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SOHC.co.uk Forums => CB500/550 => Topic started by: Honda Al on July 08, 2016, 08:22:41 AM

Title: Decreased Fuel Range :-(
Post by: Honda Al on July 08, 2016, 08:22:41 AM

Hi all,

Since fitting my repro HM323 exhausts, the fuel range has decreased. I used to get ~95 miles before switching to reserve and now only get ~75miles.

Any ideas? Alan


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Title: Re: Decreased Fuel Range :-(
Post by: florence on July 08, 2016, 08:57:27 AM

what did you have fitted before?  Maybe it's breathing properly now?

Title: Re: Decreased Fuel Range :-(
Post by: hairygit on July 08, 2016, 09:16:48 AM

Check your jet sizes, often aftermarket pipes need larger jets to run properly, if you do have bigger than standard jets, that's where your fuel is going!

Title: Re: Decreased Fuel Range :-(
Post by: Honda Al on July 08, 2016, 10:22:02 AM

Quote from: florence on July 08, 2016, 08:57:27 AM

what did you have fitted before?  Maybe it's breathing properly now?

It was a 4-2 system.


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Title: Re: Decreased Fuel Range :-(
Post by: hairygit on July 08, 2016, 10:31:09 AM

Jetting may well have been altered before you bought it, especially if it's a u.s. import, the yanks love fiddling with things for no good reason! Also, it could be down to your riding style, revving high through low gears in town etc.

Title: Re: Decreased Fuel Range :-(
Post by: Johnwebley on July 08, 2016, 11:16:28 AM

also,check your airfilter,when I changed mine it made a massive difference,and it didn't look that bad .

Title: Re: Decreased Fuel Range :-(
Post by: florence on July 08, 2016, 11:25:43 AM

+1 with the main jet, it makes a huge difference.

Title: Re: Decreased Fuel Range :-(
Post by: Honda Al on July 08, 2016, 06:14:34 PM

Thanks everyone.

What other symptoms would the bike show/have if the jets were too big?


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Title: Re: Decreased Fuel Range :-(
Post by: Johnwebley on July 08, 2016, 06:28:34 PM

sooty pipes,

  no need to use choke ,

 sluggish performance

 dark plugs

Title: Re: Decreased Fuel Range :-(
Post by: Honda Al on July 09, 2016, 06:55:24 AM

Quote from: Johnwebley on July 08, 2016, 06:28:34 PM

sooty pipes,

  no need to use choke ,

 sluggish performance

 dark plugs

Hmmm, I have all four. I'm going to investigate this weekend.


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Title: Re: Decreased Fuel Range :-(
Post by: Johnwebley on July 09, 2016, 12:00:22 PM

if you find your jets are wrong,it may be cheaper to get a set of rebuild kits from Cruzimage,

 last year,a set of 4 kits was less than £40 ,p&p included direct from japan,

they are on Ebay

Title: Re: Decreased Fuel Range :-(
Post by: Bryanj on July 10, 2016, 06:08:44 AM

Or go to Sirius in Canada and get a multi size jet "Kit"

Title: Re: Decreased Fuel Range :-(
Post by: Honda Al on July 10, 2016, 07:42:00 AM

Had a quick look yesterday and it looks like I have 100 mains with 40pilots.


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Title: Re: Decreased Fuel Range :-(
Post by: Johnwebley on July 10, 2016, 11:53:53 AM

Quote from: Honda Al on July 10, 2016, 07:42:00 AM

Had a quick look yesterday and it looks like I have 100 mains with 40pilots.


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 those are standard for (my CB500) a K2 ,not sure about US imports,
next check the ignition timing,is it getting to full advance ? try a ride without the airfilter,,see what happens