[Urgent] L100 exhaust through the air filter!

[snoopy]

Trying to get to France tomorrow but have had this problem twice now.

L100 clone, very few miles (is a new engine) runs spot on.

However twice now, when hot or having run for a while and then trying to kick it over it will start but throttle has no impact. Instead huge amounts of white smoke come through the air filter box. No fumes at all come through the exhaust. It will then die.

Seems if I leave it for a while it fixes itself. The air filter was destroyed the second time it did this and the remaining parts are thick sooty black. Even without the physical damage the air filter looks like it's 5 years old (completely clogged) despite having done about 200 mile.

Fuel consumption is excellent and oil level seems unchanged.

Any ideas?
Andrew

[pietenpol2002]

Just a classic case of a diesel running backwards. Not uncommon. Just a guess, but may be related to your starting sequence or in some cases pump timing. Time to replace the air cleaner. On a brighter note, you now have 4/5 gears in reverse.

[snoopy]

Oh right . I'll try adjusting my kick sequence!

[Sphere]

On a brighter note, you now have 4/5 gears in reverse.

ROFL

[Dan J]

Until I converted mine to electric start I got so fed up with this "feature" I used to take the air filter out every time I started the bloody thing from cold.

As Pietenpol suggests, it's user error but it's hard to get the knack of kicking these things over!

[snoopy]

As the engine has more miles on it it has rarely done it. I rode the bike from Barcelona to the UK on unfiltered air after "the feature" blew the air-filter to smithereens!

[Sphere]

I managed to start my Hatz backwards last Sunday as well. Nice smoke escaping through the air filter. It didn't respond to the throttle, except when I cut of the fuel Never bothered checking the air filter, I hope it's still in one piece, although I should have a replacement lying around somewhere...

The only way I know how to start it, is to try to get it up to TDC, right before it injects the fuel then hop from left to right and make the kickstarter enjoy the full force of my body weight I hope this gets better with time, I've seen a Sommer started by a guy wearing loafers (?). I will surely sprain my ankle if I don't wear boots.

[andrewaust]

My L100 clone has done it a few times also, no harm ever done to the air filter etc, just soot's the intake up a little, nothing bad.

If you don't give them a good solid kick right through the kick start sequence they can bounce back on or near TDC, if fuel begins to spray the engine will chug over a few times. I think the injection cam has a lobe that suppose to stop them running backwards for a long time but don't hold me to it.



A

[balboa_71]

I had a 22hp horizontal chinese engine that would start backwards as well, only solution was to use the electric start...my arm wasn't big enough to crank the engine over manually, so it would spit and start backwards

Cris

[Diesel Dave]

For those with Yanclone motors or any others that have manual decompressors, using the bounce-start method will make it easier.


Check out this video on YouTube:

http://www.youtube.com/watch?v=j_U-Jltn ... ata_player

[balboa_71]

Dave,
Haven't heard from you in a coon's age!! Didn't know if you were still posting. I myself ducked out for a while, but the high cost of fuel re-sparked my interest in high efficiency travel. My Kubota may need some tuning with checking the injector advance. I know we discussed this 4 years ago, now I have an engine that maybe a tad retarded

Can I do a check electronically???

Thanks,
Cris

[Diesel Dave]

Hi Chris,

I don't know of a way to check timing electronically, unless you have deep pockets and Snap On have something up there sleeve.

If you have a video camera with a high speed function you could video the injection cycle, use a clear tube on the high pressure line so you can see the injection cycle and a degree wheel on the crank.

To be honest I found it just as easy to set the timing by e method in the manual (clear pipe and watch for the fuel jerk/flywheel position. After this I made about 6 test runs up a local slope, checking the speed that the bike reached. After this I removed another thin shim to advance the timing a little.

One thing you should check when in search of efficiency from a diesel engine is the bump clearance (distance between piston crown and cylinder head. Again the factory manual method involves straight edges and feeler gauges but I find it easier to put a ring of soft electrical solder on the piston crown, replace the cylinder head and turn the motor over compression once. Removing the head and checking the thickness of the squashed solder with a micrometer or digital vernier will show you the clearance. Usually the clearance should be about 0.7mm to allow for con rod stretch and big end slop. I have set mine to 0.6 and even 0.5mm without I'll effect and you will notice the difference.

More difficult on a multi- cylinder unit as you would need to work to the lowest common denominator, for the Lombardini 6LD series motors different thickness copper ring head gaskets are available to set this clearance.

Fuel makes a big difference to the timing, depending in the Cetaine rating, there is a delay after injection before the fuel ignites and the higher the cetaine the faster this happens. In the UK and Europe a rating of 51 is regular pump diesel and 55 is available at extra cost, in the US it can be much lower even down to 40.

If you want to change the timing without stripping down then try using a cetane booster additive and see if the performance improves. Just looking at the fuel stats would suggest you need more advance then the UK to account for the fuel rating.

The cetane rating has little to do with power, it's just how easy the fuel is to ignite so does have an impact on cold starting.


Happy tinkering

[alexanderfoti]

Hi Chris

your piston crown distance comment has me intrigued.


How do you adjust this clearance, by changing the thickness of the head gasket?