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[nige]

Hi all,my crusader sport has poor acceleration,erratic tick over and is getting very hot after a short run,the exhust is gold colour,it starts fine,is this a ignition prob or carb,ps it is a new amal carb, thanks.

[Mark M]

It sounds like it's running weak but this could be carb or ignition timing. Need more info really. What carb, what internal settings and how did you time the ignition?


REgards, Mark 

[Alan R]

Hello nige -------OK matey, shall we start at the beginning?   I know this may feel simplistic but let's just tick off the boxes. First--how long have you owned the bike ie how well do you know it ?? So, thinking back,  how did the bike go before you changed  the carb ?? Have you done anything else to the bike at the same time. ?? Are you sure that is the correct carb for the machine ? Did you personally check all jets, needles, settings before fitting ? Initially it has all the classic (sorry) symptoms of a weak mixture or wrong ignition timing or  contaminated fuel maybe. If it was brand new, did you give it a good internal wash-clean and blow -through before fitting? There's a few thoughts----let's see if others can help out with this one.?? Cheers for now-----------

[nige]

Mset on midonobloc carb ,1"1/8 25 pilot jet,190 main #3,1/2 slide.set on middle groove on think its 106 needle,as for the ignition timing and reading the tech notes you turn the back plate forward or back,so if its running hot which way do you turn it,cheers mark ,allan.

[Howzie]

Hello Nige,


It's good advice what the other guys have replied to.


Carb, try moving the air mixture screw in 1/4" of a turn first.


screw in to make the mixture rich or out to make it weak.


Next ignition, with my 1959 250cc Clipper I set the ignition as follows.  With the bike on the main stand a place a bit of plywood under the stand on the generator side only, this lets you turn the back wheel over by hand.


Then with the spark plug out & generator cover off I set the engine at T.D.C. on compression stroke.


Set the points to the right gap 14"/16" thou with the contact assembly in the middle of it's slots.


With some bluetack I stick a protractor onto the nut holding the rotor on.


You can slide a bit of white cardboard in behind the protractor & in front of field coils of the alternator, this will give you a chance to mark a reference point to line up with the protractor, slacken the two outer screws holding the contact plate to the casing then turn the back wheel by hand carefully anticlockwise till you see 5   degrees movement on the protractor, at this point move the contact plate clockwise till you just get the points to open on the cam, you can do this with a bit of paper in the points or on the ampmeter with the ignition switched on then nip the two outer screws up.


Sounds a lot to take in Nige but it's not that difficult, run throu it a couple of times till your happy then give it ago. 


Handbook says 1/64" for the timing but try measurung that 5 degrees is equal to 1/64"

[Beezabryan]

I might have expected a blued exhaust if it was running weak not gold coloured

[Howzie]

Hello Nige,


If & when you get your problems sorted out try changing your fuel.


I drained my tank & refilled with BP Ultimate, it has no Ethanol in it, bike starts better & runs fine.

[MadMike]

Hi Nige, If your bike is now running weak or the ignition is out or whatever, it is essential to know what has changed in total. Otherwise all suggestions about correcting the problem(s) are no more than inspired guesses I am afraid.


So back to basics.


Was the bike running OK? If so what have you changed?


Wew know about the carb already, but what else, if anything, has changed? Have you rebuilt the engine, and if so to what extent have you fitted new parts? Has the ignition been changed or adjusted? Tappets, are they too tight? Have you for instance tightened the head bolts and not thought to reset the tappets?


Anything that has changed can and/or will affect running.  

[nige]

Hi,Mad Mike, bought a new amal carb from surry c, 1"1/8. not sure about the settings, jets needle slide ect. would the thickness of the spacer make a difference,cheers

[MadMike]

Nige, how did you determine the size and jetting etc of the carb you have bought? Does it match the original carb spec? What diameter is the inlet tract in the manifold/cylinder head?


What spacer are you refering to? If it is a tufnol one between carb and manifold its removal should make not one jot of difference. As I said in another posting today there appears to be no logical reason to put a specer in this location. I frankly doubt that the original had a spacer fitted. Most bikes had either an O-ring groove and, obviously an O-ring, fitted to the carb flange, or simply a gasket between the  two.


Remember that many bikes had the carbs fitted to the manifold by a simple push on stub with a screw clamp!