Finally built it but one problem

Discussion in 'Motorized Bicycle General Discussion' started by jerrydellg, May 18, 2011.

  1. jerrydellg

    jerrydellg New Member

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    Just installed a 48cc 2 stroke on my schwinn clairmont. Started right up the first time. It's pretty cool. Had a small problem with the exhaust. Didn't know there was an end cap that needed to be checked for tightening and lost the darn thing. Son of a gun sounds like a damn harley now. I ordered a replacement muffler as I could not figure out how to buy just the end cap. No big deal. Was having some problems with the clutch and choke but seem to have figured it out. The chain tensioner bracket was too big for my frame so I cut a piece of the old handlebar grip I removed to install the throttle and took up some of the extra space. Still need to reinstall my rear fender and rack(you should be able to see it in the before picture). I need to do a small modification on the fender on the motor chain side. It rubs so I plan on cutting a section with tin snips and bending it to allow clearance. The only problem I'm still having is that the engine bogs down when I try to accelerate more the quarter throttle. Any ideas?
     

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  2. matthurd

    matthurd New Member

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    turn the air fuel mix screw all the way in (thats the one on the left of the carb), helps a lot on those carbs.

    later you may need to adjust your carb, theres lots of guides out there already, but try that screw first. if that doesn't fix it to your content use the search bar and look up carb/carburetor tuning.

    if you still can't figure out what needs to be done send me a pm and i'll try to walk you through it.

    also the stock chain idlers with grubee kits are JUNK. the best one i found as a reasonably priced replacement was this one http://www.kingsmotorbikes.com/bike_motor_engine_idler_pulley.html

    theres also better solutions to making the idlers grip if you're interested, again just send me a pm.
     
    #2 matthurd, May 18, 2011
    Last edited: May 18, 2011
  3. Pilotgeek

    Pilotgeek New Member

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    The screw on the left of the carb is NOT a mix screw on most models. It is just an idle set screw. Things to check:
    Plug color?
    Is the gas cap venting? Try with cap unscrewed.
    Mess with the choke a bit.
    Try moving the c-clip in the carb to the second from top position. You'll see it when you unscrew the top of the carb.
     
  4. BarelyAWake

    BarelyAWake New Member

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    umm - it looks like he has a CNS, which means it does have a fuel/air set screw - tho it may be glued in... if ya do/can mess w/it do remember to check your plug coloration to establish proper mix (white = lean & dangerous, black = rich, brown/tan = sweet).

    There's a TON of threads concerning the various CNS variants, ya can use the custom google search to get an idea - this 'un may help *shrug* http://motorbicycling.com/f51/cns-mid-range-bogg-solved-29723.html or replace it w/a NT fer like $20 or so...
     
  5. jerrydellg

    jerrydellg New Member

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    I followed the link to the dicussion about the mid range bogg problem. I'll try the suggestion. Thanx.
     
  6. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Be careful of that chain tensioner!
    Many builders advise putting a screw through the tensioner & into the frame rail to keep it from ever moving & causing chain problems. ;)
     
  7. F_Rod81

    F_Rod81 Dealer

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    looks like a nice build,
     
  8. Pilotgeek

    Pilotgeek New Member

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    My bad, I did not see it was a CNS >.<
     
  9. Greg58

    Greg58 Well-Known Member

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    Here is the cns-2 or b as some call it.
     

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  10. 2door

    2door Moderator
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    I concur. That rubber handlebar grip is eventually going to compress, loosen and the tensioner is going to rotate inward trashing your rear wheel/spokes.
    Secure that bracket so it CAN NOT move. It might feel tight now but give it a few miles and you'll see what we're talking about.
    Tom
     
  11. jerrydellg

    jerrydellg New Member

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    Is there any other option other than drilling through the tensioner/frame? I saw the tensioner (idler pulley) they have on SBP. It clamps down with 4 bolts instead of two but I believe I'll still have the same problem with the undersized frame rail. I'm trying not to drill through the frame if I can avoid it. All the information I've read seems to suggest it will considerably weaken my frame.
     
  12. matthurd

    matthurd New Member

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    what i did was replace the junk bolts for some that would let me really torque em down with out snapping.

    then take your 2 pieces that curve, and hammer em straightish. doing this then tightening it down will force the metal to contour to your frame, another thing is take a can of beans or olives or corn, dispose of the insides in what ever way you see fit, and use the ribbed section of the can to make shims, this will allow the idler to catch something much better, mine was literally unmoved by a hammer strike when i set it up.

    like i said though i'd recommend buying a replacement with a 4 bolt set up, pressure is much more evenly placed with one of those set ups.
     
  13. 2door

    2door Moderator
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    Sit back and take the time to read > tensioner - Google Search
    There have been countless discussions about the chain tensioner. Research and do what you feel will work for you.
    Tom
     
  14. dag_29307

    dag_29307 New Member

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    I agree with 2-door about the research, and as far as the whole carb. issue. I had one of those carbs. and the only solution I found for it was replacement with a NT/old style carb. Just my personal experience please do as you wish.
     
  15. jerrydellg

    jerrydellg New Member

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    Thank you for all the advice guys. The carb fix I tried seems to have done the trick (the weedeaterfuel line thing). I'll tweak it with the air mix screw after I tackle the new problem. Damn near did some major damage when my tensioner almost gave way while I was testing the carb fix. I've read most of the threads on tbhis problem. I don't have access to anything but basic tools. A ryobi cordless is my most high end tool right now. I am mechanically inclined but I am new to this type of hobby. I enjoyed barelyawake's post about the tensioners but don't know what he was referring to when he mentioned horizontal dropouts. I'll drill the thing in place if that is the best solution but was thinking of removing it all together. Like I said I read the suggestions but I'm not clear as to why I can't remove it. It seems like the easiest/cheapest/least labor intensive solution but there were all those posts about people modifying the tensioners and not removing them. I assume they're is a reason for that other than the fact that thwe chain stretches over time and will need to be repeatedly shortened (links removed) without the tensioner. I mean the whole modification thing seems like a lot of work to go through if all you need to do is remove the cover over the motor sprocket & cut the chain to length. You would check the chains tension before every ride and might have to remove one more link eventually but....... I must be missing something. What don't I know about this that has everyone else using a tensioner and not cutting the chain to length?
     
  16. dag_29307

    dag_29307 New Member

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    I have four builds I have completed, I am working on my fifth. I don't use a tensioner on any of them. I tried the first time...ended up cutting the chain down. I tried again with my fourth build but ended up letting that one go too. I am not sure why some guys feel the need to use one or if they really need to use one but I don't.
     
  17. BarelyAWake

    BarelyAWake New Member

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    "Horizontal dropouts" jus' means that the slots where yer axle goes are parallel w/the ground - making it possible to make fine adjustments in chain tension by moving your rear wheel farther back. Most newer bikes don't have this as although it does help w/chain length - it can be hard to keep the rear wheel from "shifting" and becoming crooked to the rest of the bike & the pedal chain tension is irrelevant with derailleurs anyway *shrug*

    Some folks hafta use the kit idler/tensioner because otherwise the chain will hit/chafe the chainstays, but that's not commonplace. The reason I prefer to try and have some sort of tensioner is pretty simple - while you can ofc adjust chain length by adding/removing a link, it's a suprisingly radical alteration - even using a 1/2 link is sometimes just too much, it's either way too tight and won't quite come together or jus' not enough and a lil too sloppy for comfort. Even the "simple" solution of shimming the motor mounts I feel to be awfully labor intensive for what is really a frequent maintenance task... if you ride a lot.

    My Schwinn still has the stock tensioner w/o any holes drilled or shims, but it is the four bolt tensioner which is far more secure than the newer two bolt one, even if I could route the chain w/o interference and not have a tensioner - given the miles I ride not having some quick & easy method of reducing chain slop simply isn't feasible, so I've kept it.

    If you're not planning on having yer bike be a "daily driver" & it's just for the funz and/or you don't mind futzing w/half links & shims - defo see if you can rid yerself of the pesky thing, they are a hazard and a bit of a dumb design... but if you can't you might want to try a variation one of the solutions in http://motorbicycling.com/f11/chain-tensioner-suggestions-11815.html - drilling is one option many have used & this one doesn't require much in the way of tooling, aluminum is easy to work... I keep thinkin' I'm gonna get around to copying it - but I never do lol, I'm sucha slacker;

    [​IMG]
     
  18. matthurd

    matthurd New Member

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    r.ly.
    did you read my post? hammering em out doesn't require very many tools at all, doesn't require drilling, and works quite well, because like i said, the metal gets worked into the shape of your frame.

    i literally hit my idlers arm with a hammer before i put it all back together, to make sure it wouldn't move, didn't budge at all.
     
  19. jerrydellg

    jerrydellg New Member

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    Thank you matthurd. Yes I read your post. Yours is one of the three suggestions I'm going to try. The ones that seem the most feasable are yours (the hammer), remove the tensioner, and drill the tensioner. Drill the tensioner will be my last choice. I'll probably try removing links first. If that doesn't work I'll try the hammer.
     
  20. matthurd

    matthurd New Member

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    k so just a recap, take the pulley wheel off, take the idler mounts and hammer em kinda flat, and tighten em onto your bike (like i said i'd advise you get some new bolts for this) to shape them, once they got a shape that is suited for your bike, take a ribbed can, and use the ribbed section to make shims, this gives the plates something to really grab on to.

    i'd personally recommend you use the tensioner, as chains will stretch a bit, and your sprocket will get worn a bit (causing what seems like chain stretch), making the adjustments will be much easier with one (getting a perfect alignment is also not very easy on the top and bottom either), and getting just the right length of chain isn't easy either.

    that one silly idler negates all of those issues.
     

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