quote:

ORIGINAL: KI8FR

Ok were did my post go?

Yeah, that's what i'm thinking.  It is going on a large Eindekker.  I am probably going to start out with an 18 x 6.  I may sneak a little nitro into the mix as well.

But, the airplane is still in the box, so it's going to be a while....

Acutally I have a big closet full of kits and ARF's waiting to be built, but so far, at least in my mind at the moment,  the Eindekker is the favorite to be next.  The problem is I have been concentrating on my new sandrail project, trying to get as much done as possible before it is just too hot to work outside here.  I spent all my "build a garage money" on airplanes and airplane goodies.... 

AV8TO

That's a strange thing about my GX 31.....  It runs well, turning an 18 x 8 at 7000, and it is barely broken in.  It was brand new when I converted it.  I put electronic ignition on it.  But it won't hand start.  Won't even "pop".  But with an electric starter it starts so fast you barely hit the "on" button on the starter and it is running. 

AV8TOR

I was thinking it might have some sort of a compression release, because turning it over by hand it has very little compression, but the motor runs as though the compression is fine.

You don't happen to have a pic of that compression release do you?  Is it located in the cam housing??

Thanks,

AV8TOR

Yeah, I found the little bugger, hidden behind the cam gear, and I removed it.  I hope I got the cam/gear back in time properly.  I had the lobe pointed straight down when I took it apart, and I didn't turn over the engine and I put it back together with the lobe pointed down.  I saw that there is a timing mark on the cam gear, but you can't see the timing marks on the crank gear with the seal in place.  I didn't want to remove my prop hub, etc. and take out the seal for fear of damaging it.  (It's tough getting parts here in Mexico.....)

It definitely has more compression hand flipping it now.  I'm anxious to get it on the test stand again.  I bet it will hand start easily now.  Thanks for the info guys.  If anyone has any cam timing info so that I can check mine, let me know.  (As in degrees and cam lift, etc.)

AV8TOR

on the gx31 if the timing is off it will be way off, 24 crankshaft degrees per tooth

all values @ .004"  lash and crankshaft degrees

stock gx31 cam .105" both approx.

Intake open 25 btdc close 120 btdc

Exhaust open 118 atdc close 10 atdc

 actual timing may vary due to lash settings ,wear on lobe and followers and axle hole.

Because it is a single lobe design you only need to check intake closing point to determine if the timing is correct

btw the spring in the pump chamber does not make it a four stroke carb, honda used 6 different wy models on the gx31 and only half had springs.WOT stumble and acceleration issues may be addressed by cutting one coil at a time off metering lever spring nad using fresh diaphragms, if they are more than a year old they need to be replaced, most of the pumping issues with the honda is due to stiff diaphragms.

Ah, just the info I needed.  Thanks a bunch!

AV8TOR

You are welcome.

oh by the way, you don't need to be afraid of the crank seal by the gear, just  don't try to pull it out, it has a rib in the center that keeps it from going in or blowing out, it can only be removed from crank by splitting cases.

The  key slot in the crank is aligned with tdc and the lines on the face of the cam (one line on each side of lobe) will be level when at tdc. You can insert a piston stop to zero a degree wheel and mark EI trigger for tdc. down load the free tavia wheel print out and glue to a fee cd rom attach to prop adapter etc etc, a piston stop can be made out of wood dowel.

Hi,

Thanks.  I have several degree wheels, and know how to do it all.  Just didn't have the cam timing specs for the Honda.  It seems to be one of those engines that they don't put the technical info on the web; apparently you have to be a dealer to access that data.  I hate it when they do that....

AV8TOR