Rebor

[freddyz1r]

IF it was needed, surely you'd be better having it re-bored (by a reputable company) than starting with new sleeves ?
The cheapest option IF needed is to get a replacement, second hand barrel (you must check the condition and are you ever certain, until you've re-built?)
Just a few options for you wayne
cheers freddy

[Wayne1960]

Freddy thanks for that it's all about originality to be honest and the clean of the engine which from the outside all looks the same. If I get replacements I will have to get the parts re cleaned by Steve Smethurst and so on. New sleeves feel like the easiest option and I can keep the engine 903cc as original.
Thanks for the options though it all helps.

So what is the answer on compression if it's all good? The engine will still smoke.

[z1bman]

have you had the valve guides replaced? the liners from web bike would most likely need to be bored out anyway when they have been installed into the cylinders as most liners i have fitted are rough & are bored to suit each individual piston bear in mind £30 each cylinder to re bore this option is going to cost you £380 + the cylinder will need to be skimmed once the liners have been installed. is yours on standard bore? z1 enterprises have genuine piston set 66.5 mm 1st oversize at $339 & ring set at $165. they have a complete kit not genuine that includes pistons rings gudgeon pins & cir clips for $265. if you are on maximum bore you either have to get another cylinder on standard bore or get a big bore kit

[Wayne1960]

I think it's on standard bore and has never been re bored. When I strip the engine I will have the valve guides replaced.

[buzzard]

Wayne, I did say it would smoke and I advised you it would need a rebore. If you remember number 2 cylinder had damage to bore from the metal F.O.D incident, also number 1 cylinder had a bad score along the length of the bore and number 4 cylinder had a bad rust/ water stain mark aswell. You need to rebore to 0.50 mm oversize pistons and if your doing that the guides which were badly worn as I pointed out at the time will also need replacing, because it will smoke from there especially when you start it from cold after the bike has been standing for a few days and it will only get worse. Personally myself I'd bore it out to 1015cc. Buzzard.

[Pigford]

Wise words from Buzzard.

A 1015 Wiseco is a good move, cheapert than standard & nice little power increase - still looks same from outside, just needs a rebore

[chrisu]

Wayne, I did say it would smoke and I advised you it would need a rebore. If you remember number 2 cylinder had damage to bore from the metal F.O.D incident, also number 1 cylinder had a bad score along the length of the bore and number 4 cylinder had a bad rust/ water stain mark aswell. You need to rebore to 0.50 mm oversize pistons and if your doing that the guides which were badly worn as I pointed out at the time will also need replacing, because it will smoke from there especially when you start it from cold after the bike has been standing for a few days and it will only get worse. Personally myself I'd bore it out to 1015cc. Buzzard.

This is the right answer................

[Wayne1960]

Hi I thought I posted a reply yesterday. Checked the compression.
1 = 9 and smokes
2 = 7 and smokes
3 = 7 no smoke
4 = 8.5 no smoke
!!!!!!

[z1bman]

take on board what buzzard has said someone who has good knowledge in re building an engine. forget what the compressions are unless you rectify the problems buzzard has highlighted / scoring in the cylinders / corrosion marks / worn valve guides your bike will still smoke. so the only answer is re bore & fit new valve guides & seals