Engine Trouble 7000ft+ carb jet tuning help? I've tried almost everything.

[Lucknuts]

okay, I'm as stunned as y'all may be. but apparently I'm 1 degree from the mayor here. My buddy Benito (career elected official, last time county assessor) is friends, like since grade school with the bleeping mayor.

It's something I take in stride these days since my wife works on movie stars regularly. The do a lot of filming in New Mexico lately and most of them apparently have rotten teeth.


If only they knew that their "asthetic dentist" sucked and it was all schmoozing. I wish I could tell them sometimes. They could easily get better work done if they weren't so "fancy".

They're usually as-soles though so why would you go out of you way to help a spoiled brat? Oh yeaah, those c-note tips. Doh!

 

[Lucknuts]

so anyway what I was saying is that y'all can go back to being bored with your boring lives. Yes, I would like NO tomatoes, please. Fruity meats are reserved for Italians.

 

[HeadSmess]

youll find thats mainly clutch gear noise.

yep. its there. unavoidable. some motors are better than others, manufacturing tolerances are dismal...

cost issues. they are cheap. also, due to the clutch gear basically floating on a single row of bearings, its free to flop around and clatter against everything...when the clutch is disengaged! youll find a lot of the noise reduced once the clutch is engaged, simply cus the gears held fairly rigidly then.

i agree, why pay almost as much for the engine for a carb when its only an 8% increase? doesnt sound worth it.... whilst tools are always an investment for the future! (small drills wont snap if you use a pin chuck and be gentle...)

youre getting good results with the wires, so more kudos to you

now, over priced upgrades... if i couldnt make them, and had it conclusively proven to me that a decent exhaust system will double the power, id pay for them... two strokes depend on exhausts, and these POS china junkheaps benefit more in this area than any other mod, plain and simple. imho, it just isnt worth getting any more involved than bolting on a new exhaust. (not that that stops me!)

trust me and anyone else that thinks tuned pipes are the ducks guts. they are. take an old yz250 or similar 2stroke for a spin...with the exhaust removed compare "with" with "without"... the motor will tolerate being a bit off on the mix or compression or such, but removing the pipe makes for a noisy underpowered lawnmower. they fit that great fat shiny slug on them for a reason!

currently, as standard, you have a basic "lawnmower" muffler of course youre going to be unimpressed!


dont worry too much about the 4 stroking too much, or getting it too spot on. as long as the thing runs, doesnt produce a smokescreen, and doesnt gunk plugs or sieze, its doing fine if you can bear looking at it in 3 months time, contemplate a few upgrades then

 

[HeadSmess]

if the plug came out white, and it was running fine...quick! go back to that one! either you had the heat range of the plug and the mix spot on, or... yep. thats it...spot on. bordering on the lean but until the electrode melts and says otherwise...perfect! if the electrode does melt but motors still running fine, use a cooler plug...go UP a number or two (ngk standards). it has to run a tad leaner so a tad hotter cus of the altitude, so id be fitting, say...an ngk b8hs instead of the normal b6?

is only too lean if the engines spluttering and dying when you open the gas.

 

[Deleted member 12676]

basic elementary kindergarten stuff

I recommend a $70 carb and you complain because you say the cost is almost the same as the engine!? WTF? the engine costs $200 ! someone here is on drugs and it ain't me. The worse the product, the more money needs to be spent to make it right.

go ahead, you and all the other cheapos, run your POS chinese carb and have it too lean at idle, too rich at mid range, and too lean at top end, so that you seize it and then cry that you have to buy a new top end.

Why spend money for a good carb? Because it will run cleaner, sound better, give better power throughout the whole rpm range, not foul plugs, not seize the engine, not leak gas, allow it to breath better at high rpm, start easily, idle better, accelerate better, look better.

ANYTHING WORTH DOING IS WORTH DOING RIGHT. The chinese didn't do it right. It's up to you to finish the job.

 

[Lucknuts]

sorry for the wacky comments I was having too much fun again last night. thanks for the input headsmess.

unfortunately you can't polish a turd too much. I guess I'll wait and find myself a real engine somewhere. Forget this cheap chinese crap. It started out fun, but it's a piece of $%^ no matter how much love I give it.

I call this a scam in common lingo. It's B.S. at the highest level, like our government lately. It's simply people scamming people to make money. Why are the chinese so nefarious in business. I thought the Germans sucked but this blows them out of the water.

 

[Deleted member 12676]

OK then get a Morini (which is the same cost as a Grubee with needed modifications).

You have to make your own way of mounting it to the frame though.

 

[crassius]

sI guess I'll wait and find myself a real engine somewhere.

you could do that for sure - but you could also just be happy with what you have - 100s of folks buy kits, build them, and ride them without ever knowing that the factory main jet is leaving them 4-stroking

it gets them down the street reasonably quickly, gets them up hills very well, and they're having fun

I sometimes will jet one for better performance, but it always takes a diff sized jet from what worked on the last one, and the improvement isn't that big a deal. On days with no other stuff to do tho, I enjoy piddling with them.

 

[Deleted member 12676]

price comparison:
Whizzer 135cc 4 stroke kit $800
Morini engine $660 but is engine only. You'd have to buy a $200 Grubee kit to have all the other necessary parts although you also have to weld up your own frame mount. (min total $860)
Grubee 69cc $200 (also needed: $70 carb, $75 Jaguar CDI, $10 lighter wrist pin, $20 crank seals, $20 heavy duty chain for a total of $395)

the choice is obvious to those on a budget. If I was rich I'd get the Morini. Otherwise the Grubee is the way to go if you are willing to do some wrenching. If you aren't rich and are a mechanical dork then there's always walking or riding a normal bicycle. Or just stay home and watch TV.

 

[Poo Poo De Doo]

Ways to bore soft things.

We live at between 6500 and 10,000 ft. here and I have tried everything I can find online to fix the "way too rich" situation to no avail. Help!

Can anyone tell me where to just buy a jet that is the correct size for my altitude? Please? It's fun for me to MacGyver stuff but this is too much.

Thanks

Ummmm OK.... This is microcleverness...

A careful estimation etc....

You can do this the smart way... I don;t have the tables on me...

But there is a ratio of altitude increase to fuel decrease - as measured on a volume basis, for a given head or flow rate of the fuel.....

You need to match fittings (hoses and pipes etc., ) with the press on fit of a fuel line, over the OD of the jet.


You will need a small header tank filled with fuel - say about 2 meters above your bench. Sodder a bit of metal tubing into the side of the metal can or slide a weighted drilled out screw and sit that into a plastic fuel can etc.. remember this is only temporary.

With the tank filled with fuel, at 2 meters of head, measure the flow rate through the jet in 60 seconds.

Get a steel guitar wire that is a fairly loose fit inside the jet.

Sodder up your main jet.

Then cut your guitar wire and either point the tip or cut it at about 45* and use it as a drill to bore through the sodder.

Measure the flow rate per minute again.

Then calculate the difference on a percentage basis, and then cross reference this to the decrease in fuel, per thousand meters in altitude.

If the second fuel flow measure it too small, hammer the cutting tip of the wire to expand it, just slightly, and rebored the sodder in the jet.

Then retest the flow rate.

Or if the flow rate was too much, then resodder the jet, and rebore with a smaller wire and then retest the flow rate and hammer the wire tip a little to increase the size a little and rebore it... and retest the flow rate.

It's not hard, it's just maths.....

Someone else can dig up the tables and ratios..

It's better to calculate and set to those standards, than it is to play guessing games with tiny parts.

If you want help with the maths, put it up here and I will double check the figures for you.