Right carburation settings

[Red3446]

Hi guys

As I'm looking for a good carburation setting from long time and I can't reach a good setting (too lean at minimum, spluttering from carburetors and rpm that don't return immediately at idle but stay a little bit at 1500 then to idle), as you are more experienced on this engine then me, which in your opinion the right setting to start from? Consider that I have:

BMC air cleaner;
Dynojet stage 1 kt;
Only aftermarket silencers.

As I've found those parts already mounted when I bought the bike, I don't know if all Dynojet kit's parts (as jets) are on now. What is the right size of the kit's jets? What is the right setting of the pilot screw?

Thank you in advace!

[podman]

My take on this is no 2 engines are the same, especially older & older modded ones, if you truly want it "right" then a dyno set up bespoke to your engine cannot be beaten.

Its not even that expensive.

You'll probably end up with the (generic) dynojet kit junked as they can equally make things worse as much as better from my experience.

A good operator will also pick up on areas other than carburation that are causing running problems,.

[popkat]

If too lean and revs holding up then you need to turn the pilot mixture screws out to richen the mixture up a bit. The only problem there is it's pretty much impossible to do on the bike with it running, you will probably have to pop the carbs off, try going 1 turn out and see what difference that makes.

Also revs holding up can be an air leak, try spraying some brake cleaner or damp start around the inlet rubbers while the bike is running, brake cleaner will make it choke and the engine stop, damp start will make it rev up, either way if the engine speed changes you have an air leak.


Lastly has the bike been sat idle for a while, your symptom could also be blocked pilot jets caused by old fuel.


.

[jchesshyre]

...The only problem there is it's pretty much impossible to do on the bike with it running, you will probably have to pop the carbs off, try going 1 turn out and see what difference that makes.

Not at all impossible if you get one of these: http://www.carbtune.co.uk/bevel.html

£44 is quite pricey I know...but it's the only one of these I've found that actually make the job easy. The cheaper ones I've tried before were incredibly annoying for a number of reasons.

[Stephan]

from dynojet kit basically you need only needles, you can even use oem main jets. I would start with oem 2 slide holes, oem slide springs (probably you have), if you have 45 pilots then 2,25 front and 2,5 turns out, for 48 pilots 2 and 2,25, keihin main jets 178+180, dynojet needles set to G4 (4th groove from the down) and with oem washers under clips. I can imagine bigger main jets 180+182 (or DJ equivalents, they have different numbering).

Just a guess, every bike is differenst as podman said.

[VTRDark]

Not at all impossible if you get one of these: http://www.carbtune.co.uk/bevel.html

I prefer the Motion Pro as it gives more space for the rear carb.









Still bloody awkward though. The best tool is the genuine Honda one designed for the job if you can find one. Not cheap.