2mph increase in about 5 mins

i took out the baffle and the endcap, pretty much straight piping it now. took it for a ride and noticed a nice increase in power as well as an added 10km/h+ to my top speed which is now around 60km/h.

how long until this starts affecting the engine negatively? any way to decrease noise (not that i mind it) without losing the added power?

im also trying to think of a quick release device for endcap baffle thingy so i can keep it in a little case or something during the daytime and be able to stick it back on easily at night or whenever i need to be stealthy.

how about a cutoff 2 way valve and 2 mufflers,one muffler stock and one non restrictive muffler. and i have a intake silencer,its just a rubber boot from the carb to a 9" aluminum pipe pointed down toward rear of bike,it cuts down on intake noice by a lot.

mike check the other post you made in my thread for jetting info.

i dont think it will gernade the engine. just rejet and be very wary about the way you ride.

*** and if you want to hit a midway point, take a 1/4" drillbit to the endcap and put 5 holes in the end. it quiets it down alot, and makes it work a little better without risking the engines life.

I ride 8 miles to work one way, and the end cap fall off once I couldnt even hear myself think. Noway I would leave it off, it did give the bike more punch, but not worth it. my .02

what a can of worms this topic is! I think you have to realize where you are going to ride at when you decide this. i have two kit bikes one is totally stock the other is modified. The mod bike has better flow thru the muffler. Why assume the bike needs re-jetted. Are u sure the engine was perfectly jetted when u got it? I first tried a run with the end cap off, bit too l;oud for me and i noticed it was too low on back pressure(popping and snapping upon deceleration), although i have seen worse cases of the same before such as a car with a performance muffler. So i cut the tube that is welded to the cap very short an run i8t like that. There is a bit of extra noise but the bike has plenty back pressure. I have never rejetted it although i am no in the middle of an engine strip down. After 1000 miles or so i have no noticble wear on my rings or cylinder walls. It has broken in well and 90% of these miles were run with the mod to the muffler.
I live right off a rural highway where transports can be heard braking and shaking the plates in the cupboard every hour of the day an night so i get no complaints, however if you live in the middle of a posh suburb maybe consider an e bike or at least a four stroker. As far as the enviroment is concerned you have to put it all in perspective-when i am not driving my bike i drive an 87 chev 4x4 that gets 15 m.p.g. so.... which is worse? if i drive an e bike the local power plant burns coal is that better? what about the dead batteries i produce? it's real hard to find good stats on these things to understand which is best for the environment. For example i am a licensed heating tech. Propane companies will tell you that propane produces much less carbon dioxide per leiter than standard furnace oil, however they dont tell you that have to burn almost double the amount of it to do the same job. Since most of these studies are done by large companies who are looking for ways to promote thier product i usully doubt the integrity of the study. Personelly i will conserve energy as much as i can cuz thats all i can do.

Lincoln said:

Why assume the bike needs re-jetted. Are u sure the engine was perfectly jetted when u got it?.

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not to shoot you down or anything, but id like you to know that im a small engine mechanic.

# 2 i have tuned 80hp + banshees and various other two stroke engines for years, since i was 13..... i have the papers from school that said i got a 99 average on the course so.....

FYI: any time you play with the intake or exhaust as far as opening or closing it up you check your jetting, its not as important when it comes to a 4 poker but it is totally necessary on a two stroke.
When you run a chainsaw for a job you start turning mixture screws in a few weeks just because you know.

You always assume proper mixture before anything.....

other than that your right about everything else, especially popping and snapping but even that wont hurt anything if your careful and dont ride like a jackass (which most people who think they are tuners or mechanics will surley do)

I dont disagree with fuel/air ratio needing to be set humsuckler, but what i am saying is the motor isn't set when you get it! My mod bike shows no signs of running with too much air, though it should be due to the fact that i have modified it. I am not a small engine mechanic, and i must admit i have very little experience with the same. I'd love to know how it is i could set it if i did want to- i have been trying bike sahops for diffrent sized jets and so far found none and there appears to be no adjutment of any kind on the bike other than the idle screw. If there is a way of rejetting these little bikes i would love to know how ! Again i have the 68c.c. chinese built two stroke engine's on two of my bikes.

well, your pretty much out of options as far as purchasing main jets goes. the same for the needle.

i kind of figured that you menat that they were off from factory but i didnt want others steered wrong!

as far as "jetting" goes with these about all you can do is adjust the slides bottom out height with the cable adjuster on top of the carb, and combine that with needle settings. thats about it, until you get into filling the stock jet with lead and redrilling.

again, sorry for butcherin ya up fellow easterner lol

I rejetted my carb with some Dellhorto jets. I can"t remember which part number, but I run the .65 mm jet. my motor doesn't bog down at WOT anymore. Getting my bike back together today, and trying out my new needle setting since it quit wanting to idle. I remember once when my exhaust enncap came off, the motor was so rich that it would shoot flames out. Looked cool at night. Was running rich during break-in.

Humsuckler said:

well, your pretty much out of options as far as purchasing main jets goes. the same for the needle.

i kind of figured that you menat that they were off from factory but i didnt want others steered wrong!

as far as "jetting" goes with these about all you can do is adjust the slides bottom out height with the cable adjuster on top of the carb, and combine that with needle settings. thats about it, until you get into filling the stock jet with lead and redrilling.

again, sorry for butcherin ya up fellow easterner lol

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As mentioned in another thread recently it is a huge mistake to "adjust the slides bottom out height with the cable adjuster on top of the carb". That is the job of the idle setting screw on the side.

As far as air/gas ratio there are a couple options. C-clip on the needle for low to mid RPMs. For WOT in addition to jet size you can adjust float level via the two prongs.

xlite said:

As mentioned in another thread recently it is a huge mistake to "adjust the slides bottom out height with the cable adjuster on top of the carb". That is the job of the idle setting screw on the side.

As far as air/gas ratio there are a couple options. C-clip on the needle for low to mid RPMs. For WOT in addition to jet size you can adjust float level via the two prongs.

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im going to point out to you too. adjusting the slides bottom out height with the adjuster on top is not to lift the slide at all. that can cause undue stress on the cable at full throttle, the only purpose if this is to take up slack in the cable.

but thanks anyway

also, adjusting the float lever wont give you any more fuel through the jet buddy.... hate to think you think that way but thats only a cure for starvation.

I was told by a guy at the death race that my bike was rich and not making power. He told me to shut off the fuel valve and that before the motor would die is would surge with power. Once I put the smaller jet, it was like a new motor. Twice as powerful and twice as fast. Still haven't got the bike back together because I'm waiting for a part. Final tuning and should be a blast. The best mod a have is a welded in motor mount for the front mount. I'll get pics up as soon as I'm finished.

Mrakulous said:

I was told by a guy at the death race that my bike was rich and not making power. He told me to shut off the fuel valve and that before the motor would die is would surge with power. Once I put the smaller jet, it was like a new motor. Twice as powerful and twice as fast. Still haven't got the bike back together because I'm waiting for a part. Final tuning and should be a blast. The best mod a have is a welded in motor mount for the front mount. I'll get pics up as soon as I'm finished.

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yea but what do you do when the motor dies?

he was right in a way, the main reason you get that surge in performance is a lean condition when the gas starts to burble. however, the happytimes are notoriousley air starved stock, so a smaller jet is where its at

The Chinese are cheating on the CAT's you got to be kidding, I thought they just put antifreeze in baby formula

these things actually have catalytic converters? do they even do anything, i heard they pollute more then a car almost

hey can you give me your necromancer spell.
my 19 year old cat died last december.
i figure if you can bring a 2 year old thread back from the dead, my cat might have a chance.

Hmm...

Revive an old thread w/relevant info - or create another duplicate?

While we don't pester folks to "use the search" here, it is somewhat refreshing when it's obv someone has

no backpressure?