Forum

[Cranky]

Has any one done this. I like a low thud thud idle as I feel this is half the fun of a Royal Enfield. The decomp that comes out at a 600 RPM or so , you know that little weight thing that pushes out and raises a peg onto the exhaust cam. I mean you cant have a 500 RPM idle with a de comp that like that. I have mine set as low as I can and I can hear the de comp clicking in and is probably why I can maintain that thud thud idle---it stops.

[stinkwheel]

You could well be doing a lot of damage by allowing your engine to lug at 500rpm, I'd worry about oil pressure for one thing and it'll be peening your main bearing races.

You could land up with mains looking like this:

[Rattlebattle]

Lots of owners have removed the decompressor device without issues arising. Some advocate filling in the empty slot in the exhaust cam to prevent wear o the hydraulic lifter roller ( probably overkill).
I’ve kept mine, mainly because it has never caused any issues, unlike some. I tend to agree that the tickover shouldn’t be set too low on account of lubrication. Apart from that I’ve never come across anyone who has had starting issues because they removed the device.

[Cranky]

Sometimes i hear it click in and try to shut down the egine only for it to restart before it stopped. The inertia pulled it over another compression and started it again.

In other words the decomp came in and it stumbled almost stopping. Im wondering if that is normal.

As the bearings are roller i dont think a slow idle is any issue at all. There is a lot of splash going on in there. See how much oil gets splashed from the timing hole when strobing.

One of the benefits of UCE is the splash lube off the gearbox gears.

Its very impressive at starting though. My Thai 45 kilo girl friend can start it. And it is a girl not a bloke in a dress Ive been here too long for that.

[Harald]

There is a good reason why the idle factory setting is 1050 +/- 200 rpm. The main bearings and the gear box bearings do not need a high oil pressure, but a good oil pressure is a must for the cylinder head. The cast iron rockers are running in blocks of aluminium that require a good oil pressure to prevent wear. Very important is a good lubrication of the rocker tips where they touch the valve shaft top ends. A lack of oil will result in severe wear and tear. A do not forget that the hydraulic lifter's function depends on the oil pressure.
To get a good impression how the oil supply in the head depends on the engine's rotational speed you may run the engine with the rocker covers removed. There has to be a constant oil flow from the chink between the rockers and the aluminium blocks as well as around the rocker arm tips. The valve shaft upper tips have to be covered with oil, even at idle and with hot oil.
I have a little bit problems understanding why the (low idle) sound of the engine or the sound of the exhaust system is so important for some people . As long as the bike runs without issues and bringing me to where I want to go I do not care about the sound. It is more an unavoidable side effect.

[Wheaters]

I don't really see the need to set the idle too low, I'm more bothered about a reliable idle, simply because it's too bothersome if the engine stops in traffic (but then my bike doesn't have an electric starter).

As far as excessive wear on the rockers is concerned though, it would take a long time at idle with a normal lubrication system to get the amount of wear Harald's bike suffered. Having read the sad saga of his bike, I don't think there was much lubrication at ANY engine speed!

I recall the days when engines had open valve gear and it was necessary to get out and use the oil can! I used to see John Rowlands, who became the head chemist for Silkolene/Fuchs Oils, do this to the Matchless V twin engine in his Morgan three wheeler at our bus stop.

I'm more interested in how high I can safely rev the engine of my bike - I did once find the rpm at which the valves float!

[Rattlebattle]

I wouldn’t place too much store on gearbox lubrication. The shafts run above the oil level. There is a plastic oil flinger plate that chucks oil up to the shafts, assisting the oil supplied by churn. Engine revs are needed to maintain a decent supply. I had to replace the gearbox output bearing on mine.

[PeteF]

Surely the decomp is there to make starting easier?
If you remove it you'll be giving the battery/ starter motor/sprag clutch a harder time.

[Cranky]

The sprag gets a hard time when the engine kicks back, not from when the starter is turning the engine. When the engine kicks back it is through a much different gear ratio.

My EFI is now modified to a Carb. The old now unused temp sensor has been modified to a Vauxhall corsa oil warning light working the also now unused MIL light. When cold it goes out immediately but when hot it is on at idle.

I don't think there is anything wrong with this. I mention it because the upstairs oil pressure is minimal and probably just a flow. Oil pressure switches are usually 7 psi.