SRX400 - cuts out at low revs/idle

[beeman]

For what it is worth, when things like this happens I eventually find it is something I have done.
The one thing that sticks out is that it ran ok before but you filled up with fuel.
My first port of call is was it crap or water in the fuel.  When I'm in this position I try and reverse what I have done to when it last worked ie think rationally. In this case drain the tank and try fresh fuel and empty the carb float chambers of old fuel.
If your like me I would already have decided the worst case scenario is the problem and have costed a full engine rebuild.

goodluck
beeman

[Andy M]

The ProTST or equivalent I think will reduce the amount of energy in a given amount of petrol. The fact that it won't even start with it in there is saying to me that with only the idle jet open there is just enough go to make it start, or it's flooded. Reduce the fuel quality and it won't even burn. I assume you held the throtle open to try and make it burn, in which case it shouldn't IMHO be flooded. This is saying not enough fuel to me which brings us back to blocked idle jet, gummed up float etc.

Replace the fuel for sure. Any luck with the colour of the plug tips? Maybe try looking after a few minutes at idle and see if they look lean? Try some carb cleaner?

This assumes of course that simply dumping potentially iffy fuel does make it all go away.

Andy

[Steve Lake]

Well, my preference, for what it's worth..

1. cr&p in the carb....they are bu55ers to get off and clean, but worth the effort
2. Carb icing up...but if you are running standard carbs with the standard airbox and filter..this is not the most likely reason, as you say that it is the same after you have done a mile or two and then come to a stop.....if the engine then stalls, and it is left for a few minutes before restarting (it takes very little time for the ice to clear when the engine is hot) it should then idle ok if the problem was icing.
3. you filled up on the Sunday...and the problem started on the monday? mmmm....you could have taken on a load of sh1t with your petrol....so draining tank (if you remove the tank you can then remove the filter as well) is a good idea, then clean out the lines and tap assembly, and the carb...it really does help if you have access to an airline......these carbs have more holes..pipes..jets etc than a half decent life support system!....only person I know who has any idea how they work is SteveH
Good luck

[beeman]

The carb cleaners in a can work a treat and shows you where the passage ways are in the carb but...... if you get it in your eye, life gets very exciting for a few minutes. Don't ask how I know but if you try to clean a hole which you presume goes somewhere but is only a dead end you too will know. However the carbs went like new afterwards.
If the tank is letting rust through an inline fuel filter might do the trick.
beeman

[Martin Giddings]

I did have a similar problem with a sticky/pinched choke cable. Though I did have trouble re-starting, it would run fine until warm, 1st stop it would die.
Good luck!

[andy0405]

Back on the road again 

I managed to clean out the tank and strip/clean fuel pipes and tap all the way to the carbs, and then Xmas and work took up my time so got local Yamaha dealer to strip and clean the carb for me, hey presto running like a dream again.

Thanks for all the help.

Andy

[themoudie]

Pleased to read all is now better with the wee beastie.

Healthy 2008, Bill

[andy0405]

The old girl has been running great.... up until last week. Took her out of the garage, tried starting, no joy 

To cut along week short in the little time I have had to look at her I have discovered that there appears to be no fuel getting to the plug... hence no starting. After paying the local Yammy shop last time I have decided to strip and clean the carbs myself (gulp). Any tips and tricks would be gratefully appreciated. 

[Julian217]

Hi, a bit of a poor show on the part of yer local shop if they supposedly stipped and cleaned it only a couple of months ago. Are you sure there's no blockage on the way to the carbs? 

There's a drain screw at the bottom of the float bowl, if nothing comes out of that then yes its dry.

 If you do want to get the carbs off my top tip is loosen the airbox first. Ie take the screws out so you can wiggle it backwards. Then undo the carb boots, you might need to fabricate a tool to do this if they're held with allen bolts - a cut down allen key should do. After disconnecting all the cables, fuel lines, jubilee clips etc you should be able to pull the carbs out upwards and backwards with the boots still attached.

[andy0405]

yeah not happy at all, however need to save some cash so am gonna have a go myself this time (maybe even do a better job).

Thanks for the tips on getting the carbs off, I've not attempted it yet but did look and wonder what the best angle of attack was, a snug fit if ever I saw one 

Fuel is getting to the carbs as i have checked the carb drain plug several times and each time it was full. Now I'm not a mechanic but I'd expect the spark plug to be wet (or at least showing signs of liquid) but its bone dry. I've even checked with the HT lead off in case it was timing.

[Steve H]

The carbs on the monshock are easier to remove than the twinshock. You should be able to remove the top of the airbox along with the carb trumpets, before you start on the carbs.