KI8FR

I just started a on a new Conversions of a homie 25cc. I did one before and I went to far with it and it just did not work so Im trying it agian.

I took the engine a part. I want to cut the front off the engine. I do not want to mess up the bearing in it so I'm trying to get the crank out.. I do not want to brake it so Is there any thing I'm missing on getting it out..

I have two homie 25cc. One of them has a hole just above the exsost port. and the other one does not... Can any one tell me what is up with that hole.....

I have seen on the Conversions post that you can take out the gaskets on the back plate and under the jug to help with more power.. Does this work?

I will be putting pics up as I go along just so you can see what I'm doing and so you can stop me from messing it up to bad lol.

Thanks

Paul

jrjr2u

Have you seen this thread?
http://www.rcuniverse.com/forum/m_26...tm.htm#2677889

KI8FR

Thanks for the link but that is just to much work that I want to do. lol......

ROOSTERLEW

Cranks pressed into bearing, bearings pressed into case. youll need to press them out.

Thats a compression release, makes engine easier to start, There are differences of opinion, smoe say that at speed it doesn't effect performance, I've heard others claim200 - 300 EPM increase plugging it. I'd suggest leaving it alone, testing engine then plugging and retest with no other changes, see what you get.

Removing gasket under "jug" increases cylinder compression, increasing power(not exactly, but good enuff) It will also change your port timing causing one of three conditions, 1:more power 2:Less power or 3: no noticable difference!

Removing gasket under back plate increases crank case pressure, giving larger fill and increasing power(again not exactly)

With either of these mods you need to check to see if they are going to cause any interference or misalignment.
If your not sure about this, find some one who knows how to do it, or search the threads, any one of these can ruin an engine!




Would love to see some #s(prop sizes and rpm's) when your done
Good Luck

KI8FR

I have the front of the engine cut off now and the fly wheel made for the CDI. I have the magnet in the fly wheel now too. The haul sensor mount is done. Now I need to know if it is worth the work doing some timing with the ports. I hope to have to pic in on this of the work that I did tomorrow..

Paul

KI8FR

Here are some pics that I took. Ist is were I just started cutting the front off.. then some cutting.... and now after.....

Then there are pics were I was making the fly wheel...

KI8FR

Now pics of the magnet and the the hole after the ballencing.

Then some pic of the sencer mount.

What do you think?

Paul

av8tor1977

My Feedback: (6)

Yep, I've done a number of them that way. Since you're not going to use the mag though, it looks like there is a little more you can trim at the top front of the crankcase where the mag mount used to extend upward.

I'm going to be gone for a few days; when I get back I'll try to post a few pics of one of mine.

Good luck and have fun,
AV8TOR

captinjohn

KI8FR: What diameter of magnet did you use, and where did you get it? Thanks Capt,n

KI8FR

1/8" from www.cncengines.com. I asked for it when I got the hall senser. I got the hall senser for 8 bucks and the mags was 1.80 for two I think. but you can get them at Radio shack. I will have to look for the part # for it.. When I find it I will put it on here..
paul

jrjr2u

Here's some neo mags Ive used for other applications in the past. Stick one to your fridge and you will need pliers to get it off!
http://www.radioshack.com/product/in...entPage=search

Here's another source:
http://magnets-ndfeb.com/

flipflop

You can remove a bit more metal, look here:

http://www.rcuniverse.com/forum/m_41...tm.htm#4100458

KI8FR

I will be takeing more off.. I will put a pic up when I get it all off... I was going to ask if I can take off more. thens for the info..
Paul

KI8FR

Now it is time for me to stuff the box.. or do I? What I was planning on doing was, takeing some still and braze it to the back plate.. now be for I do this I would like to know if it is werth it. Will I gane by stuffing the box? I am not going to be doing any port work or pining the ring. So with out that being done will stuffing the bax help at all?
Thanks
Paul

av8tor1977

My Feedback: (6)

I have never done before and after tests, so I really can't tell you. I have to assume someone has though, as it is a very popular mod, both for airplanes and with the boat crowd. I just do mine as a matter of course with all the other mods...

I usually make a piece that fits the back plate out of 1/16" thick aluminum. I then clean the aluminum and backplate and put them together with JB Weld. I then put a screw in the center where it won't interfere with the crank. You can fine tune the crank pin to back plate clearance with gaskets....

AV8TOR

KI8FR

AV8TOR

Ok that sounds good.. I think I will look in to doing it that way.. What do you do with the intake manafold....? I see in your pics that are alot of fuel lines on your barb.. what are they all?

av8tor1977

My Feedback: (6)

Well, now you're going to get more complicated...

This one is a 30cc, which is physically identical to the 25cc on the outside. It is all ported, hopped up, etc. It turns an APC 16 x 8 prop at 9400+ rpms.

If you are not going to port, remove the exhaust port bridge, etc., then I would just leave the intake manifold alone. Everything needs to work together and just doing one mod without the others can get you into trouble.

The external line is to provide a pulse to the carb fuel pump. I filled in the pulse hole in the manifold in order to enlarge the throat to the max. As I said, this one has all the mods. (Yeah I know Terry; still no pipe....)

AV8TOR

av8tor1977

My Feedback: (6)

That didn't sound right so I checked. That was 1/8" aluminum (not 1/16") that I used to make a plate to stuff the crankcase, and I had to block sand a few thousandths off of it to get the clearance I wanted.

AV8TOR

KI8FR

Ok now that sounds beter.. I was looking at it and can see that I can put more in there and was going to ask if I can go to a 1/8th lol.

I have 2 engins and one of them haves a plastic back plate. I was thinking of takeing a pic of 1/8 plastic and e poxy it on.. What do you think about that..

I have been looking and cant find a pic of aluminum that I can put in.. Not sure were to get some..

Paul

av8tor1977

My Feedback: (6)

Aluminum would be better. Check with metal supply shops. They often have scraps you can get cheap.

AV8TOR

ROOSTERLEW

av8tor, If you remove that exhaust port bridge you will definitely want to pin ring ...correct?

captinjohn

Use pop rivets and epoxy. Place rivet heads on inside....so crank pin will not contact them. Capt,n

av8tor1977

My Feedback: (6)

YES! If you remove the exhaust port bridge, you must pin the ring so it can't rotate and get caught in the exhaust port.

Another thing; don't be tempted to just narrow the bridge in the exhaust port. If narrowed, it can become too hot, expand, and scuff the piston.

AV8TOR