Crank arm trouble..help plz

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Padraic90

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Jul 1, 2022
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Hey everyone, this will my first post so hopefully I give enough/right info. So I have a beach cruiser with a 4 stroke engine attached to it, and I'm trying to replace JUST the crank arms as the thread for the pedal has somehow gotten messed up and it's all wonky so I would like to replace the crank arms but after doing som.digginin on the web I could only find crank sets and not just the arms which is all I'm looking for. If ne one can point me in right direction i would really appreciate it thanks
 
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Tom from Rubicon

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Pedals are threaded 9/16-20. one left hand and one right hand. Option #1 take the pedal crank to a bike shop and ask them to chase the threads. #2 salvage out a junker. You would need a crank puller but at your age it will pay for it's self.
Welcome to the forum.. Just use your given name or sign off with it. It adds credence to who you are.
Also post your build photos so we don't have to guess. There many willing to help.

Tom
 

Venice Motor Bikes

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I concur with Tom when he says to 'salvage out a junker'...

Go find a junk bike with the same style cranks & then buy a crank arm pulling tool.... Or you can simply have a local bike shop swap the parts for you.

Jerry also has a good point... If you need those special 'wide' crank arms to clear the sides of the engine?, there are several companies with paid ads on both sides of this page that sell them... Start clicking on the ads & see what they have. ;)
 

Padraic90

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Thanks thank you all for the advice, here are some pictures of my bike. I have another question now...so no matter what I do I'll need the crank arm removal tool, correct? Because I just now took this nut off and seen this weird square thing in there behind it. Thanks all again for the help- Christopher
 

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Sidewinder Jerry

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Thanks thank you all for the advice, here are some pictures of my bike. I have another question now...so no matter what I do I'll need the crank arm removal tool, correct? Because I just now took this nut off and seen this weird square thing in there behind it. Thanks all again for the help- Christopher
With these bikes repairs are inevitable. Therefore one should invest in the tools that'll be required to work on them.
 

Tom from Rubicon

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Tom from Rubicon

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To be perfectly clear, the vid is of an exercycle which retains the crank arm with a bolt screwed into the spindle.
On your bike Christopher, the spindle has a threaded stud. The crank arm is retained by a nut drawing the crank arm onto the spindle taper. Same puller works on both.
Happy 4th where ever you are. Here in SE Wisconsin it rained out the parades and fireworks are postponed.

Tom
 
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Padraic90

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Ahh alrighty then thanks Tom I appreciate it. I got another question buts it's concerning the throttle, should i make a new post for this?
And thanks happy 4th to you as well. I'm in Arizona so they're still going here lol- Christopher
 

Tom from Rubicon

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Ahh alrighty then thanks Tom I appreciate it. I got another question buts it's concerning the throttle, should i make a new post for this?
And thanks happy 4th to you as well. I'm in Arizona so they're still going here lol- Christopher
Have you done a through search of the forum Christopher? Starting a new thread is no big deal. But fleshing out an existing thread has merits too. But yours is a hot new thread and will get a lot of looks so ask away.
You own this thread. As long as you keep it current and post plenty of photos.

Tom
 
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Padraic90

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I think I have trouble with my throttle, it doesn't engage the transmission until I hold the throttle down like a 1/4 of the way. Also when I take off I Have to pedal a good amount to get the bike to where I can not pedal anymore If that makes as much sense as it just made to me lol. Does anybody no whats going on? Thanks -Chris
 

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Tom from Rubicon

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Hi Chris, two questions in order to help you sort out the root of your wants per #15.

How long have you owned the bike and do you know who, was the builder and when it was built? OK that's 3.

Your engine is only 49cc which can get e bike on the flat to 35mph in a tuck. My Huffy with a Huasheng takes a bit of pedaling before the clutch fully engages. But therein is my wonder. Your transmission looks like a Grubee.
1B transmission 8 hole bracket plate. | GruBee Inc
4G 1A Transmission only: Fits Huasheng 49 & 53cc CC engines. | GruBee Inc
Look familiar?

Tom
 
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Padraic90

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I've only owned the bike for 2 months, and have only been riding it for 1 month maybe a Lil more. And no unfortunately I don't know who the builder was or when it was built. I got it from my aunt who picked it up when this guy was staying with her. And when I got it it was missing the cdi and kills witch wires were messed up and the clutch was completey thrashed and i had to replace that as well.And yes you are correct , it's the grubee 1a trannsmission. Yes on flat land with very little to no wind I can get the bike up 30( I haven't clocked it at 35 yet lol. But recently it's been a Lil more windy over here and I swear when I hit that on the bike I can only get it to like 10 mphs , and it feels like the engine is pushing hard- Chris
 

Tom from Rubicon

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Thanks for the reply Chris, chances are the centrifugal clutch pads are about shot. That engine should deliver more steam.
On take off, a little pedaling saves the clutch.
4 strokes do not need a CDI.
Sounds like your old girl just needs some TLC. Take heart.
You may have to post on other forums, as you are not getting many hits here. Though you should be.

Tom
 
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