First time jetting. How does my plug look?

I have a 1975 Peugeot TSA. After advice from here, I ditched the gurtner carb and out on a dellorto sha 15.15. It came with a stock 68 jet but didn’t run well. I ordered a range of 70’s. I started with the highest which I think was 76 and ran it on the highway for a couple of miles and this is what my spark plug looks like. I’m guessing I’m still lean and need to get an ever higher range of jet sizes next? First time doing this so appreciate any insight. Thanks!!

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Re: First time jetting. How does my plug look?

Lean. fatten the jet up.

Re: First time jetting. How does my plug look?

Nicholas Scholten /

Really lean.

Also, to get a proper plug read you need to look down inside of the plug to the base of the insulator. There should be a tiny 2-3mm ring of colour. The nose colour can be misleading.

https://www.mopedarmy.com/wiki/Plug_chop

https://www.mopedarmy.com/wiki/File:Basic_Plug_Reading.gif

Good resources. :)

Re: First time jetting. How does my plug look?

What air filter are you running ?

Re: First time jetting. How does my plug look?

I’m running the one that came with the dellorto but I removed two of the three screens as somebody recommended. Would that make such a big difference? Was it a mistake?

Re: First time jetting. How does my plug look?

Dirty30 Dillon /

If you're jetted @ 76 and you're that lean, you have something else wrong with the bike.

You should do a leak-down and see if the seals are bad.

Re: First time jetting. How does my plug look?

I am not running a larger jet than 76 and I have a 16:16 on a 70cc kit. Actually two bikes have this set up and are not jetted that high. Take advise from dillon and chase down your other air leaks. And i would always start tuning the sha with all the screens in. Get it to where you have it just a touch too rich and then remove one screen at a time until you get the nice air/fuel mix needed.

Just make tuning fun, then you wont loath the process. I havent found how to make it fun yet, but that is what I'm trying to do. Ha!

Re: First time jetting. How does my plug look?

> Art Vandelay Wrote:

> -------------------------------------------------------

> I’m running the one that came with the dellorto but I removed two of the

> three screens as somebody recommended. Would that make such a big

> difference? Was it a mistake?

A more restrictive air filter will richen the mix .

Just like a choke , only in varying degrees .

I'd try adding a screen and check . Then a second and check .

If that doesn't do , then try taping part of the filter , so it's even more restrictive .

Those steps will give you an idea of what's what . And , you may just decide to run one of those set ups .

Or , you could just spend more money on a bunch of jets .

Re: First time jetting. How does my plug look?

Thanks guys - I found I have an air leak where the carburetor bowl tightens onto the carb - which is weird because the rubber gasket is there and it's a brand new carb....... frustrating!

Re: First time jetting. How does my plug look?

> Art Vandelay Wrote:

> -------------------------------------------------------

> Thanks guys - I found I have an air leak where the carburetor bowl

> tightens onto the carb - which is weird because the rubber gasket is

> there and it's a brand new carb....... frustrating!

That is a weird place to get an air leak. I would suspect it is more at the intake where the carb goes on.. do you have an o-ring in the carb where it connects to the intake? There should be an o-ring and then the shim.

Re: First time jetting. How does my plug look?

Nicholas Scholten /

> Art Vandelay Wrote:

> -------------------------------------------------------

> Thanks guys - I found I have an air leak where the carburetor bowl

> tightens onto the carb - which is weird because the rubber gasket is

> there and it's a brand new carb....... frustrating!

You mean the float bowl? Is it a clone carb? They often have air leaking issues from what I've read. Usually it's the top cap or the clamping area.

Re: First time jetting. How does my plug look?

Dirty30 Dillon /

Yeah, you can't have an airleak between the bowl and body, that would not be detectable via carb spray.

Re: First time jetting. How does my plug look?

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> Yeah, you can't have an airleak between the bowl and body, that would

> not be detectable via carb spray.

Not to mention it would leak gas everywhere.

Re: First time jetting. How does my plug look?

Well it's very strange because I have sprayed carb cleaner at the intake, and the top cap, and nothing changes. But when I aim it directly at where the bowl meets the carb, the revs drop significantly - if i do it for a few seconds it kills the engine. I also noticed I have no o-ring OR shim where the carb connects to the intake, so I've ordered one from Treats... Thanks for all the help.

Re: First time jetting. How does my plug look?

Dirty30 Dillon /

Which side of the carb are you spraying? Towards the front where it sucks in air?

Also, not every sha has or needs an o ring

Re: First time jetting. How does my plug look?

Hope not :)

Re: First time jetting. How does my plug look?

I was spraying all the different areas one at a time, very targeted, to see where RPM's drop. I'll try to make a video later. Thanks!

Re: First time jetting. How does my plug look?

This is where you look when "reading" a spark plug:

plug_section_16.gif

This is what you need to read to know what you're looking at.

You most likely will need a magnifying glass too.

Screenshot (21).png

Re: First time jetting. How does my plug look?

Well I have never used a magnifying glass .. that’s a good idea.. but I think if I was on the track running a 125 or. 250 at red line for an hour or so ... I see that to get it just right for the temp .. sea level up the mountains etc ..

Or blow the motor .. and blow 3000 g ..

But after tunning 100s of 2 strokes from 76 to now .. I just never had to get that eye ball tuned in ..

my rule of thumb is simply this

If your plug Is a dark tan on a full speed under load plug chop .. assume its a mid tan .. if it’s light tan it’s going gray .

Lean always your a little lean ..

this way if that full speed plug chop you did over a mile run ..

Won’t drop you in shit .. when some guy comes up your side on the hwy on his custom hobbit or Honda 3 speed with leg shields or that fantic super 6 speed

And gives you the old wank sign and speeds away .. making you look like a right wanker ..

You got to have the confidence that when you hold that baby out .. head on the speedo feet up over the rear turn signals .

Slipping in to his slip stream picking up RPMs closing in for the sling shot over take ..

And it’s 2 miles of flat out .. it will lean off a little ..and as you come up side for the over take .. its locks up .. and you look like a NOB ..it’s not that complicated..

Jet so if your flat out a mile .. and you roll back the throttle just 1/16 it picks up just 1 or 2 mph your just right always be just a little fat on the main .. it don’t hurt running around 40 / mph half throttle to be just a tad fat ..

Sorry if I dragged that out to

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Re: First time jetting. How does my plug look?

Tri-ped Dave O.D.B. /

Yup^ 2 strokes run best when they are a little too lean and risk heat seizure. The ones looking for that "perfect" spot are the ones who end up on side of the road dead. I always jet that perfect spot plus 1 number or 2 richer. So I lost 1mph or maybe 2. But my kits last 20 years and counting. And i am never not at or near the front of the ride.

Re: First time jetting. How does my plug look?

> Tri-ped Dave Wrote:

> -------------------------------------------------------

> Yup^ 2 strokes run best when they are a little too lean and risk heat

> seizure. The ones looking for that "perfect" spot are the ones who end

> up on side of the road dead. I always jet that perfect spot plus 1

> number or 2 richer. So I lost 1mph or maybe 2. But my kits last 20

> years and counting. And i am never not at or near the front of the

> ride.

I end up rich most times. But I live near hills and you can seize a lean running bike easy down a big hill. I actually soft seized my polini down a smallish hill today. The slide in my sha runs the mid range a little lean I think so it got me. I need to grab a temp gauge for this bike I think. Thankfully it cooled enough and started back up by the time I got to the bottom of the hill. So far my experiences with garelli polini kits have been the same this way. Little soft seize down a hill, ripp it on home.

I did come across this fun chart for plugs.

spark-plug-color-chart_3.jpg

Re: First time jetting. How does my plug look?

Peugeot are notorious for bad crank seals. Pretty much every single one I've ever owned has had bad crank seals. Some of them even run really really well with bad seals.

I had one a few years ago that drove me crazy, everything was perfect, ran great 35 mph stocker, but it just wouldn't idle. Changed out ignition, carb, set the timing about 20 times.... Finally I got so mad I tore it down and sure enough, pretty much the whole inside of the seal was gone.

Re: First time jetting. How does my plug look?

MICHAEL FRENCH /

If you're tuning by color spend the money and get a colortune plug, way more accurate

http://www.gunson.co.uk/tech-torque/Colortune-See-inside-the-combustion-chamber

Re: First time jetting. How does my plug look?

Hepatitis J [OFMC] /

> MICHAEL FRENCH Wrote:

> -------------------------------------------------------

> If you're tuning by color spend the money and get a colortune plug, way

> more accurate

>

> http://www.gunson.co.uk/tech-torque/Colortune-See-inside-the-combustion-chamber

What the hayl

Re: First time jetting. How does my plug look?

MICHAEL FRENCH /

> Hepatitis J [OFMC] Wrote:

> -------------------------------------------------------

> > MICHAEL FRENCH Wrote:

>

> > -------------------------------------------------------

>

> > If you're tuning by color spend the money and get a colortune plug,

> way

>

> > more accurate

>

> >

>

> >

> http://www.gunson.co.uk/tech-torque/Colortune-See-inside-the-combustion-chamber

>

> What the hayl

You've never seen the colortune plugs? When i had my dirt bike color tune showed I was several jets off, plug showed I was dialed in. Dyno was spot on with color tune. Fun toy if nothing else

Re: First time jetting. How does my plug look?

> MICHAEL FRENCH Wrote:

> -------------------------------------------------------

> You've never seen the colortune plugs? When i had my dirt bike color

> tune showed I was several jets off, plug showed I was dialed in. Dyno

> was spot on with color tune. Fun toy if nothing else

Some of the big Honda guys use them to get dialed in . They seem to really like them , too .

Re: First time jetting. How does my plug look?

Seems like another learning curve to over come. But a neat toy.

Re: First time jetting. How does my plug look?

> Jay Rivett Wrote:

> -------------------------------------------------------

> Seems like another learning curve to over come. But a neat toy.

What ? It's about as simple a tool as a screwdriver . But , I guess you're right . There is a learning curve for screwdrivers alright , or is it left ? ;) (edited)

Re: First time jetting. How does my plug look?

That plug chart of Jay's is not the color of an insulator after two miles of riding..is it??? ..what about the color on the original post ...some is developing under the electrode....post a brand new plug next to any plug chop so it's possible to evaluate if it's white or even whiter ...

Here's an idea: keep jetting up until it's gurgling. Go higher and it will four stroke to death. This is the cheetachrome method...if u keep changing things and nothing happens ...other problemo...

Everybody says you gotta cut the threads off the plug to get at the base ..true..but really how many do that...it's quite a pain

If you rode for two weeks and your plug was that white ...that's real bad. A two mile chop is a pretty subtle thing. Also where the part of plug most exposed to the exhaust port is at least on a Vespa is a bit different than elsewhere, ie leaner . But perhaps I'm wrong on all of this. What u say Dillon?

Re: First time jetting. How does my plug look?

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