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DLE-111 Three Year Inspection & Overhaul


70cc twin V2
My DLE-111 is starting it's 4th year of service, approximately 25 gallons of fuel thus far. 20 gallons of that has been within this past year due to my first season flying in IMAC.

Based on my limited gas engine experience, this engine currently run great, starts easily, is tuned nicely (Walbro WJ-71 installed) and makes good power; swings a Falcon 28X9.5 @ 6500. The only thing that may be unusual is that I think the engine vibrates more than it should, but it has since day one. I especially notice it under 2000 rpm's by looking at the wing tips and pilot figure mounted in the canopy. The engine will idle down to 980 rpm's and stay running but is rough..........sounds like a Harley. My normal idle is set at 1300-1400 rpm's. I've seen other DLE-111's run much smoother.

I'm planning to give the engine an inspection in the next several weeks to make sure it is mechanically sound and ready for the 2015 IMAC and flying season. My plan:

1. Inspect the reeds and reed block.
2. Open the crankcase and inspect
3. Pull the jugs and inspect cylinder walls, pistons, etc. Will also install a set of Bowman rings at this time.
4. Check bearing for anything unusual, check seals.
5. Check the run-out on the crank, prop hub and prop shaft.

I know there are some very experienced and knowledgeable members here on GSN so my basic questions are:

1. Is there anything I should especially check or look for?
2. Based on past experience, what components should be replaced, if any, even though the part(s) may look fine. As an example bearing seals, needle bearing, etc? Maybe it's best to just wait until I have the engine apart before ordering anything needed?? I do already have the gasket kit.
3. Maybe I just pull the jugs, install the Bowman rings and button it back up. Fly it until it starts to become unreliable.

My mechanical skills/understanding is probably better than most but I'm not a small engine mechanic. Yeah........I've taken apart my trimmer engine and my PTE-36R and put them back together in good working order.........but very limited experience. This is a part of the hobby I enjoy but sometimes it's better to let an experience professional (sent it to Valley View RC) do it right the first time.....LOL.

Any insight and guidance would be appreciated.
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I'm not really certain of your experience/ability/tool set level. But if I were to judge by your description above, I'd not take the crankcase apart. Pull the jugs, inspect everything you can see, replace both pistons and/or jugs as a set even if only one is worn, put in a set of Frank's rings, replace the gaskets and diaphragms in the carb, replace the reeds with new OEM and add your originals cut in 1/2 over the top of the new reeds. Check and adjust ignition timing as needed, new plugs, and install new prop bolts.

Depending on the version you have, you may not have any factory/dealer support for anything but bearings in the crankcase. And unless you've done it before and know how to remove the crankshaft and bearings, one can easily damage a part that may not be easily acquired to replace. The bearings are IKO and NSK Japan so they should easily last at least another 25 gallons without any trouble.

As for the vibration, remove the pistons and weigh them, you want them to be within a couple grams of each other. If you replace them, ask the dealer to do the same and supply two that are as close as possible, they can be fine tuned to match perfectly if desired. There are other things one can check that are a little more technical/difficult if you have access to precision measuring equipment and possibly a selection of jugs to choose from but it's not necessary.


70cc twin V2
Thanks Jody, your help is always appreciated. My DLE is a V2. The WJ-71 was installed this past June, I do have a new diaphragm kit for it.

I'm comfortable with performing the things you've recommended.


As I eluded above, the V2 crankcase assembly has no factory or dealer support except crankshaft main bearings. If anything is wrong with the crankshaft, housing, even prop hub (less stripped threads), it's time for a new engine. So, proceed with caution.


70cc twin V2
Wow, I knew the V1 support/parts had expired but didn't know that V2 was now limited availability on some parts. If I can get three more years with new jugs, pistons, rings, and reeds then I think that would be a pretty good service life.


70cc twin V2
Do you have access to dial indicators and other precision measuring tools? I would think the pistons should be closer than a few grams. I use a reloading scale and it has much finer resolution than that. In any case good luck and please post pics.


70cc twin V2
For sure on the pictures. I have a precision scale at work that will read in 0.00 grams and we have full machine shop. There are various dial indicators and have measured the crank, prop hub and prop shaft run-out on my PTE-36 and EME.


70cc twin V2
Started to take a look at the engine this evening before it turned dark. Pulled the two mufflers and took a look through the exhaust ports. Looked pretty good from that small window.

Went ahead and removed the bolts from the left jug and slipped it off the piston. The cylinder looks in very good shape and same for the piston other than a thin deposit layer on the crown and top surface of the cylinder. The ring is moving freely in the groove and without a visual inspection the groove seems to be relatively clean of sludge/deposits. There looks to be a couple of small polished areas on the cylinder walls but no scoring or blow-by discoloration.

I'll need better light for a detailed inspection but right now if the deposits can be removed and a light "honing" of the cylinder I think the jug/cylinder and piston would be good for additional use. I haven't looked at the bearing and pin yet but will get that done tomorrow evening.
111 Lcylinder 1.jpg
111 Lcylinder 2.jpg
111 Lcylinder deposit 1.jpg
111 piston 1.JPG


I have one with over 60 gallons through it. I haven't did anything to it. Im running it till she blows.