Firstly - the bits of missing / rubbed away metal in the photo are aluminium and would not stick to the sump plug magnet so you need to try to identify what the bits stuck to the plug are.
Have a look at the trials parts usa website where the Jon Stoodly videos can be found.
I suspect there may be a washer type shim missing or on in the wrong place but not having the engine in front of me can't be sure.
dadof2, looks like it to me too. There should be a thin steel washer on the hub shaft and, like the kickstart shaft washer, usually sticks to the sidecase and clutch basket hub and falls off before reassembly.
Based on the contour of the grooves and location, I'm wondering if a tang broke off the shift centering spring and got caught up in the back of the basket. It still does not explain the steel bits on the sump plug magnet, which will need investigation.
And thanks for the compliment for the videos (and all the other info on his website) but they are made by Jim Snell, the parts importer for GasGas in the U.S. Jim has probably forgotten more that I know about the GasGas bikes....
the 27.5 appears to have done the job! running well but the plug is dark brown - will try a B6ES.
Dark brown not bad. Reading plug color is only an approximation in a Trials bike due to variations in throttle and load. If you were running an engine under load and full throttle you would generally look for a milk chocolate color, but even that is only a few of the things you look for when "reading" plugs.
amazes me that there isnt a breather on the pro.............. lots of condensation from here. at both ends of the spectrum, my ktm 300 exc and ty 175 both have breathers. I might make one for the pro - easy enough to do.
I add a breather to all my Trials bikes, since the early Bultaco days. Never had a water ingestion problem.
well, my rattly old ty is not rattly anymore, having been rebuilt with a relined cylinder, wossner piston, new rod, big end and mains etc.
the timing is spot on.
the jetting is less spot on (work in progress)
not sure if this is a new thing, or if the bike always did it - but didnt notice because of the bad rattles it made before - but on over run, it makes a sort of 'dongk, dongk, dongk' noise .................. I have read about the 'pipe bang' problem (on usa sites mainly).
is this normal for a ty?
pjme did all the machine work and the bike was put together properly - otherwise its all fine.
thoughts appreciated.
Might want to raise the needle one notch and go up a little on the pilot jet for a start.
Try draining the float bowl by loosening the bolt on the bottom of the float bowl then allowing a minute for it to refill. Choke on.Then shift the bike up into 4th gear. pull the clutch lever in and rock the bike back and forth until the clutch breaks free.If it frees immediately then release the clutch and rock it again until you've had at least 5 repetitions.Don't go more than 10 times.Shift back to neutral and kick away.
Fuel looses it's volatiles quickly these days. Draining the float bowl and refilling helps tremendously with starting.
I agree and would add to drain the tank and carb completely. Fill tank with fresh premix (from the station, NOT an old gas can). The carb, tank and gas can lose the "high-end aromatics" in fuel that are there to aid starting and their effects are cumulative. Using fuel from a stored can, if plastic, means you are not starting with "fresh" fuel and may need to change your storage techniques. If this makes the bike easier to start, it could be your problem.
The buyer has now admitted to changing the mix as well (only after I explained I had photos of before and after the sale). He set the screw fully home then turned it out 1.5 turns. He did no other testing as I can see. He thinks that he has richened the mix! He did it because his friend told him to!
He says that it was original set to 2.5 turns, I don't know, as I never set it because the plug was always a perfect colour. I live at 850 meters altitude and at home it was perhaps just a "little, tiny tiny" ?? lean (by response) but very marginal if not perfect (by my experiance) at 1100 to 1200 Meter altitude where I always ran it, except for 10 mins going and 5 mins back (its the free wheel down bit), I nearly always used it at quite slow revs appart from blips needed for obsticules, prefering technical difficulty than green lanes etc. Oh and of course the other difference is the change due to the pipe disconnection gearbox to carb that he made?.....
Anyone the carb expert? Who would like to make a difinitive statement, it would be appreciated and help me a lot. Thanks ALL!
I have more than serious doubts that a mixture change of one turn on the fuel screw had any overall effect on the engine damage situation (it has the most effect in the idle circuit metering to needle-draw transition) . The 150 vs 850 meters (jetting wise, a change of about 2300 ft., and a much bigger gap at the 1100 to 1200 altitude) could result in an overall lean mixture (if running well at 1100/1200 meters) and this may likely be a contributing factor. Experientially speaking, engine damage of this sort is usually a combination of several issues, a "perfect storm" you might say, of miss-adjustments (lean mixture due to main jet/needle adjustment, old fuel etc.). It would also seem that it is the responsibility of the new owner of any used bike (knowing-or should have known, for instance, the change needed in jetting due to altitude) to set up the new bike before use.
Knowing the above new information, detonation may be the primary cause. Detonation usually announces itself with dramatic engine noise, which in this case was possibly ignored and/or misunderstood.
Trials is a sport that always welcomes back riders who may have given it up for whatever reason, unlike most participant motorsports I've experienced. It must be the type the people that are attracted to it, they are a different bunch.
I started in 1971 and was out of Trials for a couple of years some time ago and one of my wise Trials friends said to me then "Ya know Jon? Riding Trials is like smoking cigars or riding Ducatis, you may give them up for a while, but sooner or later, you'll be back!" He, of course, was right and I'm enjoying the sport more than ever......
Been lurking for some time and just found out that I could now join with my gmail address. Been riding motorcycles forever, dabbled (and dabbed) with trials for a few years in the seventies and have rekindled the passion. I figure the '80's bikes are high tech compared to where I left off and have recently developed a serious addiction to Fantics. I've gathered a lot of info from this forum and thought it was time to contribute whatever small bits I can to the group.
Thanks
Wayne
Welcome back! I'm actually flying out your way for the weekend in a couple of hours. I also started riding Trials in the very early 70's (lived in San Jose at the time) and was a member of PITS.
You'll really like this Forum, it's a world-wide hub of information and collective knowledge and there is something on here for everybody.
Hi All, Again... What a story. For me this is turning bizarre! Went to the garage where the bike is and back today total time 6 hours.... Wanted to know if the carb had some pink (oil and water mix) in it and take some more detailed photos......Because the last time that the pump seal went the engine stopped because of the “pink stuff” in the carb ( for sure it wouldn’t burn) ummmmm! it get’s there I guess by way of the gearbox breather, that goes from the gearbox cover to the carb. Guess its a combination of the added liquid level (coolant with the oil) and the heat pressure in the box with the hot coolant, plus the carb suck? In the clear tube you could see the pink. I wanted to do this as “IF” the pump was the original cause of the problem like last time, then the pink in the carb would have cut the engine in a short time and the head and probably other parts would not have been damaged so drastically if at all, like last time!
Arrive..... the pipe is cut and another pipe is fitted that goes to atmosphere along with the one that’s been cut! So I ask who had changed the pipes? The “!!!!!! MECHANIC!!!!” says it wasn’t connected and that it’s not important and points to a Honda that has a gearbox pipe that goes to atmosphere (......He insisted that it would never of been connected! P.S this guy is NOT a GG service bloke.
I arrive home look at the sales photos taken a couple of weeks ago to advertise the machine and it’s clear that its connected before the bike was taken away.... also in the same photo it seems that the mixture screw is in a different place..........ummm!
I looked at some 07 pro photos and it doesn’t seem connected but on mine (250 TXTI pro 03) (yes TXTI?)it was always connected HELP! When was this changed and does the pipe make a difference to the carburetion mix? ..... guess you know where I’m going! (out of me head) J) Think there’s a call to the nice guys at Gas Gas UK tomorrow. PPS. the bits of metal in the pump photo were found in the water pump but the "mechanic"!!!!! says that the pump was the cause as the threads in the plastic impeller were stripped !!!!!!!!!!!! HELL
The trans breather hose is NEVER connected to the carb.
Jon.
ps. I'm not aware of a "TXTI" model. The 02' Pro was a "TXXI" model but known as the TXT Pro 03' forward.
That's a new one for me. I can understand the impellor stripping, actually fairly rare from my experience as usually caused by the rider taking the brass plug out of the pump to drain the fluid and the thrust washer falling off the shaft end and into the housing and binding the impellor to the housing (it also allows the shaft end to sit into the housing too far and the impellor scrapes the inside of the pump housing, and I don't see signs of that here).
Obviously it's hard to see details in the photos, but I don't see any obvious signs of detonation but the rings seem to be seized in the lands (could have happened due to excessive heat, and "after the fact" of the main cause). The hole in the combustion chamber is unique, however, and may have been a surface fracture that let loose and a possible cause of previous overheating issues-chamber gases pushing into the cooling system. I think that's the first one of those I've seen. You could not have normally predicted a material failure of this sort unless you carefully inspected the chamber for cracks while the engine was torn down (not a normal proceedure in my experience other than in high-end racing applications).
It does look like the engine was stopped (locked up) when the chamber wall came apart (and the piece got stuck in the squish area) but it also seems that this engine was run beyond the time it should have been shut off when the first overheating symptoms were noticed.
First rough guess is material failure in the head chamber.
I agree, if the new owner has shown total disregard and blatantly abused the bike then yes, tough titties, however, does the previous owner know that for sure, as by his posting there seems to have been some kind of misunderstanding some way along the line.
" He sent me some pics of the cylinder head which has what looks like a melted hole in it, another pic of the piston which seems to have a piece of metal stuck to it and another pic of the cylinder inside which has a big gouge in it (I think from the metal that is stuck on the piston)."
I don't think I can remember knowing a rider who would continue to ride a Trials bike, with the obvious symptoms of distress the engine undoubtedly exhibited, to the point of this type of damage. I think there is more to the guys story than he is telling you.....
Hi all, just a quick question as it's baffling me .. My gas gas is running sweet as a nut but gear oil keeps dropping ... I keep topping it up every second ride to half the sight window on flat ground and after two rides it's just a bottom of sight window .. I am oiling bike when stone cold each time .. Wheres the oil going .. There are defo no leaks as the bike lives indoors on wood floor and theres never a drip between rides.
Thanks
With no leaks noted, one would suspect an inner crank seal allowing trans oil to be sucked into crank area under vacuum (especially if you noticed an unusual amount of smoke from the exhaust). I would always look at the simple things first, that being the trans breather (I'm assuming this is a Pro). It's the small right-angle fitting and hose in front of the countershaft sprocket (the hose goes up and loops under the tank), be sure that it is clear, otherwise pressure can build up in the trans casing and force some oil past the crank seal lip. Excess trans casing pressure symptom is usually weeping from the outer seals but not always. The crank seal is vunerable due to the normal pressure differentials it encounters.
I weigh about 165ish and have 2 1/2 turns of preload on stock spring with compression adjustment untouched on left fork. 22 clicks out on right or rebound side. Replaced stock fluid with Red Line synthetic. I will tweak around on rebound adjustments (because I can't leave it alone) but end up back at 22 clicks. I never notice the forks and for me that is a good sign. If I feel or notice them something is not right. A big improvement over the Zooks.
I have a 2002 Pro and had similar problems with the clutch.
After doing lots of different things this is what I now do if I have not ridden the bike for a week or two.
I take the master cylinder top off. Flick the clutch lever very quickly but shorts strokes alternating with slow long strokes.
Sure enough some air bubbles start to rise up. After these clear the clutch lever stroke feels normal I refit the cap and the bike is good to go.
The system does not leak any fluid and all joints are tight so why it should need this bleed after being standing I don't know.
Note I do this even whenever I bleed the system, even if I have pushed fluid up from the bleed nipple on the case and get an excellent clutch.
Best bit is it is free.
Generally the clutch system will not "suck" air as it is usually under pressure. What can happen, and it's not uncommon, is that the rubber boot at the M/C will get torn, loose or for the earlier models gets enough brake fluid (DOT 3,4,5.1) on it to deform and allow fine grit to enter into the piston bore. This will wear the o-ring and piston (like grinding compound), which will allow a little air to pass by the o-ring under the slight vacuum it experiences at times and wear the outer lip of the piston seal. As the bore of the M/C can/will be worn to a slight taper, eventually the outer diameter of the seal will become smaller from wear and not start to seal when traveling down the bore until it reaches a smaller diameter of the taper. This is usually noticed after the bike has not been used for a while as the piston seal lip "relaxes" from the normally curved profile it assumes while in use.
Hey all !! So please has anyone got any tips on rear suspension maintainance .. I was thinking my rear may need a nitrogen recharge , but it's still bouncy and it's a costly job . 110 quid for new seals and oil and recharge .. How often do they need recharging and what can I do maintainance wise .. Thanks
Chris,
If the stock shock is on your bike, it's undoubtedly a Sachs unit and not normally rebuildable. Make sure the Heim Joint at the top of the body is in good shape (it should not be loose at all) and lube the suspension linkage well. Some shops can drill the shock body for a Schrader valve and replace the oil and Nitrogen. I'd suggest taking the shock off, removing the spring and checking the damping quality for a start.
On the linkage, make sure you also get the two needle bearings up in the swingarm, they are often overlooked.
Just remember just because it is a `new` kit does not mean it is actually the correct specs. Still measure the finger height. If it is a little low, some of the friction pad needs to come off. Our importer here always recommended burning it `in` in fourth gear. (Tire against an obstacle and really abusing the clutch) There is also a video floating around of sanding the friction discs.
My experience also. The finger height is the defining measurement, rather than the clutch pack width, which is an approximate.
If you don't see a cut and welded flap on the backside of the mid-muffler, the previous owner may be making it up. The rewards of a quiet exhaust compared to any slight increase of power (and loss of power at lower RPMs, where you will spend most of your time) is much greater. Your fellow riders will throw fewer rocks at you.....
You need a tool that's called a blind bearing puller.
Sometimes that will work but only if the lip on the bearing-puller collar can catch the edge of the bearing. It's a very tight fit. I use a long, thin drift and dress the end flat so that it has a sharp edge. Lightly tap the inside bearing outer race, rotate the drift a third rotation, repeat. Works a treat.
(......He insisted that it would never of been connected! P.S this guy is NOT a GG service bloke.
Txt 280 2008 Marzocchi Forks Feel Hard And Rebound Slow
in Gas Gas
Posted
I'd look into an alignment issue ("stiction"), if the forks worked o.k. before the work was done.
I'd loosen all the fasteners (especially the fork brace and axle) except the top triple-clamp bolts
and work from the top down, pushing on the forks to "center" them with each new set of fasteners
tightened. The fork brace is always last.
Jon