6 Sigma Custom Carburetor Carb Stage 1-3 Jet Kit

[VTRDark]

I just came across this jet upgrade kit http://www.ebay.co.uk/itm/230684468097? ... 1423.l2649
Just wondering if anyone has tried it or if it's any good. Seems very good value to me and I like the feel I get from reading the listing.

Your opinions/experiences please?

Got a second set of Carbs turning up, so need to start thinking about jet kit/tunning!

Thanks

(:-})

[tony.mon]

It's a jet kit; you get the main bits which are the jets.
They seem to be recommending drilling the slides; same as Dynojet.

Only concern is that they mention a spring modification.
Seems to me that the only mod you can make is to shorten it, and they don't mention a replacement one.
Not sure that a shorter spring will add anything...
But for that money, give it a go.

Can't see the point unless it's set up on a gas flow analyzer, but I suppose if you can't afford to get it done on a dyno, then it's better than nothing.

Don't like the scare tactics, though- "you'll destroy your engine".., No you won't.
It's not that lean, and without changing compression ratios or using really poor fuel (abroad, poor countries, doesn't apply to uk) it won't suffer from detonation.

I've stripped loads of these, and never seen detonation damage, even on higher mileage ones.

But for much less you could just buy the jets separately.

[VTRDark]

Can't see the point unless it's set up on a gas flow analyzer, but I suppose if you can't afford to get it done on a dyno, then it's better than nothing.

I thought that with whatever jet kit one has, it should be dynoed as well for optimum performance. Would a dyno operator change jet sizes about or do they just play with the needle height, mixture and stuff? Im confused

But for much less you could just buy the jets separately.

That suprises me. So what's the differrance between installing standard jets (whatever size one chooses) to a Factory pro, Dynojet or whatever.

I don't like the idea of drilling the slide and I think I would leave that out as suggested for the dynokits on the VTRs, see how it performs without it. It's either that or I go down the Factory Pro route.

Thanks Tony you have given me some food for thought there.

(:-})

[Stephan]

Hi, my FactoryPro 1.1Ti kit contains only titanium needles, standard main jets, and standard 50 pilots. So difference is in needles with adjustable positions. FPro 1.7 can include more, I haven´t seen.
Dynojet contains their needles, main jets, springs, and requires drilling slide holes.

FPro doesn´t solve needles slide speed, anyway you can adjust by yourself by plugging one front hole. Dynojet adjusts slide speed by slide holes, and new springs.

[tony.mon]

Hi, my FactoryPro 1.1Ti kit contains only titanium needles, standard main jets, and standard 50 pilots. So difference is in needles with adjustable positions. FPro 1.7 can include more, I haven´t seen.
Dynojet contains their needles, main jets, springs, and requires drilling slide holes.

FPro doesn´t solve needles slide speed, anyway you can adjust by yourself by plugging one front hole. Dynojet adjusts slide speed by slide holes, and new springs.

50 isn't a standard pilot jet, and I don't think the main jets they supplied will be the same size as Honda supply as standard, either.
My FP kit came with several choices of mains.

But despite trying the larger FP pilot emulsion tubes; the bike ran better with the normal Honda ones, in a side-by-side run comparison.
Bear in mind that Firestorms made for different markets had different main jet sizes installed......

[VTRDark]

My FP kit came with several choices of mains.

See that seems ideal to me. Rather than being stuck with a certain jet size provided, have multiple jet sizes to experiment with.

I notice Factory pro have various kits. Found two on the bay.
A standard kit http://www.ebay.co.uk/itm/180556692946? ... 1423.l2649
And a race kit http://www.ebay.co.uk/itm/190491317037? ... 1423.l2649

Bear in mind that Firestorms made for different markets had different main jet sizes installed......

Would that be to accomodate different altitudes?

I think I will have to end up getting the Factory Pro as it's a known brand and been proven to work. Also it's less destructive in the sense of not having to drill holes in slides.

All I have to decide now which is the right FP kit to purchase

Have Fun

(:-})

[tony.mon]

My FP kit came with several choices of mains.

See that seems ideal to me. Rather than being stuck with a certain jet size provided, have multiple jet sizes to experiment with.


(:-})

But any dyno shop worth using will have a good selection of jets in stock, not necessarily emulsion tubes, but jets, certainly.
So you don't need them in the kit, and in any case, as I recall the FP kit suggested the same main jet size front and rear, whereas Honda fit different sizes in each carb.
Just let the tech do his work.

[VTRDark]

argh, I did not realize that the Dyno techs got that involved. I thought one had to do all the work. Then take the bike to a Dyno and they just provide the rolling road and computer read outs. Go home, make any changes and then back to the Dyno agiain for comparison.

I feel like a right bloody idiot now! Doh

That clears things up thanks Tony

(:-})

[tony.mon]

Yeah, you pay for the guy's time, not just per run.
He'll pull the airbox and carbs (in half the time you or I could do it, the bar steward) and swap out jets.
He'll do one set of runs, look at the readouts, then suggest some changes, carry them out, then another set of runs; chances are that if he's any good that'll be about right.
Then maybe trying something to see if it's better or worse, maybe another little change, with a run between each.

A good one will quote you about three to four hours, but won't take that long.

And boy, will you notice the difference on the ride home....

If you can, balance the carbs and fit new plugs before you go, and the valve clearances need to be in good condition, too. If they are due, get them done first.

Lastly, I would definitely advise against dyno runs if you still have unmodified standard Honda CCT's........

[Stephan]

50 isn't a standard pilot jet, and I don't think the main jets they supplied will be the same size as Honda supply as standard, either.

bit confusing from my side, standard I ment standard size numbering, like Dynojet has their own main jets and numbering. But anyway these pilots are only "standard" :-)
But these jets you can buy separately without buying whole kit.

e: I run 48 pilots and 180+182 mains

[CruxGNZ]

Just wondering if any of you guys have actually had any first hand experience with the Sigma jet kit?

I've been looking over the interweb and there is quite a few people saying that the Sigma kit is just the same as Factory Pro & Dyno Jet kits. For the price off eBay, the Sigma jet kit seems like a decent value.

I need a jet kit (installed a filter in the lid like mik_str) and spring time is coming up soon where I live.

[StuartWags]

I got a kit but never fitted..... may try it on my current project once i get it up and running. it comes with some useful instructions on how to set it up

[CruxGNZ]

The spring modification mentioned earlier, I believe (going off second hand info) you pull both slide springs and if one is shorter, you gently pull & stretch the other one so they're both the same length. However, doing this raises the spring rate (see below):

     k = G*d^4/(8*D^3*Na)

where G = modulus of rigidity

      d = wire dia

      D = mean diameter of spring

      Na = number of active turns

Got that off the net. "Droppin' science like Galileo dropped the orange" - Beastie Boys

[VTRDark]

Excellent. ..it will be good to get some real world feedback on these kit's. Any chance you can take a pic of the instructions and upload at some point Stuart? What size jets and stuff did they supply? I'm half tempted to get one of these kits just to have the play around but I'm running the factory pro

(:-})