Rocket Gold Flash

[a101960]

Bill,

Check that the pilot jet has been drilled through properly. Can you guess why I would suggest this?

John

[chaterlea25]

Hi Bill,
Apparently sometimes the rockerbox casting has to be relieved to give clearance on the ally head 650 models
maybe the rocker box came from a std A7/10???????????????
Just a thought???

HTH
JOhn O R

[bsa-bill]

Yes Muskrat did have problems with the Camshaft have since changed it and relieved the sides of the bushes ( this was the problem).
You know John I bought new pilot jet from Amal (25), I'll check that out.
John O R I'll have a close look at the rockers, which bit do you reckon needs relieved, the valve goes down OK just seem as if it momentarily sticks and then frees but misses the quietening ramp on the cam thus the click.
Thanks for the reply guys, obviously yet another head off, this engine has/is hard to kick over once the head goes on, not hard as in high compression but stiff so that a good fast swing is not possible yet with the head off it spins over easy - I will get to an answer ---- eventually   

[bsa-bill]

Well valves does not seem bent, is free in the guide and has ample clearance I think, also absolutely no sign or mark on piston.
Cam followers rise with cam and fall back on there own.

Now the interesting bit, it's quite today and as I turned the engine over I heard a crunching/rubbibg  noise, difficult to locate exactly not the camshaft or magneto they were stationery, so I intended to remove the primary cover and disconnect the chain to isolate it to either the engine or clutch/gearbox.
removed the cover and turned the engine over before splitting the chain to eliminate the chain rubbing/catching, hey no noise.
thought of cushdrive nut rubbing on cover OR those three big studs that hold the front of the cover and Bongo one has been rubbing on the crank outside web.

 This was a purpose set for an A10 bought from a trader I have always had good stuff from. I will check that I did indeed buy them from him and have a quiet word, could be there is some explanation involving the spacer or wear in the hole the stud goes through.
Will shorten all three studs and maybe slip an extra gasket in there

Spot the culprit - the middle stud although you can see it has been rubbing is still slightly longer than the other two ( talking in thous mind) actualy looking through the camera the end stud has been catching as well

[muskrat]

Great investigation work Bill, glad you found that one. Still doesn't solve the valve problem. Are there any marks on the pushrod as John OR's line of thought? Clutching at straws but with your work on the cam bushes, could the cam be slightly out of position and the follower is just picking up on the adjacent cam lobe? Or are the valve springs binding against each other, look for marks on the out side of the inner spring and inside of the outer spring.
Cheers

[chaterlea25]

Hi Bill,
Glad you found at least one of your problems, I am always very aware of the length of these front primary case screws
Just didnt think to mention it 
It can also be an issue if these holes in the crankcase have been helecoiled as sometimes the helecoil can move inwards and foul the crank
I fit solid inserts with a shoulder (timesert)
On the rockerbox issue to the best of my knowledge they need to be relieved to clear the valve springs/cap
around the outer sides of the valve springs (if that makes sense????)
Look inside the rocker box to see if there are any rub marks
HTH
John O R

[bsa-bill]

Hi Muskrat - as the heads off I'll lift the barrels and check what cam and followers are doing, hadn't thought of the springs binding with each other will check that too.
John the bottom ex cups ( the special rocket ones) have one side clipped off to mate with a portion of the box that is ground off, this on the exhaust valves only which are the small front boxes.
I have some of that stuff that a10sausage used to free a sticking valve, don't want to put it in the oil though until the engines run in, but thought I might squirt some down the guide and work it in with the valve maybe with a little oil.

Suppose I could test the valve in the head with the head , a wood block and valve compressor (visions of alloy fins flying through the air though)

will check all this tomorrow

[chaterlea25]

Hi Bill,
I have never seen the bottom cups clipped?? (cant be right??????)
That cant really work as the springs will overhang the cups????
and rub the rocker box!!!!!!!!!! unless its ground away
I recently stripped a head that I believe is as it left the factory and the bottom cups are intact
same on my other 2 bikes
My camera memory card is full, so I must select shots to delete or get another card before I can take a pic of a spare rockerbox from this head!!!
HTH
John O R

[bsa-bill]

I think John the bit out of the cup is instead of relieving the head although the head is relieved a bit as well, it is only the Ex valves this applies to, interestingly there is no separate part number for these two which would back up what you say.Should also say these came off a big valve head which this head isn't
However without the bit cut out the cups will not sit down on the head properly? and yes as you can see some of the head is ground away.
I am wondering if when the crank came around to rub on the protruding stud from the primary case the sudden loss (even slight) of momentum or hesitation was the cause of the valve appearing to stick.
Only one way to find out, need to put the head back on and try it, but I'm working for the next four nights so it will be next week.
Just time to put the shed back together, I've been playing hunt the collet - need I say more

[chaterlea25]

Hi BIll,
Attached are a couple of pics of the head that will grace my RGS and the rockerbox that came with it
As you can see there is only the slightest mark on the side where the seating for the valve spring collar is machined
The bottom collars from this were full circle
Looking at the rockerbox I then had a thought  ???? ???? ???? ????
What part number is on the rockerbox you have?
This one is 67-260 (number on casting)
My parts book lists the following
42-0136 A7S/S
42-0137 A10 S/R
42-0138 A7 A10
I know the valve springs on the S/R are bigger diamater than the normal A's, but I dont know why the A7 S/S is listed as different??
More and more  ???? ???? ????

Regards
John O R

[bsa-bill]

Hi John - an update
after close examination of the head I'm not sure that the bottom cups need to be clipped, kind of difficult to see underneath them once their on, I do have some plastigauge stuff I might try to see if they are sitting right down.
The head they came off came from Canada, it was a big valve head at a good price even with shipping ( before things went silly) had one broken fin.
the head was marked in a couple of places with what looked like deliberate small nicks ( four in each location), I looked into the seller and it was a shop that dealt in sport/racing stuff and I think probably raced so the marks might have been to identify the head?
Anyway I've taken on board comments here re springs and ordered two bottom cups and a set of springs from SRM, ordered Thursday, Royal Mail next day delivery - not here yet Tuesday?
Think I'm finished working so should get it together again soon, taking the opportunity while the head is off to double check timing, fit lifting handle, fit slightly thinner cork breather shim.
Will look at Rocker box number but I have looked into this before and I believe the difference in part numbers is down to the different length of studs used for alloyheads and the actual box was the same casting - however as always I welcome correction.

Thanks again for all help and assistance

[chaterlea25]

Hi Bill,
Funnily enough the head for my RGS came from California!!
It has seen very little use and has not been messed with, it came complete with the rockerbox all the bolts studs and even the oil feed pipe, The rockers have been polished at some point
I had another head but wound up fitting that on the recently completed SR for a customer, along with the top and bottom collars etc from this one! new valves and springs of course!!
The head on the RGS is the earlier Road Rocket one, its shy a couple of fins (easy fix)
It is fitted with alloy valve top caps 

Cheers
John O R

[bsa-bill]

I'm hopeful things are coming good.
With the Magneto off my Flash now installed, starting is easier and fairly constant.
Timing is set at around 32/33 degrees ( as per Richards advice - thanks Richard), both points open to very near the same distance, perhaps a difference from sliding fit to dragging fit ( I think you guys will know what I mean).
Found a way to test points are open (needs a quiet shed) - with the timing set to where you want it and your smallest feeler wont go between the points ( mine is 0.0015) flick the points open with your thumb nail, if they are still shut you'll hear a click as they meet i- if they are open you wont.

Took a run on Monday around local roads, about ten miles in total, it started fine and runs sweet on tickover in fact it will run much slower than you want a rebuilt engine to do, went fine until it got nicely warmed up then when accelerating it started to sound like Geoff Capes was in there throwing hammers about, quite alarming - I'm presuming it's pinking ( I say pinking you say pinging) loud light tinkling disappears when you slacken off.
I was running without air filter I have since fitted the air filter and lifted the needle to the third notch  (it was in the second), have not been able to get out since due to weather and other stuff, I've also bought 430 and 440 jets I'm on 420 at the moment.
Plugs did not look too bad when inspected, a very light dusting  of soot probably due to the last hundred yards at tickover, central electrode and insulator a whitish grey so maybe running a bit lean.
Also pilot jet maybe needs to be smaller, it goes best with it turned way way out, similar to my flash which I cured by fitting a 25 instead of the 30
Will see how it goes with these alterations after this rain clears and I get it  back on the road

[orabanda]

Bill,
Don't forget that you can richen the mixture by using the air slide when running, if it continues to pink.
This will confirm if the bike is too lean (which it probably was as the pinking occured when hot).
Richard

[bsa-bill]

Hi Richard
Lifting the needle one notch helped a lot but still some pinking on hills so I fitted a 430 main and for  the time being left the needle where it was ( on three ), this has eliminated the pinking and dropping the air slide makes it run rough so it is rich enough at this I guess

Don't know just how a notch on the needle compares or relates with a size jump in main -if anyone reading this with such knowledge would like to share it this is as good a place as any - cheers 

Plugs are quite nice coffee/greyish - so I'm not to faraway with the carb I think

Might get away with dropping the needle back to two, but will wait until the original Maggie comes back believe it or not the Maggie that is on (from my Flash) has now decided to do the " wont start I'm warm" thing - this bike seems to eat Maggies.
I'm coming around to electronics I think

Cheers - Bill