Do wheelies starve your oil feeds and damage the engine?

**cheshirecat** · 28th June 2011, 20:37

Just read this concerning RC30's and wonder if it effects other bikes
quote
" If you decide to run the oil ¼” above the full mark your oil consumption will go up due to windage. If you do stupid things like wheelie your RC30 it is very likely you will starve the oil pump and take out rod and main bearings. Running an extra ¼” above full on the dipstick won’t save you from such antics. If you ride so hard where you must wheelie then look at putting in a deep sump oil pan. HRC made them,"

the link is here
Oh you need to scroll right down to the 'oil' section

**Laava** · 28th June 2011, 20:43

Simple answer. Fit a small oil pressure guage and when you do a wheelie, have a look to see if there is a significant drop.

**onearmedbandit** · 28th June 2011, 20:45

Wheelied my thou for miles and miles and never noticed any problems.

**Elysium** · 28th June 2011, 20:51

I'd be more concerned about damage to your steering head bearings.

**onearmedbandit** · 28th June 2011, 20:52

Originally Posted by Elysium

I'd be more concerned about damage to your steering head bearings.

Only if you can't land 'em properly...

**Hitcher** · 28th June 2011, 20:54

If it's been written about on the Internet, it has to be true. Honda owners beware!

**Elysium** · 28th June 2011, 20:54

Originally Posted by onearmedbandit

Only if you can't land 'em properly...

True, but a lot out there can't. I found out the previous owner of my bike like his wheelies after changing the bearings.

**bogan** · 28th June 2011, 21:01

Depends on the engine, if you wheelie the oil is going to sit in a different place, so it is a possibility to starve the pump. However, under acceleration it'll do the same, so the manufacturer should put the pump's pickup where it'll keep the oil going round long enough or have a small pocket of oil that continues to feed the pump. So I reckon you're good to go for a little bit, but not massive ones.

**DrunkenMistake** · 28th June 2011, 21:43

Originally Posted by Hitcher

If it's been written about on the Internet, it has to be true. Honda owners beware!

Key word Honda,

Its going to break no mater what you do....

**Big Dave** · 28th June 2011, 21:55

It's a 'known issue' with some models.

**nudemetalz** · 28th June 2011, 22:00

Originally Posted by Big Dave

It's a 'known issue' with some models.

Big Honda singles (namely XR500/600's and also the RFVC-headed 250's) have been known to have the cylinder heads starve of oil when wheelying causing significant damage.

**Big Dave** · 28th June 2011, 22:06

Not just Hondas.

**Paul in NZ** · 29th June 2011, 08:33

The answer (as BD says) is that 'it depends'. Some bikes are a wet sump design and some are dry sump. (looking in my shed - the ancient Triumph is a dry sump and the slightly less ancient Moto Guzzi is a wet sump)

BOTH these engines are plain bearing bottom ends. These require a constant feed of cool clean oil and these engines generally run higher oil pressures than roller cranks. The oil is needed to form a hydrodynamic wedge (see here a bit down the page http://en.wikipedia.org/wiki/Plain_bearing)

Windage is when the oil level in the sump is close enough to the frenticly spinning crankshaft so that it starts getting picked up and flung all around the inside of the crankcase. You would think that this isnt a problem in a dry sump engine but it can be. In a dry sump you effectively have 2 oil pumps - one is a scavanger which pumps the oil back to the tank. On the ancient triumph you can run into problems if the scavange pipe in the sump isnt sealed properly as its easier to suck air than oil so the oil level rises and Triumph changed the length of the pipe a few times trying to get it just right for a particular state of tune.

So while windage is only a problem on a dry sump if something is wrong OR you have mixed n matched the wrong bits - its more complicated on a wet sump engine and even the factories dont get it right. The Moto Guzzi is a Mk2 LeMans, the last of the classic round barrell sports bikes. Its now fitted with a sump extender from a Mk3 (1st of the square fin). This drops the sump 30mm or so NOT so you can add more oil but so that the oil is farther away from the crank and is less likely to get flung about all over the show.

In the guzzi engine the oil pump and its pick up is towards the front of the engine. If you tip the motor back (wheelie), not only will the oil level drop at the pick up it will rise at the rear and be closer to the crank and more likely to start getting frothed up by the crank. So running for any length of time with the motor tipped back in a Guzzi might not be such a flash idea. In theory, not only can the pump pick up get above oil level the oil itself can de aerorated from the widage effect.

To counter this - people often fit a windage plate which is a type of baffle that will slow the movement of oil.

Of course other bikes have oil pickups right at the rear so prolonged braking can have an effect.... (tricky aint it)

Or - some 4 stroke lawn mowers are not recommended for people that have hilly sections beacuse they will starve of oil if run side on to the slope.....

**nudemetalz** · 29th June 2011, 10:42

Interesting read, Paul,..but err...how often you get the Mk2 LM on the back wheel, huh?

**Crasherfromwayback** · 29th June 2011, 10:51

Originally Posted by nudemetalz

Big Honda singles (namely XR500/600's and also the RFVC-headed 250's) have been known to have the cylinder heads starve of oil when wheelying causing significant damage.

Think you'll find that was more of am overheating issue that fucked the heads on those models mate, not oil starvation due to wheelies.