Jetting/Plug Chops - Who Can Assist Me?

[Loud]

Hi All,

Over the last few months I've rebuilt a couple of RS125s:

The first was a complete engine rebuild back to factory specs and this turned out perfectly - it was a rocket out of the box.

The second bike, my bike, is a lot less standard. Whilst it's running and mechanically perfect it needs the jetting sorted and I'm not confident I'm the man for the job, at least not without some help and guidance. It's something I would love to learn, I'd rather not learn the hard/expensive-grenade way. I've read up on the job but am more of a learn-by-rote sort of guy.

Today I took it for it's first ride since the rebuild, a fairly joyous moment as it had been months since it last ran. As I'm running in the new barrel I was looking to keep it below 6,000rpm, however it wasn't a particularly smooth acceleration and there was plenty of black spittle on the rear end at the end of the short ride.

Is there a knowledgeable and kindly soul that can help me to jet my beast? I'm just South of the River, I'm not keen on riding it any distance but could trailer it if need be. Having had it off the road for so long I'm keen to get it done sooner rather than later and will make the time. Because I'm keeping the revs down it'd be the pilot jet, needle and I guess the air correction screw, hopefully I'll learn enough to do the main jet myself later. It's just got the one carby and I can access and change the jets pretty quickly - maybe 10 minutes stop to start. I'm looking to hit the dyno with Gangus when he returns so I'm not looking for the last hp here, just a near-on result.

I'm willing to compensate for your time by means of $, beer or services in kind. If you're a 2-stroke fan like myself you're unlikely to need my mechanical help, but I can detail the shit out of most things and am a very capable home handyman. Please let me know if you can help out!

[shaynoinsano]

not a bad pic ya got there champ!!
think the next step is to buy a zeeltronic and open that 125 up!!


you need to find out what the fuel is doing so you can work out what way to go, plug chop is deffo on the cards mate, but then your back to #1 on that as you dont want to take it past the 6000rpm,
i'll be running the EGT probe in my rocket rs250 for a live temp read out , then work out.. too hot =lean.. i do know of a bloke that could tune this up in his sleep :-).....

CALLING EEKNOWS!!!!!!

[Loud]

Thanks mate, the photo almost does it justice. ;o)

Zeeltronic is installed, both ignition/PV module and the high energy coil - hence the desire to hit the dyno in the immediate future. Apparently an EGT is being arranged for the day along with an experienced tuner but between now and then I want to put at least 600km on the new barrel (Polini 154) to bed it in properly.

EEKNOWS is fantastic and has helped me out with advice for this bike, the court case I lost, and advice on my RS250 project which we’ve also discussed him working on. But I don’t know that they make a 3,000km long EGT probe for him to help me out with!

[HK31A]

were is the egt will be instaled

will you drill a hole in your exhaust?
and what temps are you looking at for a tuned burn?

[Loud]

were is the egt will be instaled

will you drill a hole in your exhaust?
and what temps are you looking at for a tuned burn?

Installed? I thought it was a probe? Don't really want to drill a hole in the Jolly Moto Corsa ...but if I have no choice and it needs to be done then so be it. No idea on the temperature, as stated in the post I'm not a tuner and need to ask for help here.

I did do all of the mechanical work though, save the cylinder work and crank rebuild (Ray Easson). I also designed and largely fabricated the custom TPS system driven by the oil pump regulator. I even wired up the Zeeltronic gear and have worked out how to get the Master Warning light to be actuated by the Zeeltronic as a Shift light (I think).

...But I ain't no tuner. Are you? (and when are you free )

[reddog]

Have you thought about trying a Colortune plug from here www.carbtune.com

[rgvlee]

EGT will require you to drill into the pipe close to the cylinder, depending on the kit you may need to weld a bung on for it (pretty sure KOSO do an EGT probe that uses a hoseclamp). It's only going to help with your WOT runs though from what I have read/been told.

[Loud]

That Colortune kit looks interesting. Pretty sure you have to tune under load though. Without a dyno that means looking down a periscope whilst riding? Also I'm not sure that it'll work with 2 stroke all over the glass, or if there's a BR10EIX equivalent. But a fantastic concept and a great suggestion, if I'm wrong and get set straight I'll invest in it, thanks!

Lee and HK31A you're one step in front - before I worry about the EGT I need to worry about the next 600km or so But a bung up front is no big deal in my mind. The dyno will be as much for the ignition curves as anything else.

Focus people - Plug chops!!

I'm helping a fellow PSBer with his full engine rebuild for nada, I'm not expecting the same but I'm hoping there's someone out there that also has the inclination to teach...?

[ninjaa]

I'm helping a fellow PSBer with his full engine rebuild for nada, I'm not expecting the same but I'm hoping there's someone out there that also has the inclination to teach...?

Lemme know when you're doing it mate, i'm keen to play student while it's happening

....Oi, get your mind out of the gutter!

[pesty74]

well im going to take my cagiva sp 525 to a place in perth funny enough they have a mechanic for korea that has modified his NSR250 cdi unit and will do the same for my bike from 3rd gear to 6th gear power curve increase i will finally get rid of my vhst 28 mm carby to a tmx35 racing carby

[EEKNOWS]

With ULP it gets a bit harder to go by plug chops than leaded fuel but it can still be done. Your looking at something like this, with tan at the top and bottom of the insulator, a magnifying glass is good to look for any 'boil' or silver on the plug. You just need it to pull up top to go to the dyno.
With the EGT, that can vary according to ignition and compression, but as a 'safe' baseline look at 1150 deg F, I always work in deg F as it is a larger scale.
Once you get to 1150-1200F range at the end of a 6th gear pull(it will take about 20 sec) you will be on the money.

[pesty74]

[QUOTE=pesty74;2338310]well im going to take my cagiva sp 525 to a place in perth funny enough they have a mechanic for korea that has modified his NSR250 cdi unit and will do the same for my bike from 3rd gear to 6th gear power curve increase i will finally get rid of my vhst 28 mm carby to a tmx35 racing carby by the way loud your bike would of look nicer with a stainless pipe no offence

[Loud]

Thanks EEKNOWS, that's a handy quick-reference.

funny enough they have a mechanic for korea that has modified his NSR250 cdi unit and will do the same for my bike from 3rd gear to 6th gear power curve increase

Funny? Maybe, but not in the way you think: NSR250 ignition derestriction and speed delimiting

[shaynoinsano]

ahhh yes.. well its good to hear about another 2 stroker getting and learning off sir EEKNOWS :-)


sucks your not in the east your missing the 1st hand "apprentice style" hes got some far out ideas for my rs250 project..

loud your bike would of look nicer with a stainless pipe but you prob know that there brittle as all F@#k and there crap. ben there done that, mild steel all the way for me..
yes. my egt kit i'll run will be a weld bung into pipe. just working out the mounts for the dash display.

[Veefore]

That Colortune kit looks interesting. Pretty sure you have to tune under load though. Without a dyno that means looking down a periscope whilst riding? Also I'm not sure that it'll work with 2 stroke all over the glass, or if there's a BR10EIX equivalent. But a fantastic concept and a great suggestion, if I'm wrong and get set straight I'll invest in it, thanks!

I have the colortune and it works best to set the idle mixture and get the bike running smoothly down low. It is not for high RPM work as the heat will quickly melt the glass.
I've used it previously on my Norton Commando as well as a few other bikes. It even worked on a (2 Stroke) Peewee 50 that always took about 50 kicks and a lot of swearing and cursing to start and idled like a harley. After using the colortune it was a first kick starter and idled like a sewing machine.
Generally, it only takes about 20-30 minutes or so to get a single cylinder bike starting and idling cleanly.

[EEKNOWS]

I would suggest if you can't set the idle mixture correctly ,just by feel and ear, that the 2 Stroke police should confiscate your bike and bitch slap you into line.

Not a Sir just yet, have a few more pistons to hole before that

[Loud]

Thanks guys, the bike idles and starts beautifully. The 2 stroke Police can be thankful they have no reason to try

I have a JL SS exhaust with twin Carbon cans, it's not a patch on the Jolly Moto in looks.

[EEKNOWS]

Two Stroke Police are always watching

[Veefore]

I would suggest if you can't set the idle mixture correctly ,just by feel and ear, that the 2 Stroke police should confiscate your bike and bitch slap you into line.

I don't know if that was aimed at me but I used to do it that way all the time and still do most of the time but I guess I need to be bitch slapped because over the past 30 years or so I've had a few two strokes (and 4 strokes) that were absolute bastards to get to idle cleanly and most importantly start first kick and just tuning by ear didn't cut it or took too long.

I don't use the colortune often but it has been an excellent timesaver on the difficult ones since I have had it. It's especially good for bikes that just won't start. You can see straight away whether the mixture is rich or lean or if it is a weak spark, just on the kick-over.

[reddog]

Sounds like it's a good piece of kit Veefore and for once it's not from some keyboard warrior that has never used the product. I've had 2 stroke in the past that were pigs to start too. My old DT200R was an absolute bitch, but I reckon it was more piss poor spark than fuelling as once it was up and running it went alright especially when on pipe.