9.5.1 or 10.5.1 on 883-1200 conversion? New cylinders, or bore-out?

Hello all

Planning to convert my '05 883C to 1200. My local indie shop is suggesting a 10.5.1 compression, and that boring original cylinders is best - but I've also heard elsewhere that you can get a tighter seal between the rings and cylinder wall by using oversize barrels, 'cos there is more liner. Is there any truth in this, and does it actually make any noticeable difference? Also, what performance and reliability difference would you get between 9.5.1 and 10.5.1compression?

I would be interested in hearing general views and practical experiences.

Cheers all

Pat

[girlyglide]

Originally Posted by Pat

Hello all

Planning to convert my '05 883C to 1200. My local indie shop is suggesting a 10.5.1 compression, and that boring original cylinders is best - but I've also heard elsewhere that you can get a tighter seal between the rings and cylinder wall by using oversize barrels, 'cos there is more liner. Is there any truth in this, and does it actually make any noticeable difference? Also, what performance and reliability difference would you get between 9.5.1 and 10.5.1compression?

I would be interested in hearing general views and practical experiences.

Cheers all

Pat

Hi Pat
When boring cylinders to fit new pistons (of any size) you can set the ring gap and fit as you like (although we would always follow the manufacturers recommended fit and ring gap). Your comment about using oversize cylinders to obtain a tighter seal does not hold true.

Compression ratios by themselves are pretty meaningless. You have to conside the whole engine and what you want to achieve with the changes when deciding what ratio to go for.

Cool, thanks 4 the reply guys.
I'm not planning bigger valves, or a hotter cam - just want to release that extra 20hp or so without compromising reliability.
Thanks again
Pat

I recently had a weisco 883- 1200 conversion done and after 400 miles no leaks with the barrels being bored out. 10.5 compression ratio. I did have a suspicion that the engine was pinking on part throttle but the noise seems to go when the engine is hot. I took it back to the dealer and he tested it and said its not pinking, and certainly the plugs are a lovely light brown colour and also I would have thought pinking would have got worse when hot.
The performance difference is very noticeable much much faster through the rev range. I didnt change the cams or heads either. I suspect noise may be exhaust heat shields resonating.
I'm thinking of selling the bike and packing up however as I've had a few near misses recently and have lost my nerve a bit

[Rodders]

Dont sell it. Get straight back on.

Cheers Buddy ,
I've just been having a difficult patch with the bike with drivers so agressive now and the roads so poor in places.
I've been riding since the 70's and put the bike up for sale cause i've had a couple of nasty near misses recently when I've been riding carefully. The pot holes in the roads where i ride in southampton are terrible and you go into a round about carefully and you've got a 4x4 or People carrier right up your chuff. The bike feels so unsettled with the bumps and lumps. New Forest riders will know this from the Dock Gate 20 roundabout. Every side road I go past there seems to be a car driver rushing up trying to pull out in front of you.
I used to love riding, the freedom, the wind through you, the sound of the bike. Now I just dont know what to do

[Gypsy]

Keep at it me old mate ,just got to get away from the loonies in town ,get yourself on a little ride out thru new forest ,make your own speed ,dont let others push ya the more u worry the worse it gets ,most of us get fed up but on a nice day you cant beat a ride out anywhere ,,,take it easy may even catch ya about sometime

[Rodders]

I have been knocked off twice in the past year. Wanted to sell it but got back on.

Find your own space on the road and keep it. Its you space not the cars. It all goes wrong when you go out of your space like I did and had an argument with a car. They always win.

I still argue with cars but I'm young and stupid.

I'll try and stick with it for a while, unless someone buys my bike. I love my Harley , its not perfect but its full of character, its kinda vintage.
driving through the New Forest at 50 mph is just heaven.
I've got so upset recently. Every ride seemed a nightmare
Revenge is sweet however I show no mercy to 4x4 or People carriers in my Clio 182.
Back to topic the conversion certainly gives a very useful bit of extra stonk

[Rodders]

182 ?. Bore it out to a 192 . I have a MK1 MR2. And 32. Too many 2's.