So im up and running with my Minarelli v1. It has the Polini 75cc kit on it and a 19mm race PHBG. My current jets are 45 on the idle, 96 on main. The thing pulls like a MOFO until 45 then gearing gets me. The thing is that at the very top end it bucks a little.... 3/4 throttle smooth and responsive but at full throttle it actually slows down and kinda bogs. The plug chop is nice and brown even though I would like it a little richer...never expected it to go higher than the 90's on mains, but I understand that I may not have an accurate reading due to the complexity of these carbs adjustments. Any thoughts from the more advanced tuners? It doesnt four stroke , and I worked up from an 86 to a 96 gradually, but is it possible the the main is too big? Should I drop the needle a notch (or will I loose some of my wicked mid range)? Big thanks on any input. In the wiki there isnt an official tuning guide from dellorto, but is there one out there?
Idea on PHBG and V1, advanced tuners needed.
Re: Idea on PHBG and V1, advanced tuners needed.
I am running 104 on the main with a mamba pipe and mesh screem air box... hmmm 45-50.. I ride in a 50 speed limit with no traffic .. behind me I must be doing something right..:)
Re: Idea on PHBG and V1, advanced tuners needed.
Btw when jetting a carb ... Jet highest first and then down. my 2 cents.
Re: Idea on PHBG and V1, advanced tuners needed.
Yeah, I was shooting for the 86 to be big but????
Re: Idea on PHBG and V1, advanced tuners needed.
Im running one of those malossi filters....
Re: Idea on PHBG and V1, advanced tuners needed.
Estoril pipe....
Re: Idea on PHBG and V1, advanced tuners needed.
hmmmmmm.
Re: Idea on PHBG and V1, advanced tuners needed.
I have spent the past week reading about these carbs and playing around with mine, so the following info is just me interpreting what I got out of it and tinkering with it to experience the effects I have been reading about.
The thing I have noticed with these carbs is that you have to adjust every range. Just because your plug is brown doesn't mean you aren't close to seizing it at mid throttle.
The main jet controls 4/4 throttle only. I would start it, then pull back on the throttle all the way and let it bog and die. Pull the plug to see if it's wet. If it is, then a smaller main is needed. If not, a bigger is needed. You can also use the choke to check this condition. If it bogs with the choke, downjet. If it runs better, upjet.
As far as the pulling, you can hear and feel those kits running lean, and IMHO, Polinis are verrrrrryy perschnickety. A ridiculous pull can be a symptom of a lean condition (and if it was me, I'd be a little weary of it). If controlled, it's no biggie, but if you are running lean at 1/4-3/4 throttle, it's going to end up as a big ol' FAIL. I've got the 21mm PHBG-R, and I'm running a 104 as well. Bogs and dies at 4/4, but that could be because my idle jet is tooooooo small. I would guess that's where you would want to focus your attention first.
As far as features on these carbs...a quick run down...The taper, diameter, and point diameter have VERY specific jobs (please see the links below). The top notches in the needle are used to delay, or lean the mixture during throttle movements. Notches at the bottom will advance, or richen the mixture. The needle will affect the throttle enrichment all the way to 3/4 throttle, then that's where the main jet kicks in. The Idle jet is responsible for circuit transitions and is IMHO, the MOST important element in tuning these carbs. It is also responsible for the first stages of throttle movements, as well as, well...idle.
Here are some links:
http://thisoldtractor.com/gtbender/mg_manuals/dellorto_manual.pdf
http://www.thisoldtractor.com/gtbender/mg_manuals/dellorto_manual_a_guide_1.1.pdf
Re: Idea on PHBG and V1, advanced tuners needed.
PS, sorry that was a novel...then again, that was the fundamental version of the two links I posted. Have fun readin' n' tinkerin'! I've been doing it all week!!
Re: Idea on PHBG and V1, advanced tuners needed.
Gordon Jennings says to take the main jet out, and then try to start it. If it runs, your needle and needle jet are too lean.
Re: Idea on PHBG and V1, advanced tuners needed.
Hey Mike you and I have the exact same setup.
Tecno estoril
75cc polini
19mm phbg
mallossi round airfilter
This is what I can tell you:
I had the same thing happening I would hit 45 and it would do this weird fluttery jerk shit I had no idea what it was, So I carefully went from a 99 all the way down sequentially to a 84 jet, in the top end I was cherry, but my mid range was shit and I seized my kit :( so sad, so next I put it all back together and raised the needle 1 slot, now it sits at one up from the bottom, the mid range still fells a bit lean, but the kit is fucked anyway so I am experimenting like a fuckass to get this to work, I am going to up the needle one more to give it a little more juice and see how she rolls, This set up is a bitch to tune for whatever reason, lets figure this shit out!
Re: Idea on PHBG and V1, advanced tuners needed.
"I had the same thing happening I would hit 45 and it would do this weird fluttery jerk shit I had no idea what it was..." <---Best description yet!
Interesting. I think Im going to take this course:
1. Up the "idle" circuit from a a 45 to 55, adjust
2. Drop main to 94 or 92
3. Raise Needle 1 notch
If anything its safe....until the next chapter
Josh, at least we have cast iron cylinders--Hah, scotch brite that shit and put a new ring on it.
Re: Idea on PHBG and V1, advanced tuners needed.
Dropped the main jet to 92 and the 55 idle was too much fuel around the whole power band...boggyish, dropped back to a 50. Dropped the needle from 2nd to 3rd notch from top, bogged in the mid range. Back to second from top....Still around 45 at full throttle it does the jerking thing....back off the throttle a bit, smooth and slightly faster....I afraid to lean the main more even though the wiki states that it is a sight of too large of jet.....idears?
Re: Idea on PHBG and V1, advanced tuners needed.
Could the petcock be starving the float bowl of fuel? THe holes in it are fairly small???
Re: Idea on PHBG and V1, advanced tuners needed.
do you still have that bullshit little disc in the carb? the one that goes by the main jet?
Re: Idea on PHBG and V1, advanced tuners needed.
If you do throw it away...
Re: Idea on PHBG and V1, advanced tuners needed.
Tossed it already...
Re: Idea on PHBG and V1, advanced tuners needed.
Yup that means its rich. When you are backing off the throttle a bit it gets better because it gets a chance to burn off that excess fuel that got dumped in.
Re: Idea on PHBG and V1, advanced tuners needed.
Let me clarify that a bit. If its bogging because of too much air its more of a smooth bogginess. If its too much fuel, its more of a sputtery sound like its choking.
You can test this to be sure by engaging the choke like angelique said. If it gets better with the choke then you're bogging because of too much air, if it gets worse with the choke then its sputtering out and choking itself on all that fuel.
Re: Idea on PHBG and V1, advanced tuners needed.
Someone please start a PHBG tuning page in the wiki. All of this stuff is great.
Re: Idea on PHBG and V1, advanced tuners needed.
Ok, Update. Now at a 90 main, top end is nice and clean, no more of the jerking. Im at the 2nd notch from bottom for the needle, but the take off hesitates. I get the best response from the throttle with the idle mixture screw 1/2 turn from completely closed...that is I sign I need to lean out the idle jet, right? Might have to go back to the 45....
Re: Idea on PHBG and V1, advanced tuners needed.
Just for shitz and gigglez, have you tried tossing that 55 idle jet back in there and positioning the needle on the first notch (leanest)?
Listen for a lean condition...It sounds like "WAHHHHHHHH" instead of "WOHHHHHHHHHH". Also, the engine gets very hot in a lean condition.
Re: Idea on PHBG and V1, advanced tuners needed.
Oops, you're too quick.
Re: Idea on PHBG and V1, advanced tuners needed.
Actually, you can adjust the idle AIR screw...It's not the idle SPEED screw that has the spring on it. The idle air screw is a flat screw located toward the front (venturi) of the carb. I have not done this myself, but refer to the manual to get the exact specs. on adjusting it.
Re: Idea on PHBG and V1, advanced tuners needed.
"Actually, you can adjust the idle AIR screw
Re: Idea on PHBG and V1, advanced tuners needed.
sounds like you are doing too much at once. Tune for top end first. Once you have that worked out, start working out the rest.
As for the idle screw, I was taught to turn it all the way in, then turn it out half a turn, then never touch it again. Worked for me.
Re: Idea on PHBG and V1, advanced tuners needed.
I think I have the top tuned out about right...now Im attacking the bottom end....oh well back to tuning.
Re: Idea on PHBG and V1, advanced tuners needed.
http://www.users.tsn.cc/rdd/TT/contents/CARB/dellorto/dellorto_3_4.html
I recommend a Dellorto Tuning Manual, they usually provides the best info on tuning there carbs. They did design it and hopefully know something about how to tune them as well. Well we can all hope anyways.
-naz
Re: Idea on PHBG and V1, advanced tuners needed.
The users guide given by michaeln as above does not cover the PHGM model carb, but it does give a lot of general info.
Re: Idea on PHBG and V1, advanced tuners needed.
Yeah I like it... and try to pay attention to the info. It's actually some of the better rules and they aren't even all that crazy and are fairly piratical.
-naz
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