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About drca

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  1. I am looking for recommendation for a place to send my crank to get it rebuilt (I have new rod kit). Someone with experience (and any necessary jigs) with Gas Gas trials crankset would be great. Thanks. DC
  2. The clutch was designed by XIU-rdi. These guys (Josep Serra “Xiu” is the main guy I believe) have some pretty impressive credentials in the trials world, including designing the TXT Pro, the Ossa TR 280i etc.
  3. I have a 2013 Gas Gas TXT Pro 250 and my experience is that there is always a little bit of clutch drag on the bike (and I believe that I am not the only one). It's worse when the bike is cold (cold oil). Too much drag can be not only annoying but possibly dangerous as it can cause the bike to stall at inopportune times. Oil wise, some people recommended ATF (never tried, or the Elf brand (very hard to find in the US). I use Maxima MTL Transmission Fluid 75wt ($10 at my local Cycle Gear) and I've been pretty happy with it. It's unlikely that you will "burn" your clutch on a trials bike short of riding stupid! Adjustment wise, you might want to try the shortly levers like the Apico's Flex levers. They allow to adjust independently the reach and engagement point. That might help too. The Gas Gas clutch is actually pretty good and better than most traditional spring designs. The diaphragm clutch is used by GasGas, Ossa, JTG, TRS, Vertigo, Sherco-Scorpa and Electric Motion. The thing to know about the Gas Gas clutch is that it's highly (and easily) tunable by adjusting the clutch pack thickness (3 fiber plates + 2 steel plates): Thinner pack makes for an easier pull and a slower engagement (which is what most riders at the beginner to intermediate level will need). If you go too thin, you'll get clutch slip tho. Thicker pack = harder pull at the level and much faster engagement. By fine tuning the thickness of the clutch pack you can go from a bike that will be mellow and easy to ride to a bike that will want to jump up 4' ledges when you dump the clutch. At my level (SI), and age (!), I go on the "easy" to ride side. But I have experimented with various configuration and this is definitively something you can feel at any level. How thick or thin should you go? Below are Gas Gas recommendations. Honestly I don't understand why the numbers change depending on the year, but they should be a good place to start. And in my experience, these are really guidelines and considered as starting points for your own experimentation. How you change the pack thickness? You buy steel plates of different thickness (as a set or individually) and swap them in / out until you arrive to a combination that you like. Hope this helps. DC
  4. Yep, that's probably the way I'll have to go. Now... more of a concern are the brake shoes. They have stamped on them NAGESTI BARCELONA and Mg (for Magnesium?). No model number or size information on them tho. They are approx 118 mm outside diameter. The springs have a funny hookup (first time I see that): they slide in holes in the shoes and are held with cotter pins.
  5. Thanks for the info. The hub I have has a 130 mm sprocket ID with the bolt holes on a 150 mm diameter circle! So it looks like it's not a 348 hub. I emailed the guys at In Motion UK and they confirmed that they have no sprockets this size. Aaaaaarg!!!!!!
  6. Thanks, very much appreciated.
  7. Great. Thanks. Would you mind trying to measure the ID of the sprocket (approximately) to see if it's anywhere close to 130 mm. What year is your 348?
  8. I have this hub that I am planning to use for a project but I am not sure where it comes from. Someone mentioned it might be an old Montesa unit, could anyone confirm? ID for the sprocket is 130mm, I can post additional measurements if that helps. If it is, where can I find sprockets / brake shoes? Thanks in advance for the help.
  9. Theoretically with the constant torque of the electric motor, you really don't need gears. Now in practice the motor has a max RPM, so not having gears is a compromise between torque at the rear wheel and maximum speed on the trails. Alta had a motor that could spin up to 14,000 RPM (if I remember correctly) while delivering a very healthy amount of torque, so you could really have both torque (acceleration) at the rear wheel and good top speed. That's not the case on the EM, but in my experience the top speed is plenty enough. One issue tho is when you are close or at the max speed and want to pull a power wheelie over something... That's not going to happen. On the positive side, not gearbox = lighter weight, less maintenance, less failures! As far as muddy climbs are concerned, not much experience here in California, but plenty of very dry and slippery hills and the EM is pure magic on these. More torque than needed to go up most hills (you'll probably loop the bike or loose traction before you run our of torque), no need to worry about having the slip the clutch to avoid stalling, just constant rear wheel torque with a direct link to the throttle. And you can hear what your rear tire is doing and dial the throttle accordingly. The one thing I haven't been able to do as well on the EM as I can do on the Gas Gas is to synchronize weighing the rear suspension (to get traction) while blipping the throttle. But I am sure that if I work on it for a day that'll come. Balance - I am not that great at static balancing, but I haven't seen much difference between the Gas Gas and the EM. Hope this helps.
  10. Here you go... And the Lite version for reference.
  11. I am planning to make my own sticker kit for my 2013 TXT pro. It's relatively easy to find template files (free or $) for MX or enduro bikes but I haven't been able to find anything for my TXT in vector format with a precision good enough that I can design, print and make the final stickers. Would anyone have either a template file (vector graphics would be best, 1:1 size) or know where I can get (purchase?) one? Something like what's below but in vector format: Thanks.
  12. Quick update on this topic: I received my Tech fork (see above post) and I found a cheap Gas Gas front hub with rotor on eBay to experiment with setup without having to use the front wheel of my current bike. Bearing wise, I got a pair of cheap 6004 (20 x 42 x 12) to accommodate the 20 mm Tech axle (instead of the 25 mm from the Marzocchi fork axle). The 6004 are 3 mm wider than the stock 6905 (25 x 52 x 9) bearings. As expected the 6004 bearings stick out from the hub by 3 mm on each side: When mounted in the fork: There are three problems with this approach: The axle now sticks out by 6 mm (2 x 3 mm from the 6004 bearings) which also means 6 mm less thread engagement on the left side fork tube, which can't be good. The wheel is offset in the fork on the right side by 3 mm (not sure how this affects handling) The brake rotor is offset by 3 mm to the right side, requiring a spacer to put it back inline with the caliper. Spacers (and longer bolts) could be used on the caliper side, but that's extra parts that will need to be dealt with every time I take the caliper off) So, the ideal is to get 20 x 42 x 9 bearings either the 98204Y (which are hard to find especially in 2RS and $$$ - like $75 a pop) or, per benbeta23 recommendation get some B20-157 bearings. The B20-157 are easier to find (well not in the USA even tho these are products from a US company!) and pretty well priced at around $10 a pop). Here is what is looks like with the B20-157 bearings: And it all lines up with the caliper almost perfectly (it's offset by 0.4 mm to the right but that's an easy fix). Before I can get in on the bike I need to get an internal spacer. I might have to make my own because since Ga Gas uses 6004 bearings on the bikes with the Tech fork, it means that they must be using a different front wheel hub for these fork. I'll keep updating this post once I get it all working. Thanks again everyone for the help.
  13. For those who are curious... I just weighted both the Tech and Marzocchi fork and here is what I got: Each assembly was with the fork, front axle, triple clamp, steering stem, bottom bearing, steering nuts. Triple clamp for the Tech are Costa Special Part units The Marzocchi is the older model without the slimmer tubes in between the two triple clamps. Tech - 5.72 Kg / 12.6 Lbs Marzocchi - 7.6 Kg / 16.7 Lbs So close to 2 Kg / 4 Lbs advantage to the Tech fork. Not bad!
  14. Whoa, that's a lot of information, thanks! So, it looks like you kept the hub the same as for the Marzocchi fork (with the 6905 bearing and internal spacer). So if I get this right, you have some spacers do step down the ID of the bearings from the stock 25mm to the 20mm for the Tech axle. What I am not sure is how these spacers fit. Would you mind shooting me some photos? The disc rotor spacers make sense (SplatShop sells a one piece unit) and for the triple clamp (yokes), mine came with a shinny set of CSP that fit the Tech fork. Thanks again for all the help.
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