lowbrow

I bought an IRC recently fitted it to the latest style GasGas rim and yes, I spent the first trial pumping it up between sections! Then re-fitted it using a bead of clear silicone on the rim where the tyre seats and it was fine for the next trial. Time will tell whether this is a temporary or permanent fix. My next tyre will be a Michelin.

Seems a very user friendly design with ease of maintenance and simplicity in mind. Its not fuel injected but has a Dellorto carb.

My link What do you think?

Never checked the compression on a trials bike, but those pressures look pretty good to me and certainly not so low that the motor won't run at all. Ok, so you've got a spark, but are you sure it's at the right time? Check to make sure the woodruff key on the ignition flywheel hasn't sheared and allowed the timing to slip.

Next time it starts farting around see if it behaves when you take the fuel tank cap off. Could be a blocked one way valve on tank cap breather pipe, or its on the wrong way round or the pipe itself could be blocked. Worth a try; costs nowt!

I guess you mean an 06 Raga? Yes, give the carb a good clean and blow through, but also check the rubber the carb' fits into for wear and splitting. The symptoms you describe hint at an air leak between the carb and the motor.

Difficult for us Brits to comment as the air is colder, damper and more dense here; we run different (JJH) needles too. Problem is if you set your carb' up for the road it won't be good in the sections, and vice versa. GasGas UK offer advice to riders in the Scottish 6 Day Trial and recommend that they never ride on the road with a steady throttle because the bike runs weak and overheats. The Keihin is better than a Dellorto on the road, but if the bike is good in the sections just try varying the throttle on the road (rolling it on and off) to keep it from 'pinging' which is when it is running weak.

Is it easy to clean this stuff off the rim again when you next change the tyre or does it leave you with a nasty mess?

Swap your IRC for the one your mate has and see what happens. I'd bet against your tyre rather than the rim.

Interesting point and that's not something I've noticed, but as others have said these tyres will remain inflated until the bike is ridden.

That's been my experience too. Also true of new IRC's fitted to older rims that have given no trouble with IRC tyres in the past; however it's always been the case that they've tended to lose pressure if you hit something really hard.

That is a surprise! Hopefully a dealer has one on a shelf somewhere. Its the sort of thing you see on ebay when you don't want one. In what way are the later ones too small?

Any GasGas cap from 1998 onwards should fit. The later ones are vented.

The spitting out of coolant suggests one of two things; you overfilled the radiator or the rubber 'O' rings between the cylinder and head have perished and need to be replaced. Its probably a good thing to replace them anyway on a bike of this age so you know they're good. Other things I'd check is the inlet rubber the carb' fits into and the joints between the inlet rubber and reed block and crankcase. The inlet rubber can split (always at the back where you can't see!) and I use new gaskets and a smear of silicone jointing compound whenever I remove the reed block and inlet; you can check the reeds at the same time but I doubt this is your problem. The carb' mixture adjustment you are at is about right. Is the float height correct? I'd be inclined to check these simpler things before embarking on a drastic engine overhaul.

What's the betting that Jack Burnicle attributes Raga's win in wet conditions to the fact he contested the British Trials Championship a dozen or so years ago?

If you don't like the chisel approach to remove those that won't budge use a hacksaw to cut a slot for a regular screwdriver. You'll be throwing them all away anyway as the later hex bolt replacements are much better.

If the oil is white and milky its been contaminated by water and the most likely souce is the water pump seal which should be changed. The crankshaft main bearings are fed with oil from the gearbox and if the crank seals are 'shot' the motor could be sucking in oil and water. Badly worn crank seals will also reduce power. Changing crank seals is probably beyond your capabilities but changing the 'O' rings between head and barrel is straight forward. Drain the coolant and undo the allen bolts securing the cylinder head. Lift off the head, retrieve the old 'o' rings and clean the faces of the head and barrel. Apply a smear of grease to the grooves in the head to help hold the new 'o' rings in place and refit the head using new copper washers (if fitted) under the allen bolts. A search of this forum will confirm the correct torque setting which I think is about 14 foot pounds. Take a look inside the barrel while the head is off for scoring, seizure or wear. Alternatively, and before you spend any money take the bike to someone like Robin Martin who should be able to diagnose the problem by listening to the motor and give definitive advice.

You need to listen to Mr Shannon. White smoke is caused by the motor trying to burn coolant with the petrol/air mixture. The most likely cause of this is that the rubber 'O' rings between the cylinder barrel and cylinder head have failed and need to be replaced. This will make the motor run hot and could result in a piston siezure if you keep using it like it is.

I'd be inclined to set the rear up with just a hint of static sag (say 5 - 10mm of movement before the wheel leaves the ground when you lift the back of the bike) and then see if the suspension compresses evenly when you adopt a riding position and bounce on the pegs. Your weight should be fine for the standard springs. Are you saying its too soft or have you just become concerned after reading a technical article? Its all a matter of personal preference at the end of the day.

Mike Yiend took some excellent photo's. You can view his gallery HERE

Thanks to everyone who supported this trial, we hope you all had an enjoyable day. See here for RESULTS

Does this help you? Renthal

Cheltenham Spa Scrambles Club are organising a club trial on 14th August, in aid of Gloucestershire Air Ambulance. Three laps of 14 sections with multi-route choices suitable for all grades of riders and solo machine classes. Enter on the day. For more info' see CSSC regs

Its mostly a matter of personal preference but from what you describe it sounds like the spring rates are matched front to rear but the shock itself could do with an overhaul, unless you're happy with it as it is? That's the good thing with the Ohlins,its fully rebuildable and a dose of fresh oil and a re-charge of gas will probably be all it needs and give it a new lease on life. Good time to renew the seals too. Not a DIY job though.

The only real problem with having the shock body at the bottom is it increases inertia in the suspension, but having said that I doubt you'll notice a difference and Sherco have used shocks that way in the past and maybe still do? To use the shock as intended but with a different (parallel sided) spring you'll need to turn a new slotted collar or spring retainer which is thicker to raise the bottom of the spring so it clears the linkage as it moves.