PHGB 21 tuning - Puch Metra 65

Hi, Im looking for some help fine tuning my PHGB 21. Its been a long ride so far, but I think im almost there.

My setup:

Puch maxi, Metrakit 65, Techno Bullet

Needle #7 at the top clip

Main 78

Starter 60

Idle 42

Slide 40

air speed screw 1.5 turns out

I had a hell of a time getting the bike rideable initially, the bike just bogged in the midrange. It wasnt until I went all the way down to my 78 main jet and the top most needle clip position that the bike was rideable. And most of the improvement came from the needle position. Now, the bike idles fine, midrange and top end are very strong but bogs in the low end. From a stop, it bogs and spits fuel until about 15mph and then goes great all the way to the top. Should I go smaller for the main jet? A different needle? Any help would be awesome.

Re: PHGB 21 tuning - Puch Metra 65

Overpriced Parts /

Yikes How many months you been jetting that bike?

Timing before jetting.

Is it timed at 17 degrees/mm on flywheel with a light or stock wrong setting?

Is the clutch tuned (thicker springs, lightened etc)?

Stock bushing or aftermarket needle crank?

Gearing?

Do you run a head temp gauge? What is your head temp?

Atomizer#?

What filter or none?

Cylinder base spaced correctly?

Head squish and compression set?

Was your kit ever seized?

Top speed?

See where I'm going with this.

Seems lean on main jet and just not tuned

I bet more then half of the things I Said You did nothing to them

You need to tune it all

If tuned correctly tuned You should have take off fast as a normal part throttle take off in a car, about 50 ish mph top speed and cool running less then 400 degrees F head temps @ WOT

Re: PHGB 21 tuning - Puch Metra 65

Yikes How many months you been jetting that bike? been sitting in the garage for a long time

Is it timed at 17 degrees/mm on flywheel with a light or stock wrong setting? will have to check

Is the clutch tuned (thicker springs, lightened etc)? stock

Stock bushing or aftermarket needle crank stock

Gearing? 16t 40t

Do you run a head temp gauge? What is your head temp?

Atomizer#? 262

What filter or none? treats foam filter

Cylinder base spaced correctly? yes

Head squish and compression set? not sure

Was your kit ever seized? never seized

Top speed guessing 50 but not officially clocked

one other note: plug chop showed golden brown

Re: PHGB 21 tuning - Puch Metra 65

degrees and mm arent the same.

Re: PHGB 21 tuning - Puch Metra 65

you should be in the 80's

Re: PHGB 21 tuning - Puch Metra 65

thats what everyone says, but ive tried every increment from 78 all the way up to 100. Each increment up it gets worse until the midrange is just gone. My instincts tell me to go down further, like below 78, because lowering the main jet plus the needle position change is all that made it rideable. I feel like im close, but based on Kens post, maybe not.

Re: PHGB 21 tuning - Puch Metra 65

What change is expected between a 7 and a 9 needle? Im running a 7 now.

Also, has anyone ever ended up in the 70s on the main jet with a similar setup as mine (metra 65, PHGB 21)? Seems like most people say 80s, but like I mentioned above, my problem worsens as I go up (so naturally I want to try smaller).

Re: PHGB 21 tuning - Puch Metra 65

Josh Leigh /

I'm running an 40/88 in a 19mm carb with a w8 needle on my Metra, no complaints

Fully retarded timing,I wanted to go all the way to 1.8 btc but that would require me to dremel out my stator more.... (edited)

Re: PHGB 21 tuning - Puch Metra 65

The difference in atomizers AN/AU will change jetting at least 10 from experience so whos to say what your best jetting. Metras like small idle jets because of the piston port design. Have you worked with your mixture screw?

Re: PHGB 21 tuning - Puch Metra 65

Josh, what gearing are you running?

I just ordered a few needles too. If I drop a needle size am I leaning it?

Re: PHGB 21 tuning - Puch Metra 65

yes I have played with my mixture screw. Runs better around 1 - 1.5 turns out. More = more bogging (but not a huge change).

Re: PHGB 21 tuning - Puch Metra 65

you need to double check your timing. I ran my mk65 @ 1.6mm BTDC and stayed around 380deg ... 19phbg 42 idle 84 main de-restricted estoril ... 16x40 gearing... 51mph. I used w7 needle, clip second notch from top. w9 needle is a leaner needle than w7 --- just compare the tapers.

Re: PHGB 21 tuning - Puch Metra 65

ok this is a big help. Thanks. I have only adjusted my timing per the Puch manual, so this input is great.

When you say 1.6mm below TDC, you mean piston position relative to TDC with point contact. Correct? Sorry for the newbie question.

Re: PHGB 21 tuning - Puch Metra 65

Overpriced Parts /

Do you mean 16degrees/mm on the flywheel or 1.6mm in the plug hole

Re: PHGB 21 tuning - Puch Metra 65

"...I ran my mk65 @ 1.6mm BTDC and stayed around 380deg"

Trying to understand exactly what this means. My guess is 1.6mm at the plug hole after TDC, but im not totally clear.

Re: PHGB 21 tuning - Puch Metra 65

Overpriced Parts /

I run 1-1.1 at the hole 16-17 degrees mm on flywheel

Re: PHGB 21 tuning - Puch Metra 65

I don't do degrees, just 1.6mm BTDC... measured with calipers and checked with a timing light. different strokes fer different folks.

Re: PHGB 21 tuning - Puch Metra 65

Overpriced Parts /

1.6 mm = 20 degrees way too high of timing if static for a kit

you are lucky or your less timed then you know to run 380 degrees F

380 still kinda high though

Re: PHGB 21 tuning - Puch Metra 65

Josh Leigh /

Tried for 1.8mm btdc from the plug but it came out to more like 1.6 without the dremeling, no clue how people are getting anymore retarded with standard spacing

Measured with one of those micrometer piston stop tools

Gearing is 16 40

An 262 atomizer, treats is out of the au bushings

Hits low 50's (edited)

Re: PHGB 21 tuning - Puch Metra 65

Ken Roff Wrote:

-------------------------------------------------------

> 1.6 mm = 20 degrees way too high of timing if

> static for a kit

> you are lucky or your less timed then you know to

> run 380 degrees F

> 380 still kinda high though

Ken,

Sorry I didn't dremel my stator bud, and ran 1.6mm BTDC @ 380deg, and was safe and could hold WOT for miles without fear of seizing.

Timing was checked with a timing light.

Thanks.

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