Allens came up trumps with the new slide guides and o rings, Overnight service! Carbs are now rebuilt and sat on the bike ready for reconnection . Set float height to 13mm and the main jet to DJ recommended 144 Air screws are set to 3 1/2 turns as a starter for 10 see how it goes from there. Air cut off diaphragms and choke needles are fine so here's hoping the running woes have been sorted.
I did indeed. all ports airways and other orific's have been blown through and seem to be doing what they need to in terms of letting stuff pass. There is fresh fuel in the tank and I will be adding a little redex just for good measure.
Perseverance is the best way.... .....when my 750 developed carburation problems out of nowhere (after two years running perfectly OK, the next minute it was popping and banging like mad); I think I had them off the bike about 6 times before I got them right. Mind you, I was plagued with several little problems that shouldn't have existed in the first place, like a really poor jet block casting that had put a nick in the gasket, plus a brand new float assembly that turned out to be faulty. However, the main problem was hard lump of float bowl residue that had got into the pilot circuit on one carb. Repeated application of Wynns carb cleaner and a stiff-ish nylon brush bristle, followed by 125psi air blast seemed to do the job. In the end I even had the carbs set up at the correct angle in a vice; filled the floats with petrol via a tube, then connected a footpump with a gauge to the tube and used it to see at what pressure the float valves let go. If it helps anyone, they released at 12 psi which is easily greater than the tank pump pressure.
Mechanics 101. Pop carbs onto inlets, secure manifold rubbers. reconnect throttle cables place battery tray and associated electrics onto carbs, reconnect same, place fully charged battery into tray, reconnect plug leads open fuel cock. start motor with kill switch to build oil pressure. flick kill switch to run. hit the tit enjoy the gorgeous sound of a 900 ss on 2 pots running up to 3000rpm. listen as it coughs once and continues running. wonder where light smoke is coming from? stop engine, immediately detect the strong smell of fresh fuel. inspect carbs closely then go into abject panic as you realise that you haven't closed both carb drain screws fully and are now watching a steady stream of Esso's finest pouring onto the now hot exhaust. Grab masses of blue towel and an 8mm tighten same and slightly panic at the thought that the incident may have required the services of the local firefighters. Lesson? don't rush, don't get distracted and check your work!!!!! Ok so now that's cleared up tomorrow in daylight I need to set the idle and she is still coughing a little bit but nowhere near as much as she was. The idle is high that when you knock the choke off it makes no difference, That said she is together temporarily and I need to adjust the cables etc up. I ran her for 10 mins or so which is probably as much as the neighbours can cope with, and then pulled the plugs. Front, lovely light brown and dry, Rear, a little sooty but dry. so its running a little rich on the rear although that may be down to standing and the need for a good thrash out when roads and weather are reasonable! I genuinely think I'm getting close to sorting this and that its a shit in the carb issue rather than anything a damn sight more serious. Thanks all for your input thus far.
You need a decent run on the bike to be able to judge the spark plug colours. Also, the pilot screws may not necessarily be the same setting....in fact it is unlikely they will be. Did you pre-balance the carbs before you fitted them? I use a bit of 0.5mm lockwire under the butterflies when they are closed. Get the choke cable properly adjusted, then try the choke on half setting when you fire the bike up......you can probably feel a slight notch where that should be. Once the engine is hot, bring the tickover down to about 1200 -1500rpm and then balance them. Protect your arm from the front header......it hurts otherwise. Once you have got them about right there, check balance at about 1800rpm. Bring the tickover down to 100rpm to 1100rpm. PS.....Make sure the throttle grip flange isn't rubbing against the throttle cable/switchgear case.....that will cause a high tickover or a slow drop to tickover.
superb info Al, Im going to let her cool down overnight to see how she stats off the choke tomorrow and reduce the risk of her setting herself on fire! Ill take a good look at her in daylight tomorrow, but reassuringly, I don't think I am far off.
When I first rebuilt the carbs on mine I fired her up and was gutted to have a steady backfire from the horizontal cylinder, approx every 10 seconds BANG!, then I remembered I hadn’t set the mixture screws, doh!, one more turn out on that carb and the bike ran perfectly, phew!, that was a few thousand miles ago and she’s never missed a beat, it surprised me how quickly she starts from cold after sorting the carbs, barely turns a full revolution on the starter and she’s running, hopefully it will all go as well for you tomorrow.
from my experience these bikes dont even need the choke if set up right.. certainly the few i have owned and my current one does not. in fact the use of the choke seems to do not alot other than foul the plugs... it would be good if they just had a fast idle switch so i didnt have to hold the throttle for a few mins till it will idle ok... the one i have at the min just needs a slight tickle of the throttle as i hit the button then holding at about 2k for 2 mins before she settles down to idle at around 1100 rpm... i could use the choke and walk away for a few mins but it just seems to cause probs.
can you effing believe this? Rolled the bike out this morning intending to warm her up and set idle etc only to find the cow wont start. Starter turned weakly and then nothing as if the battery was flat. Checked same, no problems, engaged 2nd gear and rocked bike in case it was the sprag clutch.. nothing. checked starter solenoid, Clicks no problems, checked lead from battery to solenoid No issues, checked solenoid is switching no issues checked lead from solenoid to starter motor, no issues...... All connections clean sound and in fine fettle Twatted starter motor with rubber hammer, moved once then nothing.... Bugger. So now, order some 3 bond and prepare to remove the damn side cover to remove the starter motor. Anyone know where i can get the SM rebuilt / replaced? Just when things were going well!
Assuming the little white connector is in the solenoid. Check the battery....with all the starting and testing you have been doing, it won't have been charged enough. You need at least 12.6 volts https://www.electrexworld.co.uk/acatalog/SM9162.html#SID=705 https://www.electrexworld.co.uk/acatalog/SMBK175.html#SID=720 If you find it is the sprag bearing, get it from KTM...identical, same manufacturer; half the cost.
Thanks again, battery is at 12.8 v If I recall the dim and distant past, I think the starter may have been "looked at" before. I may invest in a new one Not sure its the sprag bearing although I wont know for definate until cover comes off.... Next weekend now!
Probably just the brushes....you should be able to take the end cover off and see what they are like....be careful with the terminal post though.
As previous post, if it is the starter motor that's gone duff chances are it's the broshes, these can be replaced with the starter motor in situ. New brushes unit available from electrex world. Test the motor by putting battery direct onto it , you'll know instantly if it's the motor or something else.
Check that white connector on the back of the solenoid before you do anything else, you can get to it from the other side of the bike with a long screwdriver, give it a push and wiggle with the screwdriver. Also check the starter relay, on the M900 it’s under the seat , usually a yellow box unless it’s been replaced with aftermarket, not sure where it is on the 900ss, anyway give it a sharp tap with a small screwdriver handle in case it’s jammed or take the cover off so you can see if the connector is moving/sparking.
Thanks all, All is fine with the relay, and associated electrics, I think its now down to a SM issue. Ill take a look when im in a better frame of mind.
