dang2407

My 2004 250 Rev3 used to start on the first or second kick. I since rode it back in November and it took 7 or 8 kicks to get it going from cold. I didn't think much of it at the time, but when I came to ride it in early Jan, it wouldn't start. Changed the spark plug and it started. Then, tried to fire it up last weekend and it would not start at all: changed plug, drained float bowl, blew out jets... nothing. Plug sparks when I kicj it over with the plug out. Any suggestions on what else to look at?

Getting back to the crank speed/position measurement, a multitooth (somewhere between 4 and 20 teeth) trigger wheel with an inductive pickup will do the job. As trials engines don't reve very high, you don't need much proccessing power to measure the trigger pulses. You could make something using a Pic (Microchip.COM) or similar.

Build-up of carbon on the piston (or head) is bad in 2 ways: 1) It increases compression (it could be a good thing if you wanted that...) 2) The carbon is likely to get hotter than the piston itself and glow red-hot. This can ignite the mixture before the spark-plug fires, causing pre-ignition or detonation. So, it would be a good idea to clean up the piston and head if you are chasing a pinking/detonation problem, but like the other post said, make sure your carb settings are right for your altitude and your fuel is fresh first ... because it's cheaper and easier before getting into engine dismantling...

Take the springy bit inside the tyre valve out when inflating the new tyre for the first time. This will help push the bead out. You'll need a compressor with 4+bar though - a foot pump won't do it....

The middle silencer has an effect on quitening the bike down. When I repacked mine it was significantly quieter.

The packing is wire wool. I cut mine open, removed the wool which was absolutely caked with gunk, replaced it with new wire wool and re-welded the ali skin.

Chewy, what you need is the spring constant in N/mm. You're nearly there, if you put 1 kg on top of the spring and it moves 1mm, the spring constant is 9.81N/mm. So 80% of that is 7.8 N/mm, which is what you need to ask them to make!

Result!! Heated up the swingarm area around the bolt to about 80

He said apply lots of heat didn't he ...!?

Thanks for all the tips. I'm going to try penetrating oil (cos it can't harm it) and as well as heat. Will let you know how I get on....

Any good ideas on how to remove the lower bolt from the rear shock mount? It appears to be seized as I cant budge the allen key end.

Thanks Dan, my neighbours are all a darker shade of green now! Just to add to this, it's very important to pay careful attention to the free play in the clutch lever. Adjusting it to the minimum slack you can get away with, means more separation of the clutch plates when it is pulled in.

Err, my quick answwer is No. Unless your engine is tuned for it, the extra octane rating makes no difference. The calorific value of the fuel is nearly identical and not worth the extra 10% in cost.

Regarding the noise, I found that my centre silencer was proper gummed up, so re-packing just the tail pipe didn't make it quiet enough. Unfortunately the centre part needs cutting and welding, so it's not straight forward to do - you'll need access to an aluminium welder...