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Post by chew652 on Dec 29, 2007 9:25:34 GMT -5
I am in the process of changing out my cam chain. I had observed that the adjustment plunger was sitting about 3/16 " below the surface of the locknut so I figured it was time to replace the chain as I could not adjust it to bring the plunger closer to flush.
I had bought some used components off of ebay but after disassembling the top end I decided to buy new components.As an aside I found a cam chain from Mike's XS to be the cheapest at $39.00 American.It is listed for newer XS650s but it is the correct size and number of links for the SR500. I have also ordered a new movable tensioner guide.
So now for the question. I have 3 manuals and they all seem to indicate that the tensioner plunger should be about flush with the end of the adjuster locknut with a slight pulsating movement when the engine is turning. Also this initial adjustment should be made with the chain at its loosest point.Now that have the tensioner components out on the bench I have observed that with the components assembled as the books indicate, the plunger can not protrude from the end of the adjuster at all and will be flush only when there is no play at all in the assembly. In other words the plunger end is closest to flush when the adjustment nut is brought up tight against the shoulder on the plunger. I realize that this is not the correct adjustment and the locknut must be backed off some to allow movement.
It seems to me that if the adjustment is made with the chain at its slackest the there is a chance that when the chain comes to a tighter point the adjuster will be bottomed out and maybe cause undue tension on the chain and movable guide to the point of premature wear or possibly even failure of the chain itself.
My convoluted logic tells me that the plunger should exhibit just the slightest play on the tightest part of the chain run not the loosest.
ok guys talk me out of it an tell me why I should do it by "The Book"
Thanks for your indulgence, Bill
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Post by caferacercarl on Jan 5, 2008 1:53:25 GMT -5
Make sure there is no burr on the plunger, or threaded bit, the system is designed to hold the chain just off tight riding on the blade and is designed to take up the "whiplash" when snapping the throttle on or off, the cheapest camchain is not the best, DID 219 FTSS is what you want, notice the double S, they make 3 grades, it is better than stock and should only cost around 40 US anyway, only Yoshimura do a stronger one,at around 220 USD. fit it without splitting it as well, by removing the clutch cover,primary gear etc, don't forget to rattle gun the primary after. regards Carl.
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Post by chew652 on Jan 5, 2008 9:20:59 GMT -5
Thanks Carl The DID FTSS is what Mikes XS sells. www.mikesxs.net/mikesxs-engine.php?category_id=3.6 My concern is the fact that the manual says bring the end of the plunger flush with the end of the adjuster and that when that is done there is vitually no play left in the mechanism. I have 2 sets of parts on the bench and they both look the same and have no burrs. If you assemble the parts on the bench (plunger,steel spacer ,and threaded barrel) without the spring ,the end of the plunger is flush when it is pushed up solid against the adjuster . It just seems to me that the recommended procedure is a recipe for early wear on the movable guide or possibly breaking the camchain. |
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Post by chew652 on Jan 5, 2008 10:05:45 GMT -5
Hey Carl, Do you have posts on this board under another name or did someone steal it before you got here? I know it wasn't me. Do you post on some other MC boards? I would be interested to read some other posts.
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Post by bigshingle on Jan 5, 2008 11:07:25 GMT -5
Chew, I've got my SR engine down right now and am waiting on a guy to clean up the cylinder before I can put it back together, so I haven't hit the cam chain adjustment problem yet.
When I do maybe I'll better understand your concern.
If I'm reading the manual right, yes, when the pushrod is flush with the adjuster the chain is probably going to be too tight. But since the engine is turning over slowly (at idle) this wear is going to be be very slight in the few moments until you can check for movement in the pushrod and loosen the adjustment nut if necessary.
My concern in adjusting at the tight spot on the chain, rather than at the loose spot as called for in the manual, is that with the engine running, when the loose spot comes around there then may be too much play and the chain might jump a cog or come off altogether.
That would be terribly disappointing and bring the engine to a sudden, expensive stop.
Carl, wouldn't it be better to have a cam chain without a removable link? Thumper Stuff sells one for $47 — $4 more than Mike's (chain $39, link $4.) Would that be better? Even if the chain came with a removable link I would prefer to put it together before I installed it.
What's your thinking on this?
The installation instructions at Mike's don't seem to apply for an SR500, since my manual calls for the head to be torqued down before the chain is put in place.
I'm really hoping to get my cam chain home without prying on anything. I'll let you know how that works out.
Words of wisdom and experience always welcomed.
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Post by chew652 on Jan 5, 2008 12:22:30 GMT -5
Mikes camchain comes with a link in the box. My stock cam chain and the ebay special both have a riveted link so those particular ones are not truly endless. I would be interested to know if the Thumperstuff chain comes with a riveted link or if it is truly endless. If you buy the Mikes part you have to have a tool to set the pin ends as these joining links do not come with a spring clip link like a rear drive chain. It is a rivet type link. The xs650 has the drive sprocket for the camchain in the center of the crank so you cant just slip it on over the crank end like we can. One of the benefits of owning a single.
I think the xs650 head is like ours in that some of the head bolts don't receive any torque until the rocker cover is installed. I know that when I installed an xs650 head I had to retorque it 3 or 4 times just as it sat in the garage as the bolts/nuts would loosen somewhat as the gasket material compressed. I plan to this on the SR too.
As for the camchain adjustment ,I am going to see what it looks like adjusted both ways and see if there is much difference. I do believe it is imperitive to see some movement in the plunger however the adjustment is done.
I would be interested in what an actual Yamaha factyory manual says. Does anybody have one ? Even then the translation from Japanese to English can be somewhat problematic if not downright humorous.
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Post by bigshingle on Jan 5, 2008 13:55:39 GMT -5
Chew, good question about whether the Thumper Stuff cam chain is truly endless. I'll telephone Monday and see what I can find out.
I have the Yamaha manual (from Yamaha, English edition) for 1979-80 SRs. Here's what it says:
1. Remove the left crankcase cover.
2. Rotate crankshaft in a counter-clockwise direction (viewed from the left side of the engine) to place all slack in the area of the chain tensioner.
Align the "T" mark on the flywheel with the timing mark on the crankshaft at the compression stroke.
3. Remove the adjuster cap.
4. Loosen the adjuster locknut.
5. Turn the adjuster in until the pushrod (inside the adjustor) is flush with the end of the adjustor.
Note: Start the engine. While keeping it idling, check the movement of the push rod. If it moves slightly, the adjustment is correct. If it does not move at all, the adjustor is too tight. Loosen the adjustor so the push rod moves slightly.
6. Tighten the adjustor locknut.
7. Install the adjustor cap and the left crankcase cover. Adjustor cap tightening torque: 1.5-2.0 m-kg (10-14 ft-lb)
Hope this helps. If you find a Japanese manual and scan the page, I can probably read it for you. My reading Japanese isn't perfect — slow, but okay.
I'm glad you posted on this. I thought the cam chain looked puny, and now I'll get a stronger one. I wouldn't have had the sense to do that if you hadn't brought this up.
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Post by chew652 on Jan 5, 2008 14:01:22 GMT -5
Thanks Big. Try and stay warm.
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Post by StewRoss on Jan 5, 2008 15:55:29 GMT -5
Hi, The DID 219 FTSS is a continuous chain as it comes in the box...I have one here for an engine I am doing for myself. I will have to get another one...as I am doing up my brothers engine as well now. Worth putting in a stronger chain if possible, especially if you are putting in stonger valve springs etc. SR  |
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Post by caferacercarl on Jan 7, 2008 1:02:25 GMT -5
The DID FTSS is strong enough even for racing and outlives the stocker by about 3x and is half the price, and for the guy's on the adjustment issue, yamaha does not have a problem in that area, and the chain and tensioner do not wear anything like many other models I could mention, and the adjustment mentioned is the proper method,just don't over tighten it.
Oh, and yes I couldn't use caferacer, caferacer carl or "the real caferacer" all taken?so, after many attempts, punched in stopusingmyname and it let me join!! thanks guy's , carl.
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Post by G Man on Jan 7, 2008 1:07:16 GMT -5
... Oh, and yes I couldn't use caferacer, caferacer carl or "the real caferacer" all taken?so, after many attempts, punched in stopusingmyname and it let me join!! thanks guy's , carl. Hi Carl. Go to your profile, click modify profile and enter any name you like in the display name box. It should work for you. G Man |
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Post by andy on Jan 22, 2008 13:42:33 GMT -5
Hi Chew,I reckon your spot on with your comments on camchain adjuster.if you adjust till plunger is flush you are not giving the plunger anywhere to go [when its moving backwards]so you end up with excessive guide wear.on doing a topend rebuild with a new camchain i noticed a lot of wear on the guides,this is not to much of a problem providing there is still plenty of meat on the guide,just carefully file the centre high ridge off or remove with a steady hand and a good sharp wood chisel.it is also important to remember there is a rubber washer between the spring and plunger[towards the rear]this absorbs any rattle.i might be going against what the bible says but the slotted end of the plunger sits about 6mm further down the hole,definitely not flush,i can assure averybody it runs fine and quiet and aint munching my gudes excessively!if it should all turn to sh** then thats my problem!
Regards,Andy
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Post by wotavidone on Jan 22, 2008 17:47:46 GMT -5
Buggered if I know what the problem is. I do it the way Bigshingle says, and the pushrod ends up oscillating maybe 0.5 - 1 mm, and any slight rattle I imagine I can hear goes away. I change the oil at 3000 k as per the owners manual, and check the tension at the same time. Seldom need more than a fraction of a turn on the adjuster.
Only trouble I have had is splitting the plastic adjuster cover, no doubt I did it up too tight, though I tell most people it got old and brittle.
Mick
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Post by caferacercarl on Jan 22, 2008 20:19:59 GMT -5
they do get old and brittle ,but the adjustment method is correct and the system is only designed to hold the chain just tight enough not to ride on the tensioner to much, but more importantly to tension the backlash that can occur from backfire or snapping throttle shut at higher RPM, I have no wear problems in this area even in my race engines which rev to 10500 rpm no worries, regards Carl
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Post by chew652 on Jan 23, 2008 18:35:55 GMT -5
Well boys I put the new chain and movable guide in the machine. I originally had the barrel of the adjuster locknut bottomed out in the threaded bore and the pushrod 3/16ths " below the end of the adjuster. With the new parts in, the pushrod comes flush with the end of the locknut long before it would bottom in the thread. I adjusted it so as the pushrod just ocillates below the flush setting. The pushrod at its highest point is just a hair below flush. Because the pushrod movement is not very large , my conclusion is that my method and the factory method are essentially the same.By setting the pushrod at or near flush and backing off until you see some movement is about what I ended up doing. I guess the problems arise when you crank that sucker down until flush and then try to get it even a little bit tighter.
I am amazed at how much difference the new parts made. With the old ones it wasn't possible to get the parts too tight but with the new ones you defintely could . I think the importance of the pushrod movement could be emphasized a little more possbly with a warning that when the pushrod is flush it is essentilly bottomed out.
I think I have put entirly too much thought into a simple process. But it is Winter here.
Cheers Guys, Bill
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