The 320 developed a bad habit of cutting out while stationary. You heard it running rougher and rougher at tick over, and with a big yelp would quit on me. Could live with that, if it would start the first kick after that, but it didn't. It would take 5 min of frantic starting, walking of frustrated, come back 15 min later, and having it running without trouble.
Messed with the carb settings, but I was unable to get it behaving the way I wanted, and never got solid feedback from the motor on the air screw. (3/4 out).
Not sure where to start, I stumbled on the Maikuni PWK carbs.
US $34.00 | Motorcycle Racing parts Carburetor pwk 21 24 26 28 30 32 34 mm PWK Carb With Power Jet Fit Scooter ATV Dirt Bike cub
Price was good, it looked the bizz, never mind the reviews, just order and see. I choose a slightly bigger one this time, 26mm. (the OKO was 24)
It's a quality item, different to the OKO in many ways. The gas slide was a perfect fit on this one, as opposed to the OKO, which had quite some play all around.
Fitting it was a half an hour job, but could not get it to run using slightly larger jets.
Tried 6 other configs, until there where signs of life. Settled for the Maikuni on a 35 pilot jet (38 on the OKO), and a whopping 115 main jet. (85 on the OKO).
It likes a first kick with choke. Choke off, one kick, running very stable on low tick over. Generally speaking this carb seems to suit the bike very well. Instant grunt, easy starting, also when warm.
We will see if the cutout problem has been solved with this mod.
The CSP Air screw is 1 1/2 turns out, and bike responds well to changes.
Jobs left to do: there's 1 cm (1/2") of rear wheel suspension play at the bottom, probably because of linkage bearing play. Have a set new ones laying around.
Might top it off with a new TRP shock.
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.
Having read some of this info in the past, I just do not get it! What, Gasgas cannot provide for what they built?
What are they putting in the new ones and what has changed to make it work?
The current replacement is the complete clutch pack which:
There may be slight variations in thickness of the fiber discs, this is done at the point of manufacture to ensure precise total pack width.
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
The total pack width is 10.0~10.01mm
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.
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:
2006 and newer model Installation note: The clutch fiber and steel discs were changed in the 2006 model year. The three fiber discs have a variation in thickness and the two steel discs are thicker than the previous models. There may be slight variations in thickness of the fiber discs, this is done at the point of manufacture to ensure precise total pack width. The total pack width is 10.0~10.01mm – The two steel discs measure 2.0mm each – Two of the fiber discs measure approximately 1.80~1.85mm thick and the third one is 2.2mm thick. All steel and fiber discs are symmetrical (there is no specific front or back side)
IMPORTANT: Of the three fiber clutch plates, one is noticeably thicker. (about 2.2mm thick) This thickest plate MUST be the one that is placed into the engine first. (Farthest into the interior and against the rear surface of the center clutch driven hub.)
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:
2006 and newer model Installation note: The clutch fiber and steel discs were changed in the 2006 model year. The three fiber discs have a variation in thickness and the two steel discs are thicker than the previous models. There may be slight variations in thickness of the fiber discs, this is done at the point of manufacture to ensure precise total pack width. The total pack width is 10.0~10.01mm – The two steel discs measure 2.0mm each – Two of the fiber discs measure approximately 1.80~1.85mm thick and the third one is 2.2mm thick. All steel and fiber discs are symmetrical (there is no specific front or back side)
IMPORTANT: Of the three fiber clutch plates, one is noticeably thicker. (about 2.2mm thick) This thickest plate MUST be the one that is placed into the engine first. (Farthest into the interior and against the rear surface of the center clutch driven hub.)
Thanks for Reply , its the shaft thats broken , and i havnt found anywhere to supply another from this model hence looking at the alternative fix unless you know of source for spare part, i have some contacts in engineering , so wouldnt be a problem with that side , its all the other stuff , fuel mix , gear oil , cooling system etc , what to use , how much ,
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
Thanks For the reply , its good to know that my bike isnt a one of a kind , ill keep you upto date with progress if i need a photo or 2 to guide me from your bike how you fixed ?
Anyone have experience with this tyre? Supposedly knobby pattern on a trials type tubeless carcass. Developed specificaly for freeriding, LDT or Trail Bike Trials?
Gt 257 Trial Hybrid is a Tube Type tire designed for Freeriding and mountain riding. Compared to the Gt 256 Trialera it has a new knob design and a compound that guarantees greater durability. It combines the traction qualities of a Trial tyre with the self-cleaning features of an Enduro tyre. Use of Goldentyre Mousse 120/80-18 is recommended with the Hybrid as it maintains grip features on any terrain without risking punctures or cuts that cannot be repaired immediately
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...
Seavoyage, here's me on the 370 at a PITS Trial event at Frank Raines Park, where you also have probably rode. Great place to ride, used to be a County work farm for inmates, hmmmm, maybe still is in a way.....
Jon
Did the British-American Cup at Frank Raines last month on the JT35... and stalled it on a steep hill climb
That JT350 is exactly the same as my bike. I love it!
TLTEL
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.
Seavoyage like the mods and the bikes . How's the 225 go ? Think that in it's self is a good mod . What difference does the silencer make if any apart from maybe clearing the rear tyre when the shocks compressed?
Ted .
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.
anyone know how much those tech forks cost?
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.
interesting 225cc bike seavoyage! liking the mods. may i ask how much the tech forks are? might get some fr mine:) how much of a difference does the high comp head make? get some silcon spray or back to black on your jt35. it will refresh all paint and faded plastics.and makes it look new:)
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.
Based on jse comments, got 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. 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. 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.
Mark - WTF! Still making strawberry milkshakes after the rebuild?
UPDATE: mbeers6 was supplied the water pump seal for the TXT and not the Pro. Confirm the part number.
After comparing your photos and the parts microfiche: http://www.lewisport...o_all_parts.pdf ; and having disassembled my waterpump 2 hrs. ago (after adjusting my SHIFT SELECTOR SPRING 'ECCENTRIC' TOP SHAFT) ;
On my water pump,,when assembled, the AXLE TURBINE in flush against the seal.
Watch video at 1:39 showing snapring is flush with seal.
BTW - Upon inspection my WATERPUMP TURBINE needs replacement. I just ordered a waterpump rebuild kit, but probably have to wait till next week due to the World Rounds (USA),
The press on interference fit GG UK flywheel weight would not stay on. I prefer not weld it on and used Green Loctite.#680. Results: Easy to apply and holds the flywheel in place.
On the shifter: I plan on grinding some material off the lever to clear the plastic side cover.
I just installed a GG UK Flywheel weight on a Pro 200 with the S3 225 kit (250cc piston/cylinder and a high compression head). Unfortunately even with the spacer it rubs on the inside of the left stator cover. There isn't more space I can add as the shift lever is already past the outer edge of the shift shaft.
Any other Pro owners have this experience and figured out a solution? I noted that the Pro 125 flywheel kit is half the thickness of this 225 kit.
Without the flywheel weight the engine revs to the moon but tends to stall easier.
I replaced a seized fan motor (Daughters GG200) in November and a burned out Leonelli rectifier.
2-weeks ago (5-months later) fan stopped running.performed function test: 12V to (Blue and Black wires) fan = Motor not running. Replaced fan and Leonelli rectifier (Again).
Fan did not work when engine running. Bypassed thermostat switch = No fan. Confirmed Leonelli rectifier is grounded (Yellow to Green wire grounded to bolt on coil); Has power (Yellow to Blue wire). Performed 12V test directly to fan = Fan does not run.
Lesson Learned: Bench Test a brand new fan before installation.
Update: Flushed the clutch and replaced clutch hydraulic fluid . Worked the master cylinder piston and backed out the adjustment screw. Voila! Works just fine. I guess I'm returning the Master Cylinder Rebuild kit. BTW - Adrian (LewisportUSA) thought that it was a low probability that the root cause of the creaking would be the master cylinder which wasn't leaking, and more [probable it was the clutch pack... so I took a look, everything looked fine and the stack measured within specs.
1995 JT35. Noticed that the clutch lever 'creeks' like a cable clutch engaging a spring and releases clutch on the final 10mm of release.Often the lever sticks in position right before the last 10mm of release, then suddenly releases.
I use 75W transmission oil on this motor and not theDEXRON III ATF (on my Pro). No issues shifting, but when slipping the clutch, it isn't gradual - the clutch doesn't engagement until the last 10mm then it's a light switch - kind of like dropping the clutch but not as dramatic.
When the clutch lever is pulled in (engaged) - no creeping forward. It's fine on tick-over.
I thought it may be the pivot bolt was too tight at the clutch lever at first or a lack of lubrication on the plastic bushings on the AJP levers where catching. - but it's seemed ok.
I already know it is not Mandi`s old bike. I was referring to that model was pieced together with odd parts. Mandi`s old bike was recently changed to all red and they used TXT 50 parts to match it up. The TXT 50(TXT80) had a very similar frame as the pro.
That's an interesting piece of information on the TXT80 parts. I'll follow up with Adrian on the parts they used: probably the red plastic bits.
I rebuilt Mandi`s old 200 pro engine about a year and a half ago. Had to replace the shift drum as it broke into pieces. The old spark arrestor that Adrian had made was completely plugged up. I had an old txt muffler (brand new) that bolted right on with no clearance issues. So I would say the early 200 was a strange mixture of parts.
I'm quite sure this bike wasn't Mandi's. It was originally sold byJason Steensma/ Moto Meccanica, I purchased it for my daughter last year from the 2nd owner who had it for a year.
A great bike to learn on! Unfortunately the 200 wasn't offered after 2006. I was considering a newer model, but odds are I won't be able to get a California Green Sticker to ride all year round for a 2-stroke manufactured after 2002; so... an upgrade seemed like the wisest option.
I've sorted out the 2002 clutch issues, and the crankshaft bearings should be OK. Next phase is the 225cc kit followed by a suspension upgrade.
Any advice on a suspension upgrade from the GasGas 38mm forks (The aren't marked as Paioli, but seem similar to the 40mm Marzocchi); and the Sachs rear shock (rebound adjustable only)?
'09 Sherco 320 4T Rebuild Blog
in Sherco
Posted
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.