Maintenance?...how to get a higher top speed?

Discussion in 'Motorized Bicycle General Discussion' started by themotorbike, May 16, 2011.

  1. themotorbike

    themotorbike New Member

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    hi, i bought my 80cc bikeberry kit about two years ago, and still have original everything except rear wheels. i was wondering if there was some sort of maintenance i should be preforming after this long. Because i havent done anything more then fill the tank and grease the chain. The motor is well broken in and it flys like **** now, i love it <3.
    I really yern for a higher top speed though. Advice on the quickest way to do that too? Thankyou!
     
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  2. matthurd

    matthurd New Member

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    speed gains can really be picked up from lowering your sprocket count (so if you're running a 44 tooth in the back, switch it out to a 40 or 36 for example), expansion chambers, and then changing out the intake for a more straight shot from the carb should also help i think.

    any of those should help a bit.
     
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  3. Nashville Kat

    Nashville Kat Well-Known Member

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    The $15 billet intake is the most gain for the money- A 66 Speed carb helps if you can find one, for another $25 and shipping, or a CNS they say- don't have one

    Thinner tires give a much easier roll- 1.75 workgreat,but you can go down to 1.4 or even 1.25- personally I recommend the 1.75 with a nice road tread- they've made them for 50 years or more.
     
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  4. mapbike

    mapbike Active Member

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    1.) SBP expansion chamber from Pirate cycles or of coarse Sick Bike Parts

    2.) If your engine has the Aluminum intake get the Manic Mechanic Ported intake or the Stock steel intake for it and if you get the stock steel one get a dremel tool and grind all the rough spots out of it, that will help it flow better.

    3.) replace the spark plug with an NGK B6HS

    4.) get a high grade plug wire from Pirate or SBP

    5.) Order new head gasket and then remove head and get a piece of plate glass at home depot or Lowes 8 1/2" X 11" in size or approx. then also get some 220grit & 400 wet dry sand paper and tape one sheet of the 220 paper on the glass with some duct tape nice and flat, then lay head on glass and then with very even lite to med. pressure move the head in a circular motion and remove 1/2 to 3/4 of the squish ring ( the raised surface sealing ring ) on the head and then finish it off with the 400 to give it a very smoothe sealing surface, also spray head gasket with copper coat gasket sealer for a good seal on the head gasket, doing all this will increase the compression a bit which will give the engine a bit more kick for helping to reach those higher speeds you're looking for.

    4.) All of these things done will require that you retune the carb most likely so after you make any mods to exhaust or the intake you should run the engine a few blocks and then back, let it sit and cool for a few minutes and then remove and check the color of the spark plug to make sure it is a nice light to medium brown and not white which would mean the engine is too lean on fuel and too rich on air, clean the plug with wire brush and carb or brake cleaner between each test run after adjustments are made to clip on needle or jet resizing until you get it right, and you will pick up some speed by doing all or some of these mods. several MPH possibly and/or likely in my experience.

    If nothing else do the Expansion chamber, plug and wire, this will help a bunch if you are still running all the stock stuff guaranteed..... this will give you more speed and more low end power as well, the stock mufflers are very restrictive on most of the kits and are huge power robbers on these little engines.

    put a smaller sprocket on the rear whel like a 40T or 36T this will help if you do the expansion chamber and intake for sure, dont go with a 36T and not get away from the stock exhaust, the engine will likely not pull the 36T very well unless you free up the exhaust especially

    Best wishes.....

    Peace
     
    #4 mapbike, May 16, 2011
    Last edited: May 16, 2011
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  5. mapbike

    mapbike Active Member

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    Thats Dax has a RT carb. that is claimed to perform very good, I just ordered one last night to try myself... will likely need to be rejetted smaller but that is common on even the stock NT carbs from my experience.
     
  6. Richie rocket 72

    Richie rocket 72 New Member

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    Question I bought an expansion chamber for mine I bought the CNS Carburetor I bought the high compression head the 36 tooth sprocket as well as the high-performance spark plug and I cannot get them the bike to go over 30 miles an hour why
     
  7. MacZulu

    MacZulu Member

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    Did you rejet? It could be you just need to tune the carb, rejet and maybe change the needle to a different position. Have you pulled the plug when the engine is warmed up and killed at WOT?

    I'm well over 30 mph with stock muffler and nt carb with a 66 jet and needle set to the richest point. I have done internal work, but I did all when the engine was new so I dont know if I improved or harmed it. These engines take patience when it comes to tuning.
     
  8. crassius

    crassius Well-Known Member

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    how fast did it go before adding those parts?
     
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  9. Nashville Kat

    Nashville Kat Well-Known Member

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    One's weight is a factor- these are still fairly small engines-
    A 415 "Industrial/ Trike" chain- sometimes hard to find-

    is half the weight of a kit chain with plates not as tall- though same pitch otherwise- and rolls much much better- you can definitely feel it even pedaling so you know the motor feels it too.

    I can't tell you why- I have a 66 with a billet and plain NT Speed carb, with the Industrial Trike chain on a 34 alloy sprock from Kings Sprockets- they used to advert here-

    and with 700 x 28 front and 32 rear tires, on a Micargi cruiser frame, I can cruise at 30 and get to near 35- though I never do after seeing it at first- analogue bicycle speedo- probably more geared for 26" so the speed maybe a MPH more-
    Haven't put 100 miles in 3 or 4 years- still the first motor I got from Bikeberry in '09- usually ride my 50 cc and now more recently a 36v 500 watt hub wheel bike. I keep it pretty tame in my mid 60'snow.
     
    #9 Nashville Kat, Oct 26, 2018
    Last edited: Oct 26, 2018
  10. Nashville Kat

    Nashville Kat Well-Known Member

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    If I wanted more speed these days I'd go to a 40mm wider intake- file larger THAT billet interior and probably a 32 or less sprocket. It'd be a faster pedal to get popped and running though- not desirable here. One reason I prefer the 50cc is that it pops to running much easier, and I'm shutting off with the kill switch and coasting all the time for efficiency and an experience closer to cycling than motorcycling.
     
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  11. Richie rocket 72

    Richie rocket 72 New Member

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    Thanks for all the advice I did all of that and more I also ported it out as well and I now reach 50 miles an hour on my bicycle
     

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  12. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

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    Your bike is so fast at 50 mph because of that boost bottle!
    What size rear sprocket did you end up using?

    If you turn the camera sideways your pics will look better.
     
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  13. Richie rocket 72

    Richie rocket 72 New Member

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    I ended up using a 36 tooth sprocket however I do have one coming The Hub and sprocket adapter with the 30 tooth.I ordereed the chrome tank that attaches to the seat pole. Thanks for the advice on the picture. I will do that
     
  14. javy mcdees

    javy mcdees Active Member

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    I ride daily and cruise speed is 25-35 mph 30 is my average speed. here in miami fl i travel many 80 mile round trips into the city with many stop and go situations. got a 26 wheel 2.10 tire, 39 tooth sprocket, a MZ expansion chamber pipe with kx80 muffler a rt carb 61 jet, fred head 5.5cc, c7hsa ngk plug, and use AMSOIL 100:1 SABER oil. I am getting around 60 miles a tank almost a half gallon. the bike will scream right on up to 43mph with the powerband trying to slip the clutch. I also woke up in the hospital one day going 30 mph to work from the front wheel bearing failing. dont hink I need to go any faster on a bicycle. what you think?
     

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  15. crassius

    crassius Well-Known Member

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    no thinking needed - bicycle parts weren't made for those speeds - when was last time you heard of a motorcycle wheel bearing failing
     
  16. javy mcdees

    javy mcdees Active Member

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    20180823_104433 (1).jpg
    View attachment 99387 they fail but not like a bicycle wheel bearing fails.
     
  17. crassius

    crassius Well-Known Member

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    sorry, I meant real motorcycle - even a moped from the 70s has stronger wheels that that pic
     
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  18. javy mcdees

    javy mcdees Active Member

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    Now I am ready to try in the morning a 12-36 tooth combo, done worn out two ten tooth sprockets and the new 12 tooth wont last 500 miles I am sure. Need to find some well made sprockets. these are just paper thin. 20190124_151956 (1).jpg 20190124_151947.jpg 20190124_161743.jpg
     
  19. tanujagdale

    tanujagdale New Member

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    Great information
     
  20. javy mcdees

    javy mcdees Active Member

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    got it all to work 12-36 but could not get the rpm needed so went back to a 10-36 and it is a very good city cruiser gotta pedal a little but if the engine is in good tune it will pull you from a low rpm and mph and accelerate without pedaling just fine. I was probably getting close to 50 mph with the 12-36 but the engine could not push any faster and got hot so the 10-36 it is and it is good.
    For commuting it is excellent, if you gonna go hi rpm with it better have a new cylinder and piston waiting for ya at home in case you had too much fun.
     
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