fredo

Hi folks
I thought I share my project. So here is my Bucker... I haven't assembled the whole thing yet, still a lot of finishing to be done icluding all the pluming.

kipuetz

Dear Jaketab,
with regards to the correct valve setting,I have run up against the same problem!
The instruction sheet says,0.05-0.08 mm,wich are metric hundreths of a millimeter,in brac.it says,5-8thou.This is dead wrong!!!
The thou. is widely known asthe imperial system,wich as we all know ,thousands of an inch.
so,since the engine is made in a european country I go metric,and use the first numbers,witch is 0.05 mm to0.08 mm.translated into the imperial system is
0.002" to 0.003" thousants of a n inch.
Hope this will help,
Regards,Karl.

mick15

I have to say, all this is a bit over the top, the cam is not ground that accurate! lol.

m

Straightleg

Hello Jaketab !

With all respect for your bending of exhaust tubes, but with this exhaust setup you will loose almost all the good sound from the Moki. A better way is to plug the orginal holes and weld on thin walled alu tubes which will go through cowling on each side. See attached picture. If sound is not so important for you, this setup is good, I guess. Just a friendly "warning" !!


regards Straightleg

Straightleg

Regarding valves, I have flown with a good slack and tight valves, the rpm remains the same.....

/Straightleg

Scott Prossen

I happen to agree with Mick.....completely! Lol too......

I have been using and instructing the use of .007" ( seven thousanths of an inch) since day one for me with very good results. This has been stated in the thread several times and used by countless numbers of MOKI Owners. So please use the info. It's thhere for that reason. Set them and move on.

Your MOKI friend,
Scott

mick15

Steady on Scott, that's twice!

m

didiwatt

My Feedback: (38)

Just for your info,

The RCS 4 stroke tool kit that I purchased with my 250 contains a .007" feeler guage for setting the valves as well as an oiler and wrenches to fit the valve nut. This is a nice little kit to own and is still available from Troybuild here

.http://www.troybuiltmodels.com/items/RCS4STROKETK.html

Paul

BIGDAMMODELS

Well today's testing has led me to some great findings for our Moki t-28 combo with run issues here, and quite a few good notes for my memory banks on Mokis ignition system......I also found a great tool today for checking spark at the local advance auto...5.99us...with a slight mod for Mokis plug wire, it has helped so much to find the suspect ghost with this Moki....hopefully...I first want to say that I tried quite a few different valve lashes today...several carb settings...a few dozen ignition test...and my crude but effective troubleshooting has given me results that has led to the problem suspect area here...for starters I disagree somewhat with the differences in lash not being that critical...not for the sake of argument, but here at sea level it is noticeable if you change them from .007 to 6mm or what-ever...it doesn't affect my rpms per say on the top, but it will affect idle rpm, L & H carb adjustments, and overall cylinder temps...there's lots of variables involved for each individuals Moki set-up, but it can and will affect the running of the engine somewhat from my findings...with that being said, I decided to go with Scott's recommended .007 and made the small but important changes to the carb needle settings after doing so and it settled in as nicely as before....so I agree that this is a good point to start with for anyone seeking a good stock all around proven user setting for valve lash settings...todays plug gap, .018....I'm leaving the settings here at these numbers for the moment til I get the real culprit weeded out with the 150 misfire...I'll get the final cyl temps,adjustments,and data posted here after the bench repair on the Moki is finished...she ran great today...except on the high end and mid range rpm...under 1800 or so...she's great...stable...with an ever so slight increase in throttle made gradually, she picks up a misfire around 2500, give or take 500 or so...throttle back below 1800...great and smooth again...repeat...same thing...a distinct misfire...at this point I get the spark tester and make the minor mods to it...this thing can be adjusted to any gap size btw...I choose .018 for starters....same as the plug gap....I install the tester to the firewall so I can visually see the spark jump the gap and repeat test...sure enough...the spark color drops with the engine misfire...still had spark faintly, but it was not as blue now...reddish and faint...weak looking...during this misfire, I slowly started to decrease the tester gap to see if the coil is suspect or weak maybe...I start closing the gap...get to approx.015...misfire gets better but still there...close a little more...misfire goes away...engine is smooth as silk...nice blue spark again...tester gap now at approx.012 to .014...at this point I check overall temps...great everywhere...cyl#3 was 10f cooler than its closest neighbor showing 190f or so, temp taken 1/2 way the exhaust header for reference...#3 now hoovering around 180f steady...smooth running....at this time I began to increase the gap from this low point and before it got back to .018....misfire...reddish faint fire at the tester...I then moved the tester at this point to another known good cylinder and repeated the same test...this time the engine performed exactly the same, except when the spark testers gap began to increase on this cylinder, it showed no problem at .018...it ran good at .025 gap and beyond...the spark had no issues bridging the gap and the engine ran fine at the same rpm...nice blue spark...but you could still tell it was misfiring...I then moved it back to cylinder#3...it done the same thing as it had before, before moving the tester...I'm now thinking that the issue here is a weak coil breaking down with the added throttle and load...one of the most common issues reported on the Moki 150, are mostly related to the #3cyl as the most problematic, the cylinder that most have reported issues with...now...as we all agree that given the design of the radial engine, it goes to reason that this bug is inherent with it's design, but still,even the fatty mix of fuel reported with cyl#3 should not effect the overall performance of the stock engines top rpm range if the rest of the system is in check per Moki's settings...since the engine was first started new and ran on the 32:1 ratio....cyl#3 was different somewhat....wet plug...a little spudder...moved to the 50:1 ratio...things got better with #3 overall, but my beliefs are now that with the given facts, the #3 coil has a harder job than the others in the system, solely because of the engines internal mechanical design and excessive fat fuel mix on the #3...I feel that long term this would be the one part to fail because of the residual that settles there....it's fatter fuel mix...cooler temps...etc... we now know that it works harder given the same as the others to produce an even burn...replacing the plug is the quick fix and it works for most repairs, but I feel it's only a matter of time before a coil problem will arise here....given the dynamics of the available data...this time frame of failure would be dependent in ones mechanical skills, routine of flying, and running of the engine I believe, and how well they have things in "perfect" check overall for their given set-up and altitude...I feel this coil is the weakest link in the entire ignition system solely because it works harder every single time the engine is started, and the fact that "close" is not good enough tuning here....this is not your normal run of the mill 4-stroke I'm finding....think of it as a fine tuned race car engine and throw all your previous model engine stuff out...she is only capable of performing as well as your care and precise up-keep will allow...nonetheless she's a great running marvel and worth it all if all things are kept in check...another interesting thing observed and modified today, was how to keep that random reported failed ignition pick-up from hitting the magnets inside and failing...I made a gasket from a piece of the thinnest poly-ply from BVM stock...it raised it about .010 thousandths and eliminated the rub completely...I noticed no difference in performance, but feel it will save the pick-up from future damage...preserve it's longevity, and give me peace of mind it ain't hitting the cams...while I had it off, I observed the 4 cams inside that was reported...looking from the prop...and they do turn opposite the prop rotation....the first disc has 2 magnets that make a complete 360 degree rotation with 2 full revolutions of the prop...the next one is a valve cam that opens all the intake valves...the 3rd...a cam that opens all the exhaust valves....and the 4th... it has a total of 10 magnets on it for spark timing control I'm thinking...there are 2 groups of 5...evenly spaced...each group of 5 were 180 degrees apart but evenly spaced in their group...my thinking or best guess here is that the ignition system functions as follows....lets start with the 2 magnets on the front disc first...they pass by the forward part of the pick-up btw...my guess is 1 triggers the ignition module that someone is trying to start it...ie 150 rpm flip maybe...the other senses rotational rpm for selecting either idle or wot timing....the 2 cams next...they have no magnets...they only work the valves open and close...and finally the rear disc...with it's group of 10 magnets it would be to control the needed signal for multi- cyl spark timing control....adjusted accordingly by the Ignition module...these pass over the rear of the ignition pick-up btw...given this assumption, I feel that the only thing in the whole system that could cause the spark to disappear from the same cylinder every time, and leave the others to remain unaffected, would be the coil or ignition module...given the reported problems from my research here on the Moki, I would believe the #3 coil to be most problematic first...#1...solely because of the above mentioned work load it carries....the ignition module 2nd...but given it's position and job in the ignition, I feel that only incorrect batteries applied or shorted, or misadjusted voltage regulators would lead to the cause of it failing...it's possible to get a bad one, but very unlikely from my overall electrical experience...of course a shorted coil could lead to it's demise, but the possibility of it being a defective part from the get go is rare overall indeed....but still possible btw...these are the only things I believe that could single out only 1 plug and it's spark from my findings thus far...we gonna order a coil and see what happens, but we feel like this is gonna repair this engine to run without a hitch as designed...once we get this done we will more than likely add the pump and turbulator to the engine to further enhance the performance...I'll get up some pics to show the tester and it's mod's to assist anyone having possible ignition problems...the inductive pick-up timing light worked fine but the manual tester enables you adjust gap and load the coil with the engine running and it enables you to see the sparks color...A great inexpensive tool for Moki owners...sorry for the long wind...but I feel we got this puppy whipped...I'll post all final engine run data as soon as we get the coil replaced...thanks all...Bill

BIGDAMMODELS

Here's the spark tester for those interested...the piece removed for fit to Moki's ignition wire is shown...just chop it off...it's a bit long for the application and will jump to the plug cap without this mod and lead to misdiagnosis with the spark... I also added the tie wrap to assist in holding the gap setting on the tool...it's a bit loose thread-wise and will change with vibration...this fixed it for my testing...a possible lock-nut may be a better way...the other one is a good tool as well for testing spark, but I chose not to use here as you have to pierce the wire to use it...I wasn't fond of that at all given the application...it will lead to rf problems...not recommended here PERIOD with the shielded ignition cable....the seller will try to convince you it's ok to use here...don't fall for his/her advise...just a word of caution....you can also see in the included cyl photo's that the piston is very clean compared to the other...a sure sign of something wrong....a coil is in route and will arrive hopefully in a week or so from Vogelsang...I'll keep all informed of the results....Bill

Der Goetz

My Feedback: (9)

Hello Bill,

thank you for sharing - the coils are on order, I am now waiting on Moki to get on their feet.

SERVICE BULLETIN APS FUELPUMPS:
As per our own experience we now recommend actually using the return loop.
Please contact us should you have any questions and we do apologize for the inconvenience this may cause.

DENTO

G-DAY Der Goetz
You are talking about the new pump???
REGARDS
JOHN

Scott Prossen

Timing is everything! I have recently reversed my thoughts on this as well. I hope you are all paying attention because I believe I have seen a pump damaged from being run without the return loop whereas the pump ran dry for an extended period and became damaged. I am in the process of running a return loop on all my pumps. This is the opposite of recent advice I gave here just a few weeks ago. Until then I didn't think it was a risk and now I see that it is. I appologize for any difficulty I may have caused.

BTW, in my case I was able to run the return loop on two newer style pumps in just minutes apiece. Very easy!

Scott

JPate147

I am running the PowerFuel 380 on two Moki 250's. I do not have the return line.

My pumps DO NOT have the third nipple on top as shown on Vogelsangs website. My pump only has two nipples. Does this style pump require the return line ? If so, do I simply add a 'T' to the pressure side of the pump - and run a line back to the fill line on the tank ?

If I do this, will the carb receive sufficient fuel - or will the pressurized fuel simply return to the tank as that would be the shorter path.

Thanks in advance,

Jerry

BIGDAMMODELS

Thank you for your info and prompt service...

DENTO

Jerry
Is your pump like this if so no third nipple return valve is in the metal byparse between the lines . I THINK

fredo

Does this mean the pump is now highly recommended?
Could someone post the latest connection schematics?

Scott Prossen

I think having the pump only has benefits and for some more than others. I ran my Moki's for 2.5 years and never had a problem. I have installed the pump on all my Moki's and they have all seen benefits. I will not fly one without one now. Is it required......NO! Is it beneficial.....YES!!!

See this post for schematic: http://www.rcuniverse.com/forum/fb.asp?m=10686416

Scott

fredo

Thanks Scott, I'll be getting one soon.
Just one silly question. In that picture above, what is that cross piece in front of the pump? Is that a check valve?

Scott Prossen

Fredo, it's simply a T.

Der Goetz

My Feedback: (9)

Please allow me to post the diagram for the older style pump:

FormerCA.

My Feedback: (8)

Dr. Vogelsang

Did you get any pumps in yet?

Der Goetz

My Feedback: (9)

Pumps are in, as are many other products (EMHW, Severin, JW, Tomahawk, Fiala, Moki, Kunkel (Turbolators), Airworld etc), I am trying to catch up with work enough to where I can contact everyone on the waiting list and process their orders.
But yes, pumps are in, everyone on the list will be contacted today.

Best regards,

Gotz

FormerCA.

My Feedback: (8)

Thank You Sir

I enjoyed speaking with you and look forward to recieving my pump and props.

My CA Pitts will be in the states about the first week in november, so i'll be putting them to good use.


Thanks again

Ron

fredo

Guys, I ran my Moki150 for the first time only for a short period but noticed a few things. As I'm still a newbie to this little marvel you have to excuse my incorrect wording. First of all it started easier than I thought. I basically did the same thing
I normally do with my 2 strokes. Anyway, after it started, I noticed black oil getting discharged more from the left-hand exhaust than the right- hand one. (Looking from the front) The idle sounded rather rough but soon as I advanced the throttle
it got smoother. When I stopped I checked cylinder temp just by hand and noticed (again looking from the front) that cylinder at 7 o'clock is quite ambient in comparison to the others. Is that the one you call #3? It must've been running on four cylinders. I was using 28x14 Fiala prop with 50:1 TTS Castrol synthetic oil. My question is: Is that black stuff going to disappear after it runs a bit? Also can someone tell me what is the thread size on the choke and the throttle lever holes?