bleeding the oil pump

Post by **admin** » 13 Feb 2006, 20:49

Dudes, just to chip in here, has anyone ever seized a motor with too much oil ?? i have.
After my rebuilds i tend to do the following.
I assume that even with oil pipes primed and oil used in re-assembly that it will take a little while for oil to get back to normal circulation.
I have run my strokers after a rebuild like this
1 litre of fuel in the tank, and at a premix of 40:1
Boot it into life (or electric start on my RGV 250SP) and let it tick over for around 2 - 3 mins with light throttle blipping and holding the oil pump cable out to achive max pump watching for air bubbles moving to clear.
Stop the bike and allow to cool for an hour checking for leaks and topping up coolant etc etc
Start the bike again wit the oil pump cable normal, and run upto temp for 10 - 15 mins again gently blipping the throttle, then kill it and leave for a couple of hours to cool.
Start the bike again, warm upto temp with blipping and holding at around 4k to clear the oil / smoke, get nice and hot and leave to cool once again.
Remove the fuel oil mix and fill with fresh fuel and then take it out on the road to clear the excess oil and break her in.
Too much oil will result not only in it looking like batman owns the bike and it's running on coal, but it also runs hotter due to the increased oil its burning and weakening the fuel mixture.
Granted a CRM single is a pretty hardy beast but when you dealing with TZ's TZR's RGV's RS's all highy stressed strokers i tend to give a bit more mechanical sympathy initialy then so long as the motor isnt bogging down i ride it at the revs it feels happier to be in without sticking to a strict RPM quide
HTH's

Bargos · Post by **Bargos** » 13 Feb 2006, 20:53

So there are now 3 different opinions on this!!

I think the answer is, there is no right answer, only differences of opinion...

Post by **admin** » 13 Feb 2006, 20:55

Great the poor lad's head will be wrecked.

Use extra oil if you feel you need it, but IMO and experience if running a light mixture then only use that for some heat cycling to break it in a bit before it gets the arse ragged out of it down the road 5 mins later.

CRM'er · Post by **CRM'er** » 13 Feb 2006, 22:40

When i stripped bike down to frame for bead blasting and powder coating, i just bled the pump for a while until no more bubles were coming out pluged it in and started her up lol, maybe im lucky i didnt do any damage

oops mind you i hadnt done an engine strip down and rebuild though.

ugly1171 · Post by **ugly1171** » 14 Feb 2006, 11:59

Admin's right, too much oil is as bad as not enough. The fuel mixture will run weak with oil in the tank as well as from the pump. Those clever people at Honda run the engines on dynos to calculate the fuel required for the engine. So when they decide on a jet size it's to flow petrol not petrol & oil!
I've always rebuilt with plenty of oil on the bore & piston (where the oil needs to be on start up) as the crank bearings are ball bearings they will be ok til the oil gets to them.
Check & double check that all the air is out of the oil pump then you won't have any problems.

Ugly

edarter · Post by **edarter** » 14 Feb 2006, 13:21

any ideas on where I can get satin black high temperature spray paint from though guys ?

Toad555 · Post by **Toad555** » 14 Feb 2006, 21:32

Hi

I just painted mine with normal satin black and its mainly stayed on so far, I don't exptect it will last long on the first 6-8 inches but neither does the other stuff.

Toad

kinney · Post by **kinney** » 15 Feb 2006, 00:33

ugly1171 wrote:Admin's right, too much oil is as bad as not enough. The fuel mixture will run weak with oil in the tank as well as from the pump.

Ugly

Wow, I think its great when a thread takes off like this.
As you read on, just remember, I'm only trying to help.
My bike runs fine because I understand 2 stroke engines. I've been around them many years and made it my buisness to study every aspect of them.
I was a mechanic for a national cart racing team for two years (and beleive me...they can be problematic) and I competed in motocross on the CR250 for 4 years so have lots of in depth 2 stroke background.

Right........Ugly1171.
Please don't take offence here but you're wrong.
(see quote at top)
With a 30 or 40 to one premix already in the tank, the supplement of autolube oil will not weaken the mixture any further.
I'll explain.........
Once the fuel and air leave the carburetter, the mixture (fuel vs air) is already established. The addition of autolube oil, which is introduced down stream of the carb, cannot weaken the mixture further because it is supplementing both air and fuel and not taking the place of fuel as it would if you premixed the extra oil in the tank.
So it is perfectly safe to use premix and autolube. No extra weakening of the fuel/air mixture will result.

CRMR Administrator.
You seem to have more understanding of 2 strokes.
I can tell you though, there is little difference between 30:1 and 40:1 premix ratios when used in a CRM250 just for establishing oil pump operation.
25:1 and 30:1 are very old fashioned ratios from the early seventies and early eighties. Oil technology has come a long way since then, and a CRM is perfectly capable of running 40:1 with no ill effects.
30:1 is a good safe ratio though and if you're premixing permanently, then its fine. If you're premixing temporarily, anywhere from 30:1 up to 40:1 is fine. Your engine won't wear out in just a few hundred miles.

On to Bragos.
C'mon Bargos.......get a grip!

No ones questioning your previous advice and that poll is just silly.
What you should have polled is......."Who thinks running on an unknown premix ratio is good for an engine"
Then you might have seen a more relavent result.

I'm sure your previous advice has been fine but you've got to admit, that last batch was well dodgy.

Anyway.......time for bed.
I hope everyone enjoys reading this as much as I enjoyed typing it. I kept going on just 2 bottles of beer.(Old Ember)

Looking forward to some great comments.......

Andy.

edarter · Post by **edarter** » 15 Feb 2006, 12:42

Andy,
I don't understand the reply to ugly..... Agreed that the fuel air mix is established in the carb, but the 'fuel' in the carb (if using pre mix) will have an oil content, so if the pump is then putting more oil in downstream of the carb surely the oil content of the entire fuel / air / oil mix at that point is going to be higher ?

probably not grasping something but always good to understand !

kinney · Post by **kinney** » 15 Feb 2006, 14:13

No problem Ed. It is a little tricky.
It was suggested by Ugly that using extra oil in the fuel will weaken the fuel/air mixture because the oil is taking the place of petrol in the jets.
This is true, but not when the extra oil is via autolube.
Because the autolube oil doesn't pass through the fuel jets, it can't take the space which would be normally occupied by petrol so it doesn't affect fuel/air mixture ratio.
It will, of course, take up space in the combustion chamber but that space would have been occupied by both fuel vapour and air so all that happens is the engines power is reduced slightly. The fuel/air ratio is again unaffected.
This is why is is beneficial, in competition, to run with as little oil as possible. Excessive oil reduces the size of the bang and also causes increased drag for the moving parts within the engine.

Glad you were interested Ed.
I can go on all day about the wonders of 2 strokes.
If I still haven't made anything clear, please let me know.

Andy.

lee_p · Post by **lee_p** » 15 Feb 2006, 23:14

Edarter bet you wish you had never asked the question now

ugly1171 · Post by **ugly1171** » 16 Feb 2006, 19:06

Well that's me put in my place, 25yrs in the trade, the last 13 years in R & D in engine performance, endurance & emissions testing obviously counts for nothing............ I always thought that in a 2 stroke engine a main jet flowed petrol which mixed with the incoming air, to provide a combustional fuel, the oil either via premix or auto lube was to lubricate various surfaces inside the engine before being burnt off.
Therefore if you add oil to the fuel, this oil will also go through the main jet. If that jet flows say, 20ml3 of petrol into the air, when you add oil, it will flow 20ml3 of petrol & oil into the same volume of air, therefore weakening the mixture because you won't be getting 20ml3 of petrol. A weak mixture will run hotter regardless of how much oil you add, causing heat related damage to the head, piston & bore.
Having ridden a CR250 for 4 years (Oh get me!

)you will also know the (correct amount of) petrol is also used to reduce the cylinder temp to fend of pre-ignition of the fuel.
I must be old cos it was called Karting in the tuning shop I worked for some 27 yrs ago!

Ugly

kinney · Post by **kinney** » 16 Feb 2006, 20:23

ugly1171 wrote:Admin's right, too much oil is as bad as not enough. The fuel mixture will run weak with oil in the tank as well as from the pump.

Ugly

C'mon Ugly.........catch up. I'm losing the will to live.
Check your original quote above.
You said "oil in the tank as well as from the pump"
This implies that oil in the tank is ok but not with autolube too.
Remember, this whole procedure was only until oil pump operation was proven established.
Your last post is arguing a different point although, cleverly, very similar so most won't spot it.
And yes.....your scarcasm did make me blush.

Oooh......the force is strong in this one.

Your years of experience is very impressive but it's still ok for you to be wrong, Ugly.

Coming in from your angle.........I've already cofirmed that premixing will weaken the mixture slightly, of coarse it will, but no where near enough to bother a CRM while we're ESTABLISHING OIL PUMP OPERATION.
Look you've made me shout now. (joking)

It was also implied that when the autolube kicked in, the extra oil would further weaken the mixture but as you've probably realised

...............it won't. Ahhhhhhhhhhhhhhhhhhhhhhhhhhhh (relief)

Ugly, PM me for further discussion...............this thread has wandered too far from its original dispute subject. ie The importance of using a known premix ratio.
I have already made my point on this matter and made my peace with Bargos by PM.

Andy.

ugly1171 · Post by **ugly1171** » 16 Feb 2006, 22:45

Andy,
I can see where you're coming from & agree that minimal damage would be done to the engine while running at idle to get the air out of the pump.
The point I was trying to make was, (for people with little or no knowledge of 2 stroke engines) is, don't think that once the pump is working properly, it's ok to carry on with a tank of pre-mix as well as autolube. Hence my statement, So once the pump is working, drain your tank & replenish with fuel.
I might concede I could've worded it better but it made sense to me!

Ugly