How much dmage

[sydduckett]

Coming home tonight and scooter was running rough, not pulling as it should. Changed down from 4th to 3rd and as i went to open the throttle there was a sort of pop as opposed to a bang and the engine just died...

Onto the hard shoulder, hardly any compression, can push down with hand easly... Anyways the 2 mile push home in the only rain we have had here for 2 months had me running through possible causes. Obvious one i guess is a holed piston and maybe more damage. Im really hoping its only piston damage as its an rb and i thhink its about £250 to get them re-lined...
Funny thing is the base gasket was replaced only a week ago and all nuts washers replaced and re-tourqed to the correct tightness. Checked the head, piston barrel and the rings and all seemed fine. In hindsight after doing this it didnt run as well and the power was dropping off and i was chasing the revs, like i was riding into a strong wind or uphill..

Will have a look and see whats what tom, looks as though i will going to the parts fair after all....

[bazman]

Dropped ring peg ?
Hope not as that will ruin your whole top end !
I should know !!!!!!

[#1GP200]

Exactly the same thing happened to me recently, the same symptoms, even pushed it home in the rain too.
Thought it was a holed piston but after investigation it turned out that the spark plug worked loose and
popped out. Hopefully thats all thats happened to you.

[Andy Pickering]

Youve been tinkering with jetting lately sef so hopefully just a holed piston and not complete kit fecked..what colour is the plug..?

[carlos fandango]

Could be the crank.
My RB20 big end went on the way back from the iow (AF crank) they replaced it with a rebuilt SIL crank and that went in france on the way to cobblesoul. mind you i was trying to keep up with Eden on both occasions so its his fault
When the first one went it shot the cage up the transfers and fooked the lot up but the engine would turn over, easily. when the second one went it was locked solid. but the barrel and piston was not damaged.
Ill be interested to know if yours is the crank ? what crank it is ? and if there are alot more RB big end issues?
I hope you damage is limited, but theres only one way to find out?
Russ

[sydduckett]

To be honest by the time i had got home a combination wearing my lid and leathers for an hour pushing a scooter i was knackered, scarfed a quick pastie and was then handed the little un to feed. Cant face looking at it tonight. Spoke to Twinny and he will pop over at some point so we can open her up and see whats what.

Oh how i hope it is the plug....lol

The crank from memory is a taffspeed one which i believe is an uprated indian jobby..I have given the kit a fair ahmmering to be fair and smash the arse out of it when ever i can so i cant really moan i guess. I have given up on speedos so have no idea of how many miles iv done on it but its between 4 and 6 thou i guess.

Ill post some pics tomorrow and we can all have a stab at prob causes. If the lots gone then i may well take it down to Jb to get it lined and ask him to do some porting and polishing whilst he at it. Iv thought about getting her tuned so may as well do it at the same time. Quite how im going to hide the bill from she who must be obeyed is another matter...

[sydduckett]

Exactly the same thing happened to me recently, the same symptoms, even pushed it home in the rain too.
Thought it was a holed piston but after investigation it turned out that the spark plug worked loose and
popped out. Hopefully thats all thats happened to you.

Panic over, just been out to the garage and checked the plug. same as you plug had jumped straight out. Looks abit knackered so will swap for a new one tomorrow and see how it goes.

Could have done it at side of road and saved myself a hernia...

[Bilko]

Happy days! No put your wallet away!

[Andy Pickering]

Sweet great news..

[mac]

At least you'll sleep well tonight