New problems With Gilardoni 80cc

Newport is sick.

74cc Gilardoni

21 PHBG

Simonini

99 main jet

im out of ideas.. here's the problem and what ive done..

one day fine, running great, really fast,.. next day sick, slow, 4-stroking. WTF!

i thought maybe first it was the heat, so i down jetted 12 sizes to get it to stop four-stroking!

also changed oil-gas ratio from 32:1 to 40:1. ~it stopped four-stroking but goes about 30-35 at full throttle on 80cc gila! bullshit!

and still kinda four strokes once i get to top speed of ohh 34 mph. (was going 50)

rings are fine, timing is good, carb is clean, clutch seems to be okay (no jerking), gas flows good, sounds great at idle, changed plugs multiple times, reeds look good, exhaust port seems to be pretty clear, everything electrical seems good ?????

Re: New problems With Gilardoni 80cc

with 21 phbg dellortos, tuning is a combination of needle position and main jet. read manual and work these two until you get to the best results. I am still 4stroking a little at the top and most people I know who have this carb are. also, tune the bike in regular weather conditions, not when it's too hot or too rainy.

Re: New problems With Gilardoni 80cc

yeah it seems i've tried every combination as far as carb tuning.

needle is all the way lean, any other position will cause four-stroking at all throttle positions.

Re: New problems With Gilardoni 80cc

wow the combinations are in the millions you must work fast! they run around a 90 main first of all...

Re: New problems With Gilardoni 80cc

seriuosly! extremely frustrating, i can't even get up enough speed to hit the pipe.

Re: New problems With Gilardoni 80cc

Damn...dude.

I think Monica hit it right on the head. It sounds like what happened to you, happened to me the first time I put a PHBG on my Parmakit. Jet was too big and the needle was at factory setting (2nd richest setting, I believe...).

You probably had a brand new plug in there, right? Well, like me, it probably ran like a motherfucker for the first trip but you were about to start fouling your plug as it richened.

I'd be willing to bet your plug looks blacker than charcoal soaking in an oil field.

You absolutely have to fuck with the needle and try some different jets in there. My guess is that you'll be somewhere in the mid 90's with the needle all the way down (leanest setting).

Re: New problems With Gilardoni 80cc

1. Jetting requirements will change after your engine breaks in. This usually takes about 30 miles.

2. Are you using something retarded for an air filter?

3. What is your idle circuit set to? Mixture screw and throttle stop screw.

4. Check yor timing. This can also cause four stroking. Don't just move the stator, measure where before top dead center the points are opening, and make sure they are clean.

Re: New problems With Gilardoni 80cc

1. i put about 200 miles on it before this happened

2. uni pod filter

3. mixture screw was about a turn and a half out, throttle stop screw? I saw this on the PHBG tuning chart but couldn't figure out what this was, is this the small screw between the idle and main jets?

4. timing is good, will clean my points again, they might ot be opening as much as they should be

thanks doot

Re: New problems With Gilardoni 80cc

yeah man, my needle was put to its leanest setting first off, but still running quite rich, and now won't get off the four-stroke

Re: New problems With Gilardoni 80cc

No one else sees a problem with him running an 87 jet on this set-up? Are you kidding me? Thats what I rad on a 65 metra.

Re: New problems With Gilardoni 80cc

i started out running a 99, and it blasted its way to the 50's no problem.

i had to jet down to 86 to get it to stop 4 stroking.

but soon i'll have some different needles and idle jets coming my way.

i heard mid to low 90's for main jets are typical for this setup..

Re: New problems With Gilardoni 80cc

How many mm is "good"?

Re: New problems With Gilardoni 80cc

i eyeballed it, so maybe good isn't good enough

Re: New problems With Gilardoni 80cc

🇮🇹💦 Of the Loin /

tommy i run a 90 jet, and even thats a little rich.

ive got a 21mm dellorto, gilardoni with malossi reeds (i had an 86 jet before i put those in, little rich on stock reeds) w7 needle on the 2nd leanest setting and it blasts, all around. idle mixture screw 2 turns out. blasts. right into the pipe like WHOAAAAAAAAAAA

check your timing for sure, I run a full advance, with an eyeballed point gap (i think slightly larger than stock by .002 mm, if stock is like .016 or .018 right? .002 larger than that, whatever measurement its in)

I was having problems with the flywheel slipping on the taper, it made it feel like it was 4 stroking, but it wasnt. Make sure that shit is on there tight. Gilas tend to make it slip if it isnt.

Re: New problems With Gilardoni 80cc

maitland, did you have to adjust your idle screw at all, or was 60 fine?

Re: New problems With Gilardoni 80cc

ur needle i too rich or "late" what number is it?

Re: New problems With Gilardoni 80cc

🇮🇹💦 Of the Loin /

on a 19mm i used a 50 idle jet, on the 21mm i had to upgrade to a 55. the 60 should work fine, you might be a little rich from 0-1/4 throttle though, but nothing that would stop you from blasting.

after re-reading your OP, Im like 95% positive your rotor has slipped. Take it off, reset it on the woodruff key and really fucking tighten that sucker down. you have to use a piston stop of some kind, HAVE TO. Then locktight your magneto nut.

thats what exactly happened to mine, several times. I've stripped 2 keyways, and always it starts 4 stroking at about 35 or so every time.

Re: New problems With Gilardoni 80cc

See? Timing.

Re: New problems With Gilardoni 80cc

BootyClap Ninja /

im so glad I decided not to run a PHBG and went with the Mikuni instead.

They are much less finicky when it comes to jetting.

Good luck with the gila dude. Should hit 55+ no prob.

Re: New problems With Gilardoni 80cc

That was the problem! my rotor slipped.

straightened it out and it runs great.

still a little rich around mid range, i'll probably try out a 9 needle.

thanks!

Re: New problems With Gilardoni 80cc

🇮🇹💦 Of the Loin /

bahhh makes me wish i didnt shear the fuck out of mine!!!!

Re: New problems With Gilardoni 80cc

i think i may have lost a few threads, but it should hold for a while.

thanks for the help man!

Re: New problems With Gilardoni 80cc

🇮🇹💦 Of the Loin /

red loctite and itll stay on forever

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