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Discussion in 'Suzuki 250cc In-line 4's' started by Arch_Althalus, Jan 17, 2019.
Just ordered a set of coils from Kiffsta. Fingers crossed this solves the issue.
The courier picked them up today ,
Should be with you tomorrow
Thanks for that Kiffsta, They are fitted but haven't done anything for the issue. I have pulled the spark plugs again to see if I can find any more clues and now have cylinders 1,2,3 running lean, (I have them on needle setting 2), and cylinder 4 running rich according to the build up on the spark plug. It is also on needle setting 2. I have replaced the pilot jets, cleaned the main jets, replaced the plastic clips in the carbs, cleaned the needle jets and the jet needles, adjusted the valves so they are now all in spec and tried to fix the airbox fittings for the 4th time. Can anyone offer any ideas on what this could be? I couldn't be unlucky enough that both the old and the new coils had bad leads on the 4th cylinder? I'm grasping at straws here. On the plus side I am very close to being able to rebuild the entire top half of the engine and the carbs while blindfolded.. lol
You should probably try new spark plugs. Some plugs once they have been fouled or wetted are pretty much useless.
Checking plug condition should only be done when under load.
The old fashioned “ plug chop” method is to run the bike till it is warm then get it under load in say 3rd or 4th and then shut off the ignition and pull the clutch.
That way you get a clearer idea of how each plug is firing under load.
Ideally you would either change out just the suspect plug to look at it or roll into your driveway and look at all of them.
The other thing to consider is the TCI / CDI and the wiring to the coils.
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I can lend you a cdi and a set of carbs if you get stuck
I would start by moving the needle clip's back to position 3
Next have you checked the float height's ?
If they're correct (20.5mm i think i read somewhere?) then start the bike and let it warm up to normal operating temp, now adjust the mixture screw's to get it running at the highest/smoothest position ( starting at the standard position), drop the idle speed down back to normal, then go on to next carby and repeat, till they're all good.
Did you say you have a carby sync tool ?
If so sync the carby's, this should help make it run a lot smoother if you haven't done so, now take it out for a test ride to see how it goes
I have replaced the plugs less than 50kms ago while trying to work out the issue. Discovered today that the egghead that had the bike before my massively overfilled the oil. It had almost half a litre in there than it should have. I will be putting it all back together tomorrow and taking it for a ride and if I can't get any love from it I will look at bringing it down to Kiffsta for a second opinion on the missing and any other ideas. Lol.
Ok. So took it for one last ride before I sell it and despite the missfire during idle and the burbbling during deceleration, it now powers smoothly and accelerates fine. Got me stuffed but it is staying now for as long as it runs. Lol
This might sound a little strange.. but.. get yourself some Threebond (Repco have it) and give it a few sprays into each set of carby's thorugh the air filter.. It is used by Subaru to help de-coke the inlet tract and head... it wont hurt it and might help clear out any excessive carbon that might be in there... just make sure you do it outside
There will be a lot of smoke generated..
Following for tips when I pull my carbs out again
Going to adjust the needles for setting three to see if I can even them out abit, but after that it is staying as is for a while. For the carbys deffinately go premium for the access to the workshop and service manuals, and many of the people on here can offer some amazing advice so read up and listen. I really cant thank them enough. Despite my bike still being a difficult thing, the advice and help given has been amazing.