sludge trap and idle question

[chicago]

hi there, just a few questions for you. with knowing very litlle about a7s ive been trying to cram in as much as i can by reading this forum and other site's. the problem is ive just come across the issue of sludge traps and realise it would be a bad pain in the ar*e to clean it out.
the thing is that now its got me a bit worried, to me (remember no expert) my bike seems to run sweet and doesnt seem to be exssesivly noisy and the guy i bought it off did seem like a really genuine bloke, what i would like to know is that is there any syptoms to suggest the sludge trap might be blocked or blocking. ive had a look in the oil tank on my bike when running just above idle and there seems to be a healthy return of oil to the tank, when i bought the bike i was told it was a rebuilt engine, plus the crank case's look like they have been split some time recently which would suggest it has had a rebuild. am i worrying over nothing ?.
also when i bought the bike i was told never to leave the bike idling for ages as it could damage the engine ??.
all advice much appreciated.
all the best, chicago

[Brian]

Morning Chicago,
                       there is no way to tell if the sludge trap has been cleaned or not, its inside the engine and only a total pull down will get you to it.

Hopefully the previous owner did do it but even if he didnt it has to almost totally blocked before it will do any harm. As for symptoms if it is blocked, you dont want to know ! If you have a good oil return and the motor has no undue mechanical noises then you should be right. Keep clean oil in it, I would recommend changing it every 1,000 miles.

As for the excessive idling time I guess that comes down to what is excessive. A motor will idle for quite some time before it gets so hot as to cause any problem. Certainly sitting at traffic lights or leaving it idling while you go and get your helmet and gloves or something similar will not cause any problems at all. As a rough guesstimate I would say up to 5 minutes would be ok.

If the bike is running well and not using gallons of oil or anything else serious I would recommend just riding it, get out on the road and enjoy it.

[LJ.]

Hi there Chicago... Dont ever be tempted to put in flushing oil or any oil with detergent in it, this is a BIG no no. The sludge would then be loosened up and find its way into the big end bearings and you don't want that! As Brian has already said, 'Keep the oil clean', the sludge cannot build up bigger if you keep this in mind. Enjoy the riding!

[alanp]

Hi there Chicago... Dont ever be tempted to put in flushing oil or any oil with detergent in it, this is a BIG no no.

Unless you also have a modern canister filter installed in the return line.

[KiwiGF]

The big end clearance is say 001, which means bigger particles than 001 would sit indefinitely trapped in the oil hole in the crankshaft to the big ends if they got that far.....but the big end feed holes are placed at 90deg to where the particles are flung by centipetal force.....so bigger particles stay in the sludge trap.....well it looks that way to me...

I'm not sure the sludge trap can stop smaller particles smaller say than the 001 clearance from going through the big end bearing for example after flushing oil is used but maybe it can...

[kommando]

If you have a good oil return and the motor has no undue mechanical noises then you should be right.

Sadly this is not true, a blocked sludge trap that fills the oil feed to the big ends just increases the back pressure and the oil pressure relief valve releases the oil direct to the sump. Here the oil pump sucks up the oil and returns it to the tank, it looks like a good return flow but it followed a route that did not include the big ends.

Fit a good oil filter in the return line and regardless of how much is in the sludge trap now new deposits will be much reduced.

[chicago]

cheers for the replies fella's. i know in the long run the safest and cheapest way would be to split the crank case's and clean the sludge trap out, its not so much the striping of the engine that worries me it's more the grief of removing the sludge trap end caps and the possibility of making a mess of it. chances are that if the engine has already been rebuilt the guy would have almost definatly cleaned it out ???, but knowing my luck.......
there is evidence to suggest its a rebuilt engine, i.e new sealant/jointing compound between the two halfs of the crank case's, tops of pistons look very clean but but dont look like new ones (had "made in england" & i ? "1.0030" stamped on them)
what was a bit worrying was i had a look in the primary drive cover and the sprockets looked well worn to me ??. im going to try and add some photos on a new post. all the best, chicago

[duTch]

Hiya Chicargo, Bear in mind if you do decide to have a look, as others have done, as did I, the sludge plugs more than likely pretty much need to be destroyed to remove. SRM, and maybe elsewhere have Hex head (socket cap) replacements much easier to in/out in the future

[chicago]

Hiya Chicargo, Bear in mind if you do decide to have a look, as others have done, as did I, the sludge plugs more than likely pretty much need to be destroyed to remove. SRM, and maybe elsewhere have Hex head (socket cap) replacements much easier to in/out in the future

cheer's dutch, i am very tempted to strip her down, it says on the srm website they can remove and re-fit a new sludge trap for £34. might be worth just removing the crank and sending it them to do it. cheers fella, all the best, chicago

[0116harley]

Hi Chicargo  maybe a good idea if possible to get intouch with the previous owner. You could ask if he cleaned the sludge trap out when he rebuilt the engine. Just seems a lot of work if the bikes running sweet.
cheers Neil
 

[Rich]

if you do strip it down and have the sludge trap cleaned, the flywheel bolt that also secures the sludge trap really should be replaced with a new one , how I know this?
My local engineering firm, cleanede when I had the timing side bush replaced,? well they did not replace the bolt and after 50 years the bolt decided to strip the threads in the flywheel then drop down into the sump chamber, whilst I was riding up the M4 at 70mph and smashed both crankcase halfs, srm had the bolt in stock and a week later and £350+ lighter Steve Mcfarlane had repaired both crankcases and restored the crankshaft and the bike is still running, that was about 18 months ago

[muskrat]

 The short stroke A7 doesn't have that bolt, only the LJ A10 cranks. Not sure of the early long stroke.
Cheers

[duTch]

Thanks to Harley Neil, I meant to say that but forgot-
 Also to Muskrat, that's a bit enlightening as the parts books seem to be a bit vague with the variety of pictures an description of various cranks

[Ron B]

Having gone through my Long Stroke A7 this past winter I've gone the route.  Long stroke trap plugs are smaller so you will have a screw slot not a hex.  They come out reasonably easy with a little heat and a impact screwdriver.  To just check the sludge trap it will entail taking the whole package out of the frame.  A good two day project out and back in.   There is no tube inside the crank as the later A10's have, just a place to catch gunk.  A filter is the only way to go.  These engines are quiet (kind of) so you will hear if something is going bad.

[chicago]

Hi Chicargo  maybe a good idea if possible to get intouch with the previous owner. You could ask if he cleaned the sludge trap out when he rebuilt the engine. Just seems a lot of work if the bikes running sweet.
cheers Neil
 

hi there 0116harley, good suggestion but the previous has apparently passed away . heres the link for when the bike was for sale back in october 2011....
http://www.ebay.ie/itm/ws/eBayISAPI.dll?ViewItem&item=260863622775&clk_rvr_id=335822050645
and here's a video they posted on youtube of the bike...
http://www.youtube.com/watch?v=vjZdUyWVXUg&feature=player_embedded
not sure whether it sounds a bit tapperty ???. what do you guys think. all the best chicago