Ballast resistors, sorry.............

S

simesman

New member
Location
New Forest
I am just giving my RGS a bit of a spruce up and will be removing the carbs tonight, just to go through them and make sure all is well. Whilst I am under the tank, I notice I still have the ballast resistors fitted and according to the advice all over this fine forum, I should remove them. I still have the original Bosch ignition system and I have to say, I am OK with its performance. I have never noticed any issues with the crude ignition curve and all runs smoothly. I did re-wire all three pick-ups as they did have the usual problem. Anyway, although I have seen many references to removal of the resistors, I have not seen any specific instruction on what you need to do when you do take them out. Are the three orange wires the 12V coil feeds?
 
Thanks Rob, that's just what I needed to hear.
I will remove them as it seems like good practice when I search on the forum. I have sooty plugs and my thinking is that it may help. Another reason for me to spend a bit of time going through the dellorto's, check the choke rubbers, float heights, pumps etc.
 
Guess you will have checked /changed air filter. Biggest contributor to decent running (apart from replacing the BTZ ignition 😂) is replacing worn needles and emulsion tubes. They wear with age in the pulsating airflow. But float heights and choke plungers are worthwhile checks. Good luck
 
Yep, air filter done Rob. I know the BTZ ignition is universally slated, but I honestly cannot detect any issues so am happy to keep it. I even stocked up on a couple of modules and pick-ups when Ged was having a clearout!
I will check needles. Will it be obvious if they are worn, or do I just change them anyway? I guess it would be difficult to assess the tubes.
I can sense an expensive order to good old DucatiPaddy coming on!
 
Well surprised you do not suffer from the cold crank start or non start, BTZ. The 0,9 ohm resistors reduce the current in the drive transistors, ie protecting the BTZ and nothing more, as Edgar Allen Poe did describe in the Raven, speaking of Raven sooty plugs, nothing to do with BTZ and resistors per se... carby and most probable choke plungers at a distant guess. The larger pilot jet is to overcome the BTZ step advance ie pinking. Your at about 12kms per litre of fuel, better ignition and modified pilot jet will get you 17kms per litre or near 300kms on a tank of fuel... if that is of use dependent on how much you ride...HTH j
 
Very interesting, thank you. This will be the first time I have removed the carbs, so looking forward to going through them. I will be checking the choke rubbers and springs, for sure. Rob put me onto the needle issue, so will check these too and I will note what jets have been fitted by previous owners. Which pilot jet size do you recommend? As far as I know, everything engine/ignition wise is standard, just have the Coxy Jota pipes fitted.
 
Depends on previous owners or workshop, common was 65 pilot, with careful setup of carbies 55 is workable, or 58 to mitigate stop light open throttle lean out/flame out in traffic, bloody dangerous that can be, not so much on the open road and upper revs...

Choke lever off, Free play in the choke Bowden cables that is important and the seals at bottom of brass plungers, flip 'em over if expedient and order new ones.

Needle K1@middle clip, say 118 mains AB265 emulsion tubes ( others check that please ) 18mm float height ( this is important! ) before any changes are made. 1 and 3/4 out on the mixture screw to begin with. Ignore what i mention should you already be aware of basic carby setup. Personal choice, pumpers off oh and 60/2 slides from recall.... i think. Set your carby to carby balance at 3300rpm not idle. HTH j
 
iis_iis said:
Depends on previous owners or workshop, common was 65 pilot, with careful setup of carbies 55 is workable, or 58 to mitigate stop light open throttle lean out/flame out in traffic, bloody dangerous that can be, not so much on the open road and upper revs...

Choke lever off, Free play in the choke Bowden cables that is important and the seals at bottom of brass plungers, flip 'em over if expedient and order new ones.

Needle K1@middle clip, say 118 mains AB265 emulsion tubes ( others check that please ) 18mm float height ( this is important! ) before any changes are made. 1 and 3/4 out on the mixture screw to begin with. Ignore what i mention should you already be aware of basic carby setup. Personal choice, pumpers off oh and 60/2 slides from recall.... i think. Set your carby to carby balance at 3300rpm not idle. HTH j
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I should think that standard pilot jets are 55.
On todays fuels, at least around here, that may well be too rich.
Paul
 
simesman said:
I will check needles. Will it be obvious if they are worn, or do I just change them anyway?
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You'll struggle to detect wear without decent measuring tools. The brass emulsion tube that the needle sits in wears too because of the needle rattling around inside it with the pulsating airflow. I just replace both if there's no record of it being done. Sorts tendency to rich running. The other jets can be left if the sizes match spec.

Pilot jet size can be compensated for to an extent by the mixture screw. Standard one and a half turns is where it should be if the jet size is good. If you need to go one turn beyond (either richer or weaker) then by all means think about changing pilot size. Otherwise I wouldn't bother.

When you talk to Paddy he'll give you a good steer on what to prioritise for the overhaul. Worn bushes/spindles on the throttle actuator arms are often overlooked.....
 
All my triples ran very nice with the Bosch ignition. All started easy and ran great. Once I put modern ignition systems on them (three have IIS and one has a Moto Witt) they all ran even better!
 
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