A7 Super rocket now running easily well it was !!!!!!!!!!!

[steve c]

Took the old nail out for a ride Sunday (first one due to fatigue) My Missus has been dying to get out on it
( overridding my general blanket applied caution )
Went from Rugby two up to the Stanford hall Motor cycleshow on Sunday to the BSA open day at wicksteed park in kettering ok on the A14 there very vibratory 50mph, on the way back in a gale blew the head gasket, lost several bolts, loosened the side stand, still hard to get it into neutral (clutch dragging ?).

Reading other posts seems to be standard fittment with the clutch!!!!!!!!!!!!! not selecting neutral at standstill

We had to coast to a halt a couple of times after lack of power.I did the bolts up as hard as I dared  building it, Its amazing how poorly the gaskets have sealed.
The primary case Allen bolts even vibrated out. Seemed to be running hot but oil system seems to be working fine. Put thick straight 90-gear oil in (because I had some, after changing the kick start rachet) this proberly making it hard to select gears so putting SAE 50 in soon.

Loads of work to do now then

Steve

[dpaddock]

What's an A7 Super Rocket?

David

[A10Boy]

These machines do need a lot of care when rebuilding, everything must be spot on. Sorry to say this and no offence but Allen bolts don't vibrate out if they are fitted properly.

When you say it blew the head gasket, what do you mean, how bad was it?

Sorry it didnt go well for you on sunday.

[steve c]

It was quite severe vibration, it was done up well only the three larger screws directly on to the engine loosening . The vibration is coming from the crank, It has new hepolite pistons fitted
It had been ground , I fitted new shells the bush was ok, sludge trap cleaned.

The other two bolts loosening on the engine mount were caused by soft paint giving after assembly, powder coat next time.

I can only think I have made some kind of school boy error, I wouldnt expect it to be that fussy as people used fix them in the shed with very primitive tools.

I can't think that I put the pistons the wrong way or something stupid,

Can your retorque the head to clear blowing, would appear to be slight

Does anyone do away with the rocker box gaskets and use silicon alone, I struggled to assemble this


I am still getting used to BSA engineering or the lack of it, I am not surprised the Japanese manufacturers wiped the floor with them.
I had a yamaha xs250 in the eighties ( a bsa twin clone and often slated as one of the worst japanese bikes of the time) and that ran well and changed gear just very heavy and slow well I never thought I would be nostalgic for that. You seem to need a very big bank balance to own a BSA twin.

I missed several wrecked a10s at the time as I didnt get there quick enough with the cash.


I just hope I can sort the A7 fairly quickly to get some use.

steve

[steve c]

In 1960 It started life as an a7 500, the last owner took the casings out with a catastrophic a big end failure, found most of a super rocket for £35 in 1974 , Unfortunately John never got around to finishing it where I come in when he moved to Crete and emptied his damp shed of the half built seized wreck.
Now has a 61 super rocket engine, 8 inch TLS, manual mag, rgs exhaust, and nacelle ( missing when I got it ) and enclosed chain guard ( missing when I got it ) all available on request for super rocket . With the excepton of the TLS which was repatriated from the states by me via ebay, still have the superocket brake plate.
bearing in the frames are stamped a7 on all of them, ( I could have easily re registered it as super rocket but I prefer to keep the history) its far more genuine super rocket than most super rockets and RGS reps

My insurance company would call it an A7, but its 95% super rocket

Steve

[A10Boy]

A few Q's spring to mind.

Did you use new big end bolts? Did you torque them to 22ft/lbs? Did you fit the right sized shells?

Did you torque the head when you built it, if so what setting? Dont try to cure an oil leak by over torquing the head bolts especially on an ally head, you can re torque to the setting but dont over tighten.

What clearance was on the TS bush? Have you checked the valve timing?

Also, always use rocker box gaskets, silicone is only there to help, we've also had some owners who've had bits of silicone stuck in oilways from over use

If its assembled properly it shouldnt vibrate too much, it will vibrate a little but it shouldnt be excessive! It worries me that you think you dont need to be fussy, you do as with all engines they need doing right.

Good luck, let us know how you get on.

[steve c]

I asked a well known dealer and he checked the parts over, and I brought new anything suggested

A few Q's spring to mind.

Did you use new big end bolts? Did you torque them to 22ft/lbs Yes? New bolts and nuts fitted
Did you fit the right sized shells? A dealer who has built many BSAs measured the crank which had been reground before being left and supplied new shells.

I havent got the measuring gear or expertise to check much of this.

Did you torque the head when you built it, if so what setting 35lb ( from memory ) as suggested by a friends trusted bsa engine builder ? Dont try to cure an oil leak by over torquing the head bolts especially on an ally head, you can re torque to the setting but dont over tighten. May be slightly distorted will check on a surface table. Same for rocker box.

What clearance was on the TS bush ? A dealer who has built many BSAs measured and tried the crank for feel in the bush and said it was fine.

 Have you checked the valve timing? Fitted new 357 cam and good used cam followers. All lined up with marks on gears

Also, always use rocker box gaskets, silicone is only there to help, we've also had some owners who've had bits of silicone stuck in oilways from over use

If its assembled properly it shouldnt vibrate too much, it will vibrate a little but it shouldnt be excessive! It worries me that you think you dont need to be fussy, you do as with all engines they need doing right.

With the reference to the too fussy I mean I have not replaced every moving part, unless wear or damage was found and I have not got the measuring equipment or data to check every thing or budget.
When I started this I was very much on a budget and having to reuse everything I could. Head was going to be properly reconditioned this winter.

The list goes on

thanks for your interest

In hind sight I would have fitted a goldflash 356 cam, flat taiwanese pistons, new regrind new main bearing line bored timing side bush, the frame powder coated and blasted rather than hand strip to bare metal and soft enamel, wheels rebuilt with steel rather than ss , recond head the list goes on

[A10Boy]

You haven't got an A7 head on a 650 have you? I take it that its an alloy head not iron ?

Only my opinion and others can disagree, but I'm just wondering whether you have HC pistons with your 357 cam and either an Iron Flash or Alloy A7 head on it, either of those would make the compression very high and / or could cause over heating, pre-ignition and vibs.

What head gasket did you use? what ignition timing settings did you use?

Going by what you say, if your engine expert was right it should all be ok.

[steve c]

Its a 650 head ally,  Does not appear to have been  skimmed, plenty of land around the gasket faces

I swapped my over size thick flange barrel for a friends standard thick flange barrel  as the pistons he sold me would not fit my barrel , 67.5 mm from memory,  NOS 8.25 pistons hepolites.

I do not now if this barrel has been skimmed, It looks standard.

Barrel packing plate looking to be an option again

Did initially seem to run fine
thanks for ideas

steve

[A10Boy]

Is it actually knocking or just vibrating?

I think you should re check the ignition timing, it could have slipped.

[steve c]

Will check the timing , has a solid copper head gasket.

Would getting hot would indicate that's shifted? retarded the ignition and it ran better

It was just very bad vibration at between 50 to 60mph and it wasn't revving out on the way back.

The bottom nut on the reconditioned carb had also loosened itself ( dripping fuel)  and I did not have a spanner to fit. That would not help the running

It was pretty severe vibration, vibration white finger level through feet and hands, even my wife found it uncomfortable ( shes usually blissfully mechanically ignorant).More like a cheap defective 9" angle grinder than a motorbike.I was waiting for the pegs to drop off!

Could hear a faint metallic clunk, but was suggested this was normal by other a10 owners.

regards

Steve

[A10Boy]

Vibration white finger level !!  If its that bad, it sounds like there is something seriously amiss going on.

Why not get your friends trusted engine builder to take a look?

I would take the head and barrels off and see whats wrong, could be anything, a small end bush collapsed, big end cap coming loose etc etc. I wouldnt run it far like this.

If you have worn splines on the cushdrive it will rattle around and sound like a loose bush. You did clean out the sludge trap when it was apart?

[steve c]

I will re mot it and take it to bits as soon as back


I had cleaned out the  sludge trap

Steve