Leaves a nice film of oil on the crank / bearings and runs very clean. Old fuel stays in the tank for 3-4 weeks at a time, not had any carb issues yet. Starts 2nd kick every time and I get a smell through my exhaust that turns men and women into my slaves...
Squirt some oil down the plug hole, and turn the engine over do the piston is at the bottom of its stroke. After the four nuts are undone (and the ally brace is removed) it should lift / slide off fairly easily, a bit of moderate resistance at first then it'll pop off. A couple of gentle taps with a rubber mallet will help break the base gasket seal.
No can do basher. Your logic makes sense but as an engineer I'm naturally programmed to make what I have better.
All bikes have their bad features, seeing as the clutch is the only thing on my gasser that im not 100% happy with its a no brainer for me not to correct this.
Any mod I do will not effect the resale value as the mod will be reversible of course, but a point well worth noting.
An electric trial bike would be ideal for me but I know nothing about them. I could trail through x amount of web pages and learn everything one could know but I just want brief specific info:
How much does the best one cost, and which one is currently the best?
How long can you ride one for before the batteries die?
What sort of batteries power them, and what is their life span?
Changing the belleville spring washer will just make it stiffer or softer. it won't change the dwell period of the clutch biting as this is determined by the clutch disk levers (the springs), and bore size of master cylinder.
Done that chap, can't remember off the top of my head the clutch pack measure but I recall in to be around 10mm with the 2.0mm plates in.
Manuals and gas gas videos suggest I should have a relatively snappy clutch with this set up but it is not at all snappy enough for me. Perhaps I am going outside the boundaries of stock snappiness.
I'm leaning towards fitting a collar over the top hat slave cylinder (to increase the diameter) then fitting an oversize roller thrust bearing. This will reduce mechanical leverage and advantage on the clutch springs, if I go too far and lever becomes too stiff I can then use narrower plates or smaller diameter bearing / collar combo.
I have access to machine tools so spinning a few custom parts is no problem for me.
I replaced the clutch on my 2007 280cc pro with a dp clutch from Gas Gas motos uk. Kev at gas gas reccomended not to use ATF fluid as the packs swell with this oil. I'm now using putoline light gear oil.
Problem is I find the clutch a bit too progressive.
The clutch kit came with 2.0mm steel disks. These were fitted and the clutch springs are at the lowest position (15.5mm spring distance). This should make it more snappy and stiffer at the lever.
Fitting thinner disks and increasing the clutch spring measurement will apparently make it even more progressive!
I'm thinking of swapping my oil to ATF again, to try and make the disks swell.
Or
Increasing the master cylinder bore.
Or
I'm even tempted to try adding an extra fiber disk and steel plate (giving me a 4 plate clutch), of course carrying out the mods to get the extra disks fitting correctly.
Mine sits at the same height (2007 280cc txt pro) so I'd say that was about right.
Changing the combustion chamber to head o rings is an easy task, after you've removed the old ones and cleaned up the flange just use a smidge of grease to help hold the seals in place while you lower it into position.
Torque the m6 socket cap screws up gradually in a crisscross pattern, 7-8Nm if I remember correctly.
Don't be surprised if the water pump seal has gone though, even only after a year. If you didn't replace the shaft at the same time as the seal it won't last as long as if you had.
I will purposely let wobbly riders ride my bike just so I can whatch them fall off... I know it's a bit cruel and sometimes the bike gets damaged as well as their pride but it's oooooh so worth it! Especially if you catch it on camera...
Specifics of each manufacturer of trial bike differs so my best reccomendation is to take a friend along, or a club member, one who knows the type of bike you are looking to purchase.
Also, if you see a bike that you are interested in ask here on TC if there is anything specific for that model to look out for that may cost money later on. People here are great and always willing to help out.
2nd hand bikes over 3 years old are what they are, they are not new and parts on them will be worn out - yet working - or perhaps they may be about to catastrophicly fail and cost you a small fortune!
There are certain generic checks that cover most bikes, all you need is a little bit of mechanical knowleadge to carry out and assess a 2nd hand bike sensibly.
First thing is how does it look in general? Does it look tidy? Does it look like its been looked after? Can you see bits hanging off? Is there any obvious crash damage that hasnt been fixed that really should have been?
Now lets get practical...
Check it over from cold; water levels, oil levels, how clean is the oil? If its been looked after the oil should be fairly clean, not murky / milky and bitty. The cooling system should be full and again this should be fairly clean and ideally with some colour to it beit red, green or blue etc from a good antifreeze. Suspect cooling systems that are just water only - it may be loosing coolant and the owner has to keep topping it up (and they may have just topped it up prior to your inspection!).
The freind you bought along who knows this particular model of bike should take it for a ride. Most sellers wont mind it being test ridden - unless they have something to hide.
Ask your mate - Does it ride like it should? Does the clutch slip? Do the brakes work? Does it start easy weather its cold or hot? How does the engine sound? How well does the engine run? How punchy is the engine? Do the front / rear shocks feel ok? Does it feel tight and smooth or does it feel loose and rattlely? Did the fan come on? Is it smoking more then it should? DOES IT FEEL CORRECT?
Now check the water / oil quantities and quality again. It should look the same as before. The oil should still be clean and the water should still be in the cooling system. If the oil has gone milky and the seller cant give you a reasonable explanation or remedy then best you stay away as alarm bells are ringing with this old hack!
If all is good during the the pre and post test ride and it works like a trial bike should you can now check it in a bit more detail.
Ask the seller what money they have spent on new parts recently, for instance if it's been serviced it may of had a new air filter, wheel bearings, chain etc. Ask if they have receipts for any new parts, don't worry if they havnt got every piece of paper for every new part they have purchased as not everyone keeps them (I do) it just means you need to check up on the sellers claims. Some new items you cant visually inspect, but the ones that you can check are worth having a look at - you don't know the seller so don't take their word for it.
Engine:
Check for any kind of bad running I.E. Hard starting, over heating, clunky gears, smoking, knocking at low to mid rpm, smooth transition between low - mid - and full throttle. Has the foam on the air filter disintegrated? If so then when was it last serviced?? If the owner lets you carry out a compression test then do so and compare readings to spec. If they don't let you do a compression test then either they don't really want to sell you their bike or they have something to hide! It's wise to do a compression test but if you havnt got a compression tester it's still nice to hear from the seller that they would not be concerned about one being carried out.
Check exhaust for rattles, broken mounts. The exhaust brackets can break in a crash and sometimes require welding, give it a good wiggle it should be fairly solid.
Electrics:
Check general condition and that they are tidy. Are there any 'additions' to the wiring like terminals that have been crimped on by somebody in the past - if so why is this? Suspect untidy wiring or additional terminals as something that may have been 'hacked about with' and could possibly have underlying electrical issues if there is no reasonable explanation. Check the lights work (if it has them). Check plug lead and cap condition.
Clutch and drive train:
Check for correct operation. The clutch should be smooth, not clonky and certainly not noisy. It should not slip. Use as a bargaining tool if it does slip. It might save you
The graupner speed 500 e motor works a treat, good find meldrew.
The supplier sent mine accross the channel in 2 days.
My old motor failed because water had got in wich in turn had corroded the armature and it's array of gobbins. As the rear of the motor is sealed by the rubber boot (of a fashion, water can still get in) I guess water had either got in via the motor mount screws, the forward shaft bearing housing (which does have an o ring seal ) or tracking directly down the wires to the motor.
To help cure this when I mounted the motor into the housing I put a 0.5mm rubber gasket between the motor and casing. I also disassembled the fan wire connector and sealed the terminals / wire with adhesive coated shrink sleeve.
Finally I drilled a 1/8th hole on the bottom of the ally motor mount that the rubber boot sits on, where the hole was I cut away a small piece of the rubber boot then reapplied a small piece of rubber over te hole effectively making it a one way valve so water can get out but cannot get in. Sorry I don't have any pics so I hope the description is clear enough to visualise.
You may get away with a rewind, I can't quite see the pics too well on my iPhone but one of the poles of the generator looks pretty burnt out. Surely this will reduce the magnetic field and reduce the generators output somewhat? the pole of the exciter coil looks ok though.
Castrol A747
in General Trials Talk
Posted
I run shell advance kart castor oil. 80-1 premix.
Leaves a nice film of oil on the crank / bearings and runs very clean. Old fuel stays in the tank for 3-4 weeks at a time, not had any carb issues yet. Starts 2nd kick every time and I get a smell through my exhaust that turns men and women into my slaves...