andye

Well, I've found the source of the noise. I'm absolutely astonished that the crank felt so smooth when turning it over by hand, because this is the flywheel-side main bearing... I pulled the bearing cage bits out for the photo, they were all twisted up inside the bearing shell. The flywheel side crank seal looked in perfect condition (apart from the fact that it was full of bits of bearing), so I don't know if there was a specific cause of the failure. Needless to say, there are metal flakes all over the place to clean out. Here's the damaged seal on the clutch side. Nice work by the previous mechanic. With the crank and conrod in my hand, there's no up-and-down play in the conrod/big-end bearing. A fair bit of lateral play though. New mains and seals on order. Cheers all for the advice. Andy

All, Had a bit of time today to carry on with the engine. Removed the clutch, primary gear and weight and the flywheel bolt. I had a threaded flywheel extractor I thought would fit, but it doesn't, so I need to get one before I can carry on. However, did notice this - presumably the seal was fitted like this by some careless aaarse - I guess it hasn't 'prolapsed' whilst fitted. Cheers Andy

Ha ha! Thanks Boni, yes, I'm going to check that - I'm hoping(!?) to find a mashed main bearing ball - but my assumption is that it's going to be the clutch side, because the flywheel side sounds smooth (screwdriver test) and there's no play at all at the flywheel side. But I'm prepared to be surprised! Obviously the gearbox is separate, so let's hope they aren't bits of cog or dog. ;-) I'll split the cases soon and see what I find. Just need to get hold of a flywheel puller. Cheers! Andy

Hi Lee. Yes - most browsers support (and automatically play) animated GIFs. Here's what I did:1) put camera on a tripod, so it doesn't move 2) take pic 1, rod at maximum left 3) take pic 2, rod at maximum right 4) opened the pictures in Paintbrush to save them as GIFs 5) download and run UnFREEz 2.1, drag both pictures into the window, set a looped animation at 25cs 6) upload to website That's it! Here's a link to UnFREEz : http://www.whitsoftdev.com/unfreez/ Cheers Andy

Thanks Boni. I couldn't feel any up-and-down play in the conrod, but I'll have a more scientific look tonight. I need to split the cases anyway to flush all the metal flakes out, so I will order a set of mains and seals, and see if the big end feels rough at all when the crank is in my hand. Cheers

Thanks Stork, how do I measure the side clearance? Is that the clearance between the crank counterweights and the side of the conrod at the big-end end? Presumably a job for a feeler gauge?

Hi All My 2005 Rev-3 started making a noise when running recently. The noise was most obvious on the overrun, after closing the throttle from medium revs it sounded like a rumbly-grumbly noise, a bit like the engine was full of marbles. Equally, when riding, vibration could be felt through the pegs. Naturally I didn't ride the bike after that, although it would start and run - it was just noisy. Today I pulled the engine out of the bike to have a look. The piston and barrel are in good shape, and neither of the rings are broken - which is a relief. However, there are flakes of metal all over the place: Here are more pictured inside the engine: More: There is no evident play in the small end bearing, the piston doesn't rock on the conrod or seem to have any play. However, the rod does rock, apparently on the crankshaft. Is this normal? This image (which should be animated) should explain what I mean: Finally, there's no apparent play when trying to grab hold of the flywheel and move it up and down - no movement at all. When spinning the engine over by hand, there's an obvious graunching noise. So - which bearings have failed? I guess it can only be the big end bearing or the main bearings.... Any thoughts? Cheers. Andy

Hi Peter Do you know if that bush available as a part from Gas Gas? I replaced all of the dog bone bearings recently but couldn't find out if that bush was available. Otherwise, is it a job for a standard bearings-type place? Cheers Andy

Where were you today Paul? You missed a good event!

Hi Boofont I ride at Peterborough in most of their events. Their trials are usually run at Stibbington or Harringworth, Ketton is a new venue which we haven't ridden with Peterborough before. They're a very friendly bunch and quite creative with marking out the sections. Anyone there will talk to you! If you look out for someone riding the dirtiest and most poorly maintained Gas Gas there, it will be me ;-) Cheers Andy

Hi Scorpa3, is there any chance of a full copy of the results? I'm impatient when it comes to waiting for Royal Mail! Cheers Andy

Hi Jack Here it is: http://www.streetmap.co.uk/newmap.srf?x=52...p=newsearch.srf It's a nice venue - fairly large compared to most in our area. It has a good combination of terrain including mud and rocks. There's even some funny chalky stuff. Last time (in about November) it was very wet and getting to some of the sections was pretty slippery, but good fun all the same! Cheers Andy

Stu Might these be what you are looking for? Chas Lee wears some like this (all in black) http://www.bvm-moto.co.uk/images/xcting/xctingthillt.jpg Cheers Andy

Hi Jim With regard to a club trial, scrutineering can be pretty lax, and some don't have any scrutineering at all. Someone more familiar can confirm what they check but things like open-ended bar grips aren't going to be an issue. If you can get a pair of fork seals for the lad's bike it would be a good idea to change them regardless of scrutineering just so that you don't end up with fork oil all over the place (front tyre and brake being most important!) Changing the fork seals is easy. You could do the wheel bearings in 20 minutes for both wheels too. Generally people don't laugh when you fall off, they normally wince and go 'ooowwwch', most of them will have felt your pain at some point!... No need for elbow pads and knee pads (that may be more likely to get you laughed at), just wear some decent boots and a lid, the rest of your clothing can be whatever you want. Within reason... For the lad, he should have long sleeves, some clerks can be a bit funny about that. Good luck!!

Hi Stu! Good to hear from you, how is the hand? The trial today was very enjoyable! Whether it was a good plan or not I'm still undecided, but we both rode the hard route and most of the sections were possible for us, with the exception of section two; We had to cross a ditch which was two 4x4 wheel tracks, one lower than the other, but the bank the other side was almost a bike length high and the ground was clay/mud. Because of a tight turn before the drop, you can't run up and jump! Chas Lee and Olly Wareing both cleaned it once or twice (didn't see them unfortunately) but there were plenty of fives from riders going backwards down into the rut. Tony and I were not alone!! Promise! Now my questionable drawing skills to come to the fore; We both had two attempts at it, but I still can't quite see how to do this one! The other sections were challenging but rideable. I felt as though I rode well. Tony and Olly both gave me some very helpful advice. I definitely made quite a few mistakes where I know I could do better - But then, I say that after EVERY trial... With regard to Mal, it's got to be MJE! - http://www.trialscentral.com/forums/index.php?showuser=4026 Cheers!! Andy