|
-
I'm reluctant to let enduro guys try out my Gas Gas. If I let them, I would tell them not to shift or kickstart. After replacing the kickstart gear, idler gear, top hat, and splitting the cases to replace the gearshift link, I don't want anybody treating my fragile gearbox like a normal bike. I have Japanese MX, Enduro and dual sport bikes and I can hammer the shifter and kick lever all day and not do any damage. Enduro guys think they can do the same with a trials bike.
With my GG, I need to be careful with every kick and shift. Gentle with the shifts and make sure the kick start gear is engaged before kicking. I've had electrical issues also, which seem to be specific to my 2007 model.
-
I had one Ducati unit fail and the fan stopped working but the engine ran. Replaced it and a few years later it failed with no spark. There were burnt marks on the epoxy in different places. Right now I'm running my bike with the first failed unit but using a battery to run the fan. When you replaced the diode, did you have a spark but no fan or no spark?
-
Danny rides a silent motorcycle:
Over 135k views in one week with unimpressive skills.
-
Geoff Aaron is 6'4" and doesn't use risers. Looks like he runs stock height. Pretty good rider, 10x champ.
-
How fast is your fan spinning? On newer bikes you can hear the fan and feel a strong air flow. I've had problems with my Ducati rectifier where it doesn't put out enough power to make the fan spin fast enough. Those model boat motors work well as replacements.
-
I think it's normal for an average use trials bike ridden by an average rider to not need a new top end for up to 10 years or more because of the low rpms involved. MX and enduro bikes need new top ends as part of regular maintenance, but a well maintained trials bike won't need it for many years. I would look for another bike to buy as this one was probably not well taken care of.
-
My gloves of choice are the next best thing to no gloves at all, and only $5 at Home Depot.
http://www.homedepot.com/p/Grease-Monkey-Coated-Gripping-Glove-Medium-25052-030/202709678
They don't get smelly in the summer, dry quickly, and you can forget you are wearing gloves since they are so thin.
-
I had to replace my lower hose on my Section. It was so soft it would constrict when pulling coolant and overheat. I made a replacement out of a metal gas supply line for water heaters.
-
Thanks for the tip! I have a couple of burnt out rectifiers that I will try this on. A 35 cent diode is much better than $200 for a new box. I moved my rectifier to behind my numberplate to keep it cooler so it won't burn out again.
-
Yours is a common complaint and this guy makes an aluminum adapter to fix it. I bought one and it gives you confidence when you tighten the clamp down. It's much better than the rubber pieces sliding around.
http://www.vmar.com/carb.html
-
Waterproof cards I think are made of Tyvek, which is also used as a moisture barrier for home construction and you can find it at Home Depot. They are easier to punch if you put a piece of card stock (business card thickness) underneath it while punching.
-
Your Ducati regulator/recitifier box handles power for the spark plug, fan and lights. I've had three of them fail on me, once no spark, twice no fan. Each time there was a brown burn spot on the epoxy on the back where a circuit burned out. If your headlight turns on I bet your stator is working.
-
There should be two pinned posts added to the Gas Gas section: Clutch Rattle and Shifting Problems. The same questions seemed to get asked at least every couple of months.
If it's not the top hat, the shift pawl broke and you have to split the cases and replace the whole shaft assembly. A cheap temporary way to fix the broken top hat is to remove the broken square metal bar and replace it. The steel reinforcing plate that comes with a door lockset has the perfect size square steel that can be cut and peened to secure. I've done it and it didn't cost me anything.
-
Looks to me the previous owner slammed rocks hard and bent the skidplate causing metal to metal contact. Oil soaking the rubber bumpers makes it soft. I use a 16 lb sledgehammer to bend the skidplate so it has enough clearance and put a piece of tire in between.
-
An 18 inch wheel won't fit on a super mini MX bike. What might work is a 17 inch rim and Vee Rubber makes a real radial 17 inch trials tire. If you want a hybrid bike, just use knobbies since trials tires isn't such a huge advantage. Knobbies are better in the soft stuff. You don't want to spend too much time riding slowly because of overheating with a 4T, but on my 2T super mini I haven't overheated yet.
-
I think that bike would work well as a trials/trail bike. I ride a RM100 for that and while it is light like a trials bike at 150lbs, it doesn't have the low end power that a 4 stroke has. Here are the mods that I did: 13/60 gearing, homemade skid plate, Rox risers, cut the seat foam down and moved the footpegs back. I bought the huge rear sprocket from PMP. It is good for tight singletrack but on open trails it's too slow. You can't find a good 16 inch rear trials tire so I use a Kenda Trackmaster 2 which is softer than most. Shinko makes a good 19 inch front trials tire but I use a knobby. Tires are not as important as gearing and getting a good standing riding position.
Here's a video of me doing trials on my RM100.
-
It looks like the Randonne is a modern version of the Honda Reflex/TLR200. Lighter, modern suspension and brakes, more power, suitable for beginners and wives. Honda sold tons of them to non trials riders and was popular to tie on the back of motor homes of retired folks. For advanced riders, it would be fun as a dual sport bike. It is almost the same as the TY125 Scorpa and with the extra power to get over obstacles, not any obstacle, I'd like to have one. I bet it's very quiet and reliable with it's Yamaha TTR 125 engine probably bored out to 180cc.
-
There have been several times my bike came loose from the tie downs and fell over after driving on a bumpy dirt road so I made a brace to keep it secure. Simply drilled a hole in the fender and fork brace, stuck a dowel in, and no more bouncing bike. A thin metal curved sheet is placed between the tire and fender to keep the dowel from damaging tire.
http://www.flickr.com/photos/52067707@N05/12803899423/
-
If Fantic comes out with a new trials bike and follows the same formula as their enduro bikes, what's the point? They are making almost the same bikes as Gas Gas but with a different frame and plastics and a few more Italian components. They even have a model called Six Days, which is the same name that Gas Gas used a few years ago. They both use Gas Gas 2T engines and Yamaha 4T engines. The only thing the current Fantic has in common with the old company is the name.
-
When the current Fantic company introduced itself in 2006 it had this 80cc trials bike at a European bike show. They planned to enter the market with small bore trials bikes. That never happened and went enduro instead. Maybe Gas Gas and Fantic will be merging? Fantic uses Gas Gas 2T engines.
-
1.5 turns out is the starting point.
Spanky's Jetting Guide:
A correctly jetted carb makes a tremendous difference in the torque, midrange pull, top-end pull, and over-rev of your engine. If you have never jetted your bike correctly, you will almost certainly gain some performance at some point in the bike's powerband.
A cleanly jetted pilot circuit can be the difference between having to clutch the bike out of a turn or not. The needle can make all the difference in the world for the power of the machine in most situations, as it controls the throttle range that most riders spend most of their time using.
A correctly sized main jet could mean the difference between being able to rev out high enough to not have to shift one more time at the end of the straight, or the power falling flat on top and requiring you to make that extra shift.
Are you fouling plugs? Many people will tell you all sorts of band-aid fixes, from running less oil, to running a hotter plug. Both are incorrect fixes for plug fouling. It's all in the jetting.
The only way to know what jetting changes you will need is by trial-and-error. No one can give you jetting specs, because every bike is different, every rider has a different style, and jetting is totally weather dependent. Unless the person telling you what jets to use is riding an identical bike, on the exact same track, at the same time, his recommendations are meaningless.
Jetting is fairly simple, and is a useful skill to learn if you ride a two-stroke and want it to perform at it's best.
It's very important that you start with the pilot circuit. The reason is simple. The pilot circuit affects the entire throttle range. When you are at full throttle, the main jet is the primary fuel metering device, but the pilot is still delivering fuel as well, adding to the total amount of fuel that your engine is receiving.
Before you start to rejet your bike, you need a clean air filter, a fresh plug (actually you need several plugs to do plug-chop tests for the main jet), and fresh fuel.
One important detail: Make sure the engine is in good mechanical condition. If your engine has a worn top-end, fix it first. Trying to jet a worn out engine is a waste of time. The same goes for reeds that don't seal properly, and a silencer that needs re-packing. Worn reeds will mimic rich jetting, and worn rings will mimic lean jetting.
Before you start the jet testing, Install a fresh plug. Set the float level to the proper specs, an incorrect float height will affect your jetting all across the throttle range.
Warm the bike completely, and shut it off.
As already stated, start with the pilot circuit. Turn the air screw all the way in, then turn it out 1.5 turns to start. Start the engine, and turn the idle screw in until you get a slightly fast idle, or hold the throttle just barely cracked, to keep the engine idleing. Turn the airscrew slowly in, and then out, until you find the point where the idle is fastest. Stop there. Do not open the screw any farther, or your throttle response will be flat and mushy, and the bike may even bog. This is only the starting point, we will still have to tune the air screw for the best response.
Now is the time to determine if you have the correct pilot installed in your carb. The air screw position determines this for you, making it very simple. If your air screw is less than 1 turn from closed, you need a larger pilot jet. If it is more than 2.5 turns from closed, you need a smaller pilot jet.
Once you have determined (and installed it if it's neccessary to change it) the correct pilot jet size, and tuned the air screw for the fastest idle, it's time to tune the air screw for the best throttle response. Again, make sure the bike is at full operating temperature. Set the idle back down (the bike should still idle, despite what you read in the Moto Tabloids), and ride the bike, using closed-to-1/4 throttle transitions. Turn the air screw slightly in either direction until you find the point that gives you the best response when cracking the throttle open. Most bikes are sensitive to changes as small as 1/8 of a turn.
The air screw is not a set-it-and-leave-it adjustment. You have to constantly re-adjust the air screw to compensate for changing outdoor temps and humidity. An air screw setting that is perfect in the cool morning air will likely be too rich in the heat of the mid-day.
Now, it's time to work on the needle. Mark the throttle grip at 1/4 and 3/4 openings. Ride the bike between these two marks. If the bike bogs for a second before responding to throttle, lower the clip (raising the needle) a notch at a time until the engine picks up smoothly. If the bike sputters or sounds rough when giving it throttle, raise the clip (lowering the needle) until it runs cleanly. There isn't really any way to test the needle other than by feel, but it's usually quite obvious when it's right or wrong.
Last is the main jet. The main jet affects from 1/2 to full throttle. The easiest way to test it is to do a throttle-chop test. With the bike fully warmed up, find a long straight, and install a fresh plug. Start the engine, and do a full-throttle run down the straight, through all gears. As soon as the bike tops out, pull the clutch in, and kill the engine, coasting to a stop. Remove the plug, and look deep down inside the threads, at the base of the insulator. If it is white or gray, the main is too lean. If it is dark brown or black, the main is too rich. The correct color is a medium-dark mocha brown or tan.
Once you have a little bit of experience with jetting changes, and you start to learn the difference in feel between "rich" and "lean", you'll begine to learn, just from the sound of the exhaust and the feel of the power, not only if the bike is running rich or lean, but even which one of the carb circuits is the culprit.
The slide is also a tuning variable for jetting, but slides are very expensive, and few bikes need different slides, so we won't go into that here.
Keep in mind, even though this article is intended primarily for two-strokes, four-strokes also need proper jetting to perform right, although they are not quite as fussy as their oil-burning cousins. The only real difference in the two is with the pilot circuit.
Two-strokes have an air screw that you screw in to make the jetting richer, ansd screw out to make the jetting leaner. Four-strokes, on the other hand, have a fuel adjustment screw that you screw in to make the jetting leaner, and out to make it richer.
-
After three Ducati regulator/rectifiers on my 07 failed I decided to run the fan off a battery instead. I carry a large sealed lead acid battery in my fanny pack, run the wires up my back and down my arm and have a slip on connection at the bars. The fan now runs much faster than before and I can easily get a full days riding from one charge.
I also moved the regulator/rectifier, that now only powers the ignition, behind the number plate to keep it from cooking. Twice the fan circuit failed and once the ignition from what I think was excessive heat.
-
The gearbox breather tube on my 07 pro goes to the atmosphere. I don't see a reason why it would go to the carb.
If I was the buyer I would want a refund because even a 10 year old bike in good running order shouldn't seize unless you are going full throttle up a mountain for miles. Trials bikes can race 20 minute endurocross races with no problem.
-
I think older bikes are prone to overheating and seizing from having a slow fan. I have an 07 Pro and 1995 Fantic and they both run hot. The fans run at about half speed and I can't hear it above the engine sound. A brand new GG has a very audible and fast fan.
Your buyer was probably trail riding and didn't notice it boiling over and it seized.
-
A bent skidplate can cause some serious damage to the cases. Mine was curving inwards and the rubber spacer was split. The plate was almost touching the case and could have cracked it. I laid the skidplate on the lawn and hit it a few times with a 16lb sledgehammer and it straightened out.
|
|