All 2st General two stroke question

[Scootskipper]

Can someone describe to me what exactly is occurring when a two stroke engine is said to be "loading up"? For a while I was having trouble getting my engine to rev up high after any length of time in tight woods. Yesterday, I discovered the joy of slipping my clutch while grabbing a handful of throttle. Suddenly things are happening a lot quicker and as long as I can keep it off the trees, I am having a lot more fun. The added benefit is that I can pull on to a straight away, pin the throttle and she just screams! Problem fixed! Is unburned fuel accumulating in the exhaust when you go slow? I'm really curious.

 

[Motosportz]

A 2 stroke draws air into the crank case and then transfers it to the top end. When riding slow you will get some built up fuel in the crank case as the transfer is not 100% at low RPM. The next time you hammer the throttle it unloads this raw gas and thats why it is slow to rev and smokes a lot. Some of this can be tuned out via carb settings but will almost always be some of it due to how a 2 stroke operates.

 

[Dirtdame]

Depends on the engine tuning, carb size and what kind of oil and ratio you use too. Modern two strokes have reed valves to help keep everything moving in the right direction. Smaller carbs help keep air flowing faster than carbs with larger venturi's on them. I used to use a petroleum based oil in my gas at 32 to 1, now I use a full synthetic at 60 to 1. My trail bike (which has an itty bitty 33 mm venturi carb) runs better, cleans up better and doesn't load up ever....well, except when it's really cold first thing in the morning.

 

[pahusky]

Trees can be an issue when you add a handful of throttle, a slip of the clutch and traction...:smirk:

Scoot, a good woods practice is when you get the chance, clutch completely and rev.
On downhills, rolling into a corner… since you discovered slip and throttle just go one step further…

Like moto says this clears the crank and jug of the usually too rich mixture and sets your motor up to receive the mixture it's used to when you get the chance to pin it…standard operating procedure for hare scrambles/enduros.

The motocross boys usually perform this operation in the air over a jump…not really an issue with tress but they have to come down sometime, somewhere…

 

[HuffieVA]

Scoot,
As the others have said above smokers run best at certain rpms, if you listen to some YouTube videos of 125's running the track it will almost sound as if they are running a constant RPM, well its not actually constant as it would be with say, a chain saw, but they do keep it within the power range or "on the pipe" as some call it by working the clutch somewhat like a "second throttle", It a bit harder to do in the woods (those trees are pretty tough and unforgiving) but you can achieve the same thing by opening it up whenever you get the chance and staying out of the next gear until you really need it, as well as gradually perfecting your clutch slipping skills. Bigger 2strokes aren't quite as finicky but they all take a bit more effort than the four strokes to keep them running fast and smooth. Once you get the hang of it that little 125 will leave most of the 250F's in the dust and keep up with a lot of the 450F's especially in the woods.
Example:
I've had my WR360 for quite a long time and have I've loaded it up plenty of times but never fouled a plug, last weekend I took my son out to do some woods riding (he's 12 and much more at home on a mx track than tight single track style stuff) There were three of us riding so I left him go in the middle so if he needed any help I could get him up and going again... Long story short, that small difference in riding style (alot more poking around and idling) made my bike miserable... loading up terrible and fouling plugs like never before. But brought her back home and rung her out a bit and she's as good as new.
On a positive note, by the end of the day he liked the woods and was getting up to speed so we're going back!
Rodd

 

[Scootskipper]

Thanx guys! I really enjoy this forum! I found myself riding somewhat as you describe...that is to keep the revs up where she is happy and making big power, and modulating the go factor with my left index finger. It felt great and I can't wait to get back to the trails and work at it some more. My left hand was getting tired about half way through a lap (which is eight miles at our club) and I had to add a second finger for a few turns but I don't seem to have as much finesse with two fingers as I do with one. I really love how it feels using this technique through a turn. You can exit so much harder and actually feel more in control. I can see where things might get complicated in a hurry if my finger slips off.After I pulled out from the trail and on to our parking area, I would hammer it just to see how it did. Screamed like crazy every time. :ride:

 

[john01]

Well David glad to hear you having fun at the club. Best $100.00 I've spent for sure.

 

[Rob578]

Too bad I'm not a little closer, I'd come ride with you guys

 

[john01]

Where are you Rob?

 

[Rob578]

Haymarket

Outside Manassas

I usually ride at Edingburg or drive over to Kitzmiller

 

[john01]

Rob that would be a hike to Buckingham County. We have 100 acres of our own private land with a 8.5 mile woods loop, MX track, kids MX track, and kids woods loop. We get all this for $100.00 per year. Hey not to steal David's thread but how do you like your 300?

 

[Rob578]

my opinion keeps changing every time i ride it. I've been riding bikes for almost 40 years and never realized how you could fine tune a 2T powerband by playing with the carb needle.

This thing has gone from being a pig that wouldn't outrun by KDX200 to a fire breathing monster that will destory the back tire in one ride.

I plan on doing a detailed write up sometime soon

If you guys want to ride up here you're welcome to crash here. I have plenty of room

 

[john01]

Thanks for the invite Rob and once my bones are back together we may take you up on your offer. I look forward to your 300 report.