A Forum for Honda conversions.

That would be great!!!Some one must have come up with a good conversion by now.If you are out there how about helping a brother out?Some of us late starters(on gassers)need your help.I see people asking the same questions as I'm asking about what replacement carbs work what props work and where to find all this stuff.I've learned a lot about fourstroke engines on this forum but this gas thing has got me stumped.My GX35 runs ok but I want it to run better.Most of the info out there is three or four years old,and I would think there's newer stuff out now,but I can't seem to find it.
So any help,tips,or guidance would be greatly appeciated.

Thanks in advance Jim R Club Saito #509

I agree with you. most of the info is old. I would like info on home built ei. I have a 49cc gas but the flywheel is to big. This engine came out of a motor scooter and I need to lighten it up to say nothing about it noe fitting into the cawl properly.( space walker 1/3 scale) Any sugestions?

Bomberbill

Just got my GX35 in the mail about an hour ago(finally!).Carb looks like the WYL that are on the Briggs,Subaru-Robins(aka Fuji) and Ryobis I have.If it is like the others the carb jet will need to be drilled out as they are too lean, at least in my weather conditions.

jtisch,what size drill is a good place to start?You will notice if you give it full throttle it will run for a few seconds and then die.Good luck trying to get info on this engine it seems nobody's doing these engines.By the way do you know where I could find Walbro carbs?I'm looking for a WYK-16 or WYK-61 and I can't find either one.This engine is a sweet running machine except for the above mentioned problem.If you need your flywheel machined,Dave Carr(Carr Precision)does good work and reasonable too.Also I've found the best prop to be a MAS 20x10 Classic series.

Good luck Jim.

I haven't done any work on my GX35, of course,but on my Briggs I started with the only drill bit I had in approximately the right size.Top end was great but the low end was too rich.Luckily I had extra jets. I bought a drill bit set on E-bay(look for a set in the #70 to #80 range,or greater) and went to work again.At #78 I got a consistent top end and good idle,again on the Briggs.This may sound like a lot of work, but if you do it on a test stand rather than in your plane it's a piece of cake.

BTW,do you still have the choke on your GX?One easy way to tell if your engine is too lean at high end is to start closing the choke while running it and see if it runs smoother when you close the choke.Maybe low-tech,but it worked for me.

EDIT Just to be clear regarding the drilling of the jet, start with the next size up and keep going from there.

Yes I just tried that yesterday,I had a v-stack on it,took it off and put the stock airbox back on it and it ran very strong at full throttle with the choke half closed.I was able to get it up to 6500 rpm's.

Jim

Awaiting Approval?

for what?

6500RPM? On the same 20x10 prop? If I'm reading you right then I'm glad I got a GX35! On my Briggs I get @5700 on a 20x10.

If it runs better with the choke on then it is too lean.Get a drill bit set and start playing.

Ok 6488 rpm's,thats what my Glo bee tach said.This engine did'nt even sound like it was breathing hard!Thats a stock engine,except for a 1/2"x3" long straight pipe,I'm sure there's more power to be had.I just don't know how to get it.I'm hoping some of the engine guru's will chime in with some easy to do power secrets.I really need some help with the carb(source for replacement carbs)and any tuning hints for said carbs.

Thanks Jim

Does anyone know where to find a parts diagram for the GX35?I downloaded the manual from Honda but there isn't a blow-up drawing or a parts list in that.I want to remove the compression relief junk and it would be nice to have a guide.

As for carbs I have a wyk-137 and a wyk-38 that I can try.I hope they work better than they did on the Briggs.Going up in carb size with them resulted in zero RPM gain.

Hi Guy's, I too am playing with a B&S 40cc, 4-stroke. Sorry I don't have anything new to add yet but I don't think you will get much more performance out of these engines without playing with the valves. Putting more fuel and air into it will require a bigger exhaust valve to realize higher performance I believe. They are not made to be exotic but rather just a work horse of reliability (low rpm). I'll be happy just to have that reliability and 4-stroke sound (for the price) in my model. I think you really need to build your model around these engines instead of building the model and then trying to make these 4-strokes pull them. Just my two cents worth. I think we have learned that the model needs to be less than 20lbs. and preferably 15-18lbs. So far I have spent approx. $160. for this engine and that includes a new and bigger carb. which may have been a wast of money because the cylinder head may need to be modified to take full advantage of the carb. I think it would be prudent to try to find out from B&S what they recommend as maximum RPM for this engine as well.

jtish where did you get your wyk-137 carb?

Thanks Jim

I think I got the 137 from SEPW,the 38 from M&D mower.They are a little hard to find in stock.

Hey, Guys,

Anything new going on with the Honda conversions? I hate to see this thread get old, 'cause I just bought a GX-35 engine.
Sleepers.....awake!

Dave

I haven't done any modifying on my GX-31 other than the electronic ignition, a larger WT style carb, and a straight stack exhaust. It does 7500 rpms on an APC 18 x 6 prop. Other modifications are tough as there is no good way to raise the compression, and nobody makes hotter camshafts for them. The GX-35 is a slightly different story. I read somewhere that with some machining you can put a GX-31 piston in the GX-35 and raise the compression quite a bit. You might do a search for that info.

Meanwhile.... I scored a Stihl 32cc four stroke that I think is going to have a good bit more power, and will probably replace the Honda on my giant Eindekker...

AV8TOR

Hello, AV8TOR,

Thanks for the fast response.
I'm just looking for simple stuff for my GX-35: propeller hub, motor mounts, and maybe a better ignition. I'd be happy with the standard amount of power (for now).

Carr Precision used to sell these, but I talked to him and found that the demand had dropped off, so when the last prop hub & motor mount set sold, he decided not to take the time to make any more.

Did you make your own hub and motor mounts or do you have a source you would recommend?
Thanks,

Dave

Yes, I make all my own parts, but unfortunately just don't have time to do it for others.... You might give www.wackerengines.com a try. He does good work and could probably get you set up.

I know the guys at www.ch-ignitions.com have been playing with at least one. They might make parts for you as well if they have time, and they are a good source for the ignition in any case.

AV8TOR

AV8TOR,

Thanks for the lead to C.H. Ignitions. I talked with Terry and he says that they have a complete kit for this engine. It includes intake manifold, prop hub, flywheel, sensors, magnet ignition unit, motor mounts and the shielded spark plug wire and boot. Very reasonably priced.
I appreciate the tip.

BTW, nice avatar! I've always admired that profile and the way they look when in motion. Oh, and the plane is nice too.

Dave

Yeah, thanks... We broke up 8 months ago after 8 years together. I am really messed up about it. [] We have a four year old daughter as well. Oh well... [&o] Still don't have the heart to change my Avatar.

AV8TOR

The Honda, and other, four strokes has me intrigued. I have a 1/4 BUSA Fokker D-7 in progress. Since adding lead to the nose is necessary to get the correct CG, why not go with a heavy 4-stroke? It would sound good. have pleanty of power, and give me something of value for the weight.

1. Any idea if a GX35 would fit in the cowl?
2. Where can I buy a new short block?

Well, my Honda four stroke sure sounds *****in' in my Eindekker, that's for sure. I believe one would fit in the Fokker. Find the dimensions of the Honda 35, and then call Balsa USA and get the engine compartment dimensions for the Fokker. I bought my Honda from these guys: http://www.smallenginewarehouse.com/...ategory=Engine $225.00 for a GX-35 new.

My Eindekker was designed for a Zenoah G-26 and the servos mounted in the center of the airplane. With the servos in the tail, the balance came out perfect with the Honda.

That photo of your little girl would make a good Avatar. I remember in all the her photos she looked like she loves the same airplanes & engines you do. Take Care, Your Old friend Capt,n

Thanks for the nice thought Captain. And it's a good idea.

She says good night and good morning every day to all my airplanes. One time she had been away for a while, and upon arriving, actually went and gave a gentle hug to each airplane!

Every time an airplane flies over, she screams "Daddy, Daddy, AIRPLANE!", and we have to run outside and look at it.

She's "daddy's little girl" for sure...

You take care Captain John,
AV8TOR

I used to take my son with me out to the flying field when he was almost, not quiet walking and he liked to touch the props of the models sitting on the flight line. He went to sleep many nights out in my shop when I would take him out there which was most nights. His mother and I were divorced when he was about three. Gavin is now in the USMC and got back from Iraq last Sept. and is shipping out to Afghanistan in Oct. When he is home on leave we spend as much time as possible together and go to the flying field as much as we can. He even fell asleep in my new shop this last time home, lol. I left the state we were living in after the divorce and missed a lot of him growing up which i will probally feel guilty for the rest of my life.

I guess what I am getting at here is if you are where you can be with your daughter much do it as much as you can. They grow up and we grow old all to fast. Its sad when a couple who at one point in time loved one another and things happen and then they go their separate ways but that is life. It took me years to get over what happened to me and my wife of twenty years but at some point I realized that that was then and this is now. Just be a Dad to that little cutie pie you have for a daughter and when she gets older she will be with you out on the flight line making you all proud, working the sticks, making you look bad, with her little airplane earrings on.

Like my son used to tell me when he was little," I prom "

Bill