hello everybody, i'm from France and i have an DL 50 on gp patty wagstaff, i post this message to help me to rpm up my DL50.

i bought it on late Nov 2007 i have black crankshaft onto the hub and the machinery standoffs. New and absolute No compression !!! []I'm little affraid but i running in with 30:1 mineral oil 2 gallons and the perf with a 22 8 menz are 6500 a top end with the needle adjusted . I think that the cause of 30:a of mineral oil . now i have burn 3 gallons of fuel and now i'm 50:1 synthetic oil (ipone racing samourai) neddle adjusted with a bcm pitts mufflers a menz 22 8 and i take 6600 only !!![:@] there are no compression !!! it's a pain to prime the engine 30 flips environ.

explain me to richen up my compression and obtain cool result above 7300 with a 22 8 . If i change piston can i gain compression? Do you have the same problem ?

thanks a lot and scuse me for my poor english and i hope we can help me.

guillaume charozé [8D]

Those are the same numbers I was getting. It has slowly goten better as I continue to run it. Remember there are alot of things that contribute to engine power. High altitude, humidity, temperature, and exhaust can all affect it. On a good day I have goten just under 7000 rpm on a xoar 22-8. My engine was a pain to start originally also but as I continued to fly it, the engine really got better. It takes about 4-5 flips on on the cholk and less when trying to start.

The lack of compression should be looked into. If it's still in warranty and you desire too, send it back for repairs. Any engine with rings should have good compression from the start. If you are out of warranty and want to find where the compression is missing. Take it appart and inspect the rings and cylinder walls for problems. There are people here in the states who specialise in ring replacement. ie.Bowman rings. If your engine has the same horribly inadequite machine work I've seen in other china made engines, a lot of bench running might be needed to grind things into shape.
Kinda tough for a ring to seat itself with blowby leaking hot gasses and carbon grit past it.
Otherwise your rpm's sound about right for a whimpy (no compression) 50cc.
Then take into consideration a wrap around pitts type muffler is about the most power robbing type there is.

Your numbers are right on for the DL still in break in process. It takes several gallons before these engines get into peak rpms. The engines do seem to lack compression when turned over by hand slowly, but when you put a prop on it and spin it fast, the compression comes up. If anything, i'd check the reeds and make sure they're seating fully, due to your explanation about the fuel draw, or make sure the screen is clear.

I also find the needle settings, especially the low needle, have a huge impact on the high RPM. Make sure it is not rich in middle range.

The compression on mine is not particularly strong. I can turn the prop over with fingers holding the spinners, in CCW rotation. It becomes quite hard to do so (almost impossible) if turning it CW rotation.

I do not plan to switch to synthetic oil. 32:1 Air Cooled is perfect.

I have two DL50's, one with high compression, one with very little. Guess which one turns the higher rpm with the same prop, that's right, the one with the lower compression. I spoke to Bob a DLUSA because I didn't understand why. He said the factory switched to a different piston ring that results in the lower compression, but more power. Both engines run great!

Chuck

Why heck throw the ring away and you'll be doubling the power by that reckoning.

Guy,

I got 12 of the Bowman rings in the other day. Very nice and much better than the factory rings for the engines they are used in. Better still, the Bowman rings cost $5.00 less per than the OEM stuff.

thanks for your help i check the reeds it's seat perfectly , i check the inside of cylinder its not machined properly i have bought this engine on ebay shop (slyvian1975), a friend have a DL50 bought at (peakmodel) just one gallon of running in incredible compression !!! and perf are here 7200 with 22 8 just out of the box. I plan to buy a couple of piston and cylinder to solve the problem.

In my completely half-vast experienced..... a ring that permits a lot of blow by, whether due to cylinder machining or ring fit, ultimately may have more "rpm", but sure doesn't have "power" (power being defined here as ability to push a heavy prop load).

_____

On the DL 50's, there has LONG been speculation that different "sellers" obtain different quality engines. Difficult to know the truth, but my own experience with these is simply that there is a LOT of variation in quality between engines. Pure and simple. You may get a "Monday" engine or a "Wednesday" engine, and they may run completely differently. It really seems to depend on who was running the machine, or how much garbage was in the mold, or.....

If we want every engine spec'd and blueprinted to a tight factory tolerance, we better be ready (and willing) to cough up a LOT more $$$$ for the thing.

Well if Bob at DL really said that he just went way down to the bottom of the pile with a few others imo.
Sounds like the usual cover up bs for poor quality.

Hitting the proverbial nail on the head.

If you want quality, you will pay for it.