The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Amal, Carburation => Topic started by: Slippery Sam on 07.11. 2016 16:33
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Hi,
I'm just about to fit my new monobloc 389 tonight. Bike is an A10 cafe racer and is a fresh build - was not running when I bought it and carb is new out of box.
I'm running a single throttle cable and have no choke (air cable). I've ordered a blanking screw for the air cable entry - My question is -
Do I need to take out internals? Slide, spring etc or leave as out of the box and blank cable entry? Sorry if this is a dumb question - feels to me like I have to strip bits out but just not sure how the internals work (which way round slides work etc).
Thanks in advance.
Raymond.
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you can just remove the top and then pull the slide out, all the choke bits should drop out of the slide ,put the slide back keep the choke bits safe just incase you want to install later ,lots of people run without the choke ,I've got a working one on mine but barely use it as a tickle of the carb is usually all I need ,Bob
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Thanks Topdad, that's as I suspected. Spare parts now removed and stored with my other left-overs!
I need to wait a day or two now to fit as the top hat in the new carb kit isn't slotted and nipple doesn't fit through (split one ordered along with an alternative adjuster fitting (my new cable doesn't have an adjuster unlike most)).
I also ordered an air cable plug - looks like a little screw. I'll wait till it arrives but pretty sure the cable entry isn't threaded. I'll google a bit to find out the right way to blank off the air cable entry in the meantime.
Thanks
Raymond
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Struggling to find notes on the right way to fit the choke cable plug. Will I need the tap the cover? Or is the plug a self tapping effort?
Raymond
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Slippery Sam, I am not clear about which mixing chamber top you are using, but I am assuming it is the non screw adjuster type. If that is the case, then as far as the cable goes you have made life difficult for your self. The type of cable that you should have bought is shown in the picture below. It is made specifically to fit the carb mixing chamber top with no screw in adjuster holes. The cable is made with the top hat incorperated as part of the cable assembly, and also includes an in line adjuster. Amal list three different mixing chamber tops for the monobloc. One to accomodate two screw adjusters, another one to suit two ferrule (top hat) cables, and a third type that has one screw adjuster hole, and one ferrule hole. I have never seen seen a split ferrule but that does not mean that they may not be available from some where. Certainly not Amal though. As for plugging the choke cable hole a blob of silicone sealant would do just fine I would have thought. Again looking at the Amal site I cannot see a specific part listed to do this job.
John
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John, thank you.
That's been the story of my life (well this build at least). Total mix match and to be honest some of my own doing.
Yeh at the moment I have the 2x top hat type mixing chamber. Brand new from Amal and came with the separate top hats - which is why I bought the plain cable. The cable also has no mid adjuster which just compounds the issue. To be fair I was focusing on getting the right twist grip end nipple. I now have 3 cables (before I found the right nipple).
I've ordered a new mixing chamber with 2 threads so I can use an adjuster and plug (both already ordered).
I'll give it a day or two till I have all the bits in front of me before I try to put anything together.
I've had to work round these things the whole build so no biggy. I'm looking forward to selling all the left over bits once I'm up and running.
Cheers raymond.
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Raymond,there's a good reason why BSA didn't have adjusters on the carby top.
You will find that they tend to be too close to the frame and the cable run is too tight.
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Raymond, if you have the tophat and have access to a vice why not simply hacksaw a slit so you can fit it to the cable etc.
al
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Yeh, could do that or even open up the hole a little (nipple is smaller then the cable end). I actually have proper split tophats on order as well!
I know the adjuster uses up the space to the frame - but the cable I have (the only one that fits the twistgrip) has no adjustment. I just removed a brand new Mikuni kit to fit this monobloc and that had an adjuster and sat a bit closer to the frame than the amal does so I'll plough on for now and see how it looks. I will also look at fitting the adjuster at the twistgrip end - might just need tapped.
If I find a cable with an adjuster and the right nipple for my twist grip - I'll have a full house and will be able to go with any comination - or try them all - LOL Now wonder I have so many left overs!!!!!! Think I might be able to buy a new house when I have the left over sale!
Raymond
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What trevinoz says
Raymond,there's a good reason why BSA didn't have adjusters on the carby top.
You will find that they tend to be too close to the frame and the cable run is too tight
It was Trevinoz that originally told me about this (thank you Trev) If you persist in what you are attempting to do you will struggle every time you try to remove or refit the carb.
I'll give it a day or two till I have all the bits in front of me before I try to put anything together.
Well, good luck in your endeavours. You will discover that it is an absolute pig to get the carb on with fitted with screw adjusters. You will find it a very tight fit as far as clearance is concerned, and there is not much room for cable adjustment when you do eventually get it fitted. You will discover that you cannot get the carb on with the mixing chamber top already fixed in place. You will have to insert the slide a needle into the body with the top and the ring placed loosely above the body then once the body is on the manifold stubs you will then have to try and get the top to line up and fixed into place without damaging the threads. Finally put the manifold nuts on and tighten them up. I must stress though that this not an easy thing to do, and your cable will be at a very odd angle.
Raymond, if you have the tophat and have access to a vice why not simply hacksaw a slit so you can fit it to the cable etc.
Sadly, it is not as simple as that. If you go down that route then the metal finishing trim on the carb end of the cable will have to be removed, because the combined thickness of the cable outer cover and trim will be to wide to fit into the top hat. I think that you need to bite the bullet and get the correct cable. It will then become a simple straight forward job to fit, and it will save you from a great deal of heartache and frustration. For what it is worth I do not think that what you are trying to do is feasable (well it might be but the end result will be far from satisfactory). One final observation. If you cut a slot in the top hat then the inner cable will probably "wander" in use and cause yet more problems.
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I forgot to mention that the correct cable should be 42" inner and 38" outer fitted with an in line adjuster, and a "top hat" fitted to the outer cover at the carb end. Mine is made by Doherty and the part number is M42/31.
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Fair cop.
Don't know if that's one of the cables I already have, but have found one that looks right. Tricky bit is getting the right 364 twist grip nipple.
Sorry it is a mix and match and I think I have the non standard twist grip which is making it harder.
Will update in a couple of days.
Thanks for the heads up - saves days of waiting and days of pain trying to make it work.
Cheers raymond
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Would it not be simpler to get a standard twist grip then or is there a good reason to keep the non standard one ?
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Hi,
I just removed a brand new Mikuni kit to fit this monobloc
Why *????* *????*
John
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Hi,
I just removed a brand new Mikuni kit to fit this monobloc
Why *????* *????*
John
Yeh, sounds mad! Bought the SRM Mikuni kit before I had all my registration problems and I'm now having to go down the machine dating and authentication route to apply for an age related plate. Thought it would be helpful to remove the only non age related modification. That's another thing that will be in my left over sale (or may keep hold of it and see how the monobloc performs).
Raymond.
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Would it not be simpler to get a standard twist grip then or is there a good reason to keep the non standard one ?
Yeh Dave - definately an option. Reason for not doing that so far is - I'm only just realising there are a variety of twist grip types, don't know what type is standard, just bought the one I have so it's new and shiney and matches the clip ons, controls and has a new matching grip fitted.
Guess this whole thread started because I didn't realise there were so many options and combinations (threaded mixing chambers, top hats, cable ends, twist grips, adjusters, blanking plugs) and opinions of course.
Think we've flushed out more than enough to get through fitting a carb now though *smiley4*
Hope I don't sound dim! I am quite capable of replacing and fitting a throttle cable - I just was unaware of the variables and tried to replace all of them at the same time. I don't normally consider myself as impetuous but in this case I think at least impatience has got the better of me and I have chased the variables in a less than planned and thought out manner - note to self - measure twice - buy once ;)
Every day is a school day.
Raymond.
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Hi Raymond,
Keep the Mikuni,
I have one on my SR since I built it 14 years ago,
Its definitely an improvement.
I have built quite a few BSA's with both AMAl and Mikuni carbs so feel I can offer a comparison
John
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Cheers John, will do.
Finally got everything together today and eventually ended up with an adjustable cable and mixing chamber adjuster. The mid adjuster cable was just too loose with just the top hat in place! Doesn't sound normal but there you go. Had enough room to get everything fitted and kept my Amal 364 twist grip. Switching the carb top meant I got the use out of my £2 air cable plug - lol and didn't need any more cables.
THEN
I gently (well it was meant to be gently) let my bike lift table down a bit from carb being at shoulder height - and the bike rocked forward right off the centre stand and landed upside down on the floor - bet you could guess the feeling!!!
Now back on the lift and no real damage - can't believe I got away so lucky with that one. Think I've used up at least one of my cat lives tonight.
Still I feeling a bit shell shocked - just going to pour a whiskey and sit down for a bit.
Phew.
Cheers raymond
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Hope it was a very large one Raymond !
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...I gently (well it was meant to be gently) let my bike lift table down a bit from carb being at shoulder height - and the bike rocked forward right off the centre stand and landed upside down on the floor...
Bloody hell that could have been nasty! I'm very glad that you were not hurt and that the bike hasn't suffered much.
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A very lucky escape- not having the best organised workshop meant that a trunk with about 5 pairs of boots and all my fishing gear took a bit of the sting out of it.
It was just that sinking feeling you get when you see that happening and can't do a thing - kind of going so fast but feels like slow motion - then you feel your stomach heading south and your heart heading north!
Yes was a large whisky then I went out to lock up.
New smiths clocks - okay
New oil tank just painted and sealed - okay
New exhaust, polished end feed casings, headlight - all okay.
Could not believe the worst damage was a slight scratch on the clip ins where the brake lever had slipped up.
So lucky really - I was lowering it to fit the alloy fuel tank ready for its maiden start up - or the tank would have definitely have got it.
So back a step or 2 - going to check out the centre stand before I go any further. Suspect it's too straight up and down and needs a bit of fettling.
Just as well it happened here and now (rolled off the centre stand) and didn't wait till my first ride out in front of everyone.
Raymond
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Better get down the local shop and put a tenner on the lottery , seems like its your lucky week !
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Euromillions ticket purchased :-)