The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => A7 & A10 Engine => Topic started by: ronnierockets on 28.01. 2009 20:53

Title: Bottom end rebuild
Post by: ronnierockets on 28.01. 2009 20:53
Hello All,
IN your opinion,  how many  miles should i clock up on my superrockets Rebuilt bottom end,before considering it to be run in .?
The Rebuild consisted of..  crank regrind /new shells,  timing side journal regrind/new bush,(line reamed)
New camshaft c/w bushes,  new cam followers,  Bores honed ,and new piston rings fitted.
New iron bodied oil pump,   SRM oil pressure release valve,  and an Oil filter fitted on return oil line.
and thats about it..
All advice and comments welcomed.
   Thanks fellas...Ronnierockets..
Title: Re: Bottom end rebuild
Post by: groily on 28.01. 2009 21:05
Ronnie, I'd go very easy for 300 odd miles, gently for the next 500, steady till well past 1000, and then gradually press it more and more until by 1500-2000 you're there. Best to vary the revs, and not let it labour above all else in too high a gear. Stress like that is far worse than a few revs. May be a bit conservative, but better safe than sorry. I'd change the oil at about 300-500 miles, then again at 1000. Amazing how much muck even a clean engine will produce as the shells wear in and the pistons and bores settle. Plain bearings should be run-in at 300, the thing that matters is the piston/bore department. You've got a filter on too haven't you? In which case, you'll probably catch all the debris and then you can look at it in horror. Another thing to mess with and change!
Title: Re: Bottom end rebuild
Post by: stratcat on 28.01. 2009 21:22
I agree with groily's advice, although I wouldn't treat it with kid gloves. Being too gentle can be as bad as thrashing it.
Keep the engine spinning, higher revs won't cause any worries but chugging around in high gears will kill it (loads of pressure on bearings). Just keep changing the oil, oil's cheap compared to an engine rebuild.

You will feel when the bike has loosened up, and by then you will be using the performance anyway.
Title: Re: Bottom end rebuild
Post by: trevinoz on 28.01. 2009 22:15
Twice around the block is good enough. It's too hard to control yourself any longer.
Title: Re: Bottom end rebuild
Post by: ronnierockets on 30.01. 2009 08:50
Hi Groily and Stratcat,
thanks for your reply,  your advice is appriciated,  i've just changed the oil and filter, so as soon as the weather improves,  i'll clock up some more miles.

Trevinoz,  Twice around the block ??..dont be tempting me lad..Its hard enough to control myself as it is!
Title: Re: Bottom end rebuild
Post by: A10Boy on 30.01. 2009 11:53
I agee with Groily and if you are on long straights or motorways [not that I do many motorway miles], you should roll on and off the throttle a bit.

Also I was wondering what oil are you using, have you gone for a Multigrade / detergent oil since you now have a clean sludge trap ?
Title: Re: Bottom end rebuild
Post by: ronnierockets on 30.01. 2009 14:58
hi Andy,with reference to the oil, i'm using a straight  40. detergent oil ,and have been using this type of oil on all my other bsa's since rebuilding them, without any problems.
Title: Re: Bottom end rebuild
Post by: trevinoz on 30.01. 2009 22:37
Righto Ronnie, make it three.
Title: Re: Bottom end rebuild
Post by: anjimehra on 23.02. 2009 12:09
What I normally do is mark 1/4 throttle opening on the twist grip with chalk / paint whatever, & do not go above 1/4 throttle in ANY  GEAR upto a minimum of 1500 kms ( 1000 miles ). Also during first 500 miles, sstop & cool the bike for a few minutes after a 1/2 hr run. ( Unless ofcourse its snowing. In India with 36 deg temps it becomes neccessary to cool the bike ???? )
Do an oil change after the first 2000 miles & clean / replace oil filters. Check for filings.
Then head for the open roads
Title: Re: Bottom end rebuild
Post by: beezalex on 23.02. 2009 15:20
IMHO, a properly assembled bottom end shouldn't need any "running in".  Rings are the only thing that needs to be bedded if the pistons are properly clearanced.  When dry assembled and with bores correctly honed, I usually have rings seat in the 1st 30 seconds.  Aside from that, I usually allow anything but total thrashing or sustained high speed for a couple hundred miles.  Then change the oil and have fun.  This is much kinder than what my race bikes get.  They get a couple of warm-up laps and then thrashed to no end.