dellorto phbg 19mm carb from treatland tuning woes

SIMON.j.k

New Member
Apr 27, 2018
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Christchurch , New Zealand
I have two PHBG carbys ones a 19.5 and the others 21mm and DUDE your back in class . There is so many variants is not just altitude and atmosphere but how your engine setup is configured.
So I'm pretty good at it now, however it has taken quite some time to get to the point of fine tuning. So if you want to drop me an email and maybe swap phone numbers I'll share with you what I've got I've got several internet pages that I could forward to you and things like that and help you the best I can but it's just too much to do here.
hi
just wondering on how this ended up im new to the PHBG carb as well any chance i could get the links you were talking about
 

jessewsimonsen

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May 15, 2016
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Arizona
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javy mcdees

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Jul 30, 2018
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what I have now goes 40mph with the stock jet that come with runtong carb.
piston port, iron sleeve G5 style, mz expansion ex 10/36 tooth high pin style crank. looking to get either a mikuni or dellorto. the 19 seems like a larger upgrade, not looking for mor speed, like to get better acceleration in the 25/35 mph range. commuter bike extra weight and fights lots of head wind. 50:1 mix used currently planning to use 80:1 with new carb. only read a few comments on this thread at this time. good thread I wanted to find so far.
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javy mcdees

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Jul 30, 2018
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put on a phbg 19mm and runs awesome compared to the Runtong 15mm I had on that broke at usual spot again. The tune that I have is this, bike starts with choke, then runs well low speed mid range with only half throttle setting. anything more and it lose all power. Leave it at one throttle setting like almost half and the engine will go to 75% engine speed with power. anything more disrupts the carb and loses power and have to start over again. I see the phbg has needle kits instead of jetting, will be ordering needles instead of jets.
 

javy mcdees

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Jul 30, 2018
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The 19mm carb I have has a 40/50/86 jetting with a w-7 needle and a 262AU atomizer it runs good with the neeedle at second from top but will not respond above half throttle.
Change the needle clip to top position the bike runs better and even will take wot if the wind behind me but still seems a bit fat. I guess an 85 main jet is my next stop. gotta make a 80 mile round trip tommorow will see how she runs for me. I expect a huge drop in fuel milage, usually go 40 miles on half gallon.
 

javy mcdees

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Jul 30, 2018
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just did 80mile commute with the new to me Dellorto 19mm PHBG bs carb and it seems at half throttle she needs no more, she will rev out good not max but good enough to commute with authority. The smaller carb runtong would fall flat on its face in any wind, this dellorto powers right through the head wind. uses a wee bit more gas 40 miles to half a gallon the smaller carb maybe ten miles more to empty than bigger carb, the power out weighs the minimal loss in milage.

The carb has a 86 main jet and if I put any air filter on it it just runs too rich.
remove air filter runs like it should almost. It improved once I put the needle clip at the very top. will not take wot at all it dies but if I hold her between 1/4 and 1/2 throttle she will respond nice and rev out pretty good and will take small runs at wot once the rpms come up enough.
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javy mcdees

Active Member
Jul 30, 2018
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Okay a 83 main jet from treatland for Dellorto carb
20190425_150950.jpg
is the one for this little motor I have. responds very well to wot with a surge of power and some clutch slip but she runs sweet now. The 1/4 throttle is soft and boggy until I open the throttle to wot or half so a 45 pilot may be my next move or a W-9 needle. the W-7 needle I have now runs best with clip in leanest position. low end rpm a bit rich but the more air seems to help the engine respond with very good surge of power, gets to top rpm all at once.

Once the low rpm becomes lean enough the power and throttle response should be impressive, what I have untapped is nice! the cylinder is not even ported very much, the iron cylinder transfer ports have the wall and tough to port, the intake and exhaust are opened but not too much as to change timing., impressed with the power.