve sealing face to seat will wear because of the valve slamming shut every two revs of the crankshaft. This wear will make the valve train tighten up since the valve will now go deeper into the seat, however slightly (in other words it's like the stem gets longer taking up lash in the valve train). The other wear is in the valve train along various points which will do the opposite which is to loosen up the valve train.
If the metallurgists and engineers at Honda got their stuff right, these two areas will wear at approximately the same rate and cancel each other out. If the valve train wears more than the valve and seat, you get clattery valves (not serious, just annoying) and the valve will not open quite as far (we're only talking a few thousanths here). If the valve and seat have the more pronounced wear then the valve train will tighten up, possibly to the point that a valve doesn't quite seal. This is the situation that can cause damage in the form of a burnt valve.
Curtis
Quote from: Curtis_Valk on January 23, 2009, 05:22:41 PM
If the valve train wears more than the valve and seat, you get clattery valves (not serious, just annoying) and the valve will not open quite as far (we're only talking a few thousanths here). If the valve and seat have the more pronounced wear then the valve train will tighten up, possibly to the point that a valve doesn't quite seal. This is the situation that can cause damage in the form of a burnt valve.
Curtis
This is why I say if your performance or fuel economy hasnt changed from the normal averages over a period of time then no need to go looking....
But if you do notice a trend then start looking into it..
Greg, that is true but once you notice you'd better get on it fast. Almost like the oil pressure light coming on. I advise "go with your gut" but know the risks. Now if you notice your valve train getting noisier, then you're safe to put it off until the next convenient wrench session. 8)
Curtis
Quote from: Curtis_Valk on January 23, 2009, 05:22:41 PM
I'd check 'em at 50k.
If the metallurgists and engineers at Honda got their stuff right, these two areas will wear at approximately the same rate and cancel each other out. If the valve train wears more than the valve and seat, you get clattery valves (not serious, just annoying) and the valve will not open quite as far (we're only talking a few thousandths here). If the valve and seat have the more pronounced wear then the valve train will tighten up, possibly to the point that a valve doesn't quite seal. This is the situation that can cause damage in the form of a burnt valve.
Curtis
I have clattery valves, not sure if the adjustment has ever been done. I am the 3rd owner of the bike,purchased after the previous owner high sided at a low speed. If there is a wrench session before the impending knee surgery maybe I can get over there and meet some of the folks on here and get opinions as to if that noise is the valves.
David
Quote from: Curtis_Valk on January 23, 2009, 05:30:36 PM
Greg, that is true but once you notice you'd better get on it fast. Almost like the oil pressure light coming on. I advise "go with your gut" but know the risks. Now if you notice your valve train getting noisier, then you're safe to put it off until the next convenient wrench session. 8)
Curtis
M dada (retired mechanical engineer) told me basically the same things you have said, Curtis. According to him, it
is possible to have damage before the symptoms become obvious.
With that in mind, when I was on a poker run a couple of months back that had us stopping at a bike mechanic's shop, I asked his sportbike mechanic about it. His reply was this: the first adjustment interval is important and should most definitely be observed. He said after that, assuming the engine is not run at redline and that the carburetion and exhaust remain unmodified, you will likely never need to mess with it again. He went on to say that even if you do run the engine up to redline in top gear frequently in street riding, the engine may not require critical service before the rider does.
My seat of the pants assessment is that the bike is running fine. It still leaves my Harley riding friend in the dust accelerating away from a stop light. If the power loss were gradual, however, I am not sure I would notice unless it was substantial. I do keep track of my gas mileage, and it is hanging right in there.
Will a compression check reveal the malady before my "anterior dyno" does? Checking compression on the front two cylinders may be a little tough, but looks a lot easier than actually measuring the valve clearances.
I agree with Curtis' statements..
However known of many folks who have taken their 3rd Gen Magna's in for the valve clearance check and out of the double digit reports only 2 of them were off and actually didnt get shims changed...
Personally I would put that $$$ towards other goodies and keep on riding.. Heck that is exactly what I have done, Devs bike has 40K on it and runs like a top, the yellow bike had 48K on it and also ran great.
But I completely understand folks wanting to make sure their steed is running tip top....
Quote from: lragan on January 25, 2009, 09:45:23 AM
Will a compression check reveal the malady before my "anterior dyno" does?
It definitely will, the problem is that it won't fail a compression check until just around the time you burn a valve. I'm sure you'd rather check the valve clearances once and be done with it than check the compression every couple of weeks to make sure you weren't "there" yet. Besides, the biggest hassle is changing the shims if you find they are out. Checking the clearances is the easy part.
Curtis
OK.. A lot of Gen 3 bikes have come and gone through this site..
How many Gen 3's has anyone heard of with burnt / damaged valves??
Few if any, hoot. Hence my advise for Lawrence to check them at 50k miles. None that I know of that have been checked have been dangerously tight. Most come up only a little bit out of spec and more often than not the owner decides not to do anything. It's just hard to beat a Magna (or Valk) for bullet proof design!
When giving advise though, I tend to err on the safe side. I don't want the first MOOTster with a burnt valve to have done so because of me.
Curtis
Guys, thanks for your opinions, advice, and (however incomplete) statistics. Like virtually every decision one makes, there is a risk/reward tradeoff here.
I am persuaded that the risk is low and the struggle is medium (or high for a fumblethumbs like me!) so I am going to ride on and not worry about it.
All advisers, take note: I take this decision all by myself. If I wind up with burned valves, YOU WILL NOT BE BLAMED, and our friendship will remain intact!! :cool:
FWIW, I had mine checked at 36k, and they were spot on. My wrench told me that as long as it was running fine and giving no symptoms, leave it alone and ride. He's never steered me wrong in the (long) time I've known him, so that's what I'm doing. The bike is now approaching 90k, and purring like a kitten. (A cheetah kitten!) ;^)
I personally have not heard of a 3rd gen Magna having a burnt valve... I am sure it has happened somewhere to someone, but in my 13 years around them I have no information on such an event.
Quote from: Magniac on January 26, 2009, 10:31:58 AM
FWIW, I had mine checked at 36k, and they were spot on. My wrench told me that as long as it was running fine and giving no symptoms, leave it alone and ride. He's never steered me wrong in the (long) time I've known him, so that's what I'm doing. The bike is now approaching 90k, and purring like a kitten. (A cheetah kitten!) ;^)
The 90K Magna.. What year is it??
Same here.My '96 with 86K miles was checked at 50K. No adjustment needed.
You know, I'm thinking this thread has potential. If it is watered well and carefully nurtured, it could conceivably grow bigger than the rectifier/regulator thread. Heh heh heh heh...
Quote from: Guy Gadois on January 29, 2009, 01:44:07 PM
You know, I'm thinking this thread has potential. If it is watered well and carefully nurtured, it could conceivably grow bigger than the rectifier/regulator thread. Heh heh heh heh...
Not a chance... Just my problems alone will probably keep this ahead of valve adjustements. Woops, I guess I just contributed to the other direction!!!
I apologize for dragging out this thread. But I just got to wondering.What's the most mileage racked up on a Magna? There must be some 1st gen. bikes with well over 100K miles ? Maybe a mileage poll could be started of all forum members ?
Quote from: Guy Gadois on January 29, 2009, 01:44:07 PM
You know, I'm thinking this thread has potential. If it is watered well and carefully nurtured, it could conceivably grow bigger than the rectifier/regulator thread. Heh heh heh heh...
Ha!! I laugh at your puny rectifier/regulator thread. The car tire thread is KING!! It even exceeds the carburetor jet thread.
QuoteHa!! I laugh at your puny rectifier/regulator thread. The car tire thread is KING!! It even exceeds the carburetor jet thread
You judging that by pages or posts?? If your looking at pages it is not accurate cuz Hoot's posts take up about 1/4 page each (pics in signature), PLUS all the pics in the tire posting. I doubt it truly touches the reg/rectifier one in actual postings.
Quote from: DG on January 30, 2009, 02:21:45 PMYou judging that by pages or posts?? If your looking at pages it is not accurate cuz Hoot's posts take up about 1/4 page each (pics in signature), PLUS all the pics in the tire posting. I doubt it truly touches the reg/rectifier one in actual postings.
I did extensive research by taking a quick peek at the first page in the Garage board. I spent many seconds studying the data and stand by my findings.
Number of pages is the correct metric for the ... uh metrics.
Hoot! I believe you've been accused of cheating!