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Cheers guys, first I will try a little gentle persuasion!

In fact I even quoted for a gasket you won't need, so it'll be

Cost me

Easiest thing to do is just do a top end swap. Send off your old barrel and they will send you back a nice newly nicosil coated barrel with matching piston and necessary bits. Sandifords will do it but I got mine from Feetup Trialsport near scarborough. Not sure about Sandifords but Feetup just add a tenner on from what it costs them to cover the cost of keeping it in stock. Otherwise you will need to buy a new piston and send it and the barrel off to Langcourts to be coated and matched. I wouldn't change a piston without getting the barrel relined. Sandifords and Feetup both offer spot on service. EDIT: In answer to your original question my piston also didn't have a normal code on it. Both sandifords and feetup didn't seem to worry about it they just swap the whole thing over. After mine was done its tight as anything, well worth the money. What condition is the cylinder? Any scoring or dark lines? Can you still see the crosshatch honing?

It's 8Nm for both.

I'd change (or clean if I'm hard up) the spark plug and clean the air filter. If the spark plug is sooty then your problem is running too rich and fouling the plug over time. After that I'd disassemble and clean the carb ensuring the choke circuit is all clean. And then it gets trickier, low compression will cause hard starting ie. worn top end. How's the engine? Any tapping? An electrical problem could cause a weak spark giving starting problems. Difficult to diagnose, check resistances with a multimeter on the coil - Primary - 0.45 - 0.55 ohms across the two terminals, secondary 12.4 - 16.8 kilo ohms across one of the coil terminals to inside the plug cap And the alternator - Across the connectors Function----------Wire Colours--------------------Resistance Ignition Pulse----Blue/Yellow to Green/White---90 - 110 Ohms Charging Coil----Yellow to Yellow----------------0.64 - 0.79 Ohms Exciter Coil-------Blue to White-------------------10.8 - 13.2 Ohms Info is taken from the 2002 manual but should be similar. Hopefully you'll find the problem before you get to measuring resistances!! Hope this helps. John.

Mine was a swine to do as well. It took a lot of rubber mallet action to get it freed up. Once I had got a crack to appear between the cylinder and crankcase I put a screwdriver in, not as a wedge but as a lever and then malleted the opposite side. Not sure how clever an idea this was but it worked. I had one corner that was particularly stuck. I like the plasticine idea!

Nice one cheers!

Managed to have my first breakage this evening and I need a new front brake lever. I can't find any online that either seem to be specifically for the 315 or for the Grimeca Master cylinder. Can I just order any old lever or do I need to get in touch with sandifords for a proper one? Ta.

Sounds exactly like what I am planning to do. Pictures would be great, thanks!

Has anyone modded the rear brake lever on their TY mono to make it more accessible? I never noticed how tucked away it is until I started riding a Montesa as well. Was thinking of cutting it and welding on a piece of metal or something from another brake pedal to extend it out half an inch or so. What do you reckon?

Nice, cheers for the advice! I actually heard about a guy who had a full rebuild done at no expense spared, it still tapped on the overrun apparently! Good old TY's!

Cheers Billy, I checked out jet sizes but in the end just took the head off. Piston and cylinder were knackered, swapped them over today and she's running tight as a nut!

Yep, fitted and its fine. Simple job too.

Just bought a '99 315 cheaply with the intention of getting it sorted out. The bike in general seems good but at idle and low revs the top end has a metalic tapping noise. Give it some beans and it goes away, sounds spot on in fact. In general it sounds very quiet, no whirring or anything just an annoying tap! I've got super unleaded, 80:1 mix, new air filter, new plug, cleaned ehaust, cleaned carb and its still the same so next will be head off Strange thing is the guy reckoned it had had head work done recently and this is 'sort of' backed up by obviously recent gaskets. I'm hoping it might just be the top end bearing that needs doing, what do you reckon? Where is the best place in the UK to buy parts? I figure worst case I'm going to need a piston kit and a nikosil lining.

Its 1 and a half at standard according to the manual I downloaded.

I'm not sure if this will apply to your daughter but the university I've being studying at put me onto some deal with Microsoft to get the full Office package for about

White powdery residue ey? Not being doing any border crossing recently have you? Sounds the like stuff I find on inside of my bikes carbs when they've been stood for a while. I used to solve it by turning off the fuel and running till the carb was dry before I left them but this was on 4 strokes and I'm not sure how sensible this would be to do on a 2 stroke due to lubrication. I'm also using unleaded if this has any bearing on anything.

Thanks for that, I'm off to pick one up on wednesday that apparently has the same problem. I might give Haven a ring tomorrow in readiness!

Thats too much money in my book. My mate got an '05 for

I'm afraid I don't know the exact size but I made one that works fine on most forks by welding the tip of a wide (about 10mm) flat head screwdriver onto the end of some re-bar. Its a bit cowboy I know but just jam it in and it works fine. To date its done - FZR, GSX, TY, Scorpa Easy, and XV forks without a problem.

It's not bad at all, its quiet when its cold but starts to tap a bit as it warms up. I do have feeler gauges, slip them down the barrel after I've take the head off?

I'm shortly getting the top end done on my TY 250 Mono. Its currently on a .25 oversize piston and I've had two opinions on where to go next. One guy reckoned moving up to a .50 would be fine but another said I would need to go to at least .75 to make sure it was over any previous wear. Does anyone have experience or any recommendations they would like to share? Ta.

That airbox certainly looks interesting! Some kind of trick japanese aftermarket piece of kit maybe? I'm 90% sure my bike is an 'S' but yours has the kick stand on the other side which confuses me. Also looks like you have the later rear shock which I don't. Best idea is to give Yamaha a ring on tuesday!

Pics would still be nice!