CVT LF's Buggy Bike got itself a CVT today!!

Discussion in 'Transmission / Drivetrain' started by Large Filipino, Apr 24, 2009.

  1. I'm still giggling here and it's not even fully installed yet!
    I got this CVT for my birthday still not here till May but it's here now.
    I used this guy:
    Fancy Scooter: Gas Scooters and Electric Scooters Retail and Wholesale
    I couldn't use Pay Pal there's a glitch in his site when you register but it came Fed Ex within 2 days.
    Check out the pics below and the video.
    The 10 tooth sprocket the Titan kit comes with is a bolt on. The mounting bolts and the clutch bell it's all a bolt on,man.
    I do want to say I'll leave Cronus alone for to me it's plenty fast but I could rather easily put one on Cronus too!
    I'm really mixed up here as to what wheel to put on. This CVT has A LOT of drag.
    A freewheel would really make this shine.
    But my other option is a fixed sprocket but I gain a front drum brake.
    I'll figure it out.
    I'm so excited I think I'm gonna start tearing it down so I can flip the carrier.
    So for all you speed junkies out there,here's a tranny for the Titan kit.
    But I'm thinking you're really gonna need a freewheel.
    More to come when it's all put together!

    YouTube - Buggy bike CVT Titan initial install

    2nd pic shows that this tranny isn't really that big by looking at my hand or something.
    3rd pic shows the Titan sprocket. the c clip wouldn't go on but that sprocket has a tightening nut.

    Attached Files:

  2. KilroyCD

    KilroyCD Active Member

    That's really cool, Large! Keep us posted on this (I'm sure you will). :grin5:
  3. graucho

    graucho Active Member

    Nice B day present! What size chain fits the STOCK sprocket that come with it. Is it a #25 for a scooter? Im smiling with ya. Sounds like you have a few options to choose from now.
  4. loquin

    loquin Active Member

    Good news. And, Happy Birthday! (early, I know...)

    I picked up a CVT from ebay last week, so I'll be putting something together also. At the moment, I'm still collecting parts, though.

    On yours, Large, what is the gearbox ratio on it? Not the pully ratio - with the cover off, how many turns of the driven pulley to one full turn of the sprocket?

    Also, I believe that as you run it a bit, the stiff new belt will get 'broken in' and it won't drag as much.

    I see you're using the jackshaft from the titan drive. That's where you could mount a freewheel - on the output of the jackshaft. Staton makes a 5/8 shaft freewheel adapter (as well as ones for a 3/4 inch shaft, or a 1 inch shaft.) The chain from the wheel up to the freewheel would 'spin' as you coast, but, the CVT wouldn't. (and a chain/sprocket would only 'lose' a few percent of your motion when coasting.)
  5. Graucho the sprocket on the CVT is tiny so yea probably that #25 size.
    Loquin the gearbox when I spun it by hand is showing 7:1.
    And just the little gear box in itself is 3:1
    MAN! I'm gonna need to check out that freewheel jack shaft. Sounds like with that I can use my drum brake wheel.

    I ran into a little glitch today.

    Picture 1 shows the sprocket alignment that's cool though because I can just flip that huge sprocket
    around and it will line up but with the engine all the way up it the chain won't clear the housing.
    I want to retain the 3 speed for now so I can choose what permanent gearing I want to go. This is the early Titan aluminum carrier.

    Picture 2 shows the current Chrome Titan carrier I had laying around. Sorry it's a little dirty. OH LOOKY HERE!! Extra mounting holes!! With this I can have the sprockets almost vertical of each other!!

    Wife is the boss of the house. My host home guy is on a home visit but it's cold out anyway.
    She wants us to go see family today.

    So that's all for now.

    I'm excited.

    Attached Files:

    Last edited by a moderator: Apr 25, 2009
  6. Nuttsy

    Nuttsy Member

    Couple of Pointers

    Large, if I may...
    Take the cover off the gearbox and MAKE SURE it has oil in it. Some come through almost dry (which will ruin the bearings in short order); others come with (some) grease smeared on the bearings. If yours has grease, I recommend cleaning it off and refill with oil. It keeps the gears quieter also,
    Next tip: use threadlock on the set screw of that sprocket. But even then, mine worked loose and the sprocket FELL OFF amid test ride! To remedy this I ground a little off the back of the sprocket until the circlip once again was useable.
    Good luck to you, I know you're gonna enjoy that CVT.
    Oh, and the original sprockets that come with the CVT are for 8mm chain 17 or 18 tooth.
  7. THANKS for the tips Nuttsy! I really would feel safe with that clip in there. It looks like I may have to shave inside the sprocket where it seats because on the end of this shaft it gets fatter which is why it won't go any deeper.
    And I didn't even think about the oiling. The gearbox has oil in it no grease around the pulleys.
    Will check it in the morning.
  8. The drag will loosen up a bit once the gears/belt gets broken in.

    The stock sprockets they usually come with are 8mm.
    You can get splined sprockets either in 8mm or 25H chain size.

    If you'll be mounting the CVT not upright,
    be sure to replace the oil plug bolt with the hole in it with a sealed bolt.
    I fill all my CVTs up with synthetic 10w30 oil. Works great.
    Last edited: Apr 26, 2009
  9. This CVT actually has the vent plug on top when installed sideways. You can see it on the first pic. Also the CVT logo on the cover is right side up.
    Here's some pics of the finished product!
    It's a 3 speed with CVT.
    Yes,I can still shift gears.
    1st gear felt like 1st gear when I had the 5 to 1 gearbox! Sorry but that was my experience. But I did rather notice an increase in pulling power and overall higher speed but watching the belt which is easy because it's right in front of me never went to top gear. It's like it stayed on....5 to 1 but maybe a little steeper because I did go a bit faster.
    2nd gear same thing. Higher overall speeds but the gearbox never went to top gear. It's a variable tranny though so as long as there is what's that word.. resistance from my weight or the wind whatever it will stay on the right gear.
    3rd gear the engine will keep me at about the same speed as with the 5 to 1 gear box but with less rpm's.

    I do need to get rid of this 3 speed arrangement though. That huge sprocket is proving too much for the jack shaft. Because it's a 5/8 sprocket with a reducer to fit on that 1/2 inch shaft it slips unless you get it really tight on the sprocket bolts. Well one of the bolts snapped off and I couldn't get it out broke my extractor #$%$#.

    So tomorrow I'm bringing out that 5 speed cluster wheel I really need that freewheel and I have a 10,12 and a 15 tooth to play with the gearing. These are 1/2 inch size so slipping would not be an issue. And with the larger sprocket that would really take the load on the carrier.

    Today's ride was just not fair though in evaluating this CVT because I'm absolutely sure my huge sprocket was already loosening when I put on the gas. With the 5 speed cluster wheel and the smaller jack shaft sprocket that would really take the load off and I can really give a honest opinion.

    But I do know that Cronus will not get this mod because it does very well on hills the gearing is perfect and with a fixed sprocket the DAX gear box is very very close to having a freewheel when you need to pedal with engine off.

    The Buggy Bike does a lot of hauling so I need that gearing to keep me along.

    Pics below shows my install and even with a big sprocket it clears when you use the extra mounting holes and that #$%$@ huge sprocket with the stud that won't come off and the reducer that keeps slipping #$%$@!!

    Attached Files:

    Last edited by a moderator: Apr 26, 2009
  10. loquin

    loquin Active Member

    If the CVT is never getting into the high end, this means that your overall gear ratio is too low. (and, you'll end up with excessive belt wear on the CVT)

    The initial CVT ratio is 7:1, but, when the CVT belt gets into the high range, the CVT will be at 3:1 ratio. This is the ratio you need to use in your top-end calcs.

    Here's the 5/8 inch freewheel adapter, BTW.
  11. Sure enough I have the 5 speed cluster on with the 15 tooth on the jack shaft and it's staying on 7 to 1 even with engine screaming. So maybe I'll put on the 12 tooth.
    Is there any way to adjust these things? I rather like the gear it's on now because it has the pulling power.
    I do notice like in the video above at no load it still takes a lot of RPM before the belt goes to top gear as if the spring is too stiff.
  12. Wait a minute loquin. I just read your post again. My daughter has my card reader so I can't upload this video I made today of what it's doing. Right now my gearing is comparable to Cronus gearing maybe a bit taller but this gearing did okay with the 5 to 1 gearbox.
    It goes slow and it never builds up. So I should go even lower? Or should I go higher changing my jack shaft sprocket over from a 15 to a 12?
    I'm also thinking my spring on the second pulley where it's visible may be too stiff. Any way to adjust this?
  13. This post deserves it's own thread. I figured out how to adjust these CVT's. Sorry my daughter still has my card reader so I can't yet transfer any pics.
    On the secondary pulley where the exposed spring is,you can adjust the tension to the spring. I set mine as loose as it can go tonight. In the morning I'll see if the shifting improves.
    I wish I can show a pic but essentially put a socket on the chrome nut over the spring then with a thin wrench turn the thin nut that's connected to the spring cup while holding the chrome nut with your socket wrench. Turning this thin nut clockwise tightens the spring making your CVT shift at a higher RPM and turning it counter clockwise makes your CVT shift at a lower rpm because spring tension is less.
    Again I'll see in the morning how this changed anything. Originally I saw about 2 mm of thread then I turned the nut counter clockwise as much as it would go until it bottoms out and there's no threads visible.
  14. loquin

    loquin Active Member

    The contra spring is there just to keep the driven pulley sheaves snug against the belt. I don't believe you want to be adjusting it much...

    If the gearing is too tall then the CVT isn't going to ever be able to get out of the 7:1 low speed range.

    The gearing for the top-end speed should be chosen based on the 3.2:1 gearbox on the output of the CVT, and NOT on the 7:1 total reduction at low speed.

    So, if you want to go 25 MPH (max), and you've got a 26 inch wheel, the wheel needs to spin at 323 RPM. If the motor is running at 7000 RPM, the total reduction between motor and hub must be 21.6:1.

    Since the CVT gearbox is at 3.2:1, the remaining reduction should be apx. 6.75:1

    What are the tooth counts on the CVT sprocket, the jackshaft(in) sprocket, the jackshaft(out) sprocket, and the hub?
  15. Man the tinkering just never seems to stop. The 3 speed set up was rather okay except that I was slowly losing 2nd gear and my huge sprocket was slipping too much so naturally I have to find another way.
    Well this go around I think I got it.
    This CVT I rather have to get used to it because it loves rpm so I gotta keep the engine spinning.
    But it's eerie because when you set the rpm's to get you going you just hold it right there to allow
    the bike to catch up. It just accelerates while the engine stays at the rpm your throttle dictated
    to it..yea.
    So there was this slight downward slope I didn't video it and I gunned it. It still wanted more
    I was absolutely flying it must have been close to 40 mph.
    So to lessen the loads on this tranny I'm gonna do just one more mod and that's to change the 15 tooth on the jackshaft to a 16 tooth.
    This go around there's far less stresses on the jackshaft sprocket from slipping because the wheel
    has a larger sprocket than that tiny 19 tooth on the 3 speed. And that really makes a difference.
    Here's my riding video from today.
    Oh and that Bang Bang noise you hear when I slow down? That's my coaster hitting my bed in back.
    It's rather fixable but seeing that's my only brake this trike is rather dangerous right now.
    I really need to do a front brake.
    And maybe a ram air... and route that exhaust... some paint maybe...

    YouTube - First Ride Video Titan Front Wheel Drive Buggy Bike with CVT mod

    Attached Files:

  16. This is a 20 inch wheel so the sprocket on the wheel if I remember right is 28 tooth to the 10 tooth on the Jackshaft. Then it's 15 tooth on the end that the 10 tooth drives from the CVT.

    I'm kinda funny with math stuff. I understand better how many times an engine turns for one revolution of the wheel.
    For the 5 to 1 gearbox I always tried to go 5 gear box revs for one rev of the wheel.

    So do you think a 16 from a 15 is okay? I have a 20 tooth and I already know that's too low.

    Maybe a 17?

    Many thanks in advance,btw.

    And on that spring tension it was set down a bit needing a lot of rpm to make that belt go even at freewheel with no load. Adjusting it down made it shift up with less rpm.
    It's not slipping but I'll keep a watch on it.
    Last edited by a moderator: Apr 30, 2009
  17. loquin

    loquin Active Member

    Currently, you have a total ratio of 13.44, motor to wheel

    If you go to a 16t, the ratio would be 14.34, and for a 17t, 15.23.

    at 7000 RPM, the top end with a 20 inch wheel is about 31 MPH.

    With a 16T sprocket, that would drop to about 29 MPH, and for the 17T sprocket, it would be about 27 MPH

    (the 20T sprocket would drop it down to about 23 MPH)
    Last edited: May 1, 2009
  18. loquin

    loquin Active Member

    BTW. Were you using the 20T sprocket at the same time as the 19T sprocket at the wheel?
  19. Yep. The 3 speed got the 20T and that puppy had the 19 tooth sprocket at the wheel so you can see how that would strain the whole setup but with the 28 tooth at the wheel the strain is significantly less.
    Also the 15 tooth has a 1/2 inch bore. The 20T has a 5/8 bore with a reducer. Aside from actually drilling a depression so you can screw into the axle I've done this and snapped my axle down the road that's how much strain it was getting there really was nothing much else to do aside from just welding the #$%^ thing on there but it would snap sooner or later.
    But because the wheel sprocket is larger on that 5 speed cluster wheel currently on my bike then there's much less strain on the system so maybe I'll try that 20T on there again. 23 mph is acceptable because this is a load hauling trike I get my groceries on a daily basis and I really want to tackle that hill.
    Then my other thoughts are the bigger the wheel sprocket the less strain on the jack shaft so I have an answer right here with a 36 tooth bolted to my original drum brake wheel but without that freewheel and I need to get this welded better at the local muffler shop.
    In real world situations the only times I'm actually pedaling though and loving the freewheel is when I go to the flea market walking my trike with no drag is just sweet and it's a rolling shopping cart you wouldn't believe how much %$#^ you can fit back there.
    Then there's that stretch of park when I shut it down and pedal in the park area when I'm gonna walk my dogs trapped in my cage.
    Also a freewheel when you throttle down just keeps that trike rolling. That's always a good thing but down hills sometimes a fixed sprocket you can use engine braking.
    I may just slip that drum brake wheel on this weekend after getting that sprocket welded I really want to keep that 15T sprocket on the jack shaft because any bigger in teeth numbers then the bore is 5/8 needing a reducer.
    But what I think I'm gonna do is get with Gebee and buy a 44T freewheel sprocket to mount on a 20 inch BMX freewheel hub or get their hub that comes with their band brake and lace a rim on that puppy.
    But it seems Gebee.... there's no way of buying directly from them.
    Anyone know any distributors?
    Thanks again loquin for those top speed numbers!
    Last edited by a moderator: May 1, 2009
  20. loquin

    loquin Active Member

    I agree about the freewheel. Staton sells a freewheel adapter in various bore sizes, for 12-15 bucks, btw. So you can mount a freewheel on a shaft. Then, although the rear sprocket/chain would still spin when coasting, the drag on a chain drive (only) is pretty minimal. (properly aligned, a chain drive can be up to 98% efficient.) With setup, you would use a standard freewheel on the output of the jackshaft, and a standard sprocket on the rear hub.

    Here's Staton's standard freewheel adapters. He also has three-prong freewheel adapters. I'm not sure what the difference is with them...
    Last edited: May 1, 2009