Exol oil and standard barrells

[peejay]

hi peeps
i'd like to share a couple of clubmate's experiences with you

1 - standard GP 200 barrel, piston, head, carb, AF bigbore. 11,000 miles in total (5,000 with exol at 2%)

no smoking, plug colour good, starting ok.



























huge build up of carbon in transfer ports, i've never seen this before.

top and bottom ring sticking.


2 - standard SX 200 barrel, head, piston, carb, Ancillotti big bore. 5,000 miles in total (3,000 with exol at 2%)

no smoking, plug colour good, starting ok.







huge build up of carbon in exhaust port (almost 50% of port) nothing in transfers.

all 3 rings free.

both scoots probably run at 45/50 mph most of the time.
all the previous talk about this oil seems to be centred around tuned ali barrels.

could this fully synthetic race oil be just too good for a standard set up?

is it maybe making the engine run too cool to burn all the oil?

both these scoots have previously run for years (including rebores) with Rock Oil fully synthetic at 2% with virtually no build up.

your answers on a postcard would be really appreciated

PeeJay

[HxPaul]

I've got 2 scooters with Casa 185 kits (just rebuilt one with a Casa 210 kit),been using Exol Super semi-synth for 5 or 6 years without a problem.Been stripped numerous times and there is no wear.I too run at about 50mph to 55mph.Might be just the fully synth that gives the trouble.

[Scooter Paul]

A crankshaft oil seal leak would cause this build up of carbon. But then you'd notice your gear oil level dropping and clouds of smoke.
Paul.

[Meds]

Not a standard barrel, but here are my pics.
https://www.facebook.com/paul.thomson.1 ... 1303170681
Not sure if this is normal,

[peejay]

A crankshaft oil seal leak would cause this build up of carbon. But then you'd notice your gear oil level dropping and clouds of smoke.
Paul.

seals ok Paul

[Warkton Tornado No.1]

Not a standard barrel, but here are my pics.
https://www.facebook.com/paul.thomson.1 ... 1303170681
Not sure if this is normal,

That looks fairly normalish to me. I’d prefer to see a pattern of what the transfer ports are ‘doing’ so I suspect your squish is on the large side....

I had been using Rock Synthesis 2 exclusively for some time. However, as I was given some Exol Optima I decided to try it in an SX Rapido (Ø71 x 61) Ø30 Dell’Orto with homemade exhaust. The state of tune is probably ‘fast road’ but it is tractable & easy to ride two up.

Initially, I found the Optima to be very smoky so, as all seemed well with regular plug checks, I gradually lowered the dosage from 33:1 (as per the Synthesis 2) to 50:1.
(I may not be the only user to have found it smoky. I think Knowledge may have mentioned that same issue in the past, so it‘d be interesting to learn his opinion)

Having just stripped the top end to check things more thoroughly, I can say that I am pleased with the results & confident enough to carry on using it.

Optima is a fully synthetic race oil for air cooled motors.

Due to the inconsistent nature of ‘air cooled’ motors, such as race karts & motorbikes, that don’t have the (debatable) benefit of a fan, they are considered the most demanding test of any two stroke oil.

I, too, think it probably is ‘too good’ although I still say that with an element of caution, especially in light of the first two examples in this Post.

Undoubtedly, there will be cynics on this Forum, but I can only repeat my own experience in that the only issue I've had is that of the smoky nature & having to dilute the mix. If anybody cares to check, the product is as accredited as any other oil that I'm aware of, but we are all fickle & have our favoured brands, no doubt....

If there’s ‘nothing else wrong’ with their set-ups, such as ignition, particularly ignition timing, with those two engines, then I am amazed!

I’ve seen exhaust ports carboned up ‘back in the day’ through use of rich mixes with Ye Olde mineral oils, but nothing like the images here.

If you’re sure of your ground, I would approach Exol themselves about this & let us know their comments.....

[ToBoldlyGo]

I think the fully synth is 'too good' basically. I have used it, but in a fit of the feck its I put some Rock Oil Groundsman in instead. I swear my scooter went better on the Groundsman. Not remotely scientific of course. But it did seem to perk it up.

[Meds]

Squish was 1.2mm, checked it during the strip down.
Top ring was 0.95mm
Bottom was 0.98mm
Timing set at 17deg.

The only issue I do have is smoky on start, but everything else is fine.
What I'm trying to decide is if I keep going with the exoil or make a change.
I was expecting to see some gumming up based on other threads, the cylinder was clean, so if the piston crown is normal then I'm not seeing any that would make me change from Exoil so far.
I haven't checked the Rapido yet, that's next.

[Warkton Tornado No.1]

Squish was 1.2mm, checked it during the strip down.
Top ring was 0.95mm
Bottom was 0.98mm
Timing set at 17deg.

The only issue I do have is smoky on start, but everything else is fine.
What I'm trying to decide is if I keep going with the exoil or make a change.
I was expecting to see some gumming up based on other threads, the cylinder was clean, so if the piston crown is normal then I'm not seeing any that would make me change from Exoil so far.
I haven't checked the Rapido yet, that's next.

What I should have explained more thoroughly, before making comment , is this:

In my experience, even on engines that have only done very few miles between strip downs, there is the tendency to see a pattern emerging relevant to the transfer ports.

Even recently, with an engine that had too large a squish (1.5 mm) there was clearly the evidence of the flow up the transfer ports & across the piston crown.

Perhaps the differences between your piston crown & my own has nothing more than the exit angles of the transfer port lower edges. Other than you mentioning your other Rapido, I don’t know what barrel the piston is running in.The image you posted of the piston crown is exceptionally clean in comparison to what I would think is the norm, but, what carbon there is appears to be hard, not soft, which indicates that the engine has been ‘working’ or under some load. IMHO, that is as it should be.

[Scooterslag]

both scoots probably run at 45/50 mph most of the time.


PeeJay

maybe you just need to thrash em' a bit more ? reminds me of getting a old vespa 125 smallframe from a old boy years ago, he used to plod around at 30 mph and when I did a top end strip it was like a coal mine, decoking was a major task indeed! Paul

[peejay]

hi guys
thanks for replies so far.
previous threads about this oil only got replies about tuned ali barrels that's why i was specific in my new thread title.
interesting point about "squish" size, i can't quote that at this time as both motors are in bits.

[Fast n Furious]

A small leak from a failed Halite washer gasket could be the cause.
I use an 'O' ring instead for this very reason.
Whats your gear oil level like?
Do a leak down check before you remove the crank.
Modern synthetic 2T oils are supposed to leave less ash than mineral. Not more.

[peejay]

Whats your gear oil level like?
Modern synthetic 2T oils are supposed to leave less ash than mineral. Not more.

gear oil levels are perfect.

squish on both motors is set correctly