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02-15-2009, 5:58 PM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Duel sprockets/Duel range Another sprocket post, and this one, yet again more of mrgizmow's ramblings.  I have mentioned, perhaps seeming to brag about my "duel sprocket" setup in an attempt to get the best of both worlds (trail & street).  A few of you have expressed curiosity/concern regarding the issue of chain alignment.  I indicated that there was a slight mis-alignment but it did not seem to cause me any issues/concern.  A forum member some time ago suggested that perhaps two sprockets up front would allow a "duel" range with no mis-alignment.  It sounded like a fine idea/suggestion but since I was not having problems with the original 'design' and seemed to be short on time, I put further refinements off until another day.  Well, seems that day has come, and I have installed two sprockets (14 & 15 tooth) on my primary shaft.  My hope was that the splines were much longer than they turn out to be.  What this means is you only have splines for one sprocket, so for the second one, you need to grind (carbide bit) the splines off the inner sprocket so it will fit over the unsplined section of primary shaft (lots of room).  I then fabricated a spacer to fit between the two sprockets as to allow the chain to drop on either without rubbing against the other.  The duel primary sprockets are now mated via two (longer) grade 8,  5 x.8mm allen head bolts.  For my style of riding, I suspect this will work fine.  If you are inclined to drop the clutch, then maybe you would need to have the sprockets drilled and tapped for a second set of bolts (sprockets are hardened) to prevent the possibility of shearing.  Now with a 14 & 15 tooth primany and a 50 and 55 tooth final drive, in 8 minutes time on the side of any road, I can choose a road range of 15/50 or an off road range of 14/55 by doing nothing more than loosening the rear axle nut, jacking up the rear wheel (crutch brace jack) and rotating the chain tension cam so that I can drop or raise a fixed length chain into an appropriate final drive configuration without any chain mis-alignment or fuss, I hope.  I am implementing a new angle to a process that I have been using for awhile now (successfully).  Here are a few pictures.  Gerry I am left with the feeling that this is going to be even better than what I had before, since I will have an even wider choice of gear ranges with no fussing with adding/removing chain sections.  Should there be a glitch in my thinking, I am not so proud as to leave the rest of you in the dark, I will admit to my folly.  My next project (I think) will be to bore my triple tree from 33mm to 36mm (seems we have lots of metal) and I will attempt to install another (fancier) fork.  Have been real happy with my subtank mod in making things softer (for me) but guess I am just looking for projects and wanting to keep up with the fantastic mods presented by Todd, Ben, Hodaka Guy, MK and the rest.   Gerry Be safe my Friend.    Report

02-16-2009, 9:52 AM TW2007 Joined on 09-17-2007 Washington Posts 1,189 Re: Duel sprockets/Duel range Wow!!!!!!!!!!!!!!!!!!! Great idea. This gets me thinking. I never looked at the amount of room available under the engine case for a second sprocket. Two thumbs up --great job. MK The TW200 may be slow but the Earth is patient. For my Travel Log Visit http://backroadsofnorthamerica.com/ Planning a Trip to Sumpter Oregon in July    Report

02-20-2009, 11:48 PM kj7687 Joined on 09-01-2007 socal(Inland Empire/San Bernardino County) Posts 1,370 Re: Duel sprockets/Duel range Hey that is a cool idea Gerry. I might do something like this but the problem is I use my bike for street AND off roading pretty much every day, and I'm way too lazy to change it that much. 07 Honda ruckus (wire mesh around frame to provide underseat storage enclosure, storage bag)-SOLD 07 Yamaha TW200 (44 tooth rear sprocket, www.cycleracks.com rear luggage rack) 97 Suzuki DR200 (Pirelli MT21 rear tire, Bridgestone ED03 front tire)    Report

02-21-2009, 12:21 AM rhgwynn Joined on 03-02-2008 Western Mass Posts 522 Re: Duel sprockets/Duel range I would be worried about the strength of the allen bolts as the sprocket is not rigidly mounted to the shaft due to the lack of splines and you have to modify the second sprocket.  The smart thing to do would be to have a custom counter-shaft made that has long enough splines.  It would really suck if one of the bolts snapped. Please consider donating to CTF to support research for a cure to Neurofibromatosis.    Report

02-21-2009, 6:26 AM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range Attachment: sprocket tools.jpg I too am concerned about the strength of the grade 12 (metric) allen bolt. I also pressed in two roll pins and tapped down the center of the pin a section of drill shank. Of course, my bet is, it will be fine for my needs. The outside sprocket is as secure as it ever was stock. If any point of connection will fail it would impact the inner sprocket and likely under hard load. I suspect the initial condition would be like the bike going into neutral. I think it would be prudent to slow to a stop quickly. Then just switch the chain over to the rigidly attach stock sprocket and continue on your way. I will keep you folks updated. Gerry Be safe my Friend.    Report

02-22-2009, 10:22 AM Fatboy97 Joined on 05-24-2008 Yakima, WA Posts 78 Re: Duel sprockets/Duel range Fantastic work as always Gerry! I'm really looking forward to your next project about boring the triple trees out to 36mm. The suspension is the one thing I don't like about the TW.    Report

02-22-2009, 11:05 AM rhgwynn Joined on 03-02-2008 Western Mass Posts 522 Re: Duel sprockets/Duel range You can purchase or make fork caps that allow you to pressurize the forks and/or add sub-tanks.  Other members, notably the OP,  have done this and reported an incredible improvement.  See the small copper tank in his avatar?  CLICK Please consider donating to CTF to support research for a cure to Neurofibromatosis.    Report

02-22-2009, 11:07 AM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range I guess I am kind of backing myself out of that project for now. I had purchased a set of Yamaha YZ (I think) forks on E-bay last week. When I realized they were to big (41mm) I sent the seller an e-mail indicating that I would be glad to pay for them, but the cost of shipping would add insult to injury so he could keep them (I just did not do my homework before bidding). I also bid on a set of XT 225 fork (36mm) but lost. I my opinion, our triple tree has enough 'meat' to over bore from a stock 33mm to 36mm (I think Sebastian has done something like this). I found an adjustable reamer in the McMaster Carr catalogue for $94. A machinest at work suggested it would likely work but would take a long time. He guessed 3 to 4 hours. The XT has 2 inchs more travel which seems like a big plus, but then would it use the same brake caliper, ect. (?). So instead, for right now, I ordered a 'fancy' set of Hyperpro progressive fork springs (all this for a guy that only goes 15mph [GEEZZ]). Maybe we can get BigMac/Sebastian to outline his fork mod proceedure, also once I explored his website, I found that he carries some nice fork springs for the TW made by Wirth-Federn. Gerry Be safe my Friend.    Report

03-07-2009, 5:49 PM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range I feel the project is pretty much done, here is additional information. The above picture shows a cut that I made to the left case to allow me to get a better view of the primary sprockets so I can see where the chain is going when I do the switch. The above is a picture of the new chain guard that I made.  Now with the tandem setup, the chain runs straighter and seems to rub on the stock chain guard.  With the single primary before, this was not an issue, but now (duel front and rear) it is.  I used 1/8" aluminum angle to fab the guard, really to minimize mud being thrown on the chain.   The above is the back view of the duel sprockets and the new chain guard.  I have not ridden the bike with this set-up yet, but do not expect it to be different than with the duel rear, single front which I had ridden for over 1000 miles.  With this, both combo's have a 'correctly' aligned chain. Some things that I did, that you do not want to do.  My spacing between sprockets was a little to close to allow the use of a master link right now.  The master link is a little wider and seems to rub on the adjoining primary sprocket.  Since I always carry a chain tool, this is not an issue for me right now, but will change it next go-round.  I found that since the large sprocket is split, and even though I took care (I think) to make sure the diameter would not change when it got bolted to the inside of the rear hub flange, it did (change diameter).  When I rotated the rear wheel, I could see the chain going from some degree of slack to slightly tighter, suggesting that the (large) sprocket was not perfectly round.  This was not a big problem to deal with, I just loosened all the sprocket bolts and rotated the rear wheel a few times and with a screw driver, changed the gap in the large inside sprocket so I did not see any change in chain tension, then I tighten the sprocket bolts up.  This was all pretty straight forward and I suspect a one time only adjustment.  Do not think I will ride the rig this week because I am still awaiting my new fork springs (HyperPro progressive) and the forks are partially dismantled.  I do not expect any problems, but will certainly tell all should some arise.  I suspect that one of those ATV rear tire mods would not work with this duel sprocket combination as the chain is closer to the wheel (not really an issue for the stock tire).  Gerry Be safe my Friend.    Report

03-19-2009, 7:06 PM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range Well, had a sunny day and took some time off work.  Tried out the updated sprocket mod with a 40 mile off road ride in my 'trail' gear (14/55).  This combination is the one with the unsplined primary sprocket.  My riding style is still very conservative so I really was not expecting anything to break.  With the exception of the chain slapping the top of the chain guard while going down hill, there were no problems.  Upon arrival home, I affixed a rubber liner to the top inner surface of the guard so the chain will not rattle.  Gerry Be safe my Friend.    Report

06-28-2009, 6:47 PM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range Guess this is why the engineers get paid the 'big bucks'. As my duel sprocket project evolves, more changes are made. With two primary and two secondary sprockets, I came to the conclusion that I needed a chainguard slightly wider than stock. I made a nice unit out of 1/8" aluminium angle (see above). Mounted it up and it seemed fine except I could hear the chain slap against the metal on rough roads. My cure was to inset a strip of rubber that the chain would hit instead of metal. Worked great, no more noise. Today as I was heading down from the hills (dirt). I got a strange noise as I pulled away from a light. Sounded like drive-line, and I suspected that one of my duel primary sprocket attachments failed. I pulled over a.s.a.p. and inspected the driveline. Seems my 'heavy' aluminium chainguard caused the stock tabs to fatigue and break. My chainguard was now resting between the swingarm and the tire. Could not detect any damage apart from the two broken (stock) tabs. Since my 'new' chainguard had support only from the two outside attachment points, it is little wonder that flex/bounce broke the tabs. I will fix things up as good as new with heavier attachment points. My lesson, and advice to all you (us) would-be do-it-yourselfers....... THINK, THINK, THINK, DOUBLE CHECK, AND THINK SOME MORE. Don't let the Ney Sayers cast a dark shadow, but should they say, it seems XXXX, take another critical look and make the needed (if any) changes. Gerry Be safe my Friend.    Report

07-06-2009, 3:16 PM STRacer Joined on 01-01-2007 Posts 176 Re: Duel sprockets/Duel range Hey Mrgizmow, I have a gear changer from an old 10 speed with the derailer......just slap that puppy on there and you could move the chain from sprocket to sprocket.....:) Happy Trails    Report

07-06-2009, 7:05 PM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range Thanks ST. I spent a few hours in a auto wrecking yard looking at serpentine belt tension arms to do something similar. Takes alot to wrap for even a short section of chain. With some fancy fabricating I think a deraileur could be made. In the late 60's there was a product with 3 small sprockets mounted on the drive side swing arm. Primary chain went to one, and the other two went to two secondary sprockets. You move a toggle on this small transfer case to select which of the two primaries you wanted to use. Gerry Be safe my Friend.    Report

07-06-2009, 7:20 PM STRacer Joined on 01-01-2007 Posts 176 Re: Duel sprockets/Duel range And here I was thinking I was being funny! I think I am starting to understand how you got your name "Mrgizmo" lol Happy Trails    Report

07-11-2009, 7:50 PM QWERTY Joined on 11-22-2006 Posts 2,360 Re: Duel sprockets/Duel range A bicycle-type derailler will throw all kinds of slack in the chain when you try to slow down against compression.    Report

03-01-2010, 8:19 AM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range Attachment: 101_0826.JPG Well, my duel sprocket 'system' has been working fine for the last couple of years, but thought I would upgrade while I still had easy access to a machine shop (at work).  Instead of using two bolts and a couple of roll pins I will now use six bolts or two bolts and four coil pins.  Things sure look 'pro' when you have a real machinist do the job.   Gerry   Be safe my Friend.    Report

03-01-2010, 10:46 AM Ronnydog Joined on 04-29-2008 Poway Ca. Posts 458 Re: Duel sprockets/Duel range Attachment: udvar.jpg Mr gizmow, I think your Super TW will be seen in the The Smithsonian's National Museum when you finally finish with all your great ideas. Donated for future generations to see. A true thanks....... Ronnydog 9"Tire,Powder Coat\Frame,3"Extended SwingArm,TTR230 Piston,Sleve,Crank,15-70 Sprocket,Custom Rack,Brush,Gooved Siped Tires,Black-Out Switches,6006 Front Tire,Heated Grips,Ricochet Plate,Signal Mod,Kickstand Plate,Deer hauler, Oil cooler/spal fan, silencer    Report

03-01-2010, 4:54 PM mischief64124 Joined on 01-31-2010 kansas city Posts 29 Re: Duel sprockets/Duel range remember the early (pre '68) honda ct's that had a larger rear sprocket that mounted between the driven sprocket and the spokes then in off road mode was bolted directly over the on road sprocket with 4 bolts so it was in the same plane then a short section of chain and another master link made the chain long enough? i thought that system wasn't really that bad and then a 60 or larger sprocket could be bolted over a 45 in about the same 10 minutes. i might try it if i ever get to a place where i get to ride my tw off road christi why not http://www.flickr.com/photos/mischief64124/sets/72157623464070370/    Report

03-01-2010, 5:15 PM mrgizmow Joined on 10-21-2006 Paradise, Calif. Posts 2,439 Re: Duel sprockets/Duel range Ronnydog, comming from a fellow that has done so much to his TW your compliment is "high praise" and I thank you.......... Christi, I also had a CT90 (duel range) and a CT 110.  I think the overlap sprocket is a very straight forward design and is a big help in getting two extreme ranges.  My flip time is down-played and includes getting out tools, cleaning hands and putting stuff away.  The duel sprocket idea certainly limits gear ranges if you want to keep the same chain length, but in reality is "very fast".   Gerry Be safe my Friend.    Report

03-12-2010, 3:38 PM tampabrian Joined on 02-24-2009 tampa florida Posts 23 Re: Duel sprockets/Duel range since the bike only puts out 16-18 hp, i dont think it will be a problem, . nice job, now when are you going to take the next step and put in an automatice shifter :)    Report

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