Baghira pilot/mixture screw settings?

[Taipan]

Hi All
Been trawling the archives for set up tips for my Baghiras carbs now I've put a BSM Vampire on it as I'm having starting troubles ( viewtopic.php?f=3&t=4196). One thing i keep coming across is that the pilot/mixture screw is often set at 5 - 5.5 turns out? That seems a huge amount for a pilot/mixture screw to be turned out to. On Mikunis after 3.5 turns you tend to up the pilot jet size. So I'm wondering why people haven't upped the jet size on these? Does this just work well enough or is jet availability an issue and its a workaround backing it out that far? Cant be much further before it falls out I would have thought?

[Anders]

Yamaha singels in general are set up a bit rich from the factory, adding a BSM exhaust should not require any re-jet or adjustment of the carb if you can accept the occational lean popping. Also 2.5 turns out on the pilot is the startingpoint I believe.

As for jets, there are not too many sizes avaliable for the carb which in part explains why there is not a lot of re-jetting going on.

[Taipan]

5 turns out on the pilot screw and she fires up straight away! Must be worth reaming out the pilot a fraction if jets aren't freely available?

[Anders]

Well I had the main jets drilled and the bike dynoed what feels like countless times before I got the stock carb to where I was happy with the performance (tuned engine with app 60bhp). I would not recommend it to anyone, its a PITA to dial in the stock carbs

5 turns out does seem excessive, at least from a Skorpion point of view. But hey whatever works works, right.

Have you tried giving the carbs a good clean?

[Taipan]

One post I found said Holeshot racing recomend 7 turns out! I didn't clean the carbs out when I had them off. As I found they were out of adjustment I just set them up correctly and refitted. I should have cleaned them as they were off I would do normally? Dunno why i didn't?? I'll run it and see how I get on with it. Thanks for the info.

[Anders]

Also check this thread out, it might be useful to you.

viewtopic.php?f=3&t=4134&start=0

[Taipan]

Also check this thread out, it might be useful to you.

viewtopic.php?f=3&t=4134&start=0

It is indeed, thanks. Shame the postage cost is so high. I think i'll make my own spacer and if the £ ever recovers against the Euro I might go for the kit if my spacer doesn't work out.

[Taipan]

Yamaha singels in general are set up a bit rich from the factory, adding a BSM exhaust should not require any re-jet or adjustment of the carb if you can accept the occational lean popping. Also 2.5 turns out on the pilot is the startingpoint I believe.

As for jets, there are not too many sizes avaliable for the carb which in part explains why there is not a lot of re-jetting going on.

Actually got it out on the road to test it today and it will not pull full throttle at all. So the needle goes back down a notch! Hopefully that will be okay as overall the BSM Vampire seems to be a vast improvement over the OEM exhaust. The bike seems to have much more grunt and is more responsive overall.

[Anders]

You know.. at full throttle the needle position does not come into play at all, see attached picture.
Its only jet size or as I suspect in this case the diaphragm swelling issue which affects 3/4 open or more.

[Taipan]

You know.. at full throttle the needle position does not come into play at all, see attached picture.
Its only jet size or as I suspect in this case the diaphragm swelling issue which affects 3/4 open or more.

Hi Anders
Maybe thats why the carb was adjusted the way it was (incorrectly), so the bike would still run full throttle as the venturi wasn't fully opening? Looks like I'd better make that spacer up this weekend!

[Anders]

Just make sure that you round off the edge facing the diaphragm a little to avoid any damage.

[Taipan]

Found I could get the carb top off to get at the diaphragm without removing the carbs. So I reset the needle and took some measurements to make a spacer up. I then noticed that the inlet stub retaining clip was actually meant to be in the really awkward position its in as its shaped to fit there. So I probably had an air leak when I moved the clip round to make it more accessible. Be interesting to test ride it tomorrow and see what effect its had putting it back where it should be.

[Taipan]

Rode the bike into work todayand its running much, much better! I now have masses of bottom end grunt like a big single should have. I do think its suffering from that diaphragm swelling though as it just doesn't feel right at the top of the rev range. I'll try and sort a spacer out at some point i think. But for now I'm happy with it.