Framebreather barrell & piston upgrade

[Burton Comet]

Hi folks,

I'm looking to upgrade my barrell and piston on my Series 1 Framebreather however I have the original short barrell / piston set up / crank. Would I just be able to "plug and play" a cylinder kit (looking at the Gori Replica kit) or would I need a new crank too. I'm trying to keep it as standard as possible but it's time to bite the bullet and get some extra performance.

Cheers all

Wayne

[petemaisey]

The crank if original will have a small end bush rather than a roller bearing. These can be replaced if you have a reamer tool.
The crank flywheel side bearing is lubricated by the petrol/oil mix.
These two items were changed on later Li's due to wear problems on the more powerful engine. For that reason it would be a good idea to change your 55 year old crank and flywheel housing now, rather waiting for problems later.

Pete

[Nobby]

Yeah I went thru the same as you- needed to improve the performance of my framebreather but really wanted to keep it as original as poss keeping as much of the engine as it should be
viewtopic.php?f=19&t=664
(White/blue breather)


But!..... For reliability You really do have to change the crank- it's brass little end and poor bigend quality really wouldn't last very long at kind of revs and modern kit does... I also found no one does a oil/petrol fed bearing crank upgrade so not only did I have to upgrade the crank (I went for an Italian MEC) but also had to fit a new maghousing!... And obviously new gp main bearings and really because of the unreliable s1/2 four pole stata ( the coils come loose and jam the flywheel) I also upgraded to a gp stata/ flywheel to.
So in the end it was new topend, crank, maghousing, bearings, stata, flywheel, carb, exhaust!... And also different sprockets ( and chain) of course and upgraded clutch (5 plate) and springs !,
However the gearbox, clutch spider, layshaft etc I kept!
You may want to change the chaincase to... Which are weak around the kickstart shaft when you have have more compression!, I fitted a spanish s2 one

[Burton Comet]

Cheers Pete & Nobby for your replies, Food for thought!!