Hi I have a 1971 bonneville which had not run since early 1990's I have cleaned tank carbs sorted ignition change oil and got in running second kick, however I cannot make my mind up if I should flush the engine. After checking the net it appears about 50-50 for and against. What's the forums thoughts this is my first chat Regards Danny
Hi Danny and welcome to the forum. It really depends on what you define as "an engine flush". This is not as daft a question as it may first appear. Definitions: 1. Products that you can buy, that are supposed to clean out your engine. You put them in the sump full of oil, run the bike for a bit, then empty the existing oil + flush product out and refill the engine with new oil. 2. Engine flushing, a procedure. This works as follows: you buy 4 ltrs of flushing oil (lightweight engine oil); you empty the sump of the existing std. oil and replace with the flushing oil, start the engine and leave on a high tickover (usually about 2000rpm) for about 10mins, then empty out and refill with std. engine oil. https://www.ebay.co.uk/itm/Carlube-...581351&hash=item36266d8391:g:WqcAAOSwsYpaFzbF I prefer the version 2 of flushing.
Thanks for your reply as well as flushing I was thinking of using a semi synthetic oil as I presume modern oils are better ?
A lot of this stuff is quasi snake oil. Modern engine oils contain detergents anyway. It is why they get dirty....to flush out unwanted contamination. A cheap, unbranded oil that conforms to SAE or JASO specs will do the same lubricant/cleaning job and if it helps you sleep better run it for 500 miles before changing to your preferred brand. I suspect the single most important thing is to maintain engine temp and oil flow long enough to ‘melt’ dried, hardened deposits from the old oil. HOWEVER the chemical flush agents for cars are almost all poison to a wet bike clutch....... Me? On an old bike I’d fill fresh with mineral and do an early change to a semi synthetic.
Hi mate, I can't remember with your bike does it have separate oil for the gearbox and clutch or shares the engine oil ? Assuming it shares the same oil, go for a quality 10-40 semi-synth to JASO spec.
Try putting small amount of diesel or kerosene in when engine is hot , stop the engine after a ride or 10 minutes of high idle, add 200 to 500 cc of diesel and start motor , run for one or two minutes, stop wait awhile then drain, put fresh cheap oil in , run or ride it for whatever time you feel safe but I'd recommend no more than a hundred or so klms , drain and put your choice of proper oil , the oil's you drain out should be very very black if the Diesel did it's work !!! It is an oil in it's own right but it dissolves carbon deposits quite well, you'll never see carbon in a diesel engine unless it's very old and sick !! This has worked for me , be careful if you change to high detergent content oils, as you can't go back to mono oils such as Pennzoil , the detergent will strip out deposits from around seal's and bearings and may cause failure of same if you revert to simple plain oil's . Cheers capt
Hi all thanks for the reply’s next opp is draining and refilling the gear box appears now there is more EP90 about than SEA90 anybody know the difference ?
Hi Danny, Just be a bit careful when using oils with detergent in them. The main filter on older bikes is a flywheel sludge trap which collects ..... err ..... sludge, which stays there (hopefully) until the engine is stripped and it can be cleaned out. Pretty crude system really, but I guess it must work - at least a little bit! However, detergent in the oil can start to clean this trap out which means little bits of detritus start to circulate in the oil which can cause blockage of the various oilways if you are unlucky, with possible nasty consequences. I don't know how likely this is but I have read about it a few times in the past. Perhaps a specialist engine builder will be able to put your mind at ease. Spin on/off oil filter conversions are available and may be a worthwhile investment.
The only reason I was going this way was because I had spoken to Morris oils and they said to flush with there v twin 20w-50 oil which as a detergent in it, so I just decided to use a cheaper version to flush
Larger engined Triumphs from 1963 became unit construction engines but still had separate engine/gearboxes therefore requiring different lubricants. Daniels bike should have separate engine/gearbox although in unit construction cases.
Personally, my advice for what it's worth. Do not flush. Renew oil with correct spec every couple of thousand miles over the next year or so, then renew again every half distance recommended I.e. Instead of every 5k renew every 2 1/2k
I all ran it again today with just oil 10-40 semi synthetic to flush out it ran fine other than the left hand cylinder was spitting smoke out around the exhaust outlet along with specks of oil, ran it in total around 1 hour at about 2000 rpm. Right cylinder no smoke out of the end of exhaust at all left sending white smoke when revved checked plugs after right plug good left plug oiled, wondering if it could be rings sticking or worse.
Oil in the cylinder head is either getting past broken or sticking rings from below or via worn valve guides. Stripping and inspecting will tell you which.... Valve guides turn to reveal by blowing smoke on hard acceleration and again on the overrun but less at constant speed but it is not a foolproof diagnosis.
Nice article focusing on the T140V in the new (April) edition of Classic Bike Guide, some of which may be helpful/relevant. Even if it isn't, it still makes good reading. Well, I think so!
Hi Daniel, you will have to strip the top end and inspect it to see what is causing the smoking, the problem with old Triumphs is they often sit in damp sheds and moisture finds its way into the barrels and destroys the bore. Another scenario is that the sludge trap is blocked and oil starvation to the bottom end had caused over heating of the pistons leading to a previous seizure. As for engine oil its best to use normal 20/50 motorcycle classic engine oil as the clutch is lubed buy eng oil.
