juanroberts

Sorry for the late reply, but for the record, sometimes the ignitor coil is bad and as the motor heats up the heat expands the coil, the effect being the windings at the higher temperature short out and send less voltage/current to the spark plug. You can test for this by checking the resistance of the coil and comparing the readings (in Ohms) to those produced by a properly-working TXT50.

How is the project coming along? Ever thought of putting the hub motor and controller combination on a 20" mountain bike?

We have the 36V Oset. Today was our maiden voyage on LIPOs. We went with two 33V 5800 batteries that in parallel would give 11.6Ah. THE GOOD The bike's increased amperage creates a lot more power, such that there was a lot more wheel spin like on Oliver's videos, and my son Andres was doing a lot more wheelies, and zaps over obstacles. He was flying by himself on a stump he previously would not do if I was not there to catch him, so he gained a lot of confidence from having the extra power (see video below). Although the lead acid batteries we replaced were old, by comparison we did a ride that would have depleted them. Yet each LIPO cell thereafter had used less the half of its voltage (measured 3.95V, where 4.23V is max, and 3.5V is min). The new batteries are probably half the weight as well such that the bike is a lot lighter, even feels like a bicycle, but my son corrected me on that. The BAD Took me a long time to figure the lithium stuff out, I will provide a summary below on what I know now that I did not know when I ordered the batteries. Batteries are fragile, charging is delicate, etc. The UGLY The first charger I used was a cellpro (see listings below). I sent it to HobbyKing but have not heard back. It failed and I went with the one recommended here, the icharger, and even then the balance expansion board it came with had problems (see below). Each order is going to set you back about $75 in shipping from Hong Kong, and the parts listed below alone add up to about $500. I could have saved money by getting a larger number of lower capacity packs, but I wanted to keep it simple at just two. The components that worked: 1x #iCharger1010B/6609 iCharger 1010B+ 300W 10s Balance/Charger = $128.31 1x #9052000014/20968 Hobbyking 60w Power Supply = $9.99 1x #601B-12-10cm/10253 XT60 Female w/ 12AWG Silicon Wire 10cm (5pcs/bag) = $3.85 1x #601A-12-10cm/10254 XT60 Male w/ 12AWG Silicon Wire 10cm (5pcs/bag) = $5.21 1x #LPGUARD25x33/4364 Lithium Polymer Charge Pack 25x33cm JUMBO Sack = $2.73 2x #ZC.5800.9S.25/21386 ZIPPY Compact 5800mAh 9S 25C Lipo Pack = $177.20 1x #601A-2PParal/10265 XT60 Harness for 2 Packs in Parallel (1pc) = $1.97 This one did not work, maybe I was unlucky: 1x #CP10S/14743 Cellpro 10s 260W 10A Balancer/Charger = $114.95 Things to know (I apologize if am repeating previous posts, and all mistakes are mine): *You will need a soldering iron, lots of solder, and shrink wrap. *LIPOs have about 4 volts each, so a 9S = 9 cells, at 4.2 volts each gives you more than 37 volts when fully charged, and 3.5v x 9 = 32 volts when near its lower limit. *A LIPO cell damaged when charged more than 4.2V or drained under 3.5V (this is a conservative static minimum, some go lower as the lower limit is debatable). *Balancing batteries takes time, whereas charging them without the balancing part via only the two main leads is faster. *Balancing a battery is done with the weird multi-colored connectors. If all battery cells are equally charged, there is less risk that one will become overly charged or drained when only using the main black and red leads to fast charge on a later day. *LIPOs do not like to be left fully charged. So when storing them there is an ideal voltage you have to get them to either by riding them, of by using the storage feature on the icharger. *Dropping a LIPO is a good way to damage it and significantly increase the likelihood it will catch fire while charging. I placed a foam pad on the OSET battery tray, and then used the stock cover over the batteries. *The Cellpro charger requires an adapter called a balance expansion board to make it work which I had to buy separate (the icharger comes with this connector already). *The icharger's balance expansion board's second 4S slot had faulty wiring (first two leads were dead, and the other three were off by one, i.e., the one that should be wire #8 was actually #7). I guess jamming the 4S (from a 9S battery) into the second 5S slot which is wired correctly may function as a workaround. Let me know if you spot errors and I will edit them out. Thanks to all that contributed to this thread!

Too funny Steve. Hey, we have two TXT Boy 50's. On one of them my son was 4 when he started riding it, so I even cut a coil/loop off the rear shock's spring and wrapped the spring in rubber hosing, which allowed for an even lower seat height (roughly 20.5 inches) than just putting the clip on the 3rd groove (that alone gives about 21.5 inches seat height). Mind you this is while the spacers that go inside the front forks were removed. The other Boy (strong enoung for a man, but ridden by a girl) bottoms as well. I like them low for the kids to get courage, although its getting close to the point of raising the clip a notch on the latter bike. I did not get any feasible recommendations on preventing the bottoming, and despite the spring sag, I feel it is the shock body's duty to stop it from bottoming out, so what I did was wrap a cut road bicycle's inner tube 4-times around the shock's rod, and that did the trick, no more rear tire rubbing even while daddy is jumping it. Thanks and cheers! John

After these posts I was hoping for at least a sympathy reply. Did any of the 3 repliers finish reading the first sentence before replying and downing their pint? (Note to self: never ask questions during limey pub hours.) I ride a Montesa 4RT as displayed right under my name/avatar. I have too many bikes actually. And if you guys have yet to ride a "50 TXT Boy", you are missing out, its one of the best pit bikes out there. It is strong enough for a man but made for a kid, even more so than the OSETs my kids also have (again, see my Avatar). The bikes also bottom with my kids on them, I can even hear the tire rubbing and I feel bad how the involuntary braking action makes the little guys lose their balance a little bit. Now for some costructive feedback. How about wrapping climber rope around the rear shock's shaft, or would wrapping around the spring coils be better?

We have two blue little trials bikes and when they bottom out (most notably when dad is riding them) the tire rubs the rear fender hard enough to create a braking action and to wear down the fender. Any ideas on how to limit this action, perhaps a stopper on the rear spring? I have a real hard time searching this forum since the search feature seems to ignore words that are three letters in length, including boy, txt, gas, 50, etc. Any ideas on what the key to finding the "50 TXT boy" threads are? Thanks!

Can we get two out of three? Yes, I am using the ELF in the transmission, thanks for helping me get it straight. The ELF seems to work really well, but does not smell too good when spilled on the garage floor. I leaned the bike over to do the clutch, and a couple of days later (I was buying an impact wrench to remove the center nut), oil everywhere. The manual is incredible and has pictures of everything, but, when it came to the clutch plates they opted for a black-and-white fiche diagram instead. Thanks for the help.

My clutch is not very grabby, and at the last competition, towards the end, it made a whining juddering noise when put under stress. So I took it apart, and the friction plates actually look good. However, the two outer friction plates are completely dark brown, while the four inner friction plates were light brown, with green in between the friction material (i.e., they seem to have been manufactured differently, see pic below). My question is, is this normal, and if not, what are the recommended friction plates? I had read on this forum that the OEM friction plates on the 2005 were not very good, and that those on the 2006 and later on were better, as Montesa figured things out by then. This bike was bought used a few months ago, and I am not sure what the previous owners did to it. The motor oil is "Silkolene 4T - Pro 4 SX - 10W40". Thank you beforehand for your contributions. John Irvine, California

To your point, my daughter likes the Gas Gas 50 over the XR50 simply because the "brakes work better". The difference is hydraulic disc brakes to a cable and drum brake. They also have the OSETs and prefer them, but the gas bikes can in some situations offer more in terms of riding longer distances.

Not a "shop" manual, but the user manual is the best I could find: http://www.trialspartsusa.com/manuals/Manu...oy_2009_eng.pdf Oil should be much less than stated, I think the consensus is about 150cc. I would go off of what is posted on this forum more so than the manual.

I had the oldest 12.5 and replaced the 8AH batteries with the ones used by the 16.0 24v earlier version, I think they were 10AH. They barely fit on the tray and took about 30 minutes to install, a pain, but worked great in terms of duration.

I bought the first 16.0 24v that OSET put out. Have used the hell out of it. When it sheared, I was not aware. It was still working and I could not figure out why the front sprocket had migrated toward the motor, so much so the chain wore a groove into the side of the casing. I took it apart and replaced the sprocket and pin. However, I unecessarily took the motor apart and put the magneto back together backwards, so that the bike ran in reverse. I re-assembled, but then the motor was not as fast as before, maybe the contacts were damaged, as its tricky putting it back together. So, I just received the 36v swingarm today (I was already mouting a 3rd battery and running the 24v as a 36v). Long story short, I am running the chain tight now as I suspect loose chains produce pin pains. I.E, the slapping of a loose chain can act as a type of lackhammer that shears the pins.

Trying to show my kids how to go over a rock on the newer 36V, I bent the RST forks at the tube, and also bent the top clamp (not shure if it is named a "triple" clamp since the tubes do not go through). The replacement forks from OSET look the same and are also from RST but say "RST CAPA20". To be honest, the old gray forks seemed stonger provided you did not break the white plastic, and with the ACE Hardware springs that were recommended on this forum but on another thread, all I had to do was cut them to size, and the old forks, I think, work as good or better; however, the stearing head height is different, so I could not use them (they are about half the price). Mind you that I greased all the old fork moving parts to minimize stickiness. The newer forks, I was able to adjust stiffness by cutting the spring and manipulating the internal spacers, all in conjunction with keeping in mind what the adjustment knob can do. Bolt cutters were handy. The rock was a little bigger than this one:

FORKS: Take off the handlebars. If its like the earlier models, then remove the rubber caps on the top of the forks. Finally, push in the white plastic caps and you will see that a circlip ring snapped unto a ridge inside the fork tubes are what keep the white caps from popping out. While pushing the white cap in (down), remove the circlip with a small screwdriver. There was rust there that I removed with a rag. Below the white cap is a plastic tube that is about 4 inches in length, and below that is the fork spring. Remove only the plasting tube, and reassemble. Do both forks. The sag on the forks will be altered by about 3 inches as a result. SHOCK: Remove the shock. Use at least 3 fullsized vise grips (pressure pliers) at evened-out spaces to compress the spring along its length, i.e., clamp them between spring coils so the spring is compressed and not at full-length. Be very careful since the pliers can snap off at any moment, push the spring down and you will then hopefully notice there is a shaped/flanged/L washer with a circlip seemingly inside of it but its on the shock body keeping the spring from coming off. There are three grooves for the circlip, and the stock setting is in the middle of the three. Set the circlip in the soft position (farthest away from spring). It makes a huge difference once you get on the bike and try it. This should be enough, and if it is not, you can always cut some length off the spring, and put some rubber tube over the ending coil so it centers on the shock body, but that would be a last resort in my book. This is what it looks like when a loop in the shock spring coil is also cut off: The suspension on the Gas Gas 50 is the best, and the large wheels make for a very stable bike when compared to an XR50R. I may be wrong, but the forks seem to have no compression dampning.

I just bought two used TXT Boy 50s, an 01 and an 05. I put the rear spring in the softest of the three clip settings, and took out the spacers in the front forks, and that works much better for my 5- and 7-year olds. I short circuited the temp gauge that is above the motor so that the fan will run non-stop, just in case. I am going to try the thicker clutch plate trick. I also noticed the gas tank valve did not really work, so will try to order a new one. Does anyone know if a rear brake and clutch master cylinder's rebuild kit is available, particularly in the USA? When the rear wheel bottoms out on both bikes, it rubs against the top of the mudguard. Is there an easier fix than bending the subframe? Thanks.

ta51ora, great work! Some of the other improvements will come naturally, such as truing the front wheel so that the front brake works smoothly. I finally did the front forks as well. It was as easy as described here. I picked up the softer springs at ACE Hardware, and then cut them to size using a bolt cutter. I lubed the forks before putting them back together. The rear suspension linkage after torquing and greasing it works a lot better too. The rear suspension spring stiffness also came set up for an adult. I bought the softer shock (which pocket bike websites also carry), but its unfortunately shorter in length for a 16.0 (I no longer have the 12.5). The softer spring shock was shorter and made the rear of the 16.0 way too short. So I had to take the eyelet off the shock body in order to swap the springs.

String allows for quick adjustments if you have kids of different sizes or levels riding. No, it is not cheesy, I used this for years with two kids. It works. Your suggestions I already thought about many times over and could not figure out how to make them work, part of the reason for the risks you mention, and part because it is difficult to make an adjustment after the commitment was made. Have you tried them? I actually did not tie the string, I would crimp/squeeze it by wrapping it in between the throttle and the brake lever assemblies and adjust the length while the bikewas on and the rear wheel was in the air, this before every ride.

The Dead Zone = I wrapped construction string a few times around the throttle and then tied it to the handlebars at the brake lever to eliminate the dead zone. What is the dead zone? It is about 1/8 of the turn of the throttle when there is no response from the motor (typical when the governor is turned down for a smaller or beginner rider). This means the child has to turn the throttle a bit before the motor powers the rear wheel. The string trick made it so the throttle was already twisted by 1/8 of a turn, so as soon as my kids turned the throttle, the motor engaged. This made my kids a lot more knowledgeable as to when the motor would kick in, and much more sensitive to it, so that they could roll the throttle with much more finesse and effect a smooth power engagement. I never had any problems with this setup, except for when the string came loose and the throttle and dead zone returned. That said: --DO THIS AT YOUR OWN RISK--

Even a picture of the Kelley-to-OSET connectors would be a great help, or maybe forwarding the info provided by Ian? Thanks.

OK, I have the 36v OSET and just bought the KDS48200. Any guidance in terms of how to wire it, and program it, would be greatly appreciated. Also, where did you purchase the battery packs you mentioned? Thanks! John

I just received the Kelley. Can you provide a schemati? Thanks! John

From an electric bicycle dealer. Any hall effect throttle from a pocket bike website is likely to work, but you can always buy it from Osetbikes.com. To test if it is the throttle, I am pretty sure you can disconnect it with the key on, and use a wire to short circuit the bike-side connector. Careful because if the throttle is the problem, then the motor will kick in at 100% power.

Update: The thorttle on the 16.0 just gave out too. Both failures were out in the field. I am told they are cheap and not worth fixing, but it seems to me that after about 200-300 rides, our throttles gave out, apparently from wear. I was told that any Hall effect throttle will work. I tried two different brands and they both worked. The Ebay batteries lasted about 60% as long (i.e., 60 rides), so I just bought another four from OSETBIKES.COM hoping they are better quality and will last longer. For rear tires on the 12.5, since my son was heavy on the throttle, I used some white bicycle tires that look more like street tires so that the would last longer. They did.

As soon as someone finds and tests the cheap ticket, please let me know. We have an old 16.0 with 10AH batteries, and a new 36V 16.0, and would be wiling to try something new in order to 'equalize' them. Would it make sense to take the motor apart to clean the brushes?