Baffle Chop...

Discussion in 'Performance Mods' started by DuctTapedGoat, Dec 15, 2010.

  1. DuctTapedGoat

    DuctTapedGoat Member

    So, I chopped about 4-5 inches off my baffle for the extra flow and better sound, but I seem to be getting almost too much flow. I stuck an extra air filter in the air intake to restrict it somewhat, but I was just curious if anyone has any ideas to take advantage of the chopped baffle... Like, with that done, what doors does that open?

    I'm thinking of doing a modification to the fuel intake nipple into the carb to increase flow ever so slightly, but that's all I can think of.

    Welcome to all ideas.
     

  2. motorpsycho

    motorpsycho Active Member

    i have modified stock mufflers and baffles and they work great. if you increased the exhaust flow, you have to increase the air flow into the carb. to get the best results you should consider a k&n style hi-flow air filter. you may also have to richen the fuel-air ratio slightly as well. get air-fuel in faster and exhaust out faster and you will make a small amount of extra power.

    if you modify the fuel intake nipple and make it bigger, it will only increase the flow going into the float bowl. i am assuming you are talking about the fitting on top of the carb where the fuel line goes?
    the carb will only take in the amount of fuel needed because the fuel is shut off by the float when the bowl is full.
    i don't think you'll gain anything by doing this. the float goes down as you use fuel. the needle and seat are opened only long enough to top off the float bowl. the float bowl is always about 3/4 full and when the fuel level drops enough to open the needle & seat, a tiny amount of gas will be let into the float bowl to raise the float back up. it can only take in enough fuel to close the needle & seat. increasing the flow into the carb will not make you gain any power, flow or anything. it will just allow the bowl to get topped off slightly faster. but that really won't matter much because the bowl should never be empty.
     
  3. DuctTapedGoat

    DuctTapedGoat Member

    Well, I did modify an air intake, but the flow was too much! When I hit top end it would just fizzle out until the motor kicked over again. So now, I'm running with decreased intake via extra filter, and it seems to help with normal operation.

    I noticed this in a thread in introductions. I guess I don't get where you'd put a washer in the float bowl, but it peaked my interest. It seems like what I'm wanting to do, increase fuel into the combustion chamber. This is the target goal that I was thinking of by slightly expanding the fuel intake nipple. The only thing is I'm on a 48cc motor, and and I'm pulling about 10 miles an hour faster than him at 35 - 40 MPH. I know I have to start stepping into gear ratios to continue to raise my top speed, which is happening this week, but I want to be sure I'm getting as much bang for my buck as possible.
     
  4. motorpsycho

    motorpsycho Active Member

    well, by drilling a hole in the stock air cleaner cover, you won't really increase flow, the stock air filter is pretty much a peice of sponge, and really isn't very good.
    if your engine "fizzles out" on the top end now, that tells me that it may be too lean because you have a better flowing exhaust. when you get to wide open throttle and the engine just falls on it's face, looses power and bogs down, 9 times out of 10, that is a sign that it is too lean. if you have the older style stock n.t. carb, these carbs are designed for the smaller 50 c.c. engines, and every one i've ever seen has been jetted too lean for the 66 c.c. engine. (in my situation, i had to richen my n.t. carb quite a bit by going from a .70 jet, to a .74 jet). my 66 c.c. bike gets 32 mph, and my 50 c.c. bike gets 28 mph. both of these are 20" bikes with 20" wheels and 41 tooth rear sprockets. if i drop to a 36 tooth sprocket i would probably get 35 mph out of both of them.
    tuning these carbs is a pain to get them right, but when you do, you can actually get decent power out of these cheap little engines. the n.t. carb is a porr design in my opinion, but you can tune them without a lot of work. I tried a cns carb and i was not happy with the way it performed on my 66 c.c. engine.

    i am assuming that you removed the main jet, and put the washer under the jet to lower it?
    if this is what you did, it will have no effect at all, because when you are at w.o.t. the needle is 100% out of and away from the jet.
    I'm not really following where or why you put a washer in the float bowl.
     
  5. wbuttry

    wbuttry Member

    but remeber any thing done to these machines might make it illegal there fore causing legislation to be passed to make these illegal in all 50 states so be very careful dont ruin it for everybody else
     
  6. motorpsycho

    motorpsycho Active Member

    you can't be serious!
    you actually worry about that?
    i'm so glad that i don't have to worry about it.
    I don't ride on city streets, sidewalks or any areas with a lot of traffic or cops.
    I love in a very rural area, and out here, it's anything goes as far as i'm concerned.
     
  7. DuctTapedGoat

    DuctTapedGoat Member

    I'm pretty rural out here too. But - do you seriously think a cop is going to bust out his torque wrench and calipers to see what your engine size is? Do you think that on the street he's going to do a carb teardown?

    Anyways wbuttry, please don't hijack my thread. This is the proper category for my post - I'm talking about modifications, but where you're taking it is a totally different section. Maybe you should open a new thread in the Legal section.


    Well, I haven't done it, and the guy who posted that only has two posts. -_- It would seem that you and me are both wondering the same thing.

    But, now from what you're saying is that I would get a richer flow by getting a slightly larger jet... Got any suggestions as to who has them? I don't believe I've ever seen jets alone, but I'll do some digging around.
     
  8. motorpsycho

    motorpsycho Active Member

    sick bike parts sells delorto jets, and they will fit in the n.t. carbs.
    I got a whole bunch of jets from them i actually ordered every jet size that they sell (i think they range from like .62 all the way up to .76 or something).
    the stock jet in most n.t. carbs is supossibly a .70 from what others have said, but the stock jet is not marked with the size on them. (the delorto jets are all marked) so, guessing what size the stock jet is, is just that...a guess. i took out the stock jet and put in a .68 as a starting point, and it was WAY too lean for my engine. so then i worked my way up to a .74. a .72 made it run good, but a .74 made it run better, and judging by my plug color, it'ss right on the money. I went up to a .76 to see what it would do and it made it too rich, so i dropped back to the .74. there is no leaning out on the top end, no bogging, no 4 stroking, just clean power all the way through the rpm range, and it pulls a lot better than when it had the stock jet in it.

    everyones engine will run different due to the air filter the exhaust, and the air temp.
    so what works for one engine, may not work for another engine.
    but i have found out that there are a lot of these engines out there that need to be re-jetted to make them run the way they should.
    I have re-jetted 3 carbs on 3 different bikes and this made a world of difference in the way they run.
     
  9. DuctTapedGoat

    DuctTapedGoat Member

    Sweet! Sounds like the perfect answer to my question! Thanks so much!

    At only 3.49 per jet, it'll be worth it to get a .72, a .74, and a .76 then, so I can judge the performance range.
     
  10. wbuttry

    wbuttry Member

    well gentlemen good deal
     
    Last edited: Dec 16, 2010
  11. DuctTapedGoat

    DuctTapedGoat Member

    So, finally got the jets - I ordered a .72 and a .74. Dropped the .74 in first thing and it's great! On a cold start, within 30 yards I could really hear it getting the RPM I'm after. It's on a 36T driven sprocket and a 48cc motor. I have some adjustments on the carb that need to be made, but the temp dropped a lot when it got dark and I don't have a garage. So, tomorrow I'm going to be really adjusting it and see where I can get it topping out at!
     
  12. caferacer

    caferacer New Member

    So my engine should be here tomorrow (HS 49cc 4 stroke) and i was wondering if the top of the muffler can be like pulled off to remove the baffle entirely, i searched a little but couldn't get a straight answer
     
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