My son was out on his bike today and as soon as he tryed to kickstart it he knew there was a problem. took 8 kicks to get it going but as soon as he put it in gear it just stalled. It happened again twice so he had to do pritty much full revs to keep it going.He was half way down the field when the bike just backfired and just halted to a stop, (Sounded like a gun being fired), He tryed starting it but no luck. Checked the bike everythings fine, full tank, oils fine. I don't know anything about trials bikes so I have no idea what to do with it. Any tips on how to maintain a trials bike would be appreciated.
My first guess is that the flywheel hub has slipped on the crank stub and sheared the Woodruff key. This will throw the ignition timing off and can cause the symptoms you describe.
You'll need to pull the flywheel off and check the key (a half moon shaped piece of metal that fits in a special groove in the crank stub) to see if that's the cause.
Thanks for all of the helpful advice. I'll dig into the project tonight and get things looked at. Worst case it sounds like I will need to re-plate the cylinder and properly size a new piston and rings to match. Anyone out there know of a competent company that I can send off to for the re-plate if I need it. I had already checked with Rising Sun Imports here in the States regarding a swap out for a re-plated cylinder. They don't have any in stock and I thought I could save myself a few dollars by having it done by someone on my own. I would of course buy the piston and send it along with the barrel to be properly fitted.
I'd love to hear what you guys have to say about any reputable plating shops. I'm in Northern California, Santa Cruz County, so the closer to me the better.
Again, Thanks a bunch for the knowledge. It has been helpful.
tturvy
If you live in Santa Cruz, you might check in at Moore & Son's shop at 2-1431 East Cliff Drive. Johnny Moore is a Trials dealer for several brands, including GasGas and may have an idea of where you can send it that may be close. Tell him that Jon Stoodley sent you to him for his sage advice.
You will need to pull the top end and inspect it for damage. Usually, the biggest concern is what damage you do to the cylinder. You may be able to clean it up, or you may need to get it replated.
A note for future reference, use a gloved hand to plug the exhaust end and the other to hold the kill switch. Two-strokes tend to auto-ignite at full chat in neutral, but plugging the exhaust will usually bring down the RPMs to the point where the killswitch will work.
I realize it sounded like a daft question, but being new to motorcycles I'm trying to figure out a few things, namely the engine and carburetor. I have seen the pod filter set up and thought it was a very neat, tidy and simple solution. I like simple. As different people will take differing amounts pride in their machines I can see why an air box in a production bike is a must. If a manufacturer does not include the air box it's only a matter of time before one runs into problems. So, in theory if kept clean wouldn't a pod filter be a better solution than an air box?
If you are looking for simplicity a pod will work. If you are looking for long-range performance a well designed airbox is probably better. Besides insuring better quality air, the airbox/boot system helps shape the incoming air mass in a way that allows the carb to make better use of it.
Some time ago I ran a series of dyno tests on several 600 SuperSport roadrace bikes and used several types of individual aircleaners (foam and cotton gauze)/tuned flared tubes (four carbs) and the stock airbox. Although the tuned intake tubes gave a slightly better top end HP reading, the airbox consistantly gave better low-end, out of the slow turn pull type of torque that wins races.
Hey all, started having a rather annoying problem with my 2010 Gas Gas Txt Racing. The bike is a 125, should this make any difference.
Anyway - The bike will not start from cold on the kick start, I end up running down the road and bump starting it. I dont know whats causing this, but often, if I manage to finally kick her into life, she'll run as if choked for five minutes or so with lots of smoke. If I bump start her, it'll run fine.
The bike is quite hard to bump start also, takes two or three attempts.
The kickstart mechanism is not damaged atall, so it is delivering the normal stroke to the starter gears.
The bike kickstarts when warm easily.
So far, I have put it down to the fuel mix... Too much oil solidifying slightly on the plug as it cools due to too much oil in the mix and fouling the plug, the plug is often black when taken out, but the plug works perfect, and I have tried multiple plugs.
I use Ipone Samurai Racing, strawberry - 80 ml's to a Gallon of super unleaded. Just ordered a Castrol oil, see if this makes any difference.
Carb has been cleaned thoroughly, multiple times. Airbox and air filter are clean. Airbox has all modifications done and flaps fitted.
When started, occasionally the bike will run choked, and not rev out atall, occasionally at revs feel like someones holding the kill button, but once the bikes warmed up and the problem cleared (five minutes or so) it will run perfect. This is why I think its a problem with something ON the plug, as its almost like an intermittent spark when cold, but when hot (crud burnt off?) it doesn't have a single problem.
I'm completely stumped, normally I'm alright at solving problems like this, but not on this occasion.
All help greatly appreciated, its more embarrasing than annoying, turning up at a trial and having to bump start the bike.
Thanks,
Jamie
What type of plug is in the bike and is it the original one?
I removed the circlip and washer, then the spring (which looks like it will be interesting to put back), however the top hat itself does not seem to want to budge. I can see the cross pin is sheared, so maybe I am lucky.
I'm thinking about trying to get a good grip with plyers and a cloth and yank---but fear hurting something---tips?
OK I got it had to yank a bit.
TY sir.
PS just to make things interesting I forgot to grab the thrust bearing as I pulled off the cover so those needle bearings went loose--counting them now and praying one did not drop through the small hole at the center of the clutch (bike was on it's side).
Sounds good. The cross pin usually breaks on impact to the lever, but not always. Hopefully you are in good shape.
If you wiggle/twist while pulling on the top hat, it should come off easily. It's supposed to be a tight fit.
Those little needle bearings should not be loose. That's an indication of advanced wear, so you'll need to replace that bearing thrust washer, obviously. If you are missing any (put found ones in the washer housing just to be sure you have them all), you might try putting the bike upright and with drain plug removed, squirt solvent into the inside engine case to try to flush them out.
I think the newer bikes come with magnets on both lower and upper drainplugs rather than just lower plug. I run magnets on both plugs on my 02" Pro.
We took away the brake lever and used a screwdriver so you get loads more travel on the piston pushing the air out...then re assemble brake lever
That works well. Obviously keep fluid up in the M/C reservoir, but this should take the air out of the line and give you a little pressure. You can then use the bleed screw on the caliper to get air out of the "loop" at the top of the caliper housing. Some calipers have a "dead" area on the side opposite the bleed screw and in a pinch you can take the caliper off the fork, put a piece of plastic sheet or metal in between the pads to keep them from coming together and rotate the caliper to move the bubble over to the side with the bleed screw. Usually you don't have to do all this stuff but sometimes it is necessary in rare cases.
Tipped over yesterday and now shifter will rotate 360 degrees.
Did my searching here, and it seems that this is not unheard of, and I may be able to fix it without splitting the cases.
I've watched all the repair videos, which make reference to the issue, but do not actually show the procedure to repair/replace the "top hat" on the right side of the shift drum, under the clutch.
I do know that there is a circlip which holds the piece in place.
If anyone is familar with the part, could you walk me through inspection/ repair from the right side: let's say I have the clutch cover and clutch off.
Looking at the parts list I see "SHIFT SHAFT CENTER LOCATOR AND SPRING" MT280238037CT. Is that all I would need if I don't have to split the cases?
TY in advance
You'll always want to inspect for damage before ordering parts. The shift centering assembly is under the clutch basket and is removed by taking off the circlip, but you may have damaged the shift rollers on the internal shaft and that will encompass splitting the cases. The rollers have a built-in stop, which in your case, is not working now as the arms that hold the rollers may be bent. If just the centering spring assembly is broken, as I remember, the shaft will not rotate 360 but still be limited in rotation.
Really struggling to bleed up my front brake after i swapped the brake pipe, tried to bleed up using a automatic bleeder and each time it sucks one of the pistons back in and we can not stop it from doing this
Bleeding manually the brake would still not bleed up even with the pistons out in there correct position
Any help on how I can bleed the brake up would be much appreciated
Thanks a lot
Make sure the M/C piston is coming all the way back to the stop (you may need to back off the adjustment screw on the lever) and tilt the M/C up to avoid a loop in the hose. If you press the lever in/out gently with the M/C raised up a little, you should notice small bubbles coming out the bleed hole. Keep doing this until they stop coming out and then you should have enough pressure to start pressure bleeding the caliper where air bubbles hide.
funnily enough it started fine all weekend,now gonna wait until ive been out again to see if it reverts back to being a bugger,i am wondering if water is getting into stator when i,m washing bike,never washed it last week and went fine,every other time its been powerwashed before being put away,but havent a clue,would be good if its fixed itself....
One of the things I've done to keep water from being trapped in the stator area is to vent the sidecase on all my bikes since the 70's. This really helps in a wet Trial as the sidecase is a closed container of gas (air in this case) and if cooled rapidly (like in a creek) a vacuum will form and suck water into the case in any area where the gasket/seal is compromised. A cut down Schrader fitting can be used or any small fitting that a hose can be attached to. The hose is then run up under the fuel tank and into a small coil. I check my stator once in a while and spray some WD-40 on the surfaces just to cut any corrosion possibilities. It's been clean and dry for 8 years now.
This is my 02' Pro vent, which is really needed as the 02' engine is non-anodized Magnesium and really prone to corrosion if not cared for.
when i come to ride my 05 pro i tend to have little/no front brake.
if i pump the leaver it comes back and works ok but when left to sit unused for a short amount of time it will go back to the state of less pressure and need pumping again.
this is becoming a problem as between sections of trials waiting etc i loose the brake and need to pump it again before starting the section.
any advice???
Provided there is (1) adequate fluid in the M/C reservoir, (2) no leakage of fluid at the fittings (loss of fluid volume) and (3) the lever pressure is good/solid after pumping it up (no compressible air in the system), my first guess is worn piston seal in the master cylinder.
If the rubber boot that the M/C plunger goes through is compromised at all, the chances that the seal is bunged are that much greater. What will happen if the boot is broken/missing is that fine grit will get into the bore and wear the seal lip. Even with normal seal wear the symptoms will be similiar.
We usually use about the first 1/3rd of the master cylinder bore in normal brake operation so that after a while the first 1/3rd of the bore will be a slightly larger diameter than the rest of the bore due to normal wear. When the seal lip is worn to the point where it looses tension with the walls of the bore, when the lever is pulled and the piston starts to travel, fluid will pass by the lip until the seal gets down into the unworn part of the bore (smaller diameter) where it will seal again and pressurize the line. With a little pressure built up in the system the seal, due to it's shape, will expand out a little and be able to start pressure at the start of lever travel. If the brake is not used for a time, the seal will relax (become slightly smaller diameter) and the process starts again.
My bet is that if you put in a M/C rebuild kit, the problem will be solved.
Was just re-reading through this old post of yours and saw you mention Whitey Webb! He still lives here in my hometown of Victoria BC Canada. There is a great connection between Kip and Whitey and myself. Us Canadians like to know that there is some good Canuck bloodlines in that Webb family. Great people all of them!
Steve"
Great news! Tell Whitey hi for me, but it's been so many decades he may not remember me (heck, sometimes I don't remember me.....).
Whitey was at the PITS booth for a big motorcycle show at the Cow Palace in South San Francisco I went to after getting out of flat tracking. His passion and dedication to Trials was infectious and got me interested in trying it. The rest, they say, is history. The meeting was casual, but looking back, had a dramatic (and positive) impact on my life, that's for sure.
He may be part of the reason I like to go over and meet new riders at our events and take them out to ride their first Trial, showing them the rules and give them a short lesson in riding and reading sections. I had been involved in a lot of types of motorsports competition up to meeting Whitey, and he was so different from the gunfighters I had previously competed with, as were all the other people I first met in Trials, that I figured I had found a "home", which after 39 years, is more true than ever.
Hey, just stripped my front Talon disc brake down, and the diaphragm is too swollen to get back in. It's a Brembo brake lever, and the Diaphragm is a Brembo 10 271140 (The 10 is also offset upwardsso I don't know if this is relevant to the part number or not).
I can't find one anywhere online. Haven't rung round locally yet but just wondering if someone on here has ever had to find one and if so, where could I get one from?
Cheers.
I have an 85' TY350 with a Talon conversion. I ordered a M/C kit from TrialsPartsUSA/AJP America as a backup : http://www.ajpamerica.com/rebuild-kits-and-parts.html that looked like it would fit but have not needed it yet, so haven't had a chance to check it out. I'm not sure where you could get parts in the U.K.
going to be taking off stator and sending it off to get rewound,is it a straight forward job too take off and refit,i have got a flywheel puller to take off,but was wondering if it has to be set when refitting and if so how and what are clearance settings if any...
The Pro stator is a fixed item and non adjustable. When re-fitting make sure the places where the stator plate contacts the engine cases are clean (a little sandpaper works well) and I like to put a dab of dielectric tuneup grease (Silicone grease) on the contact points to ward off corrosion. The ignition timing does not involve stator plate position but is a function of crank angle and magnetic pickup sensor location.
Cleaned and repacked the silencer, I noticed that there was no seal between the silencer and middle box and the middle box and down pipe, there was some rubber on the middle box section that connects to the silencer, but this was in a bit of a mess. Should there be a seal between each section of the exhaust and
any idea what the melted rubber on the middle box section was.
Thank you in advance
Andy
Andy,
There should be special high-temp o-rings (usually an orange color) inside the female connections of the mid-muffler and final silencer.
1.) Yes it does seem to do it more going up the gears rather than down the gears - so I will look at the video
2.) I will try changing gear without the clutch to see if clutch is slipping but not sure it is the clutch slipping as I know that if I was to try and move from stationary when the bike in 3rd or 4th gear it would stall rather than the clutch slipping
Thanks again
This sounds like an adjusting of the shift centering spring under the clutch would probably fix the problem. The other possibilities are a damaged roller assembly inside the shift drum or a bent shift fork, but the centering spring adjustment should be the first step.
I would not recommend shifting the transmission without using the clutch. Trials transmissions are designed to stay in gear and not be shifted under load.
in the garage i have a big jerrycan full of petrol, and i do not know if it is just petrol or if it has been mixed to make 2 stroke stuff. being a big can of very expensive petrol, i do not want to waste its content or break my bike. does anyone know of a test i could use to find out if it has been mixed 40 to 1? apart from it having a slight tinge because that isnt so obvious. thanks
I'm not aware of a reliable test the average rider could conduct that would yield fool-proof results.
I would:
Run the car down low of fuel, dump the can in the tank and top off with pump fuel. The exhaust convertor shouldn't be damaged by a little formulated-to-burn premix oil at the temps they are designed to run at, it's tetraethyl lead in fuel that fouls them and coats the perforated cores (I'm assuming the jerrycan is of pump fuel and not high lead race fuel-which is generally not available now anyway). The premix ratio in the car tank with the added pump fuel should be at about 80/120:1+ at least, which is probably no worse than if you added any number of oil-based fuel additives people use that are available at the auto parts stores. The engine might even be a little happier for a while with the slight amount of added lubrication.
Get a fresh batch of fuel, do NOT add premix oil in the future and use a smaller fuel container each time to mix up what you will use in a days riding, which will be a better bet for your bike's engine.
Slowly getting bike sorted for trials use again after 7 year layoff
Coolant is original 2001 vintage so needs changing.
Previously used Putoline 'ready mixed' in KTM Enduro for years so tempted to stick with it.
However, I have some unopened Redline 'water wetter' from abandoned project which needs mixing with undilute antifeeze.
Any suggestions
Ready mix for bikes should work. I use a 50/50 mix of auto anti-freeze and distilled water with a little Water Wetter added to improve heat transfer from alloy to coolant.
Patrick asked me to post a note to the trials world. If you'd like to read it, click here.
Good for you, Pat.
With all the external pressure on you I know it must have been a very difficult decision. You're an inspiration for all the riders here and I, for one, support your doing what is best for you 100%.
I have a somewhat unusual request. I've had a Trials related e-mail relationship with a young man who recently passed away. His widow contacted me about finding a good home for his favorite Trials bike, a 2002 Pro (Jordi Pasquet's as I remember) and I said I would help her find a good contact. She lives in northern central Illinois in a town called Utica. I thought it might be in the NITRO club area but was not sure. If there is someone in a club in that area that could help her and maybe help a new rider find a bike, I'd greatly appreciate it. You can PM me off the forum.
It has been helpful.
Backfiring?
in Gas Gas
Posted
Actually not too bad to fix. You'll probably need a flywheel puller (from your dealer, they are special to this type of ignition),
a new woodruff key and a torque wrench. Take the flywheel off using the puller, take out any of the old key pieces, install new
key, put on flywheel and use a little Loctite on the bolt threads. Torque flywheel bolt to 32 ft lbs (42 Nm) and you should be set.
This is not an uncommon problem in Trials engines of just about any year or brand. The bolt/nut is torqued at the factory during
initial assembly but after a few heat cycles tends to loosen a little (like new spokes). With the large mass flywheels and drivetrain
shocks that are normal to Trials, the flywheel will often slip after a while and shear the key. It's always a good idea to check the flywheel
fastener on a new bike after a time, and a re-Loctite and re-torque will usually prevent this in the future.
Jon