Robin DY42 Problems

[brucey]

I took a bit of a gamble on a DY42 electric start 3000rpm engine attached to a 5 kva generator set and bought it unseen.

After removing the engine and putting it on my test bench, I noticed it didn't have any oil in it! However it turned over o.k.
I fitted a fuel tank (got a separate big tank with the genni) and bled the fuel system. Put 1 lt of oil in it and hey presto, it started on the pull start. I ran it for about a minute (until my wife complained). It did smoke slightly but I put this down to being cold and having not run for a while.
I then rigged up the electric start and it started without any issues and ran it again for another couple of minutes.

I moved it to the front of my house where it wouldn't upset too many people and started it for the 3rd time. It ran for around a further minute and cut out. It wouldn't re start.

I have re-bled and checked that fuel it coming out of the injector. I also tried squirting wd40 into the inlet but it just gives the occasional pop.

It has compression on the pull start and pops on the electric start occasionally but will not run.

Any advice what to do next.

I have aready checked and adjusted the tappets (they were pretty good) There is nothing nasty in the oil and it doesn't look or smell like it's been cooked.

I have another DY 42 Engine that runs so can swap bits.

Should I pop the head off next?

[brucey]

Having just looked at the manual, I don't think my engine has the oil level sensor option. Even if it did, it should fire up on a squirt of WD40 into the air inlet.

However, I was wondering if if something might be wrong with the Automatic Decompression System? I may loosen the intake rocker adjuster by 1 turn as suggested in the manual.

I maybe clutching at straws here but it was running and starting pretty well..........until it stopped!

[gilburton]

Funnily enough I was just thinking about you the other day and wondering if you had made any progress with a bike??
Can't really help you with the problem as it's just a matter of working your way through and checking everything.
Difficult to say on an engine that has been standing although if fuel is reaching the injector(in sufficient quantity and pressure) it should fire.
I never used to bother using the decompressor on the electric start.
I'm only going from memory but as the decompressor is part of the rocker cover it might be worth leaving the cover off to see if it will start without it??
It also might be a stuck valve??
I know my decompressor was always a bit funny and took a few turns of the engine before it would gradually click round to the off position and fire.

[brucey]

Gilburton,

Nice to hear from you

I was struggling a bit with motivation but after going to 'The Big Knock' last weekend, I am now inspired.

The tax and MOT ran out on my Bullet Trials this week so it is now ready to have its petrol engine removed (I have taken a video for when I sell it).

I would like to fit this latest DY42 engine as it has the electric start already fitted. I am very temped to make a replica of Ernie Dorsett's Yellow Peril and ride it to next years Big Knock.

We will see.

Bruce

[gilburton]

As you've got most of the parts the hardest part will be modifying the frame.
After that it should come together quite quickly.
I assumed the long silence was because you were beavering away in your workshop

[brucey]

O.k. I had another go at starting my DY 42. It pops when turning it over on the starter with a fair bit of black smoke coming out of the exhaust. However as soon as the automatic de compressor releases it just stops as the starter cannot cope.

I have tried squirting easy start into the inlet (air filter removed) whilst turning it over but it has made no difference.

My latest thought is that I have pulled some muck through the fuel system (I didn't change the filter when I cleaned the bowl). Although the injector is squirting fuel I'm not convinced it is the right pattern.

I tried increasing the inlet valve clearance to stop the automatic de compressor operating but couldn't turn the engine over on the electric or pull start. So compression doesn't seem to be a problem.

My question is:
Should the engine run by squirting easy start into the inlet, even if the injector isn't working properly?

It seems to have compression and fuel. I'm not sure what to do next.

bruce

[gilburton]

Sounds like you may be getting too much fuel and adding easy start is just adding to the problem??
You could disconnect the fuel supply then try neat easy start?
I would liken it to getting wet plugs. Possibly you are getting neat fuel rather than a spray pattern and it's hydraulicing??
The other option is your timing but unlikely.
If nothing else as you have the spares swap over another pump/injector??

[brucey]

Cheers Gilburton,

I guess I could just turn the fuel off at the filter and crank it over with a bit of easy start or wd40.

I'm going to get a couple of fuel filters from ebay or midland power so I don't damage the injector or pump from my good engine. There is a local diesel place who would probably check the injector spray pattern for me.

It's strange as it was running o.k (maybe a little smoky) and then just cut out after a couple of minutes. It could have pulled something through the fuel system quite easily.

I was getting too complacent with these engines thinking they always ran!

Not beaten yet, although it would be nice to hear it running smoothly for at least 10 minutes before I start fitting it into a bike.

Bruce.

[coachgeo]

....

It's strange as it was running o.k (maybe a little smoky) and then just cut out after a couple of minutes. It could have pulled something through the fuel system quite easily.....

Sounds like air in the system.... or not getting fuel.