Big End Big Trouble?

[newwobbler]

hi

my 2003 beta rev 3 200 has deveolped a grating, grumbling noise from the bottom end of the engine then cuts out. am i right to suspect the big end / main bearings are shot or am i on the wrong track?

any pointers would be gratefully received.

[heaton_uk]

I have a 2003 rev-3 and changed the mains twice with the help of good mechanical minded friends. Yes they do grumple and dont stay 'tight' for very long. If you remove the flywheel cover you may notice some play in the flywheels itself by movingin it up and down. Bearings and seals arent expensive themselfs its just having the knowledge to know what you are doing. I doubt this will make the bike cut out thought. Does it cut when hot? Will it restart when cool?

[betarick]

noise on bottomn end is either crank bearings or big end! when splitting cases do the job lot that means splitting the crank as well as doing main bearings! the big end wears at the same rate as the mains! these are a easy job if you have a press and some vee blocks and dial gauges! or just send me the crank i will do it for a small price! a lot of people just do the mains and not the big end this half a job as the big end wears as well and will probaly knacker your new main bearings up!

[newwobbler]

thnks for your help, i feel the cutting out problem could be related to the piston not running in the bore properly, at least that is my theory on it as it is a stall type of cut out. could this be linked to the bottom end bearings all being shot? rick i`ll get in contact when i`ve split the cases and got the crank removed if thats ok.