450 engine rebuild

[phillipjohnw]

I'll try to, but honestly I'm terrible when it comes to taking pictures of projects. I just get in a rhythm and forget.

I did come up with another question for mekanix though. Is it possible to fit a gs400 kick start onto the gs450 crankcase? Or is that nearly impossible. If I could do it without buying the 400 crankcase I might look into it because I love a good kick bike.

[pete]

Nooooooo forget it... it's been asked several times and the only way feasible is to get a 400 bottom end...

[Mekanix]

Yup. What he said :-)

[phillipjohnw]

Well I wish I had a better update, but the bike is slowly coming apart. I really wish I had more time to work on it. While I'm waiting on the parts I got on eBay, I'm going to repaint the tank. Currently its half stock blue, half primer red, and half ugly. I'm thinking of taking off the emblems, filling the little bracket with bondo, smoothing it out, and trying a red glitter undercoat with a light black top coat that hopefully the red glitter shows up in the sun. There are some pretty good write ups on here, but painting isn't my strong suit.

[wally]

My general response or 2 cents to all these helpful comments is "HUH!?" .

I have no idea what you guys were referring to, but I am watching, reading and hopefully learning.

Remember your pics!

[Big Rich]

Phil, if you do go thru with a little hybrid motor, don't forget to order the "small things" as well. Base gasket, head gasket, piston rings, etc.. It would be a shame to get snagged up on a minor detail......

[Mekanix]

Seeing as the 500 piston only comes up so far and its below the deck of the cylinder block. And that the dome on top of the 500 piston is a little shorter than the 450's. I think You could get away with the 500 base gasket and the 500 head gasket. That way the head would have only droped by 0.43 and it would bring the compression up to 10.1:1 I think. Its hard to say without knowing the exact CC's of a 450 head.

On the 500 head there are 4 washers around the 4 studs that seal the oil channels.
You'll need those as well.
you could get the gasket for the tensioner or make one.

To retract the tensioner on those you have to take the rubber plug out of the end and turn the screw to rewind the plunger until its all the way out. I think you can give it another half turn and then take the screwdriver out and it should stay that way until you have it installed. Then you just turn it back the other way slightly and it will spring out.

While you have the engine apart, inspect the chain guides for cracking. Replace them if they are bad. I don't think they are expensive.

You could use a degree wheel and a dial indicator for dialing in the cam's perfectly.

Here is a link to print one off.

Then just stick it onto anything round with a hole in the middle and put it on the stator side.
You can find out where the center of the lobe is and that's what we will adjust. I don't think it will be far off. It might be ok just the way it is as long as there is no valve interference. But if there was it should only be with the exhaust valve. The valves are moving out of the way of the piston coming up and then the intake valves chase it on the way down. By retarding the cam timing your making the exhaust valve stay down just a little longer and the intake valve doesn't come down until a bit later.

[phillipjohnw]

Wally, its not that bad once you start reading.

Rich, not to be offensive but replacing gaskets and the little things is a no brainer to me. I work with high energy nuclear fluid systems all day every day, hooyah navy, there isn't a joint I would break into without replacing gaskets, studs, and nuts.

Mekanix, thanks again for all the info. I'll definitely check the can chain pieces when I get it apart.

[Mekanix]

Send a message to Wera90ex. He has done this exact mod and he also has raced these engines like that. Definitely more knowledge there than I have Just in case I'm missing something.

[phillipjohnw]

welp, the parts fairy came this weekend. I'll get some pictures once
I find my camera and figure out how to post them. A couple things I noticed that have brought up questions. I knew the pistons had some carbon built up on them from the pictures, but what do y'all prefer to use for removing it. I hear that seafoam is fairly popular, other than that I was going to use a wire brush and get them as clean as elbow grease will allow. The thing I'm more worried about is one of the pistons is stuck in the sleeve. Its probably me being a little girl about banging up newish parts, but how would you guys go about it. The other one came out fairly easily when I pushed from the bottom. I feel like heating it in the oven would help, but I also don't want to remove the sleeve.

If you'll excuse me I have some pictures to take.

[phillipjohnw]

Apparently I can only upload one picture at a time.







Nevermind I figured it out.

[Big Rich]

No offense taken Phil! Just wanted to point it out - not imply that you would overlook a minor detail.

As far as that piston goes - I would try soaking the edges in penetrating oil and then tapping it out with wood. What about freezing the entire assembly as well?

[phillipjohnw]

I appreciate you pointing it out, not everyone has the ridiculous work controls that were beaten into me.

I didn't even think of penetrating oil. Must have just slipped my mind or something. As for cooling, I was actually thinking the exact opposite. Cooling would cause everything to contract and thus hold the piston tighter. Heating, in my opinion would cause expansion and theoretically make it easier to remove. This is all dependent on the individual materials and their volumetric coefficient for thermal expansion. Again stupid things you learn dealing with high temp/pressure systems and namely valves that like to get stuck.

Either way its probably not going to happen because my wife won't let me put it in the oven or freezer.

[phillipjohnw]

overlook a minor detail.

Aren't those the best details to overlook?

[Big Rich]

Always.

It may sound crazy.....but I read somewhere online before about getting pistons out. It was on a tractor restoration forum or something. But they made a mixture of some sort on top of the piston crown, and lit it on fire. Looked like a tiki torch. Whatever the mixture was, the oil soaked past the rings, and the fire warmed everything else up and it would break free.

Either way, you'll get that piston out, I'm sure. I'm watching your motor build with great interest - next winter I'll probably be building 1 or 2 motors up myself.