Re jetting

[scott02464]

Thanks Carl I'll give that a whirl! Iv just been reading the info Iv got but your interpretation makes a lot more sense :-)

Yes mate I synced the carbs up before my run out. It's started raining here now so going to do the changes hopefully tomorrow weather permitting.

Even tho it's not running how I like yet Iv really enjoyed doing what Iv done!

Cheers Carl :thumb up:

[scott02464]

A bit flat = too rich

I would try a half turn ish back in on the mixture screws to lean it out first. See how it feels then. So maybe I'm guessing 2 on the front and 2 1/4 rear Also did you do a carb sync after changing things.

And if your still not happy, mains could be a bit rich. But you wont know if it's better or worse until you try.
On the mains drop down to 178 front and 180 rear. But don't do this until you have played with the mixture setting. I would be tempted to remove the 1 shim from the front carb as well.

(:-})

Deffo a step in the right direction!

Just had the carbs out, took out the extra washer in the front needle, set front mixture to 2 turns and the rear at 2 1/4 turns.

Deffo more pickup at low revs (around 3k) but still I tiny little flat spot when I crack the throttle wide open (flat for about a split second)

After the flat spot it takes off like a rocket!

Oh Iv not had chance to sync the carbs as it would be a bit anti social at this time lol!

[VTRDark]

Good stuff, You my just need to turn either one or both mixture screws a 16th of a turn in either direction. You would be surprised how such little can effect things. But you need to determine if you think it is rich or leen that is causing it. Try pulling the choke out a tad (which richens) then if it's worse then you know it's still too rich, if it's better then it's a tad lean. I suspect still a little rich.

Also make a note of how your idle behaves. As you give it a rev it should drop back down to the set idle speed with no fluctuations.

Is the flat spot at 4000? the dreaded K&N flatspot.

I'm glad things are improving for you.

(:-})

[scott02464]

I'm not 100% it was at 4k although I think that sounds about right.

Although at any revs, when I crack the throttle wide open it hesitates for a split second every time I do it?

[VTRDark]

This could be helpful

Blip test:
1. Start by warming the bike up to normal operating temperature.
2. Blip the throttle up several thousand RPM's or up to redline if you so desire.

As it comes back down to idle one of three things will happen and these are the three results:

1. Upon return to idle it hangs. Where ever it hangs in the RPM's it is running lean. Even a slight hang just before returning to idle means it is running lean at idle.(Must return directly to idle without popping,lag, or hanging).

2. Upon return to idle it goes slightly past and below idle then returns back up to idle speed momentarily. This is a rich run condition.

3. It returns directly to idle w/o any lag, hesitation, or going below idle you have a perfect a/f mixture and run condition.

Like I said I suspect it's still a little rich. So Maybe a 16th of a turn more on the mixture. I would try that first. But be prepared for maybe having to put a 178main in the front and a 180 in rear, but then your back to square 1 with the needles and pilot circuit.

(:-})

[scott02464]

Thanks mate that's very helpful ;-)

I see what you mean when you say you'll get good at whipping them out and tweaking something lol!

Is it possible to get the same amount of power with a smaller jet but a better mixture?

[VTRDark]

Is it possible to get the same amount of power with a smaller jet but a better mixture?

In short yes if not more. But it's not just a case of power but getting a smooth even balance between all three circuits. You got you top circuit (mains) then the slide/needle (mid) and the pilot circuit (low) and having the right amount of fuel to air ratio for an efficient burn. The more efficient the burn the more power and economy. You change one part of the circuit and it affects another.

(:-})

[scott02464]

I tested the bike again today but not had chance to tweak any settings today.

There's no flat spot at all at 4000rpm.

However it just doesn't feel strong below 5k, so the next chance I get I'll give it 1/8 of a turn in to lean the mixture out a bit. Wish I had one of them tools, it'll save me taking the carbs out each time! :-(

[VTRDark]

Try and determine whether it's rich or lean with the choke first. I should have my cabie tool turning up this weekend I'm getting bored of taking them of just to tweak mixture.

(:-})

[scott02464]

Wow!
I had a bit of spare time and thought sod it!

Off came the carbs. My mains feel good so I thought I'd raise the needles up more to improve the mid range.

So I whipped out the needles, shimmed the rear needle with 3mm of washers and the front with 2mm of washers.

The mixtures I left at

Front 2 turns out and rear 2 1/4 turns out.

Wow very good improvement! Still feels a tad rich at low revs but everything else feels very nice to me! Will sort the mixture out another time as I'm back to work tomorrow for 4 days :-(

There's no flat spots, apart from feeling ever so slightly flat at low revs 2-3k.

I synced the carbs this time and they were out slightly so tweaked that!

Carl I think Iv caught your bug mate lol

[lloydie]

See what you started Carl !
Every one is playing with the carps :-)

[VTRDark]

Oh well there goes my thoughts on the other post in what I done today. (just answered you post scott)

So sounds like it was too lean on the mids and not rich. Don't forget there is a slight overlap into the mains so they will be slightly richer too.

You should sync the carbs every time you remove the carbs or change something. It's also best to do them when the bike is at running temp.

Keep up the good work and have fun

(:-})

[scott02464]

So if the circuits are overlapping (rich on rich) does that mean I'm using more fuel then I need to? Even tho it feels strong?

If I was the leave the shims in place and use 178 front & 180 rear would this be a smarter move?

I thought i was on the right track until you mentioned the overlapping ha

Apologise for the questions I have 'L' plates on me carbs

[VTRDark]

So if the circuits are overlapping (rich on rich)

Cant be bothered drawing a diagram but it like the following ===================================
ignore this bit it's here and here and here =========================hope that makes sense, so they overlap then tail off.
I had to put the ignore bit in because the forum php script wont allow multiple spaces

does that mean I'm using more fuel then I need to?

whenever yo make anything richer it's adding fuel but as long as it the right balance of fuel and air you will get a better burn so more efficiency, so this is where the power comes from which you feel.

If I was the leave the shims in place and use 178 front & 180

Possibly but if it feels right then go with it for now.

As you can tell from my post I'm tired now gont too my head.

(:-})

[benny hedges]

feels a tad rich at low revs

you cant tell by feel.
take it to a dyno centre for a basic run to see the fuelling line.
never mind the power curve its the fuelling thats important.
cost you about £20 but money well spent.
you might think it's rich but it could be the other way...

other way is go pinch a lambda sensor off a car in the scrappy and rig it up to a cheapo af meter off ebay and poke it down the cans.