seavoyage

I am sorting out my 2008 320 4T here near Roosendaal - and was considering the OKO 24mm (38 PJ, 85 MJ) vs the Maikuni 26mm (35 PJ, 115 MJ). Any further recommendations or updates on replacing the stock Keihin PWK 28mm (50 PJ, 122MJ, JJH Needle 3rd clip)? Local Sherco supplier is Peter M @ PMTrials and Splatshop.

The current replacement is the complete clutch pack which: The critical requirement for proper clutch operation is the depth of the finger height to inner hub (essentially the angle): 17mm +/-1mm which is usually achieved with thecurrent OEM replacement clutch pack, but probably on the thicker side as the new clutch packs measure according to the factory: The ideal clutch pack thickness is 9.75 +/-0.1mm which currently can only be acheived by using thinner (i.e. used) discs. For those that run the smaller slave cylinder volume (Magnesium cases: 2002, Raga, S3, etc). the tophat travels slightly further with the same AJP master cylinder, and this makes the issue more prominent. 16.8mm-17.0 mm finger height to inner hub measurement seems ideal. A shallower finger to inner hub height due to a thicker pack increases drag; which seems acceptable to most riders, the opposite slip occurs with too thin a clutch pack (worn out discs). Using any of the previous 1.30mm-1.50mm steel plates (or the mentioned Jitsie 1.6mm) with the current fiber plates will likely result in too thin a clutch pack.

Posted on a separate thread: Many GasGas Pro owners experience clutch drag. The GasGas Pro clutch is very sensitive to the 'finger height' and the currently available complete clutch pack is too thick resulting in noticeable drag - the slave cylinder 'top hat' can't engage the 'shallower' finger height to hold tension or complete disengage. If a 2.00mm steel plate is replaced with a 1.30mm-1.50mm steel plate, the finger height will be too high resulting in slip - top hat stays engaged. I recently replaced my Pro clutch pack and discovered the following: GasGas only sells the complete clutch pack MT280232055 : 3 Friction plates MT280232051 and 2 steel plates.MT280232050 . See note below.. Current steel plates in the complete clutch pack measure 2.00mm . 2002-2003 clutch packs were different MT280432055 . Early 2002 friction plates MT280232051 were prone to swelling; current friction plates do not swell in ATF. The 1.50mm MT280232050 , 1.40mm MT280232050/4 , and 1.30mm MT280232050/3 steel plates are no longer available. If used with the current clutch pack to replace one of the 2.00mm steel plates, the overall thickness will be too thin. If, post 2006 model, both steel plates measure 2.00mm and the friction plates vary in thickness: one friction plate is 2.20mm and the other two measure 1.80-1.85mm for a overall thickness of 10.00mm? ( I realize the math doesn't add up from the factory specs) AND The correct specification is: No less than 9.75mm and not more than 10.05mm How do we build a clutch pack that measures 9.75mm +/- 0.1mm to acheive the desired 17mm +/-1mm 'finger' to inner hub depth? I ended up going through all my old friction discs to build the appropriate clutch pack. I had trouble reverse bleeding the clutch and discovered one of the two orifices in my AJP master cylinder (small reservoir) was blocked. I couldn't clear the blockage; so I replaced the master. I discovered that the master cylinder bore and stroke was relatively the same between the AJP long and short reservoir styles. Replaced the O-rings in the slave cylinder for good measure. The GasGas Technical Bulletin (10/2006) updated 10/2012 http://www.trialspar...ober_2_2012.doc recommended conversion from DOT4 to mineral oil. We since converted back to DOT5 by replacing the slave cylinder O-rings with MT280432047.. We found the Carquest part number CTC407008 for Viton® O-rings for the slave cylinder a bit tighter fit than the OEM MT280432047 Note:

Many GasGas Pro owners experience clutch drag. The GasGas Pro clutch is very sensitive to the 'finger height' and the currently available complete clutch pack is too thick resulting in noticeable drag - the slave cylinder 'top hat' can't engage the 'shallower' finger height to hold tension or complete disengage. If a 2.00mm steel plate is replaced with a 1.30mm-1.50mm steel plate, the finger height will be too high resulting in slip - top hat stays engaged. I recently replaced my Pro clutch pack and discovered the following: GasGas only sells the complete clutch pack MT280232055 : 3 Friction plates MT280232051 and 2 steel plates.MT280232050 . See note below.. Each steel plate in the complete clutch pack is 2.00mm thick. 2002-2003 clutch packs were different MT280432055 . Early 2002 friction plates MT280232051 were prone to swelling; current friction plates do not swell in ATF. The 1.50mm MT280232050 , 1.40mm MT280232050/4 , and 1.30mm MT280232050/3 steel plates are no longer available. If used with the current clutch pack to replace one of the 2.00mm steel plates, the overall thickness will be too thin. If, post 2006 model, both steel plates measure 2.00mm and the friction plates vary in thickness: one friction plate is 2.20mm and the other two measure 1.80-1.85mm for a overall thickness of 10.00mm? ( I realize the math doesn't add up from the factory specs) AND The correct specification is: No less than 9.75mm and not more than 10.05mm How do we build a clutch pack that measures 9.75mm +/- 0.1mm to acheive the desired 17mm +/- 1mm 'finger' to inner hub depth? I ended up going through all my old friction discs to build the appropriate clutch pack. I had trouble reverse bleeding the clutch and discovered one of the two orifices in my AJP master cylinder (small reservoir) was blocked. I couldn't clear the blockage; so I replaced the master. I discovered that the master cylinder bore and stroke was relatively the same between the AJP long and short reservoir styles. Replaced the O-rings in the slave cylinder for good measure. The GasGas Pro Technical Bulletin (10/2006) updated 10/2012 http://www.trialspar...ober_2_2012.doc recommended conversion from DOT4 to mineral oil. We since converted back to DOT5 by replacing the slave cylinder O-rings with MT280432047.. We found the Carquest part number CTC407008 for Viton® O-rings for the slave cylinder a bit tighter fit than the OEM MT280432047 Note:

The kickstart shaft may be the same for 1993-2004 TXT models (250cc and larger GT/JT/JTR/JTX/TXT/'Edition' models) Confirm with the parts microfiche. http://www.gasgasmotos.es/en/manuals.html 1995 JT35 part #MO2611002 http://www.gasgasmotos.es/en/manuals/download-1995jt35partsbook1.pdf.html 1997 JTX part #MO2611004 http://www.gasgasmotos.es/en/manuals/download-1997jtxpartsbook1.pdf.html (Note part# change, confirm if interchangeable) 2001 TXT part#MT27836003 http://www.gasgasmotos.es/en/manuals/download-2001_txtpro_partlist1.pdf.html (Note part# change for 1998 onward, confirm if interchangeable) Here's my JT35: http://www.trialscen..._30#entry333722 I found another one for sale withing 2-hours from me...

Is this the tyre Graham Jarvis runs for Extreme Enduros?

Anyone have experience with this tyre? Supposedly knobby pattern on a trials type tubeless carcass. Developed specificaly for freeriding, LDT or Trail Bike Trials? http://www.lealicomm...7-trial-hybrid/

Inspected clutch pack thickness and replaced 'swelled up' plates (funny how a clutch pack on ATF DEXRON III gets thicker not thinner over time), replaced clutch slave O-rings, adjusted shift drum eccentric (what a PITA!), replaced impeller and rebuild waterpump, replaced coolant (from Maxima to Putoline), bled clutch (mineral oil), bled rear brakes (DOT 4), adjusted handlebars and levers, changed ATF DEXRON III to ATF-F then... Rode the damn thing!

A 250 may be better matched with a 26mm rather than a 28mm. Here's a related thread: http://www.trialscen...rsus-vhst-carb/ You might also consider the OKO K-101 which is used by Xispa (XPA300). http://www.mid-atlan...com/Copies.html

Did the British-American Cup at Frank Raines last month on the JT35... and stalled it on a steep hill climb

The JT35 with stock base gasket and stock timing is a beast to start isn't it? You better have committed cajones to kick start a JT35 (or JTR370)... my Keihin jetting seems spot on, so it isn't a question of if my JT35 will start on the 1st kick; it's if you can successfully kick start it. If you aren't committed the JT35 will 'bite back' and either break your foot or throw you over the handlebars. Very linear power and more than enough torque to plow a field - just don't stall it while hill climbing.

The 225 kit was an excellent upgrade. It feels like a quick reving 250 that spins up quickly with adequate torque but isn't a hand full - which is enough for me. Since GasGas ceased production of the Pro 200 in 2006; if I had a late model Pro 125, I would install the S3 mods rather than purchase a base 250. The FMF TC2 silencer definitely scavenges exhaust gas more efficiently as I had to turn in the fuel screw 2.5 turns (leaner), plus it has a very nice deep tone..No 'splooge' with 80:1 pre-mix (synthetic). If you listen to a current GasGas EC250 or YZ250 with the FMF TC2 you'll get an idea on the sound. I paid USD$1000 after I traded in my original forks (~$200). The price included the Raga triple clamps, steering stem, and front axle. These forks (~5.1 kg.) are much lighter than the stock forks, and with the rebound tuned made lofting the front without power or hopping almost effortless.. It was well worth the cost to balance out the revalved rear shock (the best investment yet) and rear spring. The new suspension makes obstacles so much easier to traverse: hard hits don't deflect or unbalance the bike, and deweighting is almost effortless. It is very compliant yet firm and doesn't bottom out on 4 foot drop-offs. The bike may not be pretty but it weighs less than a 2013 base model, steers quicker than current models; has a manageable, lightweight motor; and has absolutely brilliant suspension. It cost me less than half the price of a new base model.

In a $800 package deal from Lewisportsusa including: S3 225cc kit, S3 Stars cylinder head with high-compression insert, and GasGas UK flywheel weight.

The S3 high-comp makes a bit of difference, and seems fine with California 91 Octane (10% Ethanol). I have a similar set-up on my EC300. The S3 225 kit was well worth the $450 and changes the 173.3cc motor revs up quicker than a 250 (56mm short stroke vs. 60mm). It's simply a 250cc cylinder and head, but much less expensive as a S3 kit than if you sourced the components individually from GasGas. I rode it without the flywheel weight: revs to the moon, but if I wasn't careful on the clutch - stalled. So I made the compromise and installed the flywheel weight to make the bike easier to ride. The Tech forks: USD $1200 at a 50% discount as the 2013 aluminium tubes forks were just released, These were 2012 excess from the GasGas factory that were installed on the 2012 Raga. I needed the Tech forks to balance the rear revalved shock which is simply amazing. The revalved Sachs rear shock felt better than a Reiger and an Ohlins TXT I tested.(Can't say much more before I start offending the suspension suppliers). I highly recommend a revalve and respring if you can find a competent suspension guru that knows trials The suspension components are much lighter than stock. The JT35 was built for the World Championships so I keep in factory livery for nostalgic reasons. I just removed and stored the headlight, and a full set of NOS plastic. The JT35 is a much more appropriate machine for trail rides and LDT.

Based on jse comments, sourced the 2002 Pro chassis for the quicker steering and magnesium engine cases. Complete rebuild of engine top and bottom end. Installed S3 225cc kit, S3 Stars cylinder head with high-compression insert, and GasGas UK flywheel weight. Rebuilt waterpump, and upgraded clutch to 2006+ specs. Replaced AJP clutch master and rebuild clutch slave cylinder. Modified FMF Turbine Core 2 from my GasGas EC300 to replace stock silencer and add spark arrester. Replaced Comex radiator fan and Leonelli module.Removed lighting harness and installed kill switch Revalved Sachs rear shock (2-stage compression and rebound) and changed spring rate. Installed shock upside-down with 4mm preload. Regreased rear linkage and swingarm pivot. Installed Formula 'Factory' forks with GasGas anodized Ergal triple clamps. Installed ProTaper Hi bend SE handlebars with ProTaper Medium compound grips. Completed restoration of 1995 JT35. Put a full set of NOS body work and '2-lens' headlight in storage. Replaced Pirelli Gara Trials with Dunlop D803. Installed Renthal handlebars with Renthal Trials grips. Replaced fork fluids, and coolant. Running Maxima 75W transmission oil. This JT35 may have an interesting history: if built by Jon Stoodley AKA jse for Steve Darrow for the World Championship. Has cylinder head mods, and Keihin PWK carburetor.