air leak?

[dubster]

Hi all,

Noticed recently that my left hand BBS is almost completely screwed in (about half turn out) in order to maintain normal rpm/thrrottle balance.

Have tightened all the tubes around throttle bodies and checked seating of air filter... anything else I should be looking at?

Also noticed same side (L) cylinder causes mercury in carbtune to bounce up and down - not sure if it's related, am thinking pushrod(s) as it's making a proper racket (?)

Any pearls of wisdom from the collective? Thanks

1150GSA single plug

 

[Smug]

Try squirting some brake cleaner at the inlet areas when the bike is idling and the revs will go up if you find a leak.

 

[Slipperyeel]

Just a thought, did you check the little rubber caps under the throttle bodies - the outlets for connecting vacuum gauges - not sure if these were part of your check...

 

[Steptoe]

Also noticed same side (L) cylinder causes mercury in carbtune to bounce up and down - not sure if it's related, am thinking pushrod(s) as it's making a proper racket (?)

Any pearls of wisdom from the collective? Thanks

1150GSA single plug

Just a thought, did you check the little rubber caps under the throttle bodies - the outlets for connecting vacuum gauges - not sure if these were part of your check...

I'd assume that having connected his mercury gauges he'd have noticed anything untoward concerning the rubber caps.

 

[dubster]

Yep, caps in place. Am off to the garage to try the brake cleaner trick...

 

[Steptoe]

Do you have any slack in the lefthand cable... if it's too tight it'll be controlling the idle rather than the idle control/BBS.

 

[dubster]

Do you have any slack in the lefthand cable... if it's too tight it'll be controlling the idle rather than the idle control/BBS.

Hi Neil, that was my initial thought, but there's play in the cable.

Also couldn't find anything obvious with the brake cleaner. Bike is running fine, just worried it might be indicative of a problem further along the road, so to speak.

 

[Smug]

Have you done a compression check?

 

[Two wheels good]

Could that racket be play in butterfly shaft? A constant ticking at idle? Apply pressure to cable pulley to check.
If so, you probably have an air leak at the shaft. Refurb kits are available.
Otherwise maybe the o-ring on the brass screw. Remove and clean airway with cotton buds. Remove vacuum take-off bung when spraying carb cleaner.
Other causes of racket could be cam-chain tensioner - esp. on LH side - or guide.

 

[dubster]

Don't have the kit for a compression test unfortunately.

I did clean the TBs and brass screws but there's some play in the TB shaft, will order a rebuild kit and see if that helps the situation

The rattling seems to be coming from inside the head, as i've done the tensioner upgrade that makes me think it must be a failed pushrod (?). Will open her up when I get the chance, probably at the weekend...