Yamma-Fox

No problem.  I'll send you a PM here when I get home and we can figure out how it'd fit.

Brett

Yep, it'll run.  But you are probably right that my 80 hp guess is a little high.  I'll say 70 or 75 hp for sure though.

Here's my math:  In the snowmo forums I've guys chatted with guys that have had a coil go bad on the 3cyl rotax 1200 4tec (known problem with the connecting clip atop the coil).  With one failed, they have run home on 2/3.  They say max speed is about 65.  From all the little sleds I've owned, IMO that take around 60 hp on a 500 lb sled with a 200 lb rider.  So that is with 66% of cylinders working and about 46% of the 130hp the engine normally pumps out.

So on the  4 cyl then with %75 of cylinders working, straight interpolation puts you at 72.45 hp, but (again IMO) I think some effeciency would be gained from 2/3 to 3/4.

When I get her running I'll pull a coil connector for ya and video a little run up for ya.

Yep, true.  In any particular case there are still plenty of ways for a 4stroke to give out.  

But I'll be in the 4stroke camp now with 5 2stroke failures in the last 10 years. (4 snowmo, 1 aircraft).  I'll own 2 of the failures myself (pushing too hard on a high time motor), but I'm very sure that I would have had zero failures had each of those motors been 4strokes subjected the same duty.

And dont forget the yamaha has 4 independent coils/CDIs (one on each cyl).  If one were to fail, you'd still have approx 80HP available.

I looked into the wire loom in detail.  

Teal has full (one page!) instructions and has made it super simple:

From Teals harness:  Hook up batt positive, ground engine to airframe (my airframe is common ground, I'll run a heavy wire to it from the starter mounting bolt on motor.  Hook up the ignition supply wire (I'm going to two switches for redundancy, one to hot batt, one to engine alternator/magneto).  Hook up starter solenoid wire to the start button in plane.

That's it!  Teal also has one wire ready for the tach and the rest are plug and play connectors to the small weatherproof ECU and VR boxes, and also to the spark plug caps (with built in ign coil on each)

I will add a fused switch to the electric carb heaters installed in the carbs on the yammy. This bird will fly all winter here in N Minnesota and the elect carb heat helps supplement the standard carb heat (heated by engine coolant) 

Roughly lined up. .. 

Mine is a carbureted (RX)-1 4cyl.  Teal Jenkins  (skytrax) sells the c box adapter and wire loom (which is very simple for that motor).   I believe he is working on an  adaptation for the EFI 4 cyl (Apex) as well, which requires a MUCH more complicated wire loom mod.

More info on the RX-1:

http://www.avidfoxflyers.com/index.php?/topic/4138-yamaha-rx1-engines/

The easy part.

(Decided that the soob mount wasn't even close to what I'd need for the yammy)

Pic 2 shows tailwheel spring support.  With the motor off she'll be a wee bit tail heavy!

Pic 3 is my quick little (sorry ass) attempt for a prop flange locator jig. (Bolted to firewall)

As far as verbage, here it is straight out of mt operating limitaions (that I  got from the faa document request for my plane)

Note lines 17 and 18:

Ok guys.  This will be a big project for me and I'd like to lay out my plan of attack for ya'll to review as I go.   I will be thankful for everyone's help so please don't hold back if you have an idea or advice

I also hope that this build thread will provide good info for anyone interested in the Yamaha power option.

The goal on this one is a functional and safely done repower and install.  But this is NOT going to be a "show plane", so looks, beauty, and bling are low on the priority list.

So I got my bird crammed into my garage yesterday, pulled the prop of the subaru and am getting ready to dig in.   Here's my initial game plan:

1. Take lots of pics of the sooby and measure up location of prop flange to hopefully eliminate too much cowl rework in the end.

2. Pull the motor and take a look at the soob motor mount.  I was considering building off it if possible to simplify the fabrication process.  Any concerns with that?

3. Get things lined up, plan for airbox and exhaust, then tack together the new mount.  I am a novice welder and own only a cheapo wire feed welder.  I'd plan to emulate what others have already done and fishmouth the thing together and just tack it, then send it off to a pro to TIG it up and powdercoat.  (I'd be glad to hire out the entire mount fabrication but so far I'm the first guy I know of to put a Yamaha in a Kitfox, so it would presumably be hard for someone else to build me a mount without a KF5 firewall jig and a RX-1 motor laying around)  Any ideas / thoughts? 

Wish I could reference it, but I researched the same question and remember learning that an engine log (or propeller for that matter) is not required, nor is a specific statement regarding the engine part of the CI signoff verbage (verbage spelled out in my op lims)

Seems like the people I get along with best are "just a little rough around the edges".

Ones that are smooth around the edges make me start to squint my eyes and sniff for the "politician smell"!

That's what I ended up doing with my 532: tstat out in summer, in for the winter.  It had a somewhat marginal cooling system that you had to keep an eye on.

Not sure everyone would agree on doing it that way since it would run a broader temp range (150-180), but in the summer it helped me know when the system was nearing capacity.  When it crept up I  knew it needed some airflow soon.  With the tstat in it would hold steady but you wouldn't get much warning when it reached cooling capacity and spiked up quickly. 

I'm guessing the rebuilder went through the rave valves right?

Everyone can make a mistake.... but hopefully he stands behind his work and takes care of you on this deal!

Wow.  Guess they build them differently in the sleds.  Sure seems weird that they would make them more failproof in the snowmo engines.  The the ones I've worked with have a forged shoulder that stops travel (see pic below).

Man, I sure wish I could buy ya a beer, and I really do feel your pain.  Especially with a new motor like that...  crap.

But if the rave did it, then that helps a little i suppose.  You know that you found the problem and can get it right.

There is no way the rave valve can contact the piston... unless the wrong rave parts are installed.  I've had quite a few of these apart and am really sure about this.  The rave spring pushes it fully down where it seats in it's groove.

I know the rave looks to be really close to the piston but it does not and can not protrude into the cyl.

Oh man, yeah that looks like you had a bunch of crunching around there.  Maybe if it were a sled I'd take a chance, but if were mine, in a plane, I'd want to look in the case for debris... 

I have had sleds do that after a coolant refill.  It ended up bieng an air pocket somewhere in the cooling system that slowed flow.  I had to bleed the high points in the system.

And I like jim's idea... get the guage calibrated with the sender.  

Also consider trying with the thermostat out.

Man...  sorry to hear that happened.

From my experience in Rotax snowmo rebuilding I have found that when you melt a little aluminum like that it gets smeared into the cyl wall (even if it is imperceptible and hard to see).  So if it were mine i'd make sure to clean the cyl walls up with muriatic acid before honing.  Then IMO definitely go with a full top rebuild.  If you didn't chunk off any material, your lower (upper LOL!) end is probably OK.

Guess if it were mine I'd clean up the cyl walls with the acid and then send the jugs and head back to an expert like Rick to get spec'd out and reconditioned... have him send you new pistons, rings, gaskets.

And I have a NSI subaru that was flown regularly until last fall when I found a small amount of metal in the filter.

I decided against rebuilding it so I posted it for sale.

It is complete with extra ignition parts, full logs, all the NSI manuals and the e81 service manual, and a lot of other extra spare parts.  See listing below, and PM me if you are interested.   Brett

MORE RX-1 INFO:

For anyone hungry for more info on the Yamaha, head over to my build thread here on AvidFoxFlyers:

Sure have had some beautiful flying weather around here!   Glad ya got up and took advantage of it!

But I think he wants to hangar it in there regularly.

I'm wondering if the container is 8' inside, with the door frame taking away 3" on each side?

If so could a guy cut a slot out of the door frame sides where the folded wings would pass?

I suppose even then it'd be a near imposssible squeeze since I have to be super careful going in my 9' wide garage at home.  

Guess you might make it work with some tight tolerance guide rails for the wheels.

Welcome Adam!

It is fantastic that you located that training opportunity!!  With that in your pocket, someday you hopefully can pass some "old school" down to the next generation of pilots!

And with a certificate full of type ratings and many a thousand hours in the logbook, I'm here to tell ya that you have made a great choice in a kitfox/avid type airplane for your goal because the most fun I've had in airplanes has been in slow and low taildraggers!

Enjoy that training, and have fun when the time comes for ya to pick out that airplane!

Brett

I was waiting for ya to tow that red truck into the garage!

Sweet!

Hey, back to basics question for the smart guys out there:  Would one be required (FAR's) to carry paper vfr charts for x country, or will something like this suffice?