sirdabalot

Presuming your air/fuel mixture is perfect at sea level. You can try adjusting the pilot air screw, in for richer out for weaker. Higher altitude usualy needs the screw to be turned in up to one turn. Beta Evo air screws are tricky to get at and I fitted a flexible adjuster, from Beta, to enable on the trail adjustments. A bit of trial and error will be needed. One thing that adds to the issue, is that cooler air is denser than warm, which would tend to make the mixture weaker, but as a rule of thumb, I always try richer first to reduce risk of engine damage

I think lowbrow got the description spot on. The Dellorto ran richer than the keihin at small throttle openings, which gave the engine a bit more chug and less likely to stall. Dare say a keihin could be set the same. But the keihin runs clean all the way up. I hear more complaints from people at trials about keihin adjustment and reliability though. I've had bother with neither but always use an in line filter and finger/thumb mixture screws.

Does the needle jet extension not have a half section cut out across the diameter, which should be positioned towards the airflow.

Depending on year/master cylinder type, some used to have a poor finish to the master cylinder bore ports, the rough edge would cut the seal, the fluid would by pass the seal so would not build pressure, there would also be no leaks externally. I've had a few occasions after dropping a bike the brake or clutch become inoperative due to me pulling either lever when picking the bike up, this was because the fluid was below the inlet port so only gulped air into the system.

If you manage the obstacle described without covering the brake, carry on that way. Covering or lightly dragging the rear brake is sometimes beneficial, but for me it isn't required on every type of obstacle.

My friend is having a nightmare with his Sherco 290 fitted with a Kehein, running very inconsistently with intermittent rich/weak running. He said there's volumes of info on setting these up on forums. I suggested he test the Keheins aerodynamics and see how far it flies. Waiting now to see how it runs with his replacement Dellorto.

Nice bike. A lesson I learnt the hard way regarding Sherco and Beta clutches is, when parking it up till next ride, tie the clutch lever back to the handlebars. This stops the plates sticking on a cold start. I use a piece of old inner tube. This is after you have checked the system is in good order, as you have done.

If you have never ridden a trials bike before you will have enough on your plate getting used to it, rather than wondering about what type of engine is fitted. But 2 stroke 250 gets my vote.

Good move. I left it a bit late starting after trying the other bike disciplines. I think I lost the need to speed. Now after 14 years of it, I still look forward to my Sunday jaunt. Anyway there's a trial on at Ridsdale, Northumberland this Sunday, so what you waiting for, get amongst it.

I had a Pampera new in 2005. There was no manual adjustment for the clutch pushrod, but I found that the top hat bush that the clutch pressure plate radial bearing sits on, had oil between it and the pushrod, creating the effect of the pushrod being too long, which held the clutch plate to lift resulting in slip. I know, I couldn't have made it happen if I wanted to. The cure was to drill a small hole through the end of the bush or grind a groove along the pushrod to allow the oil to escape. Also ensure the master cylinder is not too full and can breath through the cap above its diaphragm. Then try pressing the top hat bush back to compress the slave cylinder, it should compress, returning the oil to the master cylinder. If it doesn't compress check the slave cylinder. Pumping the clutch lever should then jack the pushrod back out, go steady as it may push the piston out of the slave cylinder.

Sounds like you corrected the clutch plate arrangement. Wonder if the clutch assembly been fitted to its shaft correctly or has come loose in the past allowing contact with the cover. Regarding clutch slip, find out if plate thickness and spring lengths are still within spec. But first check lever free play and that there is play between the clutch slave cylinder and clutch pushrod.

Had weight on my 2014 & 2015 from new with no problem. Shaft splines engage in about 3/4 of lever spline depth. Both were clean, dry and unworn, maybe that's the reason they stay tight (I know the lever will fall off now for saying that), but the lever is nearly touching flywheel cover.

Ive seen this happen on other 2 strokes. I was in a van at traffic lights, there was an MZ motorbike in front, when the lights changed to green he tried to ride away but stalled. He restarted the bike, revved it up and accelerated backwards into the front of my van. His back mudguard and lights were damaged but he was ok. Here we go I thought, that's me stuffed, who's going to believe this, i'll be blamed for crashing into him. Luckily the bloke shook himself down, apologized saying it's happened a few times and rode off (forward this time).

Error on my part, I thought the 2013 fork tops were the same as the '14 + '15 Racing models.

I doubt it. Clean engine and search for leak. Is it oil, or is it oil/petrol mix residue from carb. Did you find out if the engine was flooded with petrol?

Fork with the drilled red ring at the top. The fork cap nut turns. Clockwise for more spring pre-load. It's a bit stiff to turn and will only screw in or out till it reaches its end stop.

Has it been parked up with petrol switched on and flooded the engine? Is the spark plug wet?

Dont be insulted when I ask you to check you are turning the nut anti clockwise. If it's started to round off, try forcing an imperial ring spanner on, or even an open ender if there's enough room, just to crack it loose. If that fails use a die or angle grinder, if there's room and carefully shave down the side of the nut till it just cuts through to the stud. The remains of the nut will now unscrew. Obviously a new nut will be needed and possibly a stud.

You didn't mention which bike. Regardless of that I've a few ring spanners that I've had to grind/relieve the profile of to get into corners. Give that a try.

Loosen Up 200ml for a poond from Wilko's, I got a year of weekly use out of a rubbish chain. Wash bike, squirt on chain, get on with life.

Have the carb floats jammed down causing flooding?

The stator was moved from the engine case to the flywheel cover, so the old type weight fixed with 2 cross head screws won't fit.

I prefer the standard 11t sprocket, using 1st in sections with a touch of clutch if needed. I found 10t too low in 1st, resulting in loss of traction on loose surfaces and 2nd too tall. I use a flywheel weight allowing the bike to crawl up hills. I noticed that seems to increase engine braking, but no other drawbacks. The keihin carb made my bike more responsive but smoother. I liked the delorto feeling that it gave more low down grunt but did not rev up as cleanly. The bikes concerned we're 2013 standard, 2014 & 2015 Racing 250s.

I had Evo 250's from 09 to 12, some frames and swinging arms cracked on 09's but mine was ok (Lampkins were replacing frames for free if they did). My '11 blew it's oil out after 3 months and was renewed without hesitation by Lampkins. Apart from that Check for usual neglect on linkage and steering bearings, wheel bearings may seize and then spin damaging the hub. Plastics are brittle too. I can't advise on the engine much, never had a 125, but same bottom end and they seem strong enough, they all develop clutch drag, making neutral selection dufficult and the plates stick, so when you park them up tie the clutch lever back, this'll stop you going out of control when you start the engine, select a gear and then find you have no clutch release.

I used to go to the indoor enduros yearly till a few years back. I never found any trials/off road shops or museums but I was not searching for them. But Barcalona is one of my favourites, plenty to see, good underground transport and I never got robbed. The last event I saw, David Knight won, you could hear a pin drop, there was only me and a few others cheering till we got the evil eyes turned on us. Great event and atmos though.