Discussion in 'The Garage' started by inxs, Mar 26, 2010.
thanks man, i got it
I was going to start a new thread but figured this info is best posted here. This will be a comparison of the type D and type E tensioner assemblies and also an explanation of why I feel that if you have a type D, you should upgrade it to the type E. First, a little tensioner assembly history. As noted at the beginning of this thread, there were several versions over the years, five to be exact. If you study them, you will notice all have a lock nut to hold the adjuster's setting while installing the cover nut, except the type D ......
Therein lies the problem with the type D. Yamaha decided the cover acorn nut could and would act as the adjuster screw's lock nut. Well, it does lock it down but it can sometimes turn the adjuster screw in too as you're tightening it, and there's no way to tell if this has happened. You may end up with a chain that's too tight and that can stretch it out prematurely. Yamaha realized the "error in their ways" after a few years and came out with the type E adjuster, putting a lock nut for the adjuster screw back on there. When comparing the two assemblies, the major difference is quite obvious. The plunger on the type E is longer. The length was added to the plunger head so the same amount of tension can be achieved with the adjuster screwed in less. More of the adjuster screw hanging out the back provides room for the added lock nut .....
When I first compared the assemblies a few years ago, all I had available was my original '78 type D and a type E from an '80 parts motor. All the components appeared the same (spring, adjuster screw, housing, acorn cap nut) except, of course, the plunger. This made upgrading easy - simply swap the type E plunger and lock nut onto my type D. Since then, I have acquired more type E assemblies, some from later models, and have discovered another small difference or change ......
A 2mm thick copper damper washer was used on the type D and some of the earlier assemblies. This copper washer was carried over and used on the first type E assemblies as well. Then, probably around '81 or so, Yamaha came out with a new, upgraded metal/rubber damper washer. This new damper washer is also 1mm thicker ......
But, adding a thicker washer presents a problem. The plunger will now no longer come out flush to the end of the adjuster screw. This would make adjusting per the manual instructions, making the plunger end flush with the screw head, impossible. It also makes observing the plunger for that little bit of needed in-out movement very difficult because it's inset into the adjuster screw head. Something had to change and well, it did. When Yamaha introduced the new thicker damper washer they also shortened the adjuster screw by 1mm .....
So, that means there are actually six tensioner versions, the type A through type D, and then an early and late version of the type E.
Now let's discuss the two damper washers some more. If you use the proper washer with the right length adjuster screw, you get the correct "flush with the end" results .....
If you mis-match the washer types with the wrong length adjuster screws, you get one of these results .....
As I mentioned above, having the plunger inset makes adjusting very difficult. Having it come out past the adjuster screw end wouldn't be a problem as long as you knew why it was doing it and didn't try to adjust it flush. That would result in a chain that was too loose.
It seems many discover they are missing the copper damper washer. Unfortunately, Yamaha no longer sells it. They only sell the updated metal/rubber version and as noted, that can make adjustments more difficult on older tensioner assemblies. Also, the darn thing costs like $10, lol. Well, I found a nice replacement for the copper washer on eBay. A bag of 10 will cost you less than half of what they want for one metal/ rubber version .....
They are a very close match to the original. The thickness is spot on but the I.D. is a hair smaller and the O.D. a hair bigger, but I don't see either of those differences affecting their function .....
I ordered the front guide from Mikes and was a little disappointed. The casting job was not so great and the lower bolt hole threads were shaky. I resolved the problem by using a longer bolt. My old guide looked really good and I was tempted to put it back in, but common sense prevailed....
Yeah, you've got to closely examine the aftermarket front guide's threaded holes. Maybe chase them with a bottoming tap, or, like another member did, drill them out and use a 'TimeSert' thread repair kit.
More info on the front guide bolt holes in this album:
More info on the uniqueness of the early 70-73 256-306 type 'A' and type 'B' systems in this thread:
bdholsin, be aware that the cam chain in XS1-TX650 motors had different pitch from the chain used from TX650A forward, and the idler gear on the XS2 tensioner is incompatible with late cam chains; you'd have to change crank sprocket, camshaft sprocket, and cam chain to use it. As 5twins says, it's the front damper that tends to be troublesome.
Hi I have a xs2 with type b tensioner. The black stopper material has deteriorated and I am losing my mind trying to find a replacement. Any ideas???
Willyt, the type "B" tensioner parts often show up on eBay, both used and NOS. Bring yourself up to speed on the part numbers and visual identification...
I know this is an old thread but anyone have any luck with these OEM cam tensioner parts on ebay?
That eBay vendor, out of Lockhart, Tx, is a big seller of NOS parts. I've had good dealings with them.
Your first link is for an OEM early '70 XS1 front guide. It's flat, not a curved channel shape as used on '72-up engines.
Your 2nd link is for the later 447-type rear tensioners.
Can't intermix tensioner parts, early and late.
If you're working with later 447 stuff, the fellows here recommend boats.net for parts. Their front guides are new manufacture, not 45-year-old plastic...
"If you're working with later 447 stuff, the fellows here recommend boats.net for parts. Their front guides are new manufacture, not 45-year-old plastic..."
Any chance you have a part number for the 447 stuff? A search of their site using the Yamaha part # shows unavailable.
This is the later front guide .....
The rear tensioner is not available but rarely needs replacing.
I am in the last stages of my ’72 XS2 engine re-build and have forgotten which way around the rear guide stopper 2 (new type) get mounted to the block… Looks like this
Clymer shows its orientation the same as the original type on the earlier engines in the side note box at the bottom of page 58 image 48.
If it is mounted like the older style, it doesn’t leave enough room for the front guide stopper to fit past it. Since this rear stopper is offset to the rear of the mount and has a bar in front of it, I think it mounts as a mirror image of the original. If I rotate it 180degrees and have the front and rear of the chain separated by the small bar in the stopper mount would that be correct? Can't seem to find any info as to the installation of this stopper anywhere.
Any help would be great thanks..
Yeah, that type "B" bottom slipper is shown backwards in the parts manuals. And, I haven't found any pics showing its correct installation. We discuss it more in these:
Thanks for the confirmation ...seems the manual also shows it upside down too .... so upside down and backwards makes sense now...haha. I snapped a couple of pictures for future reference.
I have a big problem! I have a 1971 xs1b with a sprocket tensioner in the rear and it's supposed to have a 2 bolt stopper in th front but it won't slide down into place because it also has a "new type" stopper at least that is what Clymer shows in the book (4 bolt) installed in the center of the jug.
Need help 'I don't know what to do. .any ideas?
The pikey 84, read thru the links in post #25...
The 1st pic is from the front of the engine he 2nd is the sprocket tensioner .mine has everything in the 3rd pic..and the long front tensioner won't slide down into place..
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