Compression question?

[ginge511]

Hello ppl.

I don't know what is wrong here but i have been told, just b4 i do a compression test to drop a bit of oil in the cylinder head.

When i done this i got a reading of around 129 compression.

But when i do it normally i get around 105.

What could be the problem here?

As sometimes when i do the test i get 120 plus when cold but when hot i get 105.

Is everything right here?

[Guest]

the oil lines the bore, much like when the engine is running.. and the bore expands when warm/hot.. which is why your piston rings are sprung.. hows it running??

[ginge511]

the oil lines the bore, much like when the engine is running.. and the bore expands when warm/hot.. which is why your piston rings are sprung.. hows it running??

It's running fine mate.

Feels ok anyway, alot better then before i changed the top end which i have done.

So is everything ok?

[Guest]

i've only rebuilt one 2 stroke engine, but sounds like its ok.. (a Suzuki GP100, way back in 1993...)

[ginge511]

i've only rebuilt one 2 stroke engine, but sounds like its ok.. (a Suzuki GP100, way back in 1993...)

Cheers mate, seems better so that is good.

Another question now...

What will changing the engine oil do for performance etc?

I'm thinking of changing it, but don't know what oil to get and how much to use?

I havbe an aprilia rs 125 2003 bike.

[Bill_on_a_bike]

i've only rebuilt one 2 stroke engine, but sounds like its ok.. (a Suzuki GP100, way back in 1993...)

Cheers mate, seems better so that is good.

Another question now...

What will changing the engine oil do for performance etc?

I'm thinking of changing it, but don't know what oil to get and how much to use?

I havbe an aprilia rs 125 2003 bike.

 

There is no "engine oil" as such, unless you mean the oil you put in the oil tank.

You've also got gear box oil you can change on a stroker.

[ginge511]

i've only rebuilt one 2 stroke engine, but sounds like its ok.. (a Suzuki GP100, way back in 1993...)

Cheers mate, seems better so that is good.

Another question now...

What will changing the engine oil do for performance etc?

I'm thinking of changing it, but don't know what oil to get and how much to use?

I havbe an aprilia rs 125 2003 bike.

 

There is no "engine oil" as such, unless you mean the oil you put in the oil tank.

You've also got gear box oil you can change on a stroker.

Yep sorry about that, i meant gear box oil mate.

Which 1 is best to use?

And how much do i put in as i bet the stuff in the gear box now is crap.

When starting off from cold, she goes in 1st easily, but in 2nd rear it is really stiff getting it in 2nd, after that it is all good.

But makes me think it needs a gear oil change?

[Guest]

get hold of a manual and a fresh oil change will do any engine a world of good..

i used to use TTS 2 stroke (semi-synthetic) smelt wonderful... for the engine..

for the box, just dont get halfords own brand, have a look at whats available, best to use a bike shop than somewhere like halfords.. better selection and advice..

[ginge511]

get hold of a manual and a fresh oil change will do any engine a world of good..

i used to use TTS 2 stroke (semi-synthetic) smelt wonderful... for the engine..

for the box, just dont get halfords own brand, have a look at whats available, best to use a bike shop than somewhere like halfords.. better selection and advice..

I bought some fully synthetic gear oil for my other rs 125 bike.

No wonder it went bang after 3 months lol.

But will do what you said mate.

Thanks for helping

Sorry last question.

I've done about nearlly 200 miles of running my new top end in.

Is this enough?

[Guest]

don't know for sure, just take things easy and build up revs gradually.. dont suddenly go from running in to revving the nuts off it...

[ginge511]

Will do cheers mate.

So from what i put before about the compression.

Is it all ok?

Like the sudden drop when hot in the compression?

[Bogof]

i used to use TTS 2 stroke (semi-synthetic) smelt wonderful... for the engine..

 

I bought some fully synthetic gear oil for my other rs 125 bike.

No wonder it went bang after 3 months lol.

But will do what you said mate.

I've done about nearlly 200 miles of running my new top end in.

Is this enough?

 

Oil - Aprilia specify FULLY synthetic for the RS

200 - Not enough. Needs at least 500/600 before building revs above 6k

[ginge511]

i used to use TTS 2 stroke (semi-synthetic) smelt wonderful... for the engine..

 

I bought some fully synthetic gear oil for my other rs 125 bike.

No wonder it went bang after 3 months lol.

But will do what you said mate.

I've done about nearlly 200 miles of running my new top end in.

Is this enough?

 

Oil - Aprilia specify FULLY synthetic for the RS

200 - Not enough. Needs at least 500/600 before building revs above 6k

 

What's the oil i have to get for it?

I've not been going mad on it anyway so should be fine.

[Bogof]

What's the oil i have to get for it?

I've not been going mad on it anyway so should be fine.

 

Any fully synthetic 2 stroke oil will do the job. I used Castrol in mine right up until the day it was stolen

Running in is quite important with those engines. If you do exceed 6k at this stage, do it for occasional bursts of speed, not for long stretches of dual carriageway, that way there's less risk of damage through overheating.