drca

I am the new proud owner of a 1983 SMW 350 Jumbo, in all it's yellow glory. Bought it from a local rider (thanks Wayne!). The engine has been fully rebuilt and has just a couple of hours of riding on it. I guess over the next few weeks (month?) as I get familiar with the bike and start riding it / tuning it to my liking I will have many questions. This Trials Central has been a great source of help in the past so I am turning to you guys again for answers. Engine oil What engine oil do people use? I my (modern) trials bike I use Maxima MTL 80WT. How to verify oil level and refill? There are no oil level windows (unlike my Fantic) and I couldn't find an oil refill cap. So I assume it's one of the screw on the clutch case. Is that right? Premix ratio What is the recommendation for premix ratio when using modern pre-mix oils? I have so many gas cans (from 32:1 to 130:1!) for various bikes / two strokes engines in my garage that I am hoping one will fall close enough! Stock jetting What's the stock jetting Carb rebuild kit Carb is leaking... I did a thorough cleaning, needs a rebuild. What's the recommended place to get genuine Dell Orto parts? Suspensions I am on the heavy side so I'll need stiffer springs (it just bottoms riding on the trails!). What's the recommended rear shocks and where to find stiffer springs in the front? Many more questions coming, so thank you all in advance for your help. DC

Happy this helped someone. Happy trails.

I usually play with the clutch pack thickness until I get the feel I want at the lever and engagement speed that works for me. Best way to adjust clutch pack thickness is to swap steel plates with different thickness. you can get them from Splat Shop: https://www.splatshop.co.uk/dp-gasgas-pro-clutch-steel-plates.html Their page even shows the recommended thickness range for each model year.

M20 bolt works fine. You can use a nut / washer and a piece of tubing to use it the same way a flywheel puller works. This way no need to bang / pull etc... Works like a charm. Getting back stuff together is another story tho... You can't bang the 1/2 axels back in as the edges are not tapered. What I did was to really carefully visually align everything then gently pushed in the 1/2 axles. Take a little bit of doing and about 3 hands 😁

From talking to my dealer, there is a small brass screw on the left side of the bike that should be the primary way to adjust idle on the bike. Range of adjustment is less than on regular carburetor but sufficient for me. Adjusting the throttle stop (as indicated above) should "theoratically" require to reset the TPS from what I understand. As always, YMMV...

Short version: Does anyone know if TRS can be registered with the DMV in California? Longer version: For those not living in California, bikes need to be registered with the DMV to legally ride on public land. This does not mean that they will be street legal, but they will get a Off Road Registration and appropriate Off Road sticker. DMV will NOT register bikes from manufacturers that have not been "approved" (or at least registered) with the California Air Resource Board (aka CARB). So... I am looking at buying a TRS and I haven't heard whether these bikes are registrable with the DMV in California. Thanks in advance for the help.

My experience is... install new clutch within or close to specs, try... if you don't like it, adjust thickness, repeat. Measure the pack with a good caliper, wet (not dry) and with a reasonable squeeze on the caliper. If you have new fiber plate, let them soak in oil overnight (some fiber plates use to swell a bit, especially in tranny oil if you listen to the old man tales!). Make sure you also measure each steel plate in multiple place around the circumference to make sure they are even and then make sure the plates are flat (use a piece of glass and you should not be able to see light between the glass and the plate). It doesn't hurt to check the fiber plates too. Thicker clutch pack will make for a faster clutch engagement, but less progressive and a harder pull and possibly more drag (beware that Gas Gas TXT Pro clutches have a reputation for drag anyways). This is the setup for advanced riders, good for zaps, etc... Thinner clutch pack will make for slower clutch engagement, but more progressive and lighter pull and possibly less drag. This is the setup for "not so advance riders". When reassembling the case on the bike, make sure the put a dab of grease on the thrust bearing and washer on the slave clutch cylinder to keep them in place during assembly. They can slip during assembly and drop in the engine (don't ask me how I learned that... the only thing I would say is that it was an expensive lesson). In my experience (YMMV) oil viscosity also has an impact on clutch drag, but not much on engagement speed (I use Maxima 75W). I never tried tranny oil, I know as many people who love it as people who hate it. I've learned to live (and embrace) the clutch drag. Clutch pull: it seems that going to Silicon based Brake Fluid (DOT 5) makes the pull a little lighter (it's less viscous than the mineral oil and is compatible with the mineral oil clutch master and slave cylinder). But in the end, a good Hand Grip Strengthener device is your best friend against stiff clutch pull 😁

Short story: I am looking for feedback on what's the general experience in getting Gas Gas parts and service under the new KTM ownership Longer story: I have a 2013 Gas Gas TXT which I have religiously maintained and upgraded throughout the years: Tech + Ohlins suspensions, Braktec brakes, did a full rebuild of the engine - new top end, changed every single bearing and seal in the engine, etc...). I do love my Gas Gas and I could maintain it and rider it for many years to come but I have the new bike hitch (I am in California and there are new emission regulations coming down that makes it the right time to get a bike). I know that KTM has done a lot of things to promote the Gas Gas brand (mostly MX and enduro bikes tho), but the fact that they require every dealer to have trials bikes on the show floor is a great thing I think. I would love to get a new TXT, but... having been a Husqvarna owner during the BMW to KTM transition (and a Husaberg owner during the transition too), I can tell you that this was a nightmare: new dealers didn't want support the prior year models, older dealer didn't have access to parts, KTM didn't buy the inventory of parts for the prior year models, etc... etc... I am hearing that the Gas Gas to KTM transition is following the same model: I know for sure that my local dealer(s) don't know sh*t about trials bike, and I am not even sure that I would trust them doing any work on a non-KTM or Husky bike (I am hearing from former Gas Gas dealer that are getting new Gas Gas owner asking them to work on their bikes!). I have also heard that getting parts for the newer bikes is a challenge. I had switched to buying parts from the UK a long time ago (better service, better availability, better expertise, better prices, faster and cheaper delivery) but the small Gas Gas dealers in the UK have been squeezed out too... So that might dry out too. So any feedback, success or horror stories on how's life for Gas Gas trials bike owners under the KTM control would be great.

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

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.

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

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.

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!!!!!!

Thanks, very much appreciated.

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?