Author Topic: carb help  (Read 1701 times)

MIKE550/4

  • Guest
carb help
« on: October 17, 2009, 11:42:57 AM »
hi

I am cleaning the carbs on my 550 k3 78, have a couple of questions on the carbs, the bike when i got it had "pod filters " on it , although in the box of spares which came with bike was the original  air filter box with good airbox to carb rubbers, and new air filter in box plus all mounting bolts

so my question  why do you convert to pods ( whats the advantage more power ? )

secondly i would like to revert back to the airbox, i have read a bit on jetting but not really fully understanding this point, would the previous owner had have to change the jets for the pods,

would i have to do anything to the carbs apart from cleaning to go back to stock airbox

thanks  mike

Offline Spitfire

  • SOHC Master
  • Posts: 1769
    • View Profile
Re: carb help
« Reply #1 on: October 17, 2009, 02:48:02 PM »
Hi Mike, from what I can understand the pods will restrict air flow through the carb less than the stock airbox/filter combination (plus there is the "looks" effect), hence you get more air into the carb, this requires the carbs to be adjusted, this could be larger jets or changed needle position, or both. You will have to check to be sure, I don't know anything about the 550 so cannot advise on stock jetting. It will also depend on the exhaust system fitted to the bike, the less restrictive the exhaust the more airflow, the more fuel is required, though unless your exhaust is wildly noisy I would think that stock jets would suffice.

Cheers

Den
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline matthewmosse

  • SOHC Master
  • Posts: 2161
    • View Profile
Re: carb help
« Reply #2 on: October 17, 2009, 06:04:36 PM »
I'd geuss that the po had richened the mixture a tad somehow unless winter mornings were'nt his thing - I tried using aftermarkett filters once just to test the engine that I'd sourced from ebay properly without the grief of fitting that swine of an airbox back in. Anyways, result seemed to be poor low down power and appaling starting preformance - particualy from cold, in my case it was running my Lazer system plus a Motad Neta was also tried to mutch the same effect. That said there's no saying what might have been done to re jett my carbs in the past, they gave pretty good economy I know that, when the 550k3 was stock bar the motad pipes it returned over 60mpg on the motorways and A roads accross from Fort William to Edingbourough and on to Glasgow and had my mates Superdream utterly whipped for fuel economy that time. I'd try running the jetting as is, I recon and see how she goes, just drop the float bowls and give a clean if needed whilst the carbs are off. I could look as I think there might be a set of k3 carbs in the shed but there is no garuntee that they'd be correctly jetted.
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

MIKE550/4

  • Guest
Re: carb help
« Reply #3 on: October 17, 2009, 09:34:48 PM »
thanks for replies

i should have also mentioned the bike did have original 4 into 4 exhausts, which are now like dust inside, so will have to be going down the 4 into 1 route, a shame as the pipes look fine but baffles look kaput

so to update will be going down the route with standard airbox and 4 into 1 exhaust

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal