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Ok, don't stone me for reviving what appears to be a dead horse, but I figure that if I still don't get it, then there might still be some hope left.



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I've been re-reading all the fork swap threads I can find, dubiously studying the AllBallsRacing fork conversion options, comparing steering bearings, wheel bearings, brake disc diameters, and fork widths, and the best alternative I can find for a raised front end to match a longer rear shock are the late 80s to '92 YZ80 forks that will bolt in to our existing triple tree.



Pretty much every other option requires swapping to a skinny front, which may certainly have some advantages that I don't yet fully appreciate, but I'm not keen on the idea of ditching the iconic TW image by adding a skinny front end.



I particularly liked the pics posted some time ago by JohnnyBlaze. The stance looked good, not quite "balanced" per se, but certainly better that just adding a tall rear shock. I appreciate the dilemma that was communicated on the 12mm vs. 15mm axle bolt...kinda hard to argue with physics, and when you do, you don't win.



On some other thread someone asked the $25,000 question, and in my opinion, it didn't get the attention that it deserved. So I'm going to stop typing shortly and get to the point:



TW200 & early YZ80 forks are the same diameter, share fork seals, and have the exact same part number for the little bolt that connects the internals to the lower fork tube. So why can't a hybrid fork be constructed from the TW outer tube and the YZ inner tube to get a taller front fork and balance a raised rear end?



I've noticed that the YZ has what is purported to be a 10" travel, which I find just delicious to think of, but I've also noted that the YZ outer tube extends about 3" below the axle to make up for this additional travel. But travel and whatever spacers inside the fork tube aside...



Why couldn't this hybrid work?



________________________________________________________________





Alright, I'm sufficiently prepared now...and a "newbie"...stone away...



 

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It would work to balance out the "look", but would only have the travel of a standard TW front end.



I wouldn't bother with getting a complete YZ front end, either. Just get the tubes, transfer your TW stuff onto them and cut a spacer to compensate for the spring height.



No stoning, nor criticism. Sounds like you already know this is a pretty much a useless swap.
 

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Ok, don't stone me for reviving what appears to be a dead horse, but I figure that if I still don't get it, then there might still be some hope left.



_____________________________________________________





I've been re-reading all the fork swap threads I can find, dubiously studying the AllBallsRacing fork conversion options, comparing steering bearings, wheel bearings, brake disc diameters, and fork widths, and the best alternative I can find for a raised front end to match a longer rear shock are the late 80s to '92 YZ80 forks that will bolt in to our existing triple tree.



Pretty much every other option requires swapping to a skinny front, which may certainly have some advantages that I don't yet fully appreciate, but I'm not keen on the idea of ditching the iconic TW image by adding a skinny front end.



I particularly liked the pics posted some time ago by JohnnyBlaze. The stance looked good, not quite "balanced" per se, but certainly better that just adding a tall rear shock. I appreciate the dilemma that was communicated on the 12mm vs. 15mm axle bolt...kinda hard to argue with physics, and when you do, you don't win.



On some other thread someone asked the $25,000 question, and in my opinion, it didn't get the attention that it deserved. So I'm going to stop typing shortly and get to the point:



TW200 & early YZ80 forks are the same diameter, share fork seals, and have the exact same part number for the little bolt that connects the internals to the lower fork tube. So why can't a hybrid fork be constructed from the TW outer tube and the YZ inner tube to get a taller front fork and balance a raised rear end?



I've noticed that the YZ has what is purported to be a 10" travel, which I find just delicious to think of, but I've also noted that the YZ outer tube extends about 3" below the axle to make up for this additional travel. But travel and whatever spacers inside the fork tube aside...



Why couldn't this hybrid work?



________________________________________________________________





Alright, I'm sufficiently prepared now...and a "newbie"...stone away...





I was the one who brought up the hybrid idea. I did purchase a set of YZ forks a month or so ago but am waiting for winter to start with the project.
 

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Why not just run some late RT180 forks? If you don't have a late TW wheel you could just purchase the hub/spokes/disk from yamaha and lace your drum rim to it...then have a machine shop bore the four triple bores and extra mm...now you'd have 35mm fork and an extra inch or two of height to play with...If the stock tw caliper doesn't fit the mount ears, then just run the RT caliper (which I believe is identical to the XT/TTr single piston caliper [late rt180 94-97 only, early ones used a 240mm disk and a 4 hole disk mount pattern, and a rare and strange caliper that won't easily work for a TW hub and disk], I believe you could probably even bolt the stock RT disk to the TW hub)
 

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In my opinion, the TW suspension is pretty much 'stone-age'. I have done a range of suspension mods. I am now very happy with my front/rear suspension as it seems to now compliment the kind of riding I do.



Not sure what kind of improvement most of you are looking for. I made a sub-tank for extra air volume and forktube pressure regulation. For me (170lb) this allowed me to have a comfortable offroad ride at 13/22mph. I then added progressive springs. I will say that air pressure and progressive springs will give you the best 'bang for the buck'.



Since it seems I carry (always) lots of stuff, I decided to go one step further in order to improve my front suspension. I had my triple-tree bored to 35mm by a machinist and installed a TRI-Z fork set.



Now all of this stuff is "seat of your pants" modding, but as for the above, I have done 'IT' and still ride the bike,,,, and the suspension is much, much nicer.



The early YZ forks hold lots of potential (I think). Don't be adversed to having your triple tree over-bored (slightly) as it seems to afford you a few more options.



Our Big-Wheel member indicated that the 'larger' Tri-Z triple-trees will fit the TW and will allow you to install a few (likely better) fork systems from Yamaha or Honda. These kind of mods present risks that generally seem to involve mostly time and money, but safety is as well a consideration.



Again, for a straight forward inprovement, consider more air (subtank) with regulation (schrader valves) and progressive springs..... A noticeable improvement. Gerry

 

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In my opinion, the TW suspension is pretty much 'stone-age'. I have done a range of suspension mods. I am now very happy with my front/rear suspension as it seems to now compliment the kind of riding I do.



Not sure what kind of improvement most of you are looking for. I made a sub-tank for extra air volume and forktube pressure regulation. For me (170lb) this allowed me to have a comfortable offroad ride at 13/22mph. I then added progressive springs. I will say that air pressure and progressive springs will give you the best 'bang for the buck'.



Since it seems I carry (always) lots of stuff, I decided to go one step further in order to improve my front suspension. I had my triple-tree bored to 35mm by a machinist and installed a TRI-Z fork set.



Now all of this stuff is "seat of your pants" modding, but as for the above, I have done 'IT' and still ride the bike,,,, and the suspension is much, much nicer.



The early YZ forks hold lots of potential (I think). Don't be adversed to having your triple tree over-bored (slightly) as it seems to afford you a few more options.



Our Big-Wheel member indicated that the 'larger' Tri-Z triple-trees will fit the TW and will allow you to install a few (likely better) fork systems from Yamaha or Honda. These kind of mods present risks that generally seem to involve mostly time and money, but safety is as well a consideration.



Again, for a straight forward inprovement, consider more air (subtank) with regulation (schrader valves) and progressive springs..... A noticeable improvement. Gerry






1997 rt180 on the left, tw200 on the right



the 180 shock is about 2" longer, has 3.5" more travel, has an xt350 caliper pattern(cheap calipers), is leading axle, and has the right Axle bore. It is a 35mm fork so it will fit modified bore TW triples.



Tw forks = 30" eye to top, Rt180 forks = 31 and 5/8" eye to top, Tri z forks look to be 37" - 4", for 33 inches eye to top













 

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Discussion Starter #7
The early YZ forks hold lots of potential (I think). Don't be adversed to having your triple tree over-bored (slightly) as it seems to afford you a few more options.



Again, for a straight forward inprovement, consider more air (subtank) with regulation (schrader valves) and progressive springs..... A noticeable improvement. Gerry


Timely response Gerry, and how ironic... My YZ forks should arrive Wed. and hope to have hands on a spare TW parts bike this weekend to do side by side comparisons of the YZ & TW internals. Using the hybrid fork approach, I hope to keep the TW outer tubes, get a taller front end that has the schrader valve fork caps, and swap to progressive springs to help take up some of the spare space in the longer inner tubes and smooth out the ride. My old KZ1100 was set up this way and rode wonderfully.



Only SNAFU I haven't worked out yet is which springs to opt for. The calculator at Race Tech recommends a spring rate of .46 kg/mm for a 185 lb rider. Most of Progressive's soft springs are in the larger diameters, but I was thinking that the 11-1114 (.45-.64 kg/mm, 19.75", & 27mm OD) would likely work, and perhaps the 11-1136 (.29-.52 kg/mm, 22.5", & 29mm OD) if the 29mm OD springs will fit in the 33mm tubes.



I'm going to start small, simple, & reversible for the time being, but if the extra bike comes through, I'll have a spare set of triples to play with as well.
 

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Frank's Maintenance and Engineering, Inc., used to make just about any fork tube in just about any length you could want. No increase in travel, just a changed ride height. Could be a good option for lowering for vetically challenged riders.
 

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An issue that the Tri-Z triple clamp introduces is increased rake. It doesn't truly seem to affect the handling on my BigWheel, but it is ridden 98% of the time offroad. Mr. Gizmow's solution, boring out the TW's triple clamp to accept the Tri-Z fork, does preserve the original geometry. The Tri-Z front end can be run with a leading or trailing axle, allowing some manipulation of the geometry with that setup.



The best aspect of the stock fork of the TW BW is that is has zero underhang of the fork tube below the axle. Other than that, I feel that it has few redeeming values. The Tri-Z has significant underhang and can be quite a handful in deep ruts or in rocky situations.



However, the improvement in the front end performance far outweighs all of the drawbacks.



Regards,



Mr. BigWheel



P.S. Mr. Gizmow: did you have to use spacers when you installed the progressive springs?
 

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Discussion Starter #11
Before:











AFTER:



 

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YOur tank mod looks 'super' with some very nice finish work as it mates to the seat and stock plastic. See that you have the stock TW fork bottoms, but can't say I can tell about the top sliders...... Please let us know whats on top and if you have completed the swap. What are your impressions?.



Should some new option prove viable, we will have to represent all ideas with more clarity and make it a "sticky".. Gerry

 

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Discussion Starter #13
YOur tank mod looks 'super' with some very nice finish work as it mates to the seat and stock plastic. See that you have the stock TW fork bottoms, but can't say I can tell about the top sliders...... Please let us know whats on top and if you have completed the swap. What are your impressions?.



Should some new option prove viable, we will have to represent all ideas with more clarity and make it a "sticky".. Gerry


Thanks for the compliments. Still need to get the risers on the bars for lock-to-lock turning, but it's working just fine as is.



That's the YZ inner tubes & internals with the TW lowers. Front end sagged a bit until I put some air in the forks. So far it feels about the same as before, but I've only been around the block as we're heading out for the evening soon. The speedo cable & brake line are stretched to the max between the longer tubes and higher bars, but those are both fixable. Don't think the 29mm springs will work well in these tubes, and I'll be finishing it off with some new schrader valves for the fork caps and the 11-1114 Progressive springs. I'll get out and put some miles on it tomorrow afternoon and will have a better report then.



But the hybrid works...net gain 2".



 

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Discussion Starter #14
Please let us know whats on top and if you have completed the swap. What are your impressions?.


Well, I put a few dozen miles on it today. Well worth it for me. I've got about 20 lbs of air in the forks and it rides great. I'm a tall guy & ride toward the rear of the seat, so the best description of performance is that the front end is balanced with the back now. The front was always stiff before bouncing along on the lines in the road like a sewing machine. Now the little bumps are absorbed nicely, but there's no crazy front end dive or anything when braking.



I could live without the Progressive springs for the time being and ride it as is with no compliants.



I've also got to say that I really like the the increased rake. When I put the 6006 on the front, it felt pretty squirrely. It's broken in ok with about 250 miles and rides much better at around 18 psi, but the stretched front end makes the steering much more neutral in the corners. I don't know how you guys handle the banshee/blaster shocks at highway speeds with the stock front...



Anyways, as for the forks themselves. The YZ & TW inner tubes are not 100% identical at the bottom. The YZ tubes have a couple bronze bushings at the bottom & a washer that sits beneath the fork seal. To separate them, remove oil, spring/spacer, fork seal covers, fork seal retaining clip, bottom bolt, & dump the fork cylinders out. Then slide the inner tube 6"-8" in and pull the tubes apart briskly, slowly driving the fork seal out of the outer tube.



With the YZ inner tube free, dump the upper bushing & washer off the top of the tube and pry the lower bushing apart and slide it off the bottom of the tube. This leaves the YZ tube with a recessed area at the bottom where the lower bushing went, however the rest of the tube retains the same diameter (to the tenth of a mm) as the TW inner tube both above & below this area so it is still tight and properly supported inside the TW outer tube. Slide the TW fork cylinders in and gently maneuver the YZ inner tube through the TW fork seal taking care to not force the recessed area through and goober up the fork seal. The remainder of the reassembly is the same.



With the factory handlebars, brake line should be fine. It might need to be moved around in the clamps, but it should work. I'm driving OK with these forks & ATV high handlebars and the brake line is taught at full extension. However, the speedo cable had to be routed around in front of the bottom of the triple tree to reach and will need to be replaced with an XT225 cable.



I'll see if I can find a better brake line & speedo cable this week & get some more pics up. Wished I'd have taken more snaps during the process, but I didn't really plan on completing the swap yesterday; I was just going to "take a look"...and then it all sort of came together at the end.



I'm sure I missed something somewhere, but that should give you a few more details.



Cheers,

 

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I was the one who brought up the hybrid idea. I did purchase a set of YZ forks a month or so ago but am waiting for winter to start with the project.
Did you ever start your yz/tw hybrid conversion? I am interested in hearing how it went.



Brock in AZ
 

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Nice wrtie up on the fork extension. I'd like to have 2 more inches of travel to go with the 2 inches of tall, but I'll take it as a solid improvement already.
 

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Did you ever start your yz/tw hybrid conversion? I am interested in hearing how it went.



Brock in AZ


I haven't done this yet. I have the forks but haven't had enough time at home to give it a shot. But plan to this winter when my schedule opens up. It's nice to know it actually works, thanks to abyssdncr!



Pat
 

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I am waiting for my YZ 80 forks to arrive. e bay ...$27 and they look extremely clean and straight. Now if I just had a clue about modifying.

Here are some schematics for the YZ 80 & TW 200 front forks and the read end for the TW if someone wants to add a banshee shock (Like me) or another shock to add some travel.



http://www.cheapcycleparts.com/model_years/5409-yamaha-1992-YZ80D/assemblies/167977 (YZ front fork - in depth)



http://www.cheapcycleparts.com/model_years/6307-yamaha-2008-tw200-ca-TW200XC/assemblies/206248 (TW front fork)



http://www.cheapcycleparts.com/model_years/6307-yamaha-2008-tw200-ca-TW200XC/assemblies/206259 (TW rear end)
 

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Having already done this, I'm gunna add my .02.



This is NOT an attack on creativity here, just my take on the matter. Fortunately whatever develops from this will largely be applicable to a standard-length front end as well, so it's a good thing, no?



For most people the shortest route to a working front end is best accomplished with the shorter, stiffer TW internals as a starting point. Make a 2" longer spacer and add extra oil (roughly 1/4 more) to get the same level from the top of the tubes as you had with the shorter fork. This will duplicate the stock fork. Play with oil levels and weights to get the most out of it.



Next step up would be a progressive TW spring.



For a "poorboy" path to more plushness you could stack the bottoming spring from the YZ over the stock TW main spring, using the stock TW spacer. If still too harsh for your liking you could add another, effectively lengthening and softening the spring in a controllable manner. This could also work with a stock-length front end and shortened spacer. I'm trying this now, but have yet to take it offroad.





As Abyssdncr has discovered, the YZ spring is both too long and the wire is too thin for this application, hence the neccessity for the 20 psi. I'm betting you could mitigate a lot of this by experimenting with progressively longer spacers and less air. This combo would be worth perfecting as it could also be applied to a standard-length tube just by shortening the spacer by 2" and adding the shraders.







Everything on the left is YZ. The two circular objects at bottom left are the bushings Abyssdncr referred to, and are not needed.The YZ brake line is perfect with ny risers and tall bars. I used an XT600 speedo cable.



Everything on the right is TW. Either setup will work within the TW lower legs, but the YZ stuff will require a bit of knowlege to perfect, as Abyssdncr is attempting to do.



Upper right and above the TW spring I've stacked two of the short springs from the lowers of the YZ. Basically what they do is give you a longer spring, rather than making up the extra 2" with a rigid, longer spacer. So far this alone has softened the front end a bit, but bottoming could be a real possibility and I need to hit the dirt with it to make sure.



I originally did this to correct the loss of trail from running a 26" tall ATV tire. Everthang affects some other thang. I would not do it again, and will return the bike to stock overall height once my swingarm has been stretched by lowering the shock attacment on the swingarm and returning to stock fork tubes.



For MY bike and MY purposes I'm on the ragged edge of losing what I consider the two of the TW's most loveable attributes, its low center of gravity and low seat height. This stuff is all well and good for evening out a hollow mod, but not of much value to me without at least gaining some travel in the bargain. At this point my bike is becoming so tall I may as well go back to my KLR.



So don't stone me, K?
 

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Fixing the front forks is my next project, loving the banshee, v-star spring and the extendended swingarm. I'll take a slightly higher seating position to level the bike out. I found myself sliding forward a lot or the last week.

Josh
 
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