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EXOL OIL

Technical help for Series one, two and three Lambrettas. Models include the Li, Li Special, TV, SX, GP, Serveta and API/SIL models

Re: EXOL OIL

Postby gaz_powell » Sun Apr 14, 2019 10:33 am

My gumming up experience with Exol Semi was on a cylinder that was worn.
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Re: EXOL OIL

Postby Meds » Wed May 08, 2019 11:00 am

Once again I’ve had gumming up on worn rings.
I noticed a slight loss of power and it was a bit harder to start.
Top ring found stuck and both rings worn.
The cylinder was ok - new rings fitted and much better starting and a lot crisper.

I’m not blaming Exol- but I need to keep watch out for the symptoms of ring wear.

So far I’ve noticed that on a normal cylinder starting becomes a bit harder to start, drop off in power and the Tick-over starts to go.
On a my reed cylinder it backfires on starting, it’s a bit harder to start, drop off in torque and tick over.

Both my scooters are set on the rich side and the 4 stroking as the the throttle is rolled off is a bit less.

If there are others or I’m way off it would be worth knowing.
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Re: EXOL OIL

Postby Warkton Tornado No.1 » Wed May 08, 2019 12:15 pm

Meds wrote:Once again I’ve had gumming up on worn rings.
I noticed a slight loss of power and it was a bit harder to start.
Top ring found stuck and both rings worn.
The cylinder was ok - new rings fitted and much better starting and a lot crisper.

I’m not blaming Exol- but I need to keep watch out for the symptoms of ring wear.

So far I’ve noticed that on a normal cylinder starting becomes a bit harder to start, drop off in power and the Tick-over starts to go.
On a my reed cylinder it backfires on starting, it’s a bit harder to start, drop off in torque and tick over.

Both my scooters are set on the rich side and the 4 stroking as the the throttle is rolled off is a bit less.

If there are others or I’m way off it would be worth knowing.


Meds wrote:I use exoil fully synth in a rapido and an RT at 3% ish
I rev them a bit and not had a problem in 3 years.


I really am not surprised.

I run engines, arguably, in higher states of tune than yours with not over-rich carburation & oil @ 2%.

To put that into context, you are feeding your engine more petroil than it needs, & running a fuel with 50% more oil than likely to be necessary......
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Re: EXOL OIL

Postby Meds » Wed May 08, 2019 3:35 pm

Yes probably, and I’ve been doing it for a while without issue until I ended up with ring wear, by monitoring and managing my ring wear I can rag the arse of them without nipping them up and I’m comfortable in pretty much all situations.

I don’t have the experience to set them up perfectly, ( that’s why I had them dyno tuned)but I am gaining the experience of when to change the rings- my post was designed to help others avoid ending up in the situation I ended up in and provide information.
As with all things engineering it’s a compromise - at 3% no seizures or unrecoverable failures for a £30 ring change every couple of years is a decent compromise in my book. This lesson has cost me a piston and rebore - but there are other factors involved so I can’t blame it all on the oil.

The oil does a decent job of lubrication - just seems that when the rings begin to wear it leads to the formation of tar.
This seems plausible if you end with the mix making its way past the ring, cooking off the petrol and more volatile parts of the oil leaves the less volatile stickier parts.
I came to this after stripping the Rapido down - everything was covered in a thick oil/petrol mix
I’m open to that being idea being a load of bollocks.
Running at 3% probably isn’t helping - but I’m confident with the way they run, which means a lot to me.
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Re: EXOL OIL

Postby Warkton Tornado No.1 » Wed May 08, 2019 4:34 pm

These days, there are a lot of good oils available, selection coming down to personal choice.

In my time, I’ve used Filtrate, Putoline, Bel-Ray, Castrol 'R', Denicol, Silkolene, Morris & Rock, the latter @ 3% in 25 plus BHP piston port engines. There must be more that I can't remember, but you'll get my point.

Of all the oils though, I am unaware of any fully synthetic two stroke pre-mix oils designed specifically to use in air cooled engines.

Because I was given five litres to try, I did so, but was, like many others, wary of the smokiness when mixed @ 3%. The main use has been in a Rapido engine with a 70.5mm TS piston & 61 mm crankshaft, not noted for their ability to stay cool, compared to all alloy/ nikasil barrels. The fact that the flywheel in use is a J range (like the AF electronics, but retaining points) also does the cooling no favours, but there has never been an issue.

Gradually, I leaned the mix down, but kept an eye on the top end.

I have to say that I would not hesitate in using Exol Optima in any two-stroke engine @ the right ratio. That’s not without potential issues, though, as carburation can be affected, but that is something I keep a keen eye (& ear) upon.

As a footnote, there are many that use Groundsmen oil in their Lambretta. In a reverse application of that, I tried Exol Optima in my two-stroke garden implements @ the manufacturers' recommended 2% & had nothing but trouble with excess smoke & plug fouling, which to my mind, verifies just how much you need to lean this stuff down :)
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Re: EXOL OIL

Postby Meds » Wed May 08, 2019 6:12 pm

I came down from 4% to 3%
I see your point - but don’t have the bottle to drop to 2
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Re: EXOL OIL

Postby MickYork » Wed May 08, 2019 6:33 pm

Happy with 2% in my Avanti......stripped down a while ago and the bore was nice and oily :)
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Re: EXOL OIL

Postby dscscotty » Wed May 08, 2019 7:42 pm

I regularly split crankshafts that have run exol and other oils @ 2 and 3%, my view and the evidence I see on big end bearings is run 4%, all the focus is on cylinder/piston , however under lubed big ends are a regular occurrence and the signs of over heating are quite evident
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Re: EXOL OIL

Postby jonashford » Thu May 09, 2019 5:46 am

its £3 a litre, if u use enough changing ur rings once a year is worth it. IMO.
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Re: EXOL OIL

Postby Meds » Thu May 09, 2019 8:10 am

dscscotty wrote:I regularly split crankshafts that have run exol and other oils @ 2 and 3%, my view and the evidence I see on big end bearings is run 4%, all the focus is on cylinder/piston , however under lubed big ends are a regular occurrence and the signs of over heating are quite evident


Now that’s interesting- as I’ve never seen this - what are the symptoms/indicators.
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Re: EXOL OIL

Postby Warkton Tornado No.1 » Thu May 09, 2019 11:19 am

dscscotty wrote:I regularly split crankshafts that have run exol and other oils @ 2 and 3%, my view and the evidence I see on big end bearings is run 4%, all the focus is on cylinder/piston , however under lubed big ends are a regular occurrence and the signs of over heating are quite evident


IMHO, the only 'fresh' crankshafts that seem guaranteed to fail are those of Indian manufacture fitted with the OEM conrod & bearing. I tend to remove these as a matter of course.

If crankshafts are rebuilt correctly with good conrods (from the likes of Grampian) with attention paid to enhancing any lubrication slots, they should be fine, as they probably would receive no better lubrication used in the engines they were intended for. In any case, relatively recently, we were running Rock @ 3% in Group Four with no issues. I take no issue with how much oil is mixed with the fuel, because, particularly in racing, it is all about power & reliability, so if somebody finds Castrol 'R' @ 6% or more is good for them, that is great!

Although the main discussion has concentrated on the piston/bore & the issues of gumming up, the general consensus appears to be that there are varying perceptions of quality versus quantity.

I remain in the camp that rates highly Exol Optima mixed with a good super unleaded & the only comparison I can think of is to liken it to 'normal' washing machine liquid versus super concentrated...... :P
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Re: EXOL OIL

Postby Hat » Thu May 09, 2019 3:42 pm

What about the argument that running too high a mix of oil makes the engine run hotter, increasing the risk of heat seizure? Is there any truth in this?
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Re: EXOL OIL

Postby missing lynx » Thu May 09, 2019 5:33 pm

As far as I understand it to much oil can lean the mix and drop the octain rating of the fuel in your tank
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Re: EXOL OIL

Postby burnside » Fri May 10, 2019 10:31 am

Hat wrote:What about the argument that running too high a mix of oil makes the engine run hotter, increasing the risk of heat seizure? Is there any truth in this?


It's logical that if you increase the oil %age then you are lowering the fuel %age so you are risking running lean if you carb is jetted right on the limit.
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Re: EXOL OIL

Postby Warkton Tornado No.1 » Fri May 10, 2019 12:53 pm

burnside wrote:
Hat wrote:What about the argument that running too high a mix of oil makes the engine run hotter, increasing the risk of heat seizure? Is there any truth in this?


It's logical that if you increase the oil %age then you are lowering the fuel %age so you are risking running lean if you carb is jetted right on the limit.
+

:lol: Wise words, but just try & stop many Lambretta fiddlers adding more oil whilst running in! The same type plod along, regardless of the fact that more revs means more fan cooling! The engine would be better off if they simply caned it!
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Re: EXOL OIL

Postby Hat » Fri May 10, 2019 1:16 pm

Yep, WOT = more fuel, more oil, more air flow = happier engine
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Re: EXOL OIL

Postby ToBoldlyGo » Fri May 10, 2019 4:21 pm

Warkton Tornado No.1 wrote:
burnside wrote:
Hat wrote:What about the argument that running too high a mix of oil makes the engine run hotter, increasing the risk of heat seizure? Is there any truth in this?


It's logical that if you increase the oil %age then you are lowering the fuel %age so you are risking running lean if you carb is jetted right on the limit.
+

:lol: Wise words, but just try & stop many Lambretta fiddlers adding more oil whilst running in! The same type plod along, regardless of the fact that more revs means more fan cooling! The engine would be better off if they simply caned it!


Very true. That's one of the most important things I've learned from riding my scooter. Where I live it's very easy to just plod along the country lanes. But it's not always good for your engine. On a good road it's better to keep the revs up and use them more freely. Your engine will love you for it. :lol:
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Re: EXOL OIL

Postby ToBoldlyGo » Mon May 13, 2019 7:46 pm

dscscotty wrote:I regularly split crankshafts that have run exol and other oils @ 2 and 3%, my view and the evidence I see on big end bearings is run 4%, all the focus is on cylinder/piston , however under lubed big ends are a regular occurrence and the signs of over heating are quite evident


It's funny you should say that. The top end has just come off one of my scooters. The barrel is pretty shagged and the small end bearing is toast. That was running on Exol semi at 3%. I don't know conclusively that it was the oil, but it's suspicious. Particularly as I'm running in on another scooter and changed to Groundsman for that reason. It seemed to settle it down and just ran smoother and quieter. Make of that what you will. Suffice to say the seed of doubt has been planted now.
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Re: EXOL OIL

Postby dscscotty » Mon May 13, 2019 10:22 pm

Soon as I get time I'll post up some pics of bearings, rods n crank pins
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Re: EXOL OIL

Postby Warkton Tornado No.1 » Tue May 14, 2019 4:08 pm

dscscotty wrote:Soon as I get time I'll post up some pics of bearings, rods n crank pins


I'd be keen to see such images if you know the full history of the crankshaft, kit & oil used.

(Ideally, the crankshaft will be one that you built in the first place & can validate runout & build quality, the actual kit utilised, &, of course, the type of Exol oil used exclusively)

For the meantime, I stand by Exol Optima Racing Two Stroke oil @ 2% with a good, super-unleaded fuel, even if there may be comparisons by some with 'snake oil' simply because it is too inexpensive.... :D
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