[ArizonaJim]

Originally Posted by a4anurag

Thanks buddy, learnt a new term and its meaning after reading your post. AFAIK this could be there for cars to then?

Yes. Any reciprocating internal combustion engine will have some blow by including those in cars. Whether this is a problem is a matter of degree.
If blow by is excessive it will produce a lack of power and often, a loss of oil.

Are you sure about this?

Of all the bikes I have seen till now have their crank case breather tube dangling below between the crankcase and swingarm joint. This pipe is coupled and held together along with the battery breather tube.

Anurag.

On older motorcycles and cars too the crankcase vent was just allowed to blow the excess fumes out into the air.

I can't say how long this has been happening in India but in the USA all vehicles made after 1970 were required to vent the crankcase back into the engine for re-combustion. This was done to protect the environment.

I know that Royal Enfield has tried several different vent systems starting around the year 2000. Most of the Iron Barrel systems use a semi-sealed catch can that did not work very well.
The new UCE models of the RE finally have a system that works very well and the vent is fed directly into the air filter box.

I would be totally surprised if every motorcycle sold in India after 2005 did not have a similar system.

The "dump it overboard" method is exactly what I was describing when I said that oil can (and will) be lost without a trace.
The oil loss wouldn't be noticed in a week or even a month of riding but by the time 2000 km has been traveled the loss could be significant.

[IndigoXLGrandDi]

My Scooty Pep (75 cc) is facing this problem of engine oil level dropping.
There is no visible smoke from exhaust. The Odometer reading is 30161 (the reading got reset as the gear was replaced).
I have got the engine block+piston replaced around 7000 kms ago. After 3000 kms, the oil level started dropping. The Amount of Oil Level Drop is not significant so I used to topup oil and use. Then after 1500-2000 kms I got the Valves replaced. Recently the oil level again started dropping. To verify this, I replaced the Engine Oil around 315 kms ago. Now today I topped up @100 ml (I had this much left in the can) oil. The level rose to just above low level mark. The capacity of Engine Oil is 750 ml.

What could be the problem?
I have not yet checked the Blow-By Point explained above.

[a4anurag]

Originally Posted by rajivanoj

yes, there is oil strain and it is like dried oil and baked, it is near the join of cylinder and top, i think its head. how to rectify it? whether have to shape it again for any defects in smooth surface?

Any update to the situation? Has the root cause been found?

Anurag.

[sagarpadaki]

Originally Posted by IndigoXLGrandDi

My Scooty Pep (75 cc) is facing this problem of engine oil level dropping.
There is no visible smoke from exhaust. The Odometer reading is 30161 (the reading got reset as the gear was replaced).
I have got the engine block+piston replaced around 7000 kms ago. After 3000 kms, the oil level started dropping. The Amount of Oil Level Drop is not significant so I used to topup oil and use. Then after 1500-2000 kms I got the Valves replaced. Recently the oil level again started dropping. To verify this, I replaced the Engine Oil around 315 kms ago. Now today I topped up @100 ml (I had this much left in the can) oil. The level rose to just above low level mark. The capacity of Engine Oil is 750 ml.

What could be the problem?
I have not yet checked the Blow-By Point explained above.

The oil could be getting consumed either at the head or from any scouring on cylinder walls. Since its a new piston and cylinder I suspect the head work was not done properly. If the valves are not correctly seated then oil gets consumed.

One solution would be to do just the head over haul once again. Or for Complete peace of mind you may get a new head assembly.

But before proceeding ensure to rule out any defects in the cylinder or piston. You have to open up the whole engine once again

Other option is that you can continue topping oil if the consumption rate is not so high and if there is no degradation in performance

[bigben]

When I had given my Pulsar for servicing I experienced a similar issue. There was no oil in the engine. The service mechanic then checked to see if oil was being consumed. He refilled the oil and then revved the engine full. There was a stream of smoke emitted. The culprits were the piston rings. However, I could not change only the rings I had to change the piston as well. Total damage was at 3k. This was about 5-6 years ago.
Have you checked the rings? That might be the issue.

[IndigoXLGrandDi]

When I took the pep to the mechanic, it emitted bluish smoke. Also the Tip of Silencer was wet with oil.

So I got the Piston and Head Block replaced.

Block+Piston = 1150/-
Head Gasket = 90/-
Nut Bolt = 8/-
Labour = 450/-
Total = 1698/-


The Engine Oil was not replaced since it was replaced with Shell Advance 20W40 just 316 kms ago.

Lets see what happens next.

[a4anurag]

Originally Posted by IndigoXLGrandDi

When I took the pep to the mechanic, it emitted bluish smoke. Also the Tip of Silencer was wet with oil.

So I got the Piston and Head Block replaced.

Block+Piston = 1150/-
Head Gasket = 90/-
Nut Bolt = 8/-
Labour = 450/-
Total = 1698/-

The Engine Oil was not replaced since it was replaced with Shell Advance 20W40 just 316 kms ago.

Drive the Scooty like when it was 'new'. It will be needed to run-in first as the piston and block have been replaced. Keep the initial 500 kms slow as you would have done initially.

Will wait if your problem solves or no!

Anurag.

[Blue_V]

My Honda Shine has accumulated nearly 60k. And it is drinking oil very much. The power seems okay, no starting problem. Is it time for a change of block+piston? How much would it cost?

[a4anurag]

Originally Posted by Blue_V

My Honda Shine has accumulated nearly 60k. And it is drinking oil very much. The power seems okay, no starting problem. Is it time for a change of block+piston? How much would it cost?

Don't go and change the piston+block. Check the source of oil leak and try to arrest that first. If the leak doesn't stop then replacement makes sense. Keep the piston+block change as a last option.

Check the flowing areas:

1) Cylinder head;

2) Spark plug tip;

3) Crankcase area;

4) When the engine is running do you see bluish-white smoke? If yes then engine is consuming oil.

Anurag.

[Swapnil4585]

I see a strange phenomena with my nearly 8 years old XCD. Every time I start the bike, the engine 'revs' for a minute on its own without any accelerator input. Is this a case of rich mixture / faulty carburetor?

[barcalad]

Originally Posted by Swapnil4585

I see a strange phenomena with my nearly 8 years old XCD. Every time I start the bike, the engine 'revs' for a minute on its own without any accelerator input. Is this a case of rich mixture / faulty carburetor?

Might be a worn out throttle cable or a ruptured diaphragm. The carburettor might need cleaning/replacement as well, but that should ideally be your secondary concern.

[a4anurag]

Originally Posted by Swapnil4585

I see a strange phenomena with my nearly 8 years old XCD. Every time I start the bike, the engine 'revs' for a minute on its own without any accelerator input. Is this a case of rich mixture / faulty carburetor?

Does the RPM decrease later on or it keeps at the same Revvs?

Get the carb cleaned and also see if the accelerator cable condition.

[ashis89]

Originally Posted by Swapnil4585

I see a strange phenomena with my nearly 8 years old XCD. Every time I start the bike, the engine 'revs' for a minute on its own without any accelerator input. Is this a case of rich mixture / faulty carburetor?

Does your bike come with Auto Choke feature? Bajaj had introduced it in the Pulsar range but I'm not sure if XCD has it. It used to activate automatically during starting and hence there was no cold start issues. If your bike has it, then could be a source of problem. If you have a manual choke too, apart from the accelerator cable and the carb setting please check the choke wire too.