1972 750SF out of storage

Update.

Had time on my hands to work on the bike yesterday, as advised by most people first port of call was to pull out the plugs and pour a little oil into the pistons and leave overnight.

I did this last evening and pulled off the cam cover and thought i would see if i could turn it over at all, if i had met any resistance i would have left it alone and come back to it once the oil had worked its way down the pistons/bores.

I applied just a little bit of effort and hey presto both pistons moved freely without any resistance. So, i continued turning it over by hand and it was so easy to do so, it seems the engine has survived the long lay up without any problems.

Certainly everything seems ok, should i fire her up or is there anything i should check?

Even though its turning over, can i be sure the rings are not actually stuck?
 
Even though its turning over, can i be sure the rings are not actually stuck?
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Not really - they could be gummed up in the piston ring grooves and so not seal well under running conditions. However, if its turning over freely I'd give it a go...there isn't much damage a stuck ring could do, apart from incurring a bit of smoking / heavy breathing from blow-by.  The bigger risk was corrosion in the cylinder bores.  So crank on starter for 20 secs with plugs out (and earthed if not original points ignition) then see if you can get it to fire!
 
It so easliy and felt very free. Of course i will change the oil before i do anything to it.

Been a while since i bought oil for the 750, any recommendations? I have lots of semi synthetic oil that i use on my modern Dukes.

 
Go through a running in procedure on mineral oil before switching to semi/synthetic

A compression check before and after will tell you the ring condition

AW
 
Well shame on you  ;) firefly ! fancy letting your bike sit idle for so long... :-[
but hey life gets in the way some times  :'( 

They are built tough those 750 Breganzies .

Now take the kid gloves off..... stab that button and ride her like ya mean it  :D
Those memories will all come flooding back...............  It was only 10 yrs ago  :LOL:
 
hooksey said:
Well shame on you  ;) firefly ! fancy letting your bike sit idle for so long... :-[
but hey life gets in the way some times  :'( 

They are built tough those 750 Breganzies .

Now take the kid gloves off..... stab that button and ride her like ya mean it  :D
Those memories will all come flooding back...............  It was only 10 yrs ago  :LOL:
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Plus one just put some fresh fuel in her a new set of plugs and give it a go........then warm her up, drop out the oil and fresh oil in and take it for a run................and once it's warm ride it like you stole it
 
I feel so bad guys for letting it stand for so long, will do exactly as you guys have recommended and start her up in the next few days.

Any advice on which mineral oil to use for start up? and should i go semi- synth after that?
 
I think the consensus is any good 20-50 with plenty of zinc...


You might also want to look at one of those proprietary additives which restores suppleness to old 'hardened' seals etc.. (might not be a bad idea whilst running in anyway)


AndyW 8)
 
If you have any friends with a borescope you can look at the cylinder walls and see how bad the rust/pitting is. If they are pitted bad then you will need to heed the advice of the forum members and have the engine gone through. I can tell you for a fact that the bike will run with pitting or out of round liners, not great but it is a beast. I bought my SF after it had sat outside in the weather for almost a year in the Naples rain so there were al to of "Unkown" issues, it was rough!

Marvel Mystery oil will help with the rings, get the pistons at BDC and fill up both sides to the top. If it goes down fast most likely rings are stuck, if it goes down slow there is partial hope but then you still have to look and see if there is a pitting issue that will cause more problems with compression and high oil consumption. I also used MMO poured into the top of the head so it would seep down through the valve guides as much as possible and then hand turned it over making sure that the valves moved like they should (I had a lot of help early on with just getting it to run). We have used MMO in aircraft engines for years to fix these type of issues (sticky valves, stuck rings) and it mixes well with the oil with no harmful effects. But, if you fill the oil, and you fill the cylinders with MMO, you will have too much oil and that's bad so you will need to take out oil until it is at an acceptable level on the dip stick (you can use a big syringe with a hose attached to it to suck it out or make a mess and drain it from the bottom). If the valves move normal, and the cylinders will hold the oil for a good amount of time leave the plugs out and crank it over by hand to force the oil out to the top as much as possible, then crank it over a couple of times with the plugs still out (oil will fly so lay some rags over the top of the plug holes to catch it). You can do a cold compression test to see how good or bad things are but you will want to do one after the engine is finally running and a few hundred mikes are on it. When I finally checked the compression after about 6K of my miles (including 3K miles across the USA) it was not pretty with less than 70 on each one, and way lower if the opposite plug was removed, that's bad! Compression was low but oil consumption was a quart about every 1000 or so miles, but she ran without issue. Hopefully your rings will be free and not broken, and the valves not stuck (if they are it's going to be rebuild time). Make sure the points are good and the timing is correct, clean pugs, carb float bowls have been cleaned, battery is at full charge, ignition leads checked, and old gas gone and premium gas in before you even think about attempting the first start. Just my 0.02 cents worth.

I still have my SF after 37 years (it's in a major restoration back to original right now) so it's a testament of how tough these beasts are.

Clay
 
'71 SF said:
If you have any friends with a borescope you can look at the cylinder walls and see how bad the rust/pitting is. If they are pitted bad then you will need to heed the advice of the forum members and have the engine gone through. I can tell you for a fact that the bike will run with pitting or out of round liners, not great but it is a beast. I bought my SF after it had sat outside in the weather for almost a year in the Naples rain so there were al to of "Unkown" issues, it was rough!

Marvel Mystery oil will help with the rings, get the pistons at BDC and fill up both sides to the top. If it goes down fast most likely rings are stuck, if it goes down slow there is partial hope but then you still have to look and see if there is a pitting issue that will cause more problems with compression and high oil consumption. I also used MMO poured into the top of the head so it would seep down through the valve guides as much as possible and then hand turned it over making sure that the valves moved like they should (I had a lot of help early on with just getting it to run). We have used MMO in aircraft engines for years to fix these type of issues (sticky valves, stuck rings) and it mixes well with the oil with no harmful effects. But, if you fill the oil, and you fill the cylinders with MMO, you will have too much oil and that's bad so you will need to take out oil until it is at an acceptable level on the dip stick (you can use a big syringe with a hose attached to it to suck it out or make a mess and drain it from the bottom). If the valves move normal, and the cylinders will hold the oil for a good amount of time leave the plugs out and crank it over by hand to force the oil out to the top as much as possible, then crank it over a couple of times with the plugs still out (oil will fly so lay some rags over the top of the plug holes to catch it). You can do a cold compression test to see how good or bad things are but you will want to do one after the engine is finally running and a few hundred mikes are on it. When I finally checked the compression after about 6K of my miles (including 3K miles across the USA) it was not pretty with less than 70 on each one, and way lower if the opposite plug was removed, that's bad! Compression was low but oil consumption was a quart about every 1000 or so miles, but she ran without issue. Hopefully your rings will be free and not broken, and the valves not stuck (if they are it's going to be rebuild time). Make sure the points are good and the timing is correct, clean pugs, carb float bowls have been cleaned, battery is at full charge, ignition leads checked, and old gas gone and premium gas in before you even think about attempting the first start. Just my 0.02 cents worth.

I still have my SF after 37 years (it's in a major restoration back to original right now) so it's a testament of how tough these beasts are.

Clay
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Thats Great advice i will take note and ensure i take all precautions so that i dont cause any long term/expensive damage to a bike standing for so long.
A bit busy over the next few days, but will follow the steps you advise.
As for the additive to counteract hardened seals/rings any idea what its called and availability?

Thanks for all the advise so far chaps.
 
firefly_1965 said:
Thats Great advice i will take note and ensure i take all precautions so that i dont cause any long term/expensive damage to a bike standing for so long..
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Unless it's been buried in soft peat for 10 years and then recycled as firelighters I don't really think 10yrs storage will have done much harm. I suspect it's more ready for a ride than you are :o :o
 
AndyW said:
Unless it's been buried in soft peat for 10 years and then recycled as firelighters I don't really think 10yrs storage will have done much harm. I suspect it's more ready for a ride than you are :o :o
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Very true, or left in a wet environment like mine was for a year. But with the price of parts and labor, and not to mention not getting to ride it quick enough after the storage period  :o :o :o, a little extra time and care might just help a little.

We use Marvel Mystery Oil but there are others that might be available at your local Auto Zone or Pep Boys  :D

I checked on eBay UK and you guys sure do get the shaft, 12 pounds for a quart (liter) while we pay less than $4 (2 1/2 pounds????)

And if you have the time to wait and the anticipation is not killing you then a good soaking over a few days is even better.

How are the petrol tank and Carburetors? And the battery??

cheers

Clay
 
I'm very sceptical of snake oil products like Marvel Mystery Oil that claim to do everything from cleaning your carburettor, increasing engine compression, to stopping oil leaks. The "mystery" part of the name refers to the maker's reluctance to say what's in it, which should ring alarm bells.

But it's not such a mystery. The stuff was analysed by NTSB after it was implicated in an aircraft engine failure (resulting in a crash) and was found to contain 74% mineral oil, 25% white spirit and 1% lard. You could mix up your own batch at home if you think that's good stuff to be putting in your engine or fuel system. But I wouldn't recommend it.

It's the same old story ... If the stuff was any good, why don't engine builders recommend it? In fact it's the opposite, with some manufacturers warning that use of such additives will void the warranty.


 
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