30 Miles and WT#!!!!

drhofferber said:
you have or have developed patience...good for you for hanging in there...flybytaco is right...the top notch is the leanest..2nd or third should be fine...ridem...Dennis
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just went for some more miles, If I move it the the 2nd or third would not it be richer? I took out the plug and looked at it and it was black with a lot of gas on it, that leads me to believe that it is toooo rich, any suggestions?

Q
 
Use the top clip position.

Then use a non contact thermomerter is a tune-up tool.

Or plug chops like racers do. (much harder and time consuming and costly ((new plug each chop)) but probably better results)

Look for ~180C next to the plug on a black painted head at WOT.

I carry it on a wrist band when testing.

Cooler is richer, hotter is leaner.

A pipe reading 1" from the head, if its painted black should be 15 to 20c hotter than the head when tuned nicely. Again Cooler is richer, hotter is leaner.

When rich you have a few options.

1. Smaller main jet or

2. Filing the botom of the slide. keeping the 1.5mm cutaway.

3. Solder a brass "hat" on the end of the needle, then tuning with 3mm washers.

I use a combination of 2 and 3 with the added bonus of cutaway variations for a strong midrange.

The best option is a real motocycle carb, 16 to 18 mm and tuned to suit.

I have 3 HT engines, 2 are tuned nicely the other one varies with weather conditions and mood.

The best one still changes it tune-up each day. Its the one with the Mikuni clone...
 
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the top notch is lean...i find little difference between 2nd and third...richer as you go down...whats your oil ratio and how do you determine..the oil amount(eye ball,applicator,etc)....keep on riding and keep a eye on that plug...remember to let the engine cool before pulling plug...Dennis
 
wildemere...those are good suggestions...would you happen to have a pic of the brass hat...thank you...is this for standard carbs...Dennis
 
For all of you all that have been following this thread and trying to help me with this problem, I would like to say,

THANK YOU FOR YOUR HELP

the motor has been running fine, just a little 4 stroking, but today I did the solder and drill mods to the main jet, started with a .026 drill and it helped quit a bit, then i went with a .025 and it did even better, so I think that I will go one more and try a .024 and see how it goes, WOW, I accualy feel power with out bogging down, I am a happy camper, thanks again all

Q


dance1
 
went for a ride today after work, about 7 miles or so, pulls great up any hills (no 4 stroking) but on the flats it still has a tendency to want to 4 stroke, I have soldered and drilled a smaller hole .024 which helpped out alot, should I go down smaller yet? the plug is still wet and black, 20:1 ratio.
 
Your engine should lightly four stroke when it's not pulling too hard, like "at cruise". It will break in and out of the two stroke/four stroke. That's about perfect.
 
Bikeguy Joe said:
Your engine should lightly four stroke when it's not pulling too hard, like "at cruise". It will break in and out of the two stroke/four stroke. That's about perfect.
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so are you saying that my motor will always go in and out of the two stroke/ four stroke no matter what I do? I understand it doing it when not pulling hard, it would be nice not to do that. It seems that the throttle is very touchy, at about 18-20 mph it really wants to "light up" is this normal?


Q
 
You can keep leaning it out until it stops but you run the risk of burning up the motor. lean=heat Not good for any 2 stroke motor. I have all my 2 stroke motors setup to 4 stroke at wide open throttle with no load but as soon as a load is applied, they stop 4 stroking and they just scream. My chain saw and weed eater have been setup this way for years.

Jim
 
Many small 2 cycle engines are basically a compromise design. They have modulation via throttle butterfly or slide, but are designed to run optimally at WOT under expected application loads (think of a commercial weed trimmer).

My bike purrs at low speeds, rattles and four strokes a little somewhere in mid throttle, esp on downhills, and just sings on anytime it is carrying the load for example on small uphill grades or upon acceleration.

Its not showing deposits in the muffler holes, or spitting/leaking any fuel out the exhaust, so I think I might even give it a little more fuel and see what it does. At 80-120mpg, I'm not worried about a few mpg if it runs well and stays lubed for long life.
 
A perfect tune up is possible, with no four stroking anywhere.

Like a real motobike,

Even with the stock HT carb.

You want a lean idle, a slightly richer midrange and a fat full throttle for the hills.

Fuel is the main coolant system on small two strokes.

I have achieved this with 2 mm ground of the bottom of the slide, then adjusting the cutaway to 1.2mm or 1.5mm, ( stock is 1.0) then running a 0.65 or 0.70 main jet.

This setup gives 2 full throttle positions, level with the bore of the carb for the flats (lean) and then 2mm more slide travel gives more fuel for big hills, high loads.

A setup like this setup runs clean on the flats then powers up hills.

No 4 stroking anywhere, and good pickup from low speeds.

Its trial and error but perfect tuneup is posible.

No more 4 Stroking ever.

Tune the needle for a nice mid range.
 
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Thats really interesting. What cutaway are you talking about? Are you talking about the notch where the idle screw affects the throttle slide?
 
A perfect tuneup is easily possible.

You don't have to put up with or accept any 4 stroking.

Its easily fixed when you know what you are doing.
 
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wildemere said:
A perfect tuneup is easily possible.

You don't have to put up with or accept any 4 stroking.

Its easily fixed when you know what you are doing.
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what about all us that looked at that site and went HUH? Pics would be nice, and a simple explination would also be great.

I look at that and see jibjab.
Q
 
GoFastBicycles said:
There was a Rich guy around here some time ago that said he knew what he was doing.
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If you mean ex-member riding rich, he was full of B.S. and more B.S. He did not know much, just enough to sound like he may have known something. He was going to make a perpetual motion machine that uses the "wave that surround the earth" to propel it....

On the other hand wildemere is right on with his info here. It's all very simple to do, and no pics are really needed. Just read the first post slowly....the cut away is the "scooped" part at the bottom of the slide, looking in from the intake side. A file, a little test and tune and some patients will yield a great running stock carb.
 
Pics for those that asked. I took 2 mm off this one. From 20 to 18mm. The new cutaway is 1.5mm, stock is just under 1mm.

Also shown is my soldered "hat" and washer method for tuning the needle in finer steps than the circlip allows (1mm steps) 3mm washers are from .3 to .5 thick.
 

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