Fighting 4-stroking

[jgreene33]

Hello,
and thanks in advance to anyone who replys to this.
i have a 66cc china engine. two actually. both perform
identicaly. i've done alot of reading. and learned all about
4 stroking. i know i need to break down and buy smaller
jets but in the meantime im doing what i can. i raised the
clip the the top notch, definate improvement. i even made
a grove on the needle so i could set the needle even deeper.
that helped as well. heres where my question is. tonight
i placed one single strand of a copper braided wired in my
jet. ive heard others had luck with this. make shift kind of
way to get the jet smaller. seemed i was too lean. even
though the wire was very tiny. i even put the needle down
a notch to see if a could get it dialed in. nope. so long
story short, will i ever get this motor to perform like a
2 stroke dirt bike without an expansion chamber? seems
like ive just about got the mixture right with the custom
setting on the needle. ive heard motors thats sound just
like a dirt bike this one is a great example http://www.youtube.com/watch?v=ZjWOki4FbtY&feature=related[/URL] mine four strokes
unless under load. and when i leaned it out just that tiny
bit with the wire it staggered under load. thanks in advance.

 

[Greg58]

One thing that will help is a sbp air filter if you don't have one. A high flow filter will compensate for a jet that is a little large. Also replacing the stock spark plug, and cap will help. Ngk b6hs is what most run, I run the bp5hs which is one step hotter and has the extended tip. This plug helped mine after it reaches operating temperature.

 

[Greg58]

By the way welcome to the forum, you can search for just about anything you need to know in the search box near the top of the page.

 

[jgreene33]

thank you so much for your reply as for the plug im running an ngk b7hs the b5 seemed a little noisy if that makes any sence. as far as the cap goes i never considered that. you think this might be a spark issue? ive heard that the stock ingition doesnt address timing curves or what have you.

 

[tooljunkie]

first time i heard of a plug being a little noisy.
b7hs is 2 heat ranges cooler,but if that works for you,than good it is.

 

[Greg58]

The stock cap and wire leave a lot to be desired. I get Ngk caps at the local m/c shop for about 2$ .

 

[jgreene33]

ok guess that didnt make since. the b5 made the motor seem more noisy just to clarify. seemed to have less motor noise with the b7. that is neither here nor there my main question still remains. will an expansion exhaust help to smooth this engine out. make it run like the video link that i gave. or do i still need to dial this thing in better? thanks to all who reply but i really need to know this.

 

[Greg58]

You can't get these engines to run like a dirt bike without major internal modifications. A expansion chamber is one of the best power increasing external upgrades you can add.

 

[scotto-]

Don't fight it.......just give in.......buy a 4-stroke and the whole 4-stroking thing will vanish. It's the best remedy for that situation.

Hello,
and thanks in advance to anyone who replys to this.
i have a 66cc china engine. two actually. both perform
identicaly. i've done alot of reading. and learned all about
4 stroking. i know i need to break down and buy smaller
jets but in the meantime im doing what i can. i raised the
clip the the top notch, definate improvement. i even made
a grove on the needle so i could set the needle even deeper.
that helped as well. heres where my question is. tonight
i placed one single strand of a copper braided wired in my
jet. ive heard others had luck with this. make shift kind of
way to get the jet smaller. seemed i was too lean. even
though the wire was very tiny. i even put the needle down
a notch to see if a could get it dialed in. nope. so long
story short, will i ever get this motor to perform like a
2 stroke dirt bike without an expansion chamber? seems
like ive just about got the mixture right with the custom
setting on the needle. ive heard motors thats sound just
like a dirt bike this one is a great example http://www.youtube.com/watch?v=ZjWOki4FbtY&feature=related[/URL] mine four strokes
unless under load. and when i leaned it out just that tiny
bit with the wire it staggered under load. thanks in advance.

 

[darkhawk22]

I used a new spark plug type NGK BP5HS and made sure to clean my air filter material with dish washing soap to remove any oil/gas and it made a world of difference and reduced 4-stroking to a minimum. I clean the spark plug and filter material regularly now and a few rides to ensure good performance.

 

[jgreene33]

to greg: Did you watch that youtube video link? I wasnt under the impression that this guy did anything too major and whatever he has going on would be just fine with me. could you advise me on reaching the same level of performance he got? thanks in advance.

scotto: very funny! seriously that was funny as ****.

darkhawk: I'm going to try your suggestion as soon as I hit reply. let you know if i get any improvement!

 

[Greg58]

The first thing he has a shift kit, you can get that at sick bike parts. It sounds like he has gutted the exhaust. The new kit exhausts that are Epa stuff are very restrictive. Some people don't recommend it but I added another pipe to my end cap to make my pipe flow a little freer.

http://motorbicycling.com/album.php?albumid=259&pictureid=1611

 

[jgreene33]

update: brand new plug and no air cleaner at all. still 4 stroking. no big supprise but hey i did try it. on thing that has always been telling at least to me. is i can take the idle screw completely out and she runs awsome. i know this isnt recomended couse everyone says it would make it too lean and i could/would burn my engine up but one thing that suprises me and maybe someone with more wisdom might understand she still acts just a touch too rich even with the screw out? all the same symptoms just much quicker to go into 2 stroke mode. oh well i guess anyone would agree i need smaller jets. guess ill just have to break down and order some. any other input would be still apreciated!

 

[jgreene33]

greg: just saw your post. and you might be onto something. I for sure have an epa pipe as i live in VA. less restriction more power is understood. you imagine it might help it to 4 stroke less? more power i sure wouldnt mind but my real aim here is to get this thing to run smoother?

 

[jgreene33]

you got any pics of our bike it looks kewl from the photo of your exhaust if it wouldnt be any trouble id like to see the rest of it.

 

[jgreene33]

if i did it right this should be pics of the two im working on...

 

[Greg58]

If you want to see any ones album just click on their User name and look at their profile.

 

[jgreene33]

like your style good job man! would like an answer to post 14 if you got one.

 

[Greg58]

Yes t will help, 2stroke engines use exhaust back pressure to keep the fuel mixture in the engine. That's why on motor cycles we used different e/chambers for different needs, longer head pipe for bottom end and shorter for top end. If you can try pulling the end cap off and do a test ride, it will be loud!

 

[jgreene33]

nice thanks for all your replys definatly will do.