After hearing a couple of other 315's today my '97 bike seems very loud indeed with a top end rattle. I suspect its going to need a new piston but when i looked at the base of the barrel instead of seeing A, B or C all I can see is O. So now I don't know what to do.

Anybody come across this before?

Pic attached of the barrel.

Edited January 8, 201214 yr by sharkbait

After hearing a couple of other 315's today my '97 bike seems very loud indeed with a top end rattle. I suspect its going to need a new piston but when i looked at the base of the barrel instead of seeing A, B or C all I can see is O. So now I don't know what to do.

Anybody come across this before?

Pic attached of the barrel.

Have a look just a bit lower, between the barrel and reed block, iam sure its between a bunch of numbers? might need a torch, to get a proper view, did you get to frodsham?

Have a look just a bit lower, between the barrel and reed block, iam sure its between a bunch of numbers? might need a torch, to get a proper view, did you get to frodsham?

Yes mate, took my girls down - I'm def in the white class! looked good though.

Not found anything else yet but will keep looking - no idea why my pic isn't showing.

Edited January 8, 201214 yr by sharkbait

i was there mate very muddy trial but good fun

the letter you are looking for is very low down and at the back

i was there mate very muddy trial but good fun

the letter you are looking for is very low down and at the back

I'll try and get the pic to display..... No other markings on the back of the cylinder.

Ahhhh, fixed the picture

Additional pic showing no other markings!

Hope this helps.

Edited January 9, 201214 yr by sharkbait

Ahhhh, fixed the picture

Additional pic showing no other markings!

Hope this helps.

Hi bud, just been to check my bike against you first pic, and it all looks the same apart from the little sun emblum with the number in the middle, yours is a 6, and mine is a 7

mine does have the o stamped on the back of the barrel, but has the another set of numbers and a letter below the o slightly to the left of the back of the barrel,,,,? some one must be able to help you out,,(come on lads)

Hi bud, just been to check my bike against you first pic, and it all looks the same apart from the little sun emblum with the number in the middle, yours is a 6, and mine is a 7

mine does have the o stamped on the back of the barrel, but has the another set of numbers and a letter below the o slightly to the left of the back of the barrel,,,,? some one must be able to help you out,,(come on lads)

Hi Clay.

Well I've since removed the head to find Z9 on the piston. Caroline at Sandifords says put an A piston in but I've also spoken to Alan at feetup and he's been very helpful.

Basically I can put a new piston in and get a potentially short term fix or replace barrel and piston with matched items and fix it long term. He's told me to measure the ring gap and piston/cylinder clearance and report back - he will then give me my options. Ring gap is 0.015 which I think is pretty big, not done the piston clearance yet.

Not sure which way to go at the mo. Bike was cheap at

ok here goes looking from the left side

look at your second pic you need to look between the barrell nut and that little 8mm just pull the clutch hose out of the way a little you will see the numbers and a larger letter in the middle about 3 -5 mm from the crankcase stamped on the back of the barrell

i have to use a torch and a magnifying glass

Edited January 9, 201214 yr by nelly1

check you pm,

unless the barrell is damaged i would replace small end bearing and rings shouldnt cost more than

I had to do a similar fix on my 1997 315 as it was also making the "rattle". I pulled the barrel which seemed in quite good condition so didn't need any work. I replaced the piston, rings, top end bearing, pin, and clips, installed a new gasket, cleaned the inside of the head, put it all back together, second kick it fired up sounding sweet as the day the trials gods created her. ran it around the block gently for the next few days and nights to bed it in, been excellent ever since.

If you don't already have a set of boyesen reeds installed you should bite the bullet and put a set in while you have it apart....makes a hell of a difference

Edited January 10, 201214 yr by Canada315

unless the barrell is damaged i would replace small end bearing and rings shouldnt cost more than

If you don't already have a set of boyesen reeds installed you should bite the bullet and put a set in while you have it apart....makes a hell of a difference

I doubt they'd help a noob like me but what do they do?

I had to do a similar fix on my 1997 315 as it was also making the "rattle". I pulled the barrel which seemed in quite good condition so didn't need any work. I replaced the piston, rings, top end bearing, pin, and clips, installed a new gasket, cleaned the inside of the head, put it all back together, second kick it fired up sounding sweet as the day the trials gods created her. ran it around the block gently for the next few days and nights to bed it in, been excellent ever since.

If you don't already have a set of boyesen reeds installed you should bite the bullet and put a set in while you have it apart....makes a hell of a difference

can you give me details of the boyesen reeds cant find any info not even on there own site