canada280i

Rushed home from work.....put it back together.....fired up first time......purring like a kitten!

Okay, so I could not wait until Sunday, I ripped into the new piston job today. All tolx it took about one and a half hours to get the barrel off, piston, bearing, rings etc. removed and new ones installed. Tope end bearing was definitely a little on the worn side and there was definite movement so I am glad I did the job. The actual piston was in pretty good condition overall, but i had the new one so in it went. With the head back on there does seem to be a noticable increase in resistance when moving the kickstarter and the piston moves very smoothly in the barrel so hopefully this will mean a sharper tighter engine. While I had evrything apart I also took the opportunity to re-tape all the loose wires and make sure everything was nice and tidy. I also gave the radiator a good wipe over and also ran some silicone sealer over the wires that go into the back of the fan motor to offer a little protection. Hopefully I manage to get evrything back together over the weekend and that it then starts and runs with no more rattle! Big thanks to all who offered advice on this, it is much appreciated. Big thanks also to my wife who got me some Harveys half way through gthe job tonight....kept me going!

Thanks Outlaw Dave, I haven't checked with Don yet (even though I ordered some parts from him yesterday...damn!)as I only noticed it was damaged last night...I was looking for a quick fix so I could hopefully ride on Sunday to get her run in. If there is no other way around it I will contact Don on Monday and order the bit. Thanks to all for the replies, very helpful!

Thanks Sherco29, before I order one do you know if one can be made or do I realy need the correct piece -the reason I ask is that to order one will take likely a week to get to me here in Canada and I was hoping to get it fixed and back together this weekend

Okay,so I have started the big strip down to replace the piston, when I removed the exhaust front pipe there wsa what appeared to be a crush washer that was mangled a little in the port, when I pulled it out it came out like a spiral as if it was wound in place. It is now knackered but I cannot seem to see the part number on the parts list. So the question is, is it really necessary tohave this type of crush washer, or can I fashion a seal washer myself from gasket material? anyone got any advice!

Subanator, I am not going to disagree with you as I do not know for sure. I was basing it on how my pegs look, the actual peg looks to be set at about 45 degrees to the mounting plate that attaches to the bike, however, when the plate is then attached to the bike the angle is changed, but that angle is only changed because the plate mounts to the frame at an angle...difficult to express properly in words!

Basher, I believe the optimum angle would be 45 degrees to allow a smooth upward and backward motion

My confidence is growing that I can do this! I have already briefed the wife that I will be "unavailable" this Sunday

Hey Chewy, are you suggesting that I leave the head attached and just remove th barrel and head as one piece? I hadn't thought of that, will the head and barrel come offas one without removing the engine?

Hi Dombush, thanks for the response. When I bought the bike it came with a spare piston kit so I wonder if the previous owner was thinking of doing it but never got around to it. I would hate to strip it down and put the new piston in only to then find it still has the rattle at idle.I think I was just trying to avoid having to take the head and barrel off, but I may have to bite the bullet and do it while I have the spare kit. many thanks!

Hi all: I also have a question regarding possible piston slap that I hope someone here can help me with. I have a 98 Montesa 315r purchased late in 2010. The bike runs perfect and has plenty of power for me, however at tick-over there is a noticable slight rattle which of course dissapears when the revs increase. I have read elswhere in these forums that some people say this is normal and okay, and other say replace the piston etc. I have removed the front exhaust pipe and when i stick my finger on the piston through the port it feels like I can move (rotate)it slightly from side to side, almost like it has a little play on the bearing. Does anyone know if the top end bearings have a little play in them or woudl this be the cause of the rattle and therefore require the new piston/bearing etc. When i look through the port the piston appears in quite good condition, as do the rings and the cyliner bore. Any advice would be greatly appreciated.

I believe I have a similar issue with my 98 315r (purchased late 2010)as you have described. I have been holding off replacing my piston as the bike still seems to still run okay. My question is, should I do the top end sooner rather than later, and if I wait am I just making things worse in the long run?

Hi there, I am new to this forum and just getting back into trials after 20 years away. I own a 315r and have the same kickstart issue as described above and would like to possibly try this mod to see if it cures my kicker. Does anyone have copies of the actual pictures that they can re-post so I can actually see the procedure? Any help is appreciated!