DA85 on pipe! Results please.

[Flatlandman]

Go to your carb bolts and tighten them a little bit and see if it stops. My 85 had a ton of problems almost all related to those bolts coming loose or breaking. When tightened to da spec the engine ran perf but the bolts would break ( the aluminum ones) and or come loose with out reason. When the bolts were retightened to the amount da told me they needed the engine ran like it was supposed to. They hav gone to steel aloy bolts so breakage isnt a problem any more.

[Royster]

OK will tighten up the bolts but after reading the "85 Burbles" thread the problem stinks of pressure issues!!

[Flatlandman]

worth checking though. When the bolts were on properly the engine ran damn good on a 27x10th when one of the bolts got a little loose the thing sounded off.

[Royster]

Will let you know the results

[RustyTumbles]

Hey Roy,

Had the cowl off my sukhoi today, just for some general maintenance and the carb bolts where loose. Mine has been running slighlty rich lately which I had put down to the weather but maybe that was the cause. I'll let you know on sunday when I fly it again.

[Royster]

Check mine last nite and they wernt loose but still moved enough to tighten up a bit.

Does your plane shake like a bugger as well on idle?

[RustyTumbles]

yep

[dbcaster]

I taped off one side and the top hole with duct tape on my when I was having issues. It did help a bit.

[Ground Pounder]

	Quote: Originally Posted by Royster
	Does your plane shake like a bugger as well on idle?

First flights with the 1090 and a Xoar 28 x 10 (5650 top end) seemed to have a lumpy idle but the needles needed a bit of adjusting.

Once I switched to the Mej 28 x 10 and tweaked the low needle the darn thing idles like a V 12. Smooth as butter. Probably the smoothest mid size engine that I have seen.

Better than my DA 100. And yes I balance all of props.

A buddy runs his with the Pitts and a Mej 26 x 12 and it is very smooth.

[RustyTumbles]

how is your engine mounted?

[Royster]

Seems like the DA85 was meant to run on a 1090 pipe. (from what I read here)

Maybe it just doesnt like cans!

[Flatlandman]

My 85 didnt shake except when the carb was a little loose. I had a Slimline pits muffler though. What canister are you using?

[Royster]

Not sure will have to look it up and let ya know

...but surely being a single yours vibrated a fair bit?

friends look at mine and comment on how much the airframe shakes!

[Flatlandman]

Not really i was surprised by the many reports from people on the net about theirs shaking. I dont know if its muffler and tune related or what it might be. The big surprise for me on the first tank the engine was tuned perfectly. It didnt stay that way as the break in happened the engine got richer with every tank, so every 3 flight or so i had to retune it until about 8 gollons then i had to tune it 2 or 3 time between gallon 8 and gallon 20. Other than when the carb got loose there wasnt much shaking. I have a DA100 old version now and the 85 that i had and the 100 are very close in she shake department.

Edit; When i first got the 100 i had mtw canns and tuning the engine was diff. I couldnt hear the diff while tuning maybe that is having an effect on your situation. For me tuning when there is canns or pipes involved is very difficult; it takes me more and more flights to tune an engine with them.

[Patrick H]

At idle the torque twist becomes more pronounced. This can be easily mistaken for vibration.