Opinion Poll: Main bearing end feed conversion?

[berger]

sorry to hear of more problems greybeard but for hard riding and reving its a yes, but as most people know a well made bush set up is perfect for the average rider.  the punishment I give mine sometimes hitting 7000rpm in 1st and 2nd the CONversion may suit my needs but its a lot of money to be sat in there when your not going to be raceing 750 H2 kwakerknackers

[Greybeard]

sorry to hear of more problems greybeard but for hard riding and reving its a yes, but as most people know a well made bush set up is perfect for the average rider.  the punishment I give mine sometimes hitting 7000rpm in 1st and 2nd the CONversion may suit my needs but its a lot of money to be sat in there when your not going to be raceing 750 H2 kwakerknackers

kwakerknackers 

True, I do not ride hard, partly for fear of destroying the engine. I took the old girl up to 75mph the other day. I don't think I've ever gone so fast on that machine. I believe she would have gone faster but I didn't want to risk damage. The sportier camshaft has made the bike quicker but I feel I may have overworked parts that I didn't get remachined because I felt they were within tolerance. We will see when I start to strip the engine.

[beezermacc]

I have built six A10 engines with new timing side bushes, reamed by myself. None of these engines have shown any significant wear during use. My black A10 which I have done 10,000 miles on still sounds sweet.

So, your vote would be a No?

I voted 'No' strictly from my own experience. I'm sure the SRM roller conversion is a superb bit of engineering. However, on a sixty year old bike, unless you bring everything up to SRM standard there will be other weak links which are exploited by time and fatigue. We did 560 miles last weekend on A10's, mostly cruising at 50-55 m.p.h. I'm not sure I would want to go any faster due to poor brakes (by modern comparisons) and my feeling that, in spite of a decent rebuild 15 years ago, the bike is still fundamentally 60 years old. I'm sufficiently confident in my own ability to put an A10 together well enough to withstand the sort of riding I do. If I was doing 70 m.p.h. all over the place maybe I'd spend the money on an SRM jobbie, but I'm more likely to get the XJR 1300 out if I'm in a rush. Incidentally my XJR 1300 (lovely bike - less than 20000 miles) didn't cost much more than some of the engine rebuild bills I've heard of from SRM.

[worntorn]

I find the SR to be a 60 mph bike for cruising and that is with a 23 tooth engine sprocket replacing the stock 21 tooth. Some loss of pep was felt with the change, but also some loss of vibes, which just get worse with rpm.

So right now, with my usage of the bike,the end feed conversion seems a bit like putting a forged piston in my rototiller.
As it is, the bike  feels like it will run forever at 60 and won't destruct from the occasional short run up to 70 or 75 when passing.

I am considering an engine tear down for dynamic crank balance this winter. I hate to do it as the engine runs great and tests 98% on leakdown ( as new)
The crank balance, if successful, could change things quite a bit.

Glen

[edboy]

i would say that it all depends on the state of your crankcases whether its worth the srm route. they are very expensive in my view. maybe motorway cruising warrants it but big end pressure depends on a oil seal fitted to the outer cover. not convenient really.

[coater87]

 I have to go with the guys who say its not necessary. I think if your oil is clean, and the bushing was sized right in the beginning it should be good for a long, long time.

 But on the other hand, being able to just replace a bearing instead of having to worry about a new bushing being installed and fitted really sounds nice. I think thats where 95% of my worry during the rebuild came from- who was going to do it? would they use a good quality bushing? would they size it right? etc. etc. I have only 80 miles on the bike and I am still worried.

 If I was doing it again, and there was a place near me that did known good work on the conversion I think I would spend a little more for the peace of mind and have it done.

 Lee

[worntorn]

On the question of oil, some major scar and friction testing is being done right now by Norton guru Jim Comstock. A number of us on the Norton site have donated to the cause and Jim is really going to town with a very sophisticated testing setup he has built.

Some interesting results are showing up and there is at least one very low cost oil (Mobil 1 15/50 ,$5 litre) that appears to be outperforming nearly everything.
Some of the $30 per litre Motorcycle specialty oils with very high ZDDP are not doing well at all.
The $5 stuff working so well is good news for those of us who change the oil frequently
Glen

[WozzA]

I'm sure the SRM conversion is a excellent bit of kit & I've only heard great reports from those with it...   BUT ... it seems like a lot of money to replace compared to not much for a bush that may only need to be done once in the next 60 years?   

[Black Sheep]

Or for those of us in the not very united kingdom, Mobil 1 15-50 is £36 for 4 litres, £9 per litre. Not that cheap. Ho hum.
I have heard the occasional not so good reports on the end feed conversion. I would need a lot of convincing that it would be worth the money. Got a 400 mile trip this coming weekend including a major off-road event. Not anticipating any problems with my ordinary plain bush crank.

[Sav]

Both my A7SS and my A10SR have been done by SRM, the A7SS before I bought it.

Had the A10SR rebuilt and it never ran right, gave it to SRM and, fair enough, parted with loads of dosh.

SRM replaced everything in sight, which made me wonder a bit, but at the end of the day you get what you have paid for and but she has run sweet as a nut for the past ten years.

You know which way I've voted 

[Topdad]

WHY I VOTED YES , Likewise I'm in the yes camp ,  back during my first connections with A10's from 1966  , I did nearly 19000 miles in 8 mths on a plunger ,first bike and hammered the hell out of her , she finally let fly coming down wheatley hill just outside Oxford , next up was a 56ish A10 ,with Ariel brakes rebuilt it using a plunger engine and just swapped everthing ing into the small jornal s/arm cases ,talk about ignorance being bliss , didn't know about the sludge trap and the importance of end float anyway I put her together being very careful and boy was it clean ,(apart from said sludge trap ) that engine proved unburstable ,I got really fed up not having to work on it ( stupid kids )and abused the motor as only a 17 yr old could and it was, also given that it had a 3 rd wheel , Board fitted no sidecar couldn't break it , in the end having got my dream job selling bikes and more importantly being given one each night to "test " it sat neglected by a friends garage until it was broken for spares .
 So actually my experience should have seen me go down the standard route but when I rebuilt my present bike back about 13 yrs ago alas  without the help of this fine forum and it's well informed members ,i remembered the "problems "with the plain bush ,could still recall a firm called Devimead and finally also it was going to be my last bike so I wanted longlevity and getting some sense at last ,coupled with min spannering so went for the SRM , they did big ends ,new  drivesidebearing ,cleaned the sludge trap ,fitted the end feed conversion ,rebored the cylinder block and supplied 8.25 pistons ,a spitfire cam ,stelight followers and finally balanced the crank ,recut the valve seats,fitted new bigger inlet valves ,guides etc  , the cost approx back then £1800  ,thats a guess ,I've put the receipts away but in my mind money well spent, I put it all together marvelled at the work they'd done and have enjoyed 10 yrs trouble free running , well almost . Hope that lot didn't bore to much, regards Bob

[RichardL]

I voted "no," mostly based on others reporting fine running with the standard bush and my 4000 miles or so since mine was line-reamed/honed (whichever my shop did, I forget).  but all this is not why I'm writing here. It seems that GB is seriously considering a complete rebuild of his engine. I assume he means the engine with the rattle in the video. Now folks, go back and listen to that engine running cold. I'd like to see a poll asking if anyone here thinks that engine does not sound really good when cold. Certainly no rod clunking or bearing grinding/whining/screeching/growling.

Richard L.