Venus 50 (Now 96cc!)

[90GTVert]

I don't have enough head gaskets around to make the aftermarket 52mm work. With 2 head gaskets the head still acts like a piston stop at about 10 degrees off TDC. I thought I used to run 3, maybe not? Instead of making things easier, I made more decisions. I tried the 54mm from T2 (if I end up using it, it doesn't bug me... I kinda know I'll want a 54mm later anyway).

1 base gasket
180
111

2 base gaskets
184
112

It needs more gaskets if I want the postin to clear at BDC, much like the stocker. The big difference being it is actually flush at TDC instead of being way low. The other difference is that I have 3 different 54mm heads to mess with. Each with squish band designs.

The transfer numbers were so low I rechecked everything. I guess it's just because they sit so low in the cylinder.

I wanted to mess around a bit more but once I got my other stuff done then I got calls from 2 friends. One looking for PC tech support... my favorite thing in the world. :lol: You guys proved how good you are with PCs, anyone want me to forward these calls to you?!? ;D

[Goosey]

Umm, no, but i remember pcmagazine had a great forum :LOL:

[190mech]

Man!What a bunch of miss matched numbers!I guess the aftermarket stuff is cast for the 45mm stroke.The only 'quick' fix I see is the stocker with the piston top trimmed at the transfer area to get 127-130,still have the top of the cyl to cut for proper squish.Ive done heads on a belt sander then finishing with a piece of wet or dry paper with oil on a pane of glass,but Ive never tried a cyl before,,

EDIT,Ya know the 54mm jug will work better if you cut the piston like I stated above,then you have the right squish and proper timing of Ex and Tran!

[90GTVert]

I never even thought of filing the piston to clear the transfers. Not sure why it didn't cross my mind that if it could be done for exhaust it could be done for transfers.

[2strokd]

I had a 49cc motor with the piston top 'cut' on the ex side.
Came factory like that, made sense too. Good idea John!

[90GTVert]

Oh and to the 45mm remark, I think the stock jug is actually much better suited for 45mm as well. It really shows how generic some parts are. I'll probably stick the stock jug on the 45mm crank in T2 to just to confirm. Timings could still be way off I guess, but I think it will end up about right on there.

[190mech]

No telling what you have with a stock motor!!

[2strokd]

No kiddn....
That same fact can make these engines very interesting!!!

[90GTVert]

First off, sorry for the long interval between updates. It's not really by my choice. There's been a lot going on this week. My father got a staph infection early in the week and he was home from work because it was in his hand and the doctor didn't want him messing with anything. Then yesterday I was called by my grandmother who was crying and kicking her legs and jumping around in her chair. Ended up taking her to the hospital. They put her on Vicodin and that stopped her from moving involuntarily. They aren't sure if it's something she'll have to continue or if it was just some odd nerve sensitivity. She just woke up and had breakfast at 10:30 and she's still dopey and tired from the drugs last night, so we don't really know how she's doing. I'm pretty much gonna have to be in the house with her all the time for now until we see how things go, so the only time I can work on anything long would be when other people are here. Even then, I'm kinda not in the right mood to do much of anything sometimes now. So just fair warning, you may see more updates tomorrow and you may not see me get anything done for a little while. I really don't know how anything is going to go right at the moment. With that said, here's what I have done since the last update...

I filed the piston crown by the transfers enough to get 128 degrees of transfer duration.

\



The piston (at it's highest edge by the exhaust port), sits about 1.4mm below deck. That's a decent street squish figure for 90cc.



The problem was that I had 3 54mm heads. 2 with a big lip to make more squish and 1 with no lip but a combustion chamber modified to allow much tighter squish clearances. I ended up filing and sanding one of the standard combustion chambered heads until there was no lip. Hopefully it's true enough not to leak. I suppose I'll find out eventually. This kinda shows a before and after filing/sanding.

[190mech]

Looks good Brent!Which cylinder is that?

Sorry to hear about your family problems!

[90GTVert]

That's the 54mm cylinder from T2. It started at 184/112 with 2 base gaskets and now it's 184/128 with 2 base gaskets, and what should be about 1.4-1.5mm squish. I don't think that's a terrible setup. Looks better to me than the other cylinders. I'm also not a fan of the mushroom head idea of a 52mm cylinder and a 54mm head. If I ever feel it necessary, I could knock 1 base gasket out and do a little more filing to the transfer area and a touch to the exhaust area and get the same durations with tighter squish. I never had much luck with really tigh clearances though, short of the modded combustion chamber. Even then, the motor that was on performed fairly similar with loose squish and a standard chamber vs tight squish and a larger chamber so I dunno if it would really be worth it.

[190mech]

Its an interesting project!!Im sure it'll run strong! :burnout:

[2strokd]

I hope your grandmother is feeling better by now.
Take your time..Its your project, and we are in no hurry .
The piston looks good! Im sure that will help out.
Head looks good too. Should run strong as hell compared to any
well tuned, "bolt-on" modded 49cc thats for sure :burnout: !

[WT100]

Hey Brent, you and your Grandma are in my prayers.

As to the rest it is great to watch a craftsman at work.

So how do you know how much is safe to shave a piston? Looking at the ones sitting on the speakers in my edit suite there does not seem to be much margin to play with.

[90GTVert]

I dunno. I just cut a little off and it looked OK to me. lol

Thanks for all the well wishes.