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Unleaded Fuel


autoavia
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This may seem a stupid question but I have a 1976 Cota 247 UKR which I have owned from new. It hasn't been used or over 20 years and I want to tidy it up and see if it will start assuming the seals are OK. I know I need to clean out the carb etc but is it ok to run on unleaded fuel from the local garage, what oil should I be using and what ratio petrol/oil mix please.

I know that with classic cars there is also a problem with modern fuels destroying the seals in the carburettor. Is this likely to be a problem and if so is there a new seal kit that I can buy which is suitable for unleaded fuels. 

Thanks

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Mine is one of the first with an aluminium tank with a fibreglass cover so the tank should be fine but I suspected there would be a problem with the carb so what fuel should I be using in the UK please.

 

Edited by autoavia
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I have never heard of any issues with unleaded and carburettor parts.  I will have a google to see if anything turns up.  What I am guessing is the issue is more likely to be the ethanol rather than the lack of lead.  Lead is (was) an upper cylinder lubricant in older engines.  In two strokes the lack of lead as best I understand it was never an issue.  You can buy a lead replacement additive but I am sceptical that you need it.

Ethanol can attack certain plastics and some people report issues with it and early petrol tanks.  There is a lot of internet noise about ethanol and Ducati.  My wife's Ducati Monster runs fine and has no issues with E5 but there is some concern as best I understand it about the new E10.  As best I can see the "super" will still be E5.  My TRS states "no ethanol" in the manual but it runs on E5 OK (Shell V Power) and as best I know you cannot buy ethanol free fuel in the UK unless you buy the Aspen fuel for chainsaws.

 

- this seems to back up it is the E10 that is an issue -

https://www.dandyclassics.com/welke_benzine_tanken_in_oldtimer/

Edited by ChrisCH
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Thanks. In the old days the lead seemed more of a hinderance then a help with 2 strokes. When I first got the bike I used to run 4 star but on running in settings the plug used to get coated in lead so I went to 2 star instead an never had any problem again.

If anyone else has any info it would be appreciated but when I get a chance I will drive to a motorcycle shop in Southend run by a former trials rider who will probably be able to help.

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The proportion of ethanol in fuel depends on location, some Shell and Esso fuels have no ethanol content...yet?‍♀️! Whilst in other parts of UK there is at least 5% ethanol present. There will be issues when 10% ethanol is used and there is a list of vehicles that will not be able to use this particular fuel, but they may be able to use the super type of fuel eg V-Power etc. All info available on Google look for Octane magazine. Old aluminium tanks may be brittle and may crack when subject to regular use...usually around any mountings and areas of chafing. Aspen 4 professional will be your best bet but its about £20 per 5 litres or £6 a litre...at least it is where I buy it but on e-bay its £33+ and then p&p!!! There are ways to isolate the ethanol shown on youtube...but I am not convinced...yet?‍♂️??

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7 hours ago, ChrisCH said:

I have never heard of any issues with unleaded and carburettor parts.  I will have a google to see if anything turns up.  What I am guessing is the issue is more likely to be the ethanol rather than the lack of lead.  Lead is (was) an upper cylinder lubricant in older engines.  In two strokes the lack of lead as best I understand it was never an issue.  You can buy a lead replacement additive but I am sceptical that you need it.

Ethanol can attack certain plastics and some people report issues with it and early petrol tanks.  There is a lot of internet noise about ethanol and Ducati.  My wife's Ducati Monster runs fine and has no issues with E5 but there is some concern as best I understand it about the new E10.  As best I can see the "super" will still be E5.  My TRS states "no ethanol" in the manual but it runs on E5 OK (Shell V Power) and as best I know you cannot buy ethanol free fuel in the UK unless you buy the Aspen fuel for chainsaws.

 

- this seems to back up it is the E10 that is an issue -

https://www.dandyclassics.com/welke_benzine_tanken_in_oldtimer/

 Your TRS states no ethonol so the tank does not swell.

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7 hours ago, lineaway said:

 Your TRS states no ethonol so the tank does not swell.

Yes, what I have read seems to suggest the ethanol can absorb water and this can cause deformation issues with plastic.  Since pretty much all UK petrol is E5 it is all but impossible to avoid without the huge cost of Aspen.  I have had no issues with the plastic tank.  I don't know anyone else that has had issues.  There are quite a few TRS in my club and everyone runs ordinary fuel from the petrol station.

The main problems seem to be on the internet and not in real life.  (I am sure there are a few real world examples)  Some people have another agenda the same as happened when lead was first removed from petrol and a section of society had an issue with "vegetarian petrol" or other such nonsense.  It is all forgotten now, but of course some old vehicles still need an UCL additive.

Interestingly a huge proportion of modern vehicles have plastic tanks.  I fail to understand the science that 5% ethanol is OK and 10% is not if I am honest.  TRS position - none at all - is at least logical.  If only the internet was not full of fruit loop conspiracy theorists we might get to the core of the real issue.  Assuming there is one  ?

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 Montesa tanks up to about 1976/7 were fibreglass rather than plastic. I have a 60's kit car to rebuild which is a fibreglass monocoque with the tanks moulded into the monocoque. Other owners have experienced problems with unleaded fuels attacking the fibreglass which has caused blocked fuel lines where the fibreglass has turned to a kind of jelly. There are also known issues with unleaded attacking some of the seals in the carburettor on older classic cars which is why I felt inclined to ask questions rather than plough ahead. Thanks for all the advice. I think I will get the bike tidied up a bit and then see if I can get her started. The bike is still very original so, having looked at the price of original parts, I will change things like the mudguards, if I decide to compete again, and keep the originals to put back if/when I decide to sell.   

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I think there is a liquid you can tip into tanks to line them? (yes - https://www.rust.co.uk/product/slosh-petrol-tank-sealer-7) 

I have read about this for fibreglass tanks.  My neighbour bought something similar to cure a leak on an old Yam  900.  However he is a bit ham fisted and managed to block up the carbs but not cure the leak ?

Might be worth investigation?  Do please have a google round first though as I have no other experience of this type of product.

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If the carb has any o-rings or other rubber seals they may swell, more often than not they'll be ok in situe but will expand when taken apart and wont be easy to refit. Ethanol has a corrosive effect on brass parts like jets but it's unclear how much of a practical problem that presents. Petcock could also have a shorter life depending on its construction. If you want to take precautions then drain the carb after each use.

I've seen multiple plastic tanks distort and fiberglass tanks start to dissolve, and I've also had two liners fail, some of the materials used are hard to bond to as well as not being resistant to modern fuels. Current manufacturers really shouldn't be using materials that can't handle modern fuels, they simply aren't fit for purpose. I used to work for a company that made fiberglass underground storage tanks that petrol stations use, and many cars have plastic tanks so it can be done with the right materials.

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I have researched a lot about this to see how it affects the Ducati.  Much of what is out there seems to contradict other articles and opinions.  I have also read about liners failing as @totty79 has posted.  I must admit I have not taken much interest in the vulnerability of old components as our Ducati is a 2012 model.  But you guys have got me googling again.

I wonder if anyone has any experience with the additives?  These are supposed to overcome the issues with ethanol and old pre-ethanol components such as O rings.  I don't know how they affect the water absorption which is the source of any corrosion.  (E60 seems to come out worse, but going from E5 to E10 doesn't seem to make much odds)  Anyway there are things out there which either work or are just to take your hard-earned.  Wonder if anyone has a view?

https://www.demon-tweeks.com/uk/frost-ethomix-fuel-additive-fstz555/

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If you live near to any small airfield, you could ask them to fill a couple of Jerry-Cans with Avgas.  

The usual is 100LL (Low-Lead.), and some airfields stock 97UL (Unleaded.),  Both of which contain no ethanol.

The price is only about 10p more, but they may charge a further 10p as you are a visitor.

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