Motorized bicycle engine top end rebuild and an engine stand

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Norman

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Guys I've been working all day today first on building an engine stand and taking pictures of this then I took the engine off the bike and tore it down taking pictures and doing some mild performance things that any of you can do I was going to get wild with it but after taking it apart and seeing its a bushed rod on both ends I pussed out as this engine wouldn't last 5 minutes doing what I had in mind to do. Anyway I'll maybe start tonight on the posts but I'm still puting the engine back in the bike and almost done So when I do start the pictures could you wait until I'm done before you make any comments on this post or if you can't wait and want to ask something pm me instead ok? I'll start as soon as I get the bike going. There's I think over 30 pictures so it will take a while.
Norman
 

Norman

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Re: Engine top end rebuild and an engine stand

Ater writing the opening on the board I found out my engine has bushing on both ends instead of needle bearing( I kind of figured it did) so no real hot rodding on this but we will go from off the bike to back together on the engine and that is where it will stop cause putting it all back on is only a reverse of takin it all off. I feel naughty when I say thatrotfl
 

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Norman

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Re: Engine top end rebuild and an engine stand

use vice grips to work arm to help get the cable out of arm same when you go to put it in, saves your fingers.

Here is whats under the clutch arms cover a ball that alot of you loose and a short rod the ball goes in first then the rod and grease everthing before you assemble it and note the screws the long screw goes on top at the back and doubles as the front chain guard mount.
 

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Norman

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Re: Engine top end rebuild and an engine stand

1. master link notice the open end is pointing to the rear when you are looking at the link as chain goes to the front sprocket, Top chain run.


2. this is the easy way to remove the master link clip pliers are pushing the open end off or towards the front pops off the pin in the rear and to come off so easy and you will not loose it this way.


3. see the clip is off the rear pin


4. the little booger that give people fits 10-4! amen and so on.
 

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Norman

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Re: Engine top end rebuild and an engine stand

1 & 2. I'm going to take the ignitioncoil out and leave it hanging on the bike cause the wiring goes through the frame and I don;t want to fish it through again.next pic. is the coil hanging.


3 & 4. no paint under front or rear mount I think this helps to keep the engine from wearing away the paint and that would allow the mounts to come loose then you get to walk or pedal.
 

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Norman

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Re: Engine top end rebuild and an engine stand

using scrap tubing and some strap this is what i'm making what I didn't know is the strap is stainless sreel and I can't gas weld stainless so in the next couple of pic I figure this out and cut a different strap. I did try to arc weld but being out of pratice I burned through the tubing really badly so while cussing I made the changes.



TADA! looks like it will work and make life a little easier and its made out of scrap
 

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Norman

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Re: Engine top end rebuild and an engine stand

off with its head and a look in the cylinder a little tapping on the side of the head and cylinder with your hand will free it up do not take a screw driver and pry it apart or a hammer as you will tear something up and thats not the idea of what we are doing if you got a stuck piston in the cylinder use a wooden dowel or hammer handle and tap on the piston while pullin up on the cylinder get inventive but don't tear it up
 

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Norman

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Re: Engine top end rebuild and an engine stand

I'm using a .004 thinner head gasket bumps up the compression a little.


put shop rags in place before you pull piston completely out of cylinder that way you won't loose anything in the crankcase good idea for rags when working on the rings or piston so stuff doesn't jump into the crankcase when you aren't looking (gremlins you know)
 

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Norman

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Re: Engine top end rebuild and an engine stand

How the rings fit on the piston and where the ring locator pin are and how the rings fit etc.



Pulling out all of the studs I'm doing this to make it easier to clean the surface where the cylinder base gasket will go the old one is toast when you clean the surface don't gouge the surface. I use a gasket scraper and the dremels wire wheel.
 

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Norman

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Re: Engine top end rebuild and an engine stand

1. another tool to make life a little easier and to protect the piston form being broke and when you put the cylinder back on this is very handy. Would this be a pain to try and describe by words alone. just a piece of wood with a slot for the rod and it steadies the piston like a third hand

2. clean up gasket areas and wash cylinder and head with warm water and dishsoap to degrease it

3. There is no machining on the cylinders top and its a good spot for a head to start leaking from in the next pic I'm lapping the cylinder to clean it up for a better seal at least it makes me feel better. I also did the seal ring on the head no need to get carried away as soon as the rasied ring turns a little dull form the sanding stop and clean it.

4. using 320 wet/dry sand paper glued to glass and soapy water to keep sandpaper from clogging just smooth it up
 

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Norman

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Re: Engine top end rebuild and an engine stand

1. after all lapping grinding etc. clean with warm soap and water.

2. this is one way to make a pattern for a gasket I'm using the studs to hold the paper in place which is computer paper and then I rub my grubby fingers on the paper transfering the grunge on to the paper.

3. explains itself


4.as you can see this is one way to make a pattern and not use a ball peen hammer and risk damaging something
 

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Norman

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Re: Engine top end rebuild and an engine stand

1 & 2. knocking out the base gasket cutting the excess with my punch then on to the scissors


3. some info on what I found on this engine


4. I only smoothed out this area and another out of focus pic. pointing to the transfer ports shoulder.
 

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Norman

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Re: Engine top end rebuild and an engine stand

1. got the studs in and the base gasket in place and the little wooden helper inplace I also cleaned the crankcase in the solvent tank blew it out with compressed air and shot some oil on all the bearing surfaces no pic. on that as you can do it with out pic.


2. oiled piston and cylinder indexed the rings so I won't break a ring and the cylinder almost falls in place.


3. I spray a very light coat of cheap aluminum spray paint on the head gasket before I install it. No I didn't paint it there I did it out side.
 

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Norman

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Jan 16, 2008
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Re: Engine top end rebuild and an engine stand

1. Grease the other side it will help hold the ball and short rod in place. I don't know if you noticed or not but I don't like to work on shlty things I have to at work but not here I've been so greasy and oily I could wring out my underwear form rolling in oil and grease while doing an industrial engine/compressor, so I take the time to clean stuff up.

2. something I forgot a light sanding on the engine mounts helps to smooth them out, knocks off any rough raised areas that will later wear down and cause your engine to jump ship. doing the front mount. emery cloth and frame tube of proper size well its kind of close to the right size. Some thing else remember to cover up all engine opening when sanding the mounts you don't want any metal dust inside of the engine. The sanding tube is a bike frame tube the same size as what the engine is going to be mounted on the bike. glue the sand paper on to the tube and sand, check the fit of the engine on the frame so you can get the engine to fit nice and snug to the frame tubes.

3. rear mount getting it as well and I hate sanding ask me about building a composite airplane what a sanding contest that was 2years of it and I quit and stuck my homemade engine on it and been flying it since 1985 and still works and hasn't killed me YET got some skid marks in the shorts tho from some of my festivity's


4. the end hope this helps and doesn't confuse you more if it does don't work on an engine take it to someone who can. Naw! Jump in there and get NASTY.
Norman
 

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