What is your top speed with "80cc" HT Kit (With stock gears)?

Discussion in 'Performance Mods' started by macarollo, Oct 12, 2008.

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  1. macarollo

    macarollo Guest

    What is your top speed with "80cc" HT Kit (With 44t gears)?

    How fast does your 80cc HT go (with 44t gears)?

    I used to be able to do 30mph (on flat road), but I think the engine was running lean. It was vibrating like crazy. Lost many nuts this way before I learned about Locktite.

    After messing with some stuff in the carb I think it goes 25-26 mph tops on flat ground. It is not running as lean... MUCH smoother.

    All my speeds are measured using a GPS.
    Last edited by a moderator: Oct 12, 2008

  2. BigFella

    BigFella Member

    35-37mph on my stingray and thats with my son as well and im a pretty big guy
  3. macarollo

    macarollo Guest

    I wonder why some people's kit goes so much faster than others? You have a 44t gear?
  4. Mountainman

    Mountainman Active Member

    not the same but -- ride that thing

    true in all engines
    just seems to show more in your type
    can be caused by MANY DIFFERENT FACTORS
    location of said factory or factories
    not re-tooling at proper times
    all of your adjustments I would think are not exactly the same - carb ect

    not the same but -- ride that thing

    HERPER Member

    very true, also many people have posted on here who deal with many of these engines and most of them say the outputs of these engines vary from like 60cc. to 80+cc

    also how you carb and idle and throttles are adjusted like above many many factors.
  6. Mountainman

    Mountainman Active Member

    is there a true 80cc HT ?

    60 to 80cc -- well - that's not the output -- that's engine size
    horse power is more about output

    those 80cc that we hear mentioned around here ?
    I have been told that they are not true 80cc HT ?

    no expert this I admit -- I ride a Robin -- and I sure do love to


    HERPER Member

    haha im far far far from being an expert myself.. just trying to shed light from stuff ive heard. the size of the engine though whether it be 60-80cc will definitely change the overall output of the engine and the resulting speed.

    and the engines im referring to are the 80cc HT. ive got one and love it
  8. andrewdavis19

    andrewdavis19 Member

    26 x 1.9 tires, 44 tooth, 80cc HT, digital Schwinn spedo, 32.5 MPH, no tuck. I find it very hard to believe that with the same set up on a 20 inch wheel that anyone got 35 mph. :shock:
  9. sparky

    sparky Active Member

    Obviously I don't have a HT, because I have a 33cc and 44t (tho my gearbox is prolly different from a HT?) on a 20" bike, and I've definitely gotten over 32mph with tucking. My new engine isn't quite as strong as the last one, but I think it's 'cause I didn't use regular dino during the break-in. The new one will get to 28mph quicker while my chest is up, but it doesn't help much at all to tuck.

    Now that I realize the differences in the engine, the more I think the only difference is the fuel/air mixture. I wish my carb had both hi & lo jets. That would be soo much nicer.
  10. macarollo

    macarollo Guest

    I found out why my bike was going so slow...

    It was going about 26 mph on flat land...

    Today the baffle shot out while I was riding (2nd time that has happened).

    I decided to continue riding to work. It was soooo loud, everyone would look at me. I turned it off at stop lights since it was soo loud.

    Despite the loudness this thing pulled like a beast... it is like it suddenly woke up.

    There is a large hill and typically my bike used to go 24 mph with me pedaling occassionally.

    This time with no baffle it hauled to 30-31 mph going UPHILL! NO PEDALING!

    It is a little too loud without baffle, but I am going to be cutting down the stock baffle and re-inserting it.

    The stock baffle is way too restrictive. I am excited about this new found speed!
  11. s_beaudry

    s_beaudry Member

    In theory a 80cc engine is realisticly closer to 67cc or so I am told...

    Guess I can chime in with my 66cc setup then, right?

    24mph clockd with a gps unit attached to handlebars!
  12. graucho

    graucho Active Member

    32 on the silver beast. I can get another 4 but I know she'll blow.
    Last edited: Oct 15, 2008
  13. I think a lot of factors go into how fast you can go. -

    The manufacturer of the engine - mine - Powerking

    The tuning you have - performance vs. economy.

    The overall weight of the bike and it's rider. - bike- Lbs? - me 155lbs

    tire pressure - more makes the ride rougher - but much faster - less surface contact.

    gas to oil ratio you use - 20 to 1 seems to work great for me.
    I read a very comprehensive survey about this, and it seems that once the bike is properly broken in - 32:1 was the best overall ratio for the best speed. After that the horsepower was reduced.

    Physical location - I live in a location that is 4,549 feet high in altitude. Like any other engine, I needed to compensate for the thinner air.

    Vibration factors - I think more bikes could probably go faster if the vibration was minimized.
    did the builder use rubber in-between the clamps? - on mine -absolutely.
    How many engine mount points did the builder use to hold the engine in place? - on mine -3
    For me, I created a front shock engine mount - which evidently seems to be working for me better than the average HT rider based upon what I have read in this post.

    My top speed was 37mph on flat land before I got a little too freaked out.
    only once though - you know - just had to see what it could really do.
    Don't recommend making it a daily activity.:shock:

    Another factor might be I have a springer front end that may also reduce some of the vibration on a high speed run.:rolleyes:

    I have posted articles on the front engine dampener engine mount I made if you are interested in it.
    I had been asked if it made a difference - at this point I would have to say _ an ABSOLUTE YES.
    If interested just do a search on my name for posts. _ I don't have that many.

    Cool to know how other bike are performing.

    Couple pic's included to show what I did: - real easy for the cost and benefit.

    Troy Fitz.

    Attached Files:

  14. itsgrowtime

    itsgrowtime New Member

    hey carrot how did you put together that little shock absorber assembly for the front engine mount? thats interesting.
  15. HERPER

    HERPER Member

    i tried that idea.a. i wish it would work on mine.. but when i added the spring and whatnot.. the angles did not meet. and the engine fit, but the exhaust wouldn't. i dont know much about metal work but i figure it could be a fairly easy fix. just not for me
  16. It was easy, I got it all at a hardware and auto parts store.


    spring - w/ good tension - "Help" section at Autozone - but I saw many at the hardware store that could have worked.

    steel spacer - got a spacer a the hardware store that fit inside the spring, but could have a grade 8 bolt slide through it.
    Just made sure the spacer was shorter than the spring - main purpose was to keep the spring centered.
    used a dremel w/ cutting wheel to make it the size I needed - easy.

    rubber bushing - any auto store will have something you can find.

    add about 15 minutes labor - and your done.

    I have never ridden w/out it on my bike, but I am building a bike for a customer w/out one, so it will be an interesting comparison.

    I would think it has to work better than a stack of washers :grin:

    If you build it, lets hear your feedback.


    Troy Fitz.
  17. beachcruiserD

    beachcruiserD New Member

    awesome...im gonna take my baffle off, and connect some flex pipe to re-direct the fumes....
    but i have clocked myself in a residential area with a roadside mounted police radar machine(with no other cars around) at 27+ mph....since then, i have inflated the tires to the proper psi....so im thinking upwards of 30mph....(with a 44 tooth sprocket)
    I have to measure it again, but i am very pleased with 27....thats bad a** on a bicycle!
    Its funny when your're going through an area where 25mph is the limit, and other cars hear and see you, and acutally pull over to let you by!(probably cause they want to know what the hll i got and they want one too....haha)
    Last edited by a moderator: Oct 29, 2008
  18. beachcruiserD

    beachcruiserD New Member

    oh yeah...mine was sold to me saying it was 80cc, but its probably really a 68-70cc....
    no matter, still more power than a 49cc....and if an officer has an issue, it will always "Be a 49cc"!.....

    CARROT-that spring mount you got is killer!....exactly what we need for the unexpected jolt... way to go!
  19. fourfeathers

    fourfeathers Member

    Cut the baffle tube off at the cap and grind it right back to the inside of the cap. Bore out the remaining tube by .5 of a mill. Get a piece of stainless steel tubing with an inside diameter tight enough so you can sweat it on over the remaining outside baffle tube. This pipe is called the stinger and should be between 10-12 times the inside diameter in length. This stinger acts as a pressure release valve and can be cut to length according to what you want i.e longer= top speed & shorter=more low end torque. You can then start tuning the carby to suit.

    Happy riding.
  20. bootlegger

    bootlegger Member

    Im getting 25-30 easily out of mine. Ive played with it heaps (66cc) since I bought it and blown it up twice (once the bottom end and once seized piston). Ive actually got it going into a powerband.

    Today I rode it 60 miles to a job but the frame broke in two from the vibration (I have rubber between the mounts). I still made it home though. I have just got another frame and Im going to make some proper rubber engine mounts. After 2 months of playing around with this thing Ive finally got it reliable.
    Here is a list of things I have done to keep it together.

    Retap the engine mounting bolts 1/4 unc rather than the fine threaded 6mm. The bolts hold in better and dont break.

    Turn the head studs over and have the coarse end of the thread in the block. Head studs dont pull through. Get rid of the Accorn nuts and use some proper nuts with loctite.

    Just use silicone instead of a gasket for the exhaust pipe. I also cut the tube out inside of the pipe, made a second mount to the frame for it. You need to weld the two parts of the pipe together. My pipe end kept coming off.

    I put an expansion chamber on it but the noise it made drove me nuts ( Im riding it to work every day).

    The chain gaurd kept cracking so I cable tied it to the frame.

    The pin that hold the clutch arm came out so I machined the side of the arm, drilled right through the housing and pinned it with a High Tensile 1/8 machine screw and nut.

    I have also ported it and have played with different oils and ratios. After the last blowup Ive gone back to 20:1.

    The only trouble Im have having now is the carb by passing the needle valve and seat. I have to continually meter the fuel flow by playing with the fuel tap. Too much flow and it floods not enough and it starves. I have had the carb apart a million times and cant get the needle valve to shut off.

    Any suggestions would be appreciated.