18rg weird noise???

[lilcrash]

is it possible for a cam bucket or shim to just disinergrate while driving, there is a horrible noise coming from (im guessing) the 3rd cyl exhaust vavle, compression is 150 150 145 155, nothign feels loose. any ideas??

thank you

[lilcrash]

im people want more info, its sounds like metal banging together.

[TA23 Racer]

more imfo eg. all the time, idle, load, no load, rpm etc. the more you canb tell the more we maybe able to help.

Cheers Dave

[Silly Rabbit]

....and what classifies as a horrible noise??...is it metal on metal noise, a rattling noise, whines etc??.......I had a valve spring break on my RG and it made a sort of rattling noise but no loss of power that I could see...got it fixed pretty quick though

[jeffro ra28]

i suggest cam chain rattle.

[thechuckster]

remove rocker cover and inspect asap - you won't detect (via compression testing) a smashed bucket unless it removes the stem of the valve or the collets.

likewise, stuffed cam shain wont show up in comp test unless the chain has broken.

[lilcrash]

more info - constant metal on metal tapping smashing noise, it misses a lil bit. the chain was the first thing i checked,

my dad had a look today and it appears that the 3rd piston is moving a few mm up and down without the crank.

[jeffro ra28]

either, small end circlips have dislodged and piston pin connects with bore, small end bush has cracked and spat it out, piston skirt smashed of causing piston slap or Big end bearing totally fucked however thats more a kocking noise.

[lilcrash]

ok my dad pulled the sump off and it looks like a spun bearing, what doesnt everyone recomend to do?? can i just chuck a new set of bearings in and see how it goes or should i pull the crank out and get it all done like new??

[TA23 Racer]

You'll have to do it properly, other wise the bearing will shit not long after you get it running again.
Might be cheaper to buy a 2nd hand crank and rods than getting the old one machined.

Cheers Dave.

[lilcrash]

do i need to actually pull the rods out??? or can i just take the crank in and get it all sorted from that??

[allencr]

do i need to actually pull the rods out???

The rod with the bad bearing has a horrible surface that won't hold & crush/squeeze the new bearing in place very well, and its big end also might not be round any more from all the pounding it's received. The piston & rings & cylinder wall have had a torrent of metal bits& oil being thrown at them, doing them no good at all. The oil pump pickup screen has only prevented the pump from jamming up, not wearing out, from all the metal trash flowing into it from the bearing, rod & journal chewing each other up. The head, piston, gudgeon/wrist pin, top ring & land might be damaged if there was enough clearance to let the piston hit the head.

rebuild/resize the rod + new bolts. It will be shorter and will slightly affect that cyl's CR.
Some would throw away rather then reuse a rod & piston that have been through that extra pounding.

[jeffro ra28]

how will the rod be shorter?

[allencr]

how will the rod be shorter?

Center to center.

[lilcrash]

does anywhere still make rods and pistons for the 18rg??