$200 Special

Very Nice 5Twins ! I really love the polish job you did on the outer tubes ! man that's better than factory !
How does the forks react after the mod and spacer ?
Bob........
 
The forks work well but the 1" preload spacer may be a bit much. I'm not going to pass final judgement on it though until I do up the rear end (TX750 swingarm, longer aftermarket shocks). My '78 with MikesXS progressive springs feels soft by comparison now. It has no additional preload spacer added and the adjustment caps are at the minimum setting. I may have to crank them up, lol.
 
Next installment - some (external) clutch work. This consisted of a new clutch pushrod seal, bushing, and installing a N.O.S. long pushrod. Also, the fabled "1L9" worm gear from an XS400. Initial inspection under the left cover revealed that the pushrod seal appeared to be the major leak point. But, I cleaned it all up and put some miles on it to be sure. The bike would dutifully "mark it's spot" with a few oil drips after every ride, lol. So, in I went ....

The P.O. had already replaced the pushrod seal but he did a shit job. He didn't replace the bushing which could have been partly, if not mostly, responsible for his failed new pushrod seal. Once I removed it, I found it was an original 8mm long bushing, and comparing it to some new ones I had, you could easily see it was worn pretty thin .....

st8JtC7.jpg


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The usual replacement is a slightly longer than stock 10mm bushing fom MikesXS. I found I could get them from McMaster-Carr for about half the price, and in even longer lengths. I decided to try some 12's and that's what I installed here. There is a counter-bore into the shaft with a lip at the end and it's 11mm deep. You can't drive the bushing in any farther .....

nSDp4tM.jpg


That means a 12mm long bushing is going to protrude a little .....

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But, that's OK, it won't contact the seal because it has 4 little "feet" on the back of it that holds it away from the shaft .....

iCH36co.jpg


So, the bushing and seal install went well and the new long pushrod was a perfect slip/sliding fit with absolutely no side to side play or wiggle. Once again, I applied that new seal tip I discovered and filled the seal lip with grease .....

3iddQQH.jpg
 
Part 2 - the XS400 worm. I've mentioned using these quite a few times. I discovered them a few years back scrounging from my dealer's bone yard. At the time, I was mostly after the female nylon part because it's the same one that the 650 uses. TwoMany was knee-deep in his worm gear manifesto at the time, modding 650 male worms by re-clocking them slightly and changing their "step up" configuration to a "step down" one. His reasoning was a stepped down worm arm would turn more efficiently without binding. Well, looking at this 400 worm I had "liberated" showed that it was already stepped down .....

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There was only one issue with it, it wasn't clocked quite as much as the 650 worm. Here's a bunch of different worms compared and as you can see, the 500 and 400 worms are clocked the same but not as much as the 650 ones .....

PcI8sQq.jpg


2M suggested that re-clocking the small amount needed may be possible by simply sanding a little off the top of the female nylon part. I tried it and it worked. You don't need to sand much off, only about 1 to 2mm. That allows the male part to screw deeper into the female part and that re-clocks it. Here's a stock 500 worm (clocked the same as the 400 worm) compared to a sanded and modded 400 one, and a stock 650 one. The clocking on the modded 400 worm now falls about midway between where it was stock and where the 650 one is, and that's enough of a change to make it work .....

EApp5U6.jpg


So, some coarse sand paper laid on a sheet of glass and a few minutes working the top of the female worm against it achieves the desired results .....

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The stock worms measure just over 22mm thick. Sanding them down to just under 21mm is all it takes .....

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Here's a modded (sanded) female part compared to a stock one, and the modded one mounted .....

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A switch from the stock Phillips mounting screws to button head Allens is recommended because they sit lower and allow the male part to screw deeper into the modded female part. There isn't much clearance between the tin housing that holds the rubber seal ring and the screw heads, sometimes not enough for the male part to screw in deep enough and "re-clock" enough .....

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The button heads give you the little bit extra space you need .....

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Besides the theoretical smoother turning and operation, there's another reason I like to use this "1L9" worm, and it's an important one I think. The stock 650 worm is actually clocked a bit too much in my opinion. To hook the cable into it, you have to rotate the end of the cable arm nearly 1/2". This backs the male worm out of the female worm, and by quite a bit, so you no longer have 100% contact between the 2 parts .....

1MHx5XO.jpg


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The XS400 worm with it's less (but enough) clocking doesn't do that. It still retains near 100% contact between the male and female parts even after it's been all adjusted up .....

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So much learning here...and your engineer-buddy is dead right about chamfering those oil passage holes in the damper rods.

You want laminar flow there and not the turbulent flow that would be promoted by sharp edged holes.

Pete
 
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Those are great modifications! All these incremental improvements 'round here add up to a more better fantasticer bike! :bike: It's getting hard to keep track of all of them! Since "The Basketcase" has been reduced to its constituent parts, I'll put as many of these mods as I can into it as it goes back together, and put it into the "What did you do to your Xs650 today" thread. Very nicely done! :rock:
 
Next installment - some (external) clutch work. This consisted of a new clutch pushrod seal, bushing, and installing a N.O.S. long pushrod. Also, the fabled "1L9" worm gear from an XS400. Initial inspection under the left cover revealed that the pushrod seal appeared to be the major leak point. But, I cleaned it all up and put some miles on it to be sure. The bike would dutifully "mark it's spot" with a few oil drips after every ride, lol. So, in I went ....

The P.O. had already replaced the pushrod seal but he did a shit job. He didn't replace the bushing which could have been partly, if not mostly, responsible for his failed new pushrod seal. Once I removed it, I found it was an original 8mm long bushing, and comparing it to some new ones I had, you could easily see it was worn pretty thin .....

st8JtC7.jpg


ZfpKWJC.jpg


The usual replacement is a slightly longer than stock 10mm bushing fom MikesXS. I found I could get them from McMaster-Carr for about half the price, and in even longer lengths. I decided to try some 12's and that's what I installed here. There is a counter-bore into the shaft with a lip at the end and it's 11mm deep. You can't drive the bushing in any farther .....

So, the bushing and seal install went well and the new long pushrod was a perfect slip/sliding fit with absolutely no side to side play or wiggle. Once again, I applied that new seal tip I discovered and filled the seal lip with grease .....

3iddQQH.jpg

Do you have the McMaster part number for the bushing? Also, what's the "seal tip" you discovered? A different/better seal? Inquiring minds want to know! :D
 
Yes, the McMaster-Carr bushing part numbers .....

mmd5igx.jpg


Prices have gone up about 25 cents since I bought these and labeled the bags, but they're still less than half the MikesXS asking price. As an aside, the 10mm long bushing can also be used to repair worn out brake and clutch lever pivot holes. Drill the worn pivot hole out with a 3/8" bit, ream and/or file it a little bit larger, and press or tap the bushing in.

The seal "tip" is nothing more than filling the space between the seal lips with grease before placing the seal on it's shaft or sticking a shaft through it. It's mentioned in this thread at the end of post #1 .....

http://www.xs650.com/threads/engine-oil-seals.52383/
 
This difference between the Standards (left) and the 81 Special (right) has just surprised me last week.
The cable pull is affected by both mechanical advantage and distance of travel. On a 78E Standard , what differences could be felt ?
Any Preference ?
Thanks-R
 

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The closer the cable anchor point is to the center of rotation, the more rotation, and hence, pushrod travel you'll get for any given amount of lift or clutch lever pull. The very early worms used on the 1st few models were very short. They gave the most pushrod travel but the clutch lever pull was very hard. Yamaha came out with the long arm worm but I guess they realized after a few years that even though it gave an easier lever pull, it reduced the pushrod travel too much. So, they "modded" it slightly, moving the cable anchor point in towards the center a little bit more. The distance to the center is still more than the early worm. For stock worms, I feel this factory "modded" late version is the best option. It gives the best compromise between pushrod travel and ease of lever pull. The XS400 worm matches this arm length.
 
Something else I should mention is that you may encounter 2 types of female worms, some made of white nylon and some made of black nylon. The earlier, and in fact most of the 650 ones were made of white nylon. Some later 650 ones as well as most of the 400 and 500 ones I've run across were black nylon. I wondered what was up with this and thought maybe the later black ones could be an improved, harder nylon. Well, after modding (sanding) both white and black ones for these 400 worm gear installs, I can verify that the black ones are indeed harder. They take a lot more time to sand down than a white one. Hopefully they'll wear less and last longer than the white ones.
 
The next little mod wasn't anything major but just something I wanted to do - install barend weights. I had done this years ago on my '78 but didn't have access to those materials anymore so I had to come up with something else. I got the idea of using vinyl tubing with steel bar inserted into it for mass and weight. I figured the vinyl material may help soak up some vibes as well. The closest size to fitting was 3/4" O.D. It was just a tad too big but the next smaller size was really loose .....

ew6Lav5.jpg


You could also work 1/2" all-thread into it but that combo wasn't going into the bar end, no way. So, I had to reduce the vinyl tubing O.D. a bit and find or make some smaller O.D. steel rod. Making the vinyl tubing fit proved quite easy. I just cut about a 3/16" to 1/4" strip out of the side .....

CMiqaD2.jpg


This made for a perfect slide-in fit. Now I just needed smaller diameter steel rod. I guess I could have just ground all the threads off some of the 1/2" all-thread, reducing it's diameter, but that would have been lots and lots of work. So I went to my scrap metal pile to see what I could find. A few years ago, I replaced the shocks on my Jeep. I cut the old ones up and saved the chrome steel damper rods. These turned out to be just what I needed .....

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But the 1/2" all-thread did prove useful for holding the vinyl tubing straight and stable while I cut the strips out of the side. Instead of one long cut down the entire length of one side, I decided to slot the tubing a bit over half way in from one end then do the same on the opposite side of it from the other end. I drilled a 3/16" hole at the end of my cut, drew cut lines, and cut the strip out with a utility knife .....

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The finished vinyl tubing was slotted it's entire length, just not on the same side, so it would compress down to fit into the bar .....

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Fitting was simple - lube up the vinyl and insert it into the bar end about 2/3 to 3/4 of the way, then insert the steel rod .....

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..... and finally, gently tap it the rest of the way in with a rubber mallet .....

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This doesn't make a night and day difference but it does absorb some of the high frequency "tingles" and buzzing. And it only cost me about $2, lol.
 
Next mod was a voltmeter. Unfortunately, it wouldn't fit in the little idiot light pod between the speedo and tach like I was able to do on my Standard, so I had to find another location and mounting method. Space is so limited up around the instruments though. This '83 had a "beauty" plate covering the handlebar mounts. "Beauty" is not an apt description, it was hideous in my mind, lol. When I removed it, I found it left behind a flat topped steering stem bolt with a nice hole drilled and tapped into it, perfect spot for a voltmeter, right? .....

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So, I made up a small mount bracket to bolt to it .....

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..... and then a housing for the voltmeter to mount on that .....

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The finished install came out pretty good .....

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The meter housing was made out of some 16 gauge angle. I folded 3 sides down to create the open bottomed housing. Obviously, the seams where the sides met were open so I needed to fill them in somehow. I thought I might be able to tack weld them so they stayed together, then fill the cracks with JB Weld. Well, to my surprise, using 1/16" rod and my welder on a lower setting, I was able to weld the sides along their entire lengths. Then, ground smooth and painted, the results were quite good.
 
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