dadof2

Hi Dan, could you translate the meaning of "Dude decafe" for the benefit of us Northern English.

Source coil on stator is most likely problem. Take off the flywheel and look for the coil with the finer windings. It resistance should (from memory) be about 250 Ohms. Check Bradford Ignitions website - they may give more accurate figures. Better method is to connect a voltmeter to this coils wires near CDI and then spin flywheel with a drill (plug out and earthed). Should see 25 to 30 volts AC at 500 RPM

An exhaust fire is not caused by running a rich oil mixture, it can happen in dry coke deposits from petrol. For a fire to occur (some basic chemistry here) you must have oxygen, a source of ignition and fuel. A correctly running / tuned trials bike runs very slightly rich of stoichiometric and therefore if your bike mixture (fuel air ratio) is somewhere near correct there cannot be "spare" oxygen in your exhaust to start or support a fire. I have no objection to people running their bikes at 80:1 or whatever, that is their choice, but some of the statements made in support of lean oil ratios and supposed disadvantages of rich ratios are a pile of rubbish. FACT more oil means less wear FACT more oil gives more power FACT more oil improves ring sealing and piston cooling FACT Sherco recommend 50:1 fully synthetic FACT GasGas recommend 50:1 fully synthetic FACT Beta recommend 25:1 on mineral or 66:1 on fully synthetic (Bardahl which is top end quality and viscosity) FACT mix ratios as rich as 25:1 do not cause plug to oil up in normal trials use. FACT Back in the days of much dirtier oils, villiers, Greeves, BSA etc used to run at 16:1 and plug fouling was only an occasional problem. FACT more oil reduces chances of engine damage if, your engine takes in water, throttle sticks open or you have coolant loss.

Bearing in mind the number of carburation problems and queries on trials central I thing quite a few may find the following link useful. Well worth a read for future reference even if you are not presently having problems. http://www.ducatimeccanica.com/dellorto_guide/dellorto.html

Yes, It cuts out the engine once the bike has been so far from vertical for a period of time. The exact angle and time are specified somewhere.

This sort of controversy is the inevitable result of riders disputing observers marking, particularly with regards as what is or is not a stop. Far too many observers have become browbeaten into over lenient marking, or quit observing. Riders riding under no stop rules need to accept that stopping will incur a five, not some favourable judgement from the observer because the only moved back a bit or moved forwards again quickly. Bending rules to different degrees, or individual observers consistently bending the rules is the road to nowhere. I feel sorry for both the observer and Dougie. I hope the 2 mark error has no influence on the result and that the observer genuinely could not see the stop from his observing position.

I would have thought the bank sensor was a useful safety and engine protection device, and therefore best left in place

I would have given a 5. But some WTC observers would possibly give a 3

Once again Dabster you are not reading exactly what I have said and misquoting me. I never said Bou's bike was not special, it obviously is. What I do believe is that its not that much different and that some of the tuning and parts cost rumours that are bandied about are ridiculous. What trial bikes and container ships have in common is that they are both suffering unnecessary failures due to being built too light.

This is a subject on which there are a lot of different opinions, I would do a search of past posts, there are many on this subject. As the beta comes jetted for 4% oil you are probably going to have to lean the jetting off a bit if you run at 1.5%. I run at 100cc oil to 3 litres of petrol on semi or fully synthetic. The bikes start easily and run clean. My mix ratio is too rich in many peoples opinion but I regard it as useful insurance against engine damage and wear. Only mix as much fuel as you need for the days riding. It never has been regarded as good practice to use fuel that has been mixed for some time but there is mounting evidence that ethanol in petrol causes fairly rapid deterioration of mixed fuel.

Check for stripped threads as many fasteners go into alloy, particularly subframe and sump guard mounts. As its only a 125 the engine may have done quite a bit of work / been revved. If it does not start easily suspect the stator may be tiring. Overall I would say they have few faults and are more reliable than other 125s.

On some hubs these are cast in. I would be reluctant to replace them unless absolutely necessary. Any subsequent failure, particularly on the front brake could result in a disastrous unexpected front wheel lock up.

Sounds as if its running too rich. Check air filter is clean and LIGHTLY oiled Check float level Check cold start enrichment is seating / sealing properly Check float valve is shutting off fully The above are all basic carb servicing, if this does not sort it check and maybe change your jet sizes and / or needle clip position.

Dabster - you said my post was rubbish, exactly why? There is far to much SPECULATION about Bou's bike and an extreme scarcity of fact. At Nord View last year I was able to have a good close look at the bike both stationary and whilst he was practicing. Sure there were a few things different to standard, but there was nothing obviously more non standard than some tricked up club riders bike. It may have a few mm on the bore or stroke, perhaps a bit of porting and even a mm or 2 on the valve diameters, but that's hardly major tuning or cost. There are also RUMOURS that it only has 3 or 4 gears to save weight, but there again, taking a few cogs out is hardly going to bust the bank. I suspect it had some form of traction control as it at times had a sort of misfire that did not appear to concern Bou or his minders. The UK importer of another major brand of trials bike also suspected it had traction control. Back to the weight limit issue. I just happened to read a copy of Maritime Engineering Review today, and guess what, ships are becoming too lightly built and fragile to the extent there are now safety concerns. Apparently a container ship with a design life expectancy of 25 years has fallen in half after only five years service, rather reminds you of the perils of Gasgas ownership.

Thanks for reply. I use Castrol high performance motorcycle brake fluid in my bikes, not because of the temperature but because I find it or Castrol Girling has better lubricity and feel compared to others I have tried. I tend to use standard halfords cheap stuff (on my trade card) in cars. Back to something closer to the original post - why do so many trials bike have the rear brake bleed nipple lower than the highest point in the cylinder, resulting in a trapped air pocket. Several bikes I know have to have the front wheel on a chair or higher to get the back brake to bleed properly.

The "choke" lever does not restrict the air flow, it lets extra fuel and air in (at a richer mixture than normal) Assuming you float height is correct - float tangs about level with carb upside down and you probably want the needle clip on middle or upper notches. Low speed mixture screw wants to be abut 1.5 turns out, 3.5 is far too much. See http://www.dellorto.co.uk/images/parts/PHBH_l.pdf I have a feeling the floats can be put in wrong way round or upside down, if this is done the bike may start and run but not much more. Check the weight of your floats, will be stamped on them in grams.

ianw, I doubt if there is much difference between 2 and 4 stroke tuning costs when it comes to a trials engine. Something I have noticed on Honda mx, road bike and industrial engines is how accurate and consistent the stock engines became in the late 1980s and I assume that trend has continued. I suspect Bou's bike, particularly regards engine mechanicals may be a lot closer to stock than people think.

Could brake fluid be getting onto your pads, or grease from rear wheel bearing. Once contaminated some brake materials are nigh on impossible to get working properly again. Ryan, why do you not like standard autostore brake fluid, its good enough to slow a 2 tonne car from 150mph, far more stress than a trials bike system ever gets.

I came across a 125 gasser (09 or 10 model) last year on which someone had assembled the kickstart washer onto the clutch release bearing.

Well, that's trout fishing on the Swale up the creek then.

It will work fine. If you have to borrow fuel from someone else (different oil) you should throw the mixed fuel away at then end of the trial. Castor oil goes off after a few days once mixed with petrol It will leave more deposits than a trials synthetic or scooter oil.

The trigger coil usually looks like a small black thing on the stator, or just outside the flywheel with a little but of metal sticking out. Its purpose is to sense the position of the flywheel to fire the spark at the correct time. The source coil is on the stator, its the one with a lot of fine copper wire windings. It provides the power for the ignition. The other coils on the stator have thicker wire windings and provide the power for the fan, lights and horn. They have nothing to do with the ignitin.

I like it when other people use castrol A747 cos it smells right, but i am too tight to buy it myself.

Does it not have an oil level sight glass?

Yes, friend of mine got ripped off well over £300 for a new stator and flywheel just out of warranty. Never bought a gassers again. The commonest fault on gassers seems to be the trigger coil, but source coils are also known to fail. Can you remove the flywheel and post a photo of the stator and I will try to advise further. Have a look on trials parts USA wiring diagrams.( their website is having problems at the moment.)