Pocket Bike Engines Tutorial

Discussion in 'Rack Mounted Engines' started by Haggard, Dec 14, 2007.

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  1. Haggard

    Haggard Guest

    This is the frame I'm going to rack the pb engine on. Its an old (not sure how old) CCM cruiser frame. (Made in Canada). It's kinda unique the way top bar from the rear flows half the hieght of most. only half way up the seat tube.
    I've fitted replacement forks after removing the origal bent ones. I bought the frame the same time as the red one pic'd which is my daily ride/work/ do the chores/ haul the trailer play in the mud ratbike.
    I got them both in real poor shape for $50 for the pair.

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    Last edited by a moderator: Dec 17, 2007

  2. Haggard

    Haggard Guest


    Look at the pics below. I use a cut off blade and trim a 1/2 '' triangle off all the corners marked in red. Then I use a grinding disc to finish rounding off all these corners. This is just for looks and not essential. The last pic shows the finished effect

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    Last edited by a moderator: Dec 17, 2007
  3. Haggard

    Haggard Guest

    HEY. check this one out. Just found the pic. My first Rackmount of this type with these engines.
    Had the jackshaft to the rear behind the engine . Worked quite well but is much more stable the way I do it now. Its a good pic as it shows the drive line quite well. Looked pretty wild. I'd even get old farmers hunkered down checking it out. I've made quite a few improvements since then but heh ,lol it worked:grin:


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    Last edited by a moderator: Dec 17, 2007
  4. Haggard

    Haggard Guest

    did a little sanding ,rc splash and have bicycle pretty much together,
    Will mount the rack tonight .
    Please understand, it's nothing fancy because its built with parts from 5 different bikes that had been discarded as most of my bikes are . The fenders are from a road bike and are a little narrow but I think they will suffice for now.
    Even the paint was from a recycling depot that I drop by every couple weeks and grab a few half full cans that some one has dripped off.
    Had to mask with electrical tape as am out of masking tape but the paint didn't notice the difference so what the heck!! : L

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    Last edited by a moderator: Dec 17, 2007
  5. Scottm

    Scottm Guest

    I really enjoy watching a project come together.
  6. Haggard

    Haggard Guest

    Yeah ,Scott , Its nice to see what others are up to. Always something different to look at and different perspectives to take into consideration.

    I've mounted the rack on the cruiser frame and did a little detailing also. The front mounting rails will be cut down to desired length and attached to the seat post tube once we do the secondary drive and decide how far forward or back we want the kit.
    A couple things to take into consideration are the exhaust proximity to your jacket!! ALSO , THE JACKSHAFT PROXIMITY TO SAME. The tank will be mounted above the exhaust and jackaxle which will act as somewhat of a shield , but its a good idea to make some kind of chain gaurd to cover the jackaxle JUst so's nothing gets caught up in the workings and also to keep any chain oil from splattering on your clothes.
    We can use these front mounts to tension the chain/belt of secondary drive once it is installed

    Other than mounting the tank , running the secondary drive to the wheel , be it chain or belt, still not sure, depends what parts fall my way first,and installing a throttle, she's pretty much good to go.
    Will continue as time and parts allow but ony a couple days till Christmas and just got orders for a couple custom builds that take priority but plan on finishing this build and riding it by boxing day at the latest.
    Only a couple hours work left but havent the parts or time at the moment.


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    Last edited by a moderator: Dec 22, 2007
  7. ocscully

    ocscully Member

    Photo Quality?


    This is a great thread and the projects you have put together and shared here on the forum are all very interesting. But the photos you attach to illustrate the builds are almost unreadable and because of this they do almost nothing to illustrate what you are trying to share with us. I know you have the ability to get clear photos because in your thread Show us Your Computer space the third photo in the line up has plenty of detail and good focus and good exposure and you seem to have the soft ware available to draw over them. I for one just wish you had better photos to go with your build threads, as you are really doing some very interesting things.

  8. gone_fishin

    gone_fishin Guest

    what can i say? a brilliant contribution, Haggard, thank you :cool:

    (i think Mark Twain had you in mind when he added "...If you live." :lol:)

    "....Get a bicycle. You will not regret it. If you live." - Mark Twain - May 10, 1884
  9. Haggard

    Haggard Guest

    hahahaaa , I be thinking "Brilliant" just a TOUCH of an overstatement, lol, but thanks.
    Mark had a fabulous amagination and was definitely brilliant .
    A Conneticut Yankee in King Authours Court is one of my favourites.

  10. Haggard

    Haggard Guest

    ~The Clutch~

    Heres a few problems I've been up against and a few of the remedies I've come with concerning the 49cc pocket bike centrifigal clutch.

    With a stock 49 cc cag, I can take off from a red light at the same time as traffic, pedal about 4 or 5 cranks with the pedals to help her climb into the torque rpm range, and help out the clutch also, and very seldom does the regular traffic keep up to me off the line . A quarter to 1/2 block distance is usually when a few will start going by . I'm at approximately 35 mph and getting into the higher rpm range at this time.

    I try to always give it a crank or two with the pedals before accelerating and letting the clutch engage. I've had clutches last approx. 3 months of everyday hard riding before needing replacing.
    Biggest problem i've had with the clutches is the darned springs.
    After awhile, ,You'll know right away by the sound and feel of acceleration when a spring breaks and want to change immediately. as the schrapneled spring will chew the snot out of the clutch pads and clutchbell aswell!!!

    Riding the old chain drive Harleys, It was a given You never left home without a quick connecter for when the chain broke.
    Notice I said when, not if??

    I NEVER go anywheres without a patch kit, AND an extra clutch spring.

    Well I try not to anyways.
    I'm remembering one rainy night ,with a failing clutch, I pedaled up a few alleys looking for something, wasn't sure what at the time until I came across an old washing machine that had been discarded and made up some clutch springs on the spot from the springs I garnered off the washer. I've used springs out of a busted up lap top computer also and a few other unlikely sources.

    Much better to carry a spare


    Thefollowing deals with experimentation. Theres a good chance You'll wreck a clutch or two if you do this and you might not notice any benifits at all, depending on your riding style. If Your clutch is engaging alright when accelerating and not wearing out real quickly, please DO NOT try the following

    Ifyou dont mind pedaling a bit when taking off,and have read the warning above, and can afford to replace a few clutches, try make some lighter springs that will engage about 3 ,4000 rpm .
    I found this lower engagement suits my riding style and didn't adversely affect the life of the pads once I got making the springs mastered.
    I was buying a clutch a week for about a month until I did though so You might not want to try this..

    I make a couple dozen or so at a time out of springs with a little less resistance to the stock ones. make a few sets of 6 varying the length a little.
    Pretty simple to cut one to size , use torch to heat while bending out the hooks on either end. You wanna nice smooth , even bend to lessen the likelyhood of premature failure.

    To get them fairly precice , I use a fish scale, not a scale off a fish, lol ,but a scale designed to wiegh in fish.

    Its a hanging scale, hang it off something solid, hang your new spring off it, then attach a couple pounds of weight to it. use some calipers or something to measure the length of spring underload.
    Assuming you made them all the same length to start with, and your using the same wieght each time,they should be close under load but sometimes there out a bit. Just make a couple sets of 5 or 6 ( 3 plus a couple spares) that are pretty even . them make a set a little lighter, a set a little stronger .

    If some have a bad bend or a kink or what looks like it might be a weak spot ,or if they fail the length/strength test you did with the wiegh scale , Throw these away. I probably toss about a 1/3 when I do my little quality control.
    Takes maybe half an hour to make up a few good sets of 5 or 6.
    Try these different strength springs in sets and see what feels Best to You.

    These homemade clutch springs are likely to fail sooner than a manufactured one will so pay attention to any change in engagement or sound(a broken spring will rattle around sounding like a light pinging noise) and one clutch pad will be dragging. You'll feel this but might not recognise it till to late.
    Its to late when the schrapnel from the Broken spring has chewed up not only your cluth pads but your clutch bell aswell. Go Spend $50 and replace .
    Last edited by a moderator: Jan 7, 2008
  11. Haggard

    Haggard Guest

    You wouldn't have a spare camera by :rolleyes:chance?? My digital got stolen and all I have now is my $25 logitech webcam.
    The pics of my computer room were taken before the theft.
    Last edited by a moderator: Jan 8, 2008
  12. CC XT rider

    CC XT rider Guest

    Buy the tutor a newer Digital camera (eBay Used?)-send donations via PayPal?

    Curious why thread is `Pocket Bikes..' when the HPV in pictures appears to be a single speed `Beach Cruiser', not a foldable frame design.
    DO you have a decent Mono-pod for better stability of your shots??
    Master builder; have you built any engine setups for a `bent trike?*? At Challengebikes.com can see `Trip around the Big-O' by BentJay for trike pic
  13. ibdennyak

    ibdennyak Guest

    extra camera

    Hey Haggard.....actually I do. PM me.....I won't have to shake my magnifying glass in sync with your pics anymore. :grin:
  14. Haggard

    Haggard Guest

    The title refers to the 49cc cag 2 stroke engine that is widely used on pocket bikes .
    Hence "pocket bike engines". probably could have named it something better.
    Any ideas??

    I havent motorized any recumbents as yet but checked out challenge bikes and they look way cool and I don't see any barriers that would limit a motored version.
    Last edited by a moderator: Jan 12, 2008
  15. Haggard

    Haggard Guest

    Hahahaa. takes me back to to '50s. WHOle ~lotta ~shakin~goin~onnnn.
    Mind you I wasnt around till the '60s.:grin:
  16. miller450r

    miller450r New Member

    Can you describe how you go about adding the pulley/ or sprocket to the bike wheel itself, is there a part you normally like to use?
  17. Haggard hasn't been around here in a little while. You should introduce yourself while waiting for a reply!
    Haggard RULES BTW.
    I wonder what he's doing these days.
  18. srdavo

    srdavo Active Member

    on this build, it looks like he used a regular "happytime" sprocket, mounted with a rubber "rag joint".

    Haggard started a new job, which takes up a bunch of his time.....

    He'll be back!!
  19. Marktur

    Marktur Member

    Where have you been, Large...been a while since I've seen a post from you...
    Hope all is well!
  20. Haggard

    Haggard Guest

    Hi sorry so long to reply .I have attached with rubber mounts similar to the HT sprokets.
    I've also garnered old aluminum steet signs and cut disks out of them ..
    I found attaching the pulley to the spokes was costing me a wheel a week on average due to broken spokes. By using a disk and attaching the pulley to it solved this as the disc actually mounts with brackets around the spoke tensioners which are a lot stronger than the sp[okes themselves.
    Heres a pic . will give you a bit of an idea.

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