Hi. I’m sorry if this has been talked about before , but I don’t see the answers I’m looking for on the forum , so here goes. My 750ss won’t start I have done the following. New fuel pump and filter. New battery. Cleaned all earths and fuses and connectors. New regulator I have spark. I have fuel to the carbs. The starter motor turns over fine. the bike will fire and run if I put fuel directly into the carbs, but only until that fuel is gone. what am I missing ? thanks in advance
I know it's difficult to reach now assembled, but can you disconnect fuel feed to carbs and briefly turn on ignition to confirm fuel is exiting from pipe? If you have any "thimble" type filters still fitted to the supply line, and it's clogged then it could be this alone. Also, have you tried with fuel cap slightly open? does pump pitch sound ok?
OK.....Does the pump run when you switch the ignition on? It should run all the time when ON. How do you get the fuel direct into the carbs? Do you mean you can get it into the float bowls? If you can get it into the float bowls (bearing in mind I don't know if you can) then I think you may have a blockage in the fuel lines. I would disconnect the carbs from the fuel lines, get a large jar and switch the ignition on to see if the pump is pumping properly. If so, you may have to get at the tiny filter in the tee-piece between the two carbs. That's all assuming you haven't accidentally forgotten to turn the petcock on. I will see what your answers are before I add any more.
Thanks for your reply. I have a filter in line to the carbs. But fuel is getting past this, even without the pump being powered up. I’m completely lost. It has new ht leads, new coils. Basically it stopped working after picking it up from a mechanics work shop. I rode it 3 km and then it just would never start again. I replaced everything listed in my post above , to try and remedy it. But nothing seems to work.
I know it's laborious, and not doubting you, but need to clarify, so if you remove the fuel feed pipe and turn the ignition on, fuel does come out of that pipe? When you say you are putting fuel direct into the pipes, are you filling up via the carb junction that above pipe is normally connected to?
I was going to offer to come an help. Then I noticed that you were in Spain! I would be very happy to come and have a look. Ah but I am not allowed to. Bugger!!!
I hope he isn't pouring petrol into the carbs via the air intake......that's asking for trouble..... Either washing the oil off the engine's guts or worse still, a fire..........not hard for a great gob of burning petrol to get spat out.
I often spray into inlets to confirm fuel starve, done it without problems all my life, but i was trying to confirm where connected, because it could confirm that there is no thimble filter problem at last junction. I think it's item 32 on here (can't find table to go with it) and shows fitted at "Y" junction here.
Hi, I only put a small amount in to see if the bike would start, I know its frowned upon, but I wanted to see if it would start with the spark that exists
Yes Chris, I agree a spray of fuel in the throat is fine, but not pouring it in. Do mean the fuel filter at the carbs in the tee-piece? (item9 below).
Hi chris the pump pitch sounds fine. I have tried to get to the fuel hose where it attaches to the carbs, via an articulating t fitting, no joy, I have lifted the air box up enough to see where the hose goes on to the t fitting, and i can articulate it, but the spring hose clamp that is holding the fuel hose in , is in such a way that I can't get to any tool to open it, which means I think I will have to take everything out, air box etc to try and get the hose off
Sideshow...... The slides you refer to will only lift when intake vacuum acts on the diaphragms, which lift the main needles and the main jets get going. That won't happen until the revs are at least 2000 - 2500rpm. Until then and/or at idle, the carbs are running on the pilot circuit. With regard to the hose clip, I recall finding a screwdrive 'jubilee' type clip at the Y junction connector, so I disconnected that joint and pulled the hose forward so I could lever the one at the tee-connector off with a long thin screwdriver.....it actually broke if I recall correctly. I then replaced both those clips with these.....what you can just about see here is the disconnected carb end of a new hose, with a new clip. The jubilee clip at the Y end can be seen as well, plus part of the Y connector....it is an awkward photo, but one I had with the new clip.
The bike wouldn't start, so you fitted a new fuel pump (and other sensible things) now it doesn't run. You say you have fuel to the carbs - how have you verified that? If you're pouring fuel into the carbs to start the bike and it runs until that fuel runs out, but it won't run otherwise, it doesn't sound as if you have a fuel supply driven by the pump getting to the carbs. Are you aware that if you switch the connections when fitting the pump ie connect positive to neutral and neutral to positive on the pump, you will hear it working, but it will be working in reverse! So, unless you can see fuel shooting from the fuel supply to the carbs with ignition on, you may well have the pump in reverse and have no fuel supply to the carbs at all......
I have just found Item 32..........They call it a 'jet' but it looks a though it just has a small-ish hole in it.........I suppose it could get blocked though. I don't even recall seeing one on my 750
ok thanks for that, one more thing to check, Im pretty sure I got that right, but its good for me to double check thanks
