dellorto vhsb atomisers

[handofdave]

hi, bit confused now,have a new ts1 set up,jl3,34 flat slide, has a dp266 and k24 top clip and is so rich it will not run at low revs,i was considering coming down to a 264 but have been advised by various dealers that you cant go that lean on a ts1?anybody using a leaner atomiser succesfully?have even gone down to a 150 main but still too rich up to half throttle,,,,,,suggestions please
dave

[Adam_Winstone]

Unlike PHBH atomisers, DQ are available in odd numbers too, which would make going to a 265 a better option.

[handofdave]

surely if a dq is alot weaker than a dp ?

[Adam_Winstone]

Soz, I'm just talking like for like diameters, whether it be a DP or DQ. From having a quick look at a K needle chart, both the K24 and K8, which I use with a DQ266 have the same needle body shaft diameter, so they should be the same until getting onto the taper. It is important to talk throttle positions with carbs, rather than revs or speeds as it is throttle position that controls which carb element (1 or more) is 'in play'. If you're talking low throttle positions then you might have an issue with pilot size or slide value, rather than needle shaft/atomiser bore, which is slightly higher up the progression stages.

It could well be that your atomiser bore + needle shaft combination is too rich for your set-up but the same works fine on mine.

I can't remember which is shorter (richer) the DP or the DQ range of atomisers, however, this is not something to worry about yet, first you need to determine what throttle positions it is rich at and what element of the carb needs to be addressed. Mark the throttle housing/grip with shut, 1/4, 1/2, 3/4 and WOT, then hold it at these and determine where the issue is.

Adam

[Tom Russell]

Is your atomiser/needle brand new, as they can wear out quickly!

[handofdave]

thanks for the replies ,the needle /atomiser set up came out of the bike running but will replace just to make sure,0 to 1/4 throttle cant keep it running(far too rich/plug dripping wet),1/4 to 1/2 throttle coughing and spluttering still struggling to keep it running,1/2 throttle clears and takes off,will try new parts then play with weaker needle,

[Tom Russell]

As Adam suggested, I'd also double check you've got correct pilot/idle jet fitted for your setup. Also, make sure float is shutting off correctly, and choke isn't (slightly) sticking on!

[handofdave]

should i be looking at a dq266 then instead of lower value dp,s

[Bufficus]

I've never had any joy with DP atomisers on my TS1s. Always too rich low down.

My best results have been with DQ268s with K21 or K24 needles on my tuned motors (NK Rally pipes). However, my mate runs a DQ262 with a K5 with a PM but this is very rich low down.

I currently have a DQ268 with K24 needle in my VHSH but have a power jet to richen it up at 3/4 because I couldn't find a needle that worked safely. This allows me to run a very small main jet.

[philtrate]

Try a k21 needle with the dq266 it works for me