Bandit help Part 2.

[instigator]

Hi

(ELECTRICAL PROBLEMS DETAILED IN POST FURTHER DOWN )

Continuing from my last thread...

The bike originally required slipping of the clutch when setting off and would bog down at low revs. At idle and low revs in 1st gear, it would let out a "tssst" release of air every now and then, mostly at a standstill or when the throttle was blipped.

This week in particular, the bike wasn't riding too well. It felt like it wasn't running on all 4 cylinders and was seriously down on power. I used it Wednesday, Thursday and Friday. Throughout these 3 days it got progressively worse - it would eventually stall at traffic lights and would need to be 'over-rev'd' to get anywhere. This slipping of the clutch got worse until Friday, when, in the blizzard, it felt like the engine was ready to blow up. I had to keep the thing on the choke most of the time and on my final trip, it spat a continuous amount of flames out of the exhaust at idle before it died and would not start, even with the choke on/off.

At this point, I turned the fuel tap onto prime for a few seconds and back and it started up and purred nicely for a brief moment before resorting to being down on power and, what feels like the 4th cylinder only kicking in until 4-5k revs. At least I managed to get home okay. I put these problems down to a fuel delivery problem.

This week, the "tssst" noise had ceased. For reasons, I'm not sure but I hadn't touched it.

So, it's off the road for now until I get it running satisfactorily.

I took it to bits today and, after examining the fuel vacuum tube as suggested by others on the previous thread, found it to be securely fastened and free of any splits/leaks. However, referring to the following photo, No.2 was found to be uncovered. No.1 being the vacuum tube connection to the fuel tap.

https://img.photobucket.com/albums/v612/greggreggreg/breathers.jpg

Upon trying to remove the bastard carbs (it is difficult, 1st time round, right?), I opened the airbox and found the air filter to be relatively containment free. However, the mesh between carbs and air filter was splattered with oil from, what I suspect is, cylinder No.2.

https://img.photobucket.com/albums/v612/greggreggreg/airbox.jpg

I am yet to inspect the spark plugs as my tool kit does not contain the correct sized deep socket (can anyone advise on the size (mm) req'd?). I am also yet to do the valve clearances which I'll do once I get feeler gauges through the post.

Any input from the knowledgeable folk? On parts I should examine etc. I have the carbs on my desk which I am intending to disassemble tomorrow.

[NiteMare]

well first off i would have tried the bike again with that vacuum point plugged/capped as that being missing would severely bugger the running and probably require use of the choke to keep it running ....

i've no idea of the plug socket size as i found an old box spanner to suit in my pile of tools...

the "tssst" "could" be a backfire thru the carbs into the airbox , my slabby spits thru the carbs from time to time, i've no idea what causes it..
excessive choke will possibly be the cause of the flames out of the exhaust, unburnt fuel
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it ain't broke...

i ain't fixed it enough

[Kennypa4]

I took it to bits today and, after examining the fuel vacuum tube as suggested by others on the previous thread, found it to be securely fastened and free of any splits/leaks. However, referring to the following photo, No.2 was found to be uncovered. No.1 being the vacuum tube connection to the fuel tap.




Just for your info my vacum tube on my 600 k2 is on where your N0: 2 marked is . As the nitemare said you will need sort the missing vacum plug will not help at all.
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Kenny
RBLS Riders
Scottishbikers Forum

[Ichy]

As snudge said, No.2 is the original fitting point for the fuel vacuum.

https://fiche.ronayers.com/Index.cfm/Module/Main/TypeID/26/Type/Motorcycle/MakeID/2/Make/Suzuki/YearID/39/Year/1998/ModelID/6335/Model/GSF1200S_BANDIT/GroupID/260713/Group/CARBURETOR

The missing vacuum cap is going to be the major cause of all your problems. Ignore the mesh in the filter box, its because the vacuum cap is missing.

I think I used an 18mm box spanner for the plugs, got it from halfords for about £3.
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[BanditsHigh]

The oil on the mesh is from the engine breather on the cam cover.

As mentioned above having that carb sucking air in will completely feck the fueling for that cylinder and it'll be a drag on the other cylinder.

Is that a K&N that's in the piccy and I take it you have a race can fitted ... if so was the bike rejetted, if not then you'll be running lean ... not good.

If you don't get anywhere then gimme a bell and I'll bring over my carbs which have dual K&Ns and have been rejetted ... and because no airbox are piss easy to fit

[instigator]

[timjim]

The spark plugs are 10 mm threads but use a 5/8" spark socket..the number 2 and 3 plugs are a bit of a squeeze,so i invested in a flexi spark plug socket to make it easier..halfords should sell a decent plug socket..make sure you get one with a rubber insert to grip the plug when fitting/removing!!Good luck.Tim

[timjim]

the reason it ran ok on prime is that the fuel tap is then switched over to a gravity feed of the fuel as opposed to the vacuum feed from the carbs.make sure the stubs are blanked off.also make sure that the coils are clean and water tight..my 96 B6 has done nearly 60k in ALL weather conditions and has suffered from coil faults in the past when wet,but it sounds like yours is pointing more to a fuel problem.If its only suffering in cold weather have a look for a thread on SILCOLENE PRO FST use..good gear!!

[BanditsHigh]

In reply to your wanted post (other section) I've posted you two links to cheap silencers on Ebay

[instigator]

Hi

It has been the cold weather which has made the bike suffer more than usual but the decline in the engines power delivery has been gradual. Which would make me think it is the cold weather more than anything else. The missing cap would have always been off. So the symptoms don't match up per se but what has been suggested should hopefully sort it.

Also noticed that the airbox has 6 extra holes that have been drilled into it. I'll duct tape those up I think and if it still doesn't run correctly, pull out the carbs and check what size jets they are running.

[timjim]

the extra holes in the airbox would make me suspect that someone has done a home improvement on the irbox along with a K&N filter..mine has!! I wouldnt say that the stubs have ALWAYS been off,possibly removed during carb balancing or possibly just perished and fallen off??If you have major concerns or worries do a compression test.Its difficult to identify the cause at a quick glance ,but id have a look at the basics first before attempting to take the carbs off!

[BanditsHigh]

Ah, the old airbox mod ... as timjim pointed out this is one of the mods to the bandit airbox which along with rejetting and a race can gives a healthy release of horses ... although usual method is to remove plastic trumpet and cut anther 2" (I think) hole

It's the cheaper method of the two, the other being the airbox getting dumped and replaced with dual K&N's as in my B12s case.

Hope you get her sorted

[instigator]

I put it all back together and put the sealed off the remaining vacuum point with the red cap which I found after disassembling the bike. Started the bike and heard the "tssst" noise and found the red cap had flown off straight away. So one can only assume that it was off from the start. The 'OEM' vacuum cap is secured on with a clamp which was unfortunately missing. So I'll order that tomorrow. Instead, I kept it on with some duct tape and a cable tie.

It idles nicely and blips the throttle fine but is well down on power, still. I did stubby the exhaust but I have a gut feeling that that is not the problem here. I still reckon it's something to do with the fuel delivery. Riding along at 30mph in 3rd and I can yank the throttle open and it won't do anything for a few seconds....or it'll "gurgle". Stupid machine, I'll sort it next weekend I'm sure.

OEM exhaust will be ordered though.

P.S Timjim am sure my filter isn't a K&N - it's a paper type material and has no branding on whatsoever...doesn't mean someone hasn't put one in before.

[BanditsHigh]

I think we both thought it was a K&N due to the colour, aren't standard filters more of a yellowish/creamish colour.

Mind you, the K&N usually has a fine wire mesh over the filter ... I think

Thing is if it was running okay up until now then, apart from the carb rubber bit coming off, I'd be more inclined to look at the silencer ... did it start going tits up when you fitted that?

[timjim]

hi,this is getting intriguing..the oe filters are an orangy gold colour from memory(cant remember as mines had a k and n for so long ,but dont tell the insurance co!!!!)id still say try some silcolene pro fst for a while in the cold weather as mine occasionally has the same symptoms..starts ok from cold,runs well/ok for a while till warm,then starts coughing,spluttering on acceleration..tried fuel additive and appeared to sort it out!!ps..ive got carb heatres fitted as welll

[instigator]

[timjim]

sorry..it did look similar to the kand n!! keep the "race" can on!!lol

[BanditsHigh]

Bastids have changed the colour of standard filters

Keep us updated

All the best ... Barry

P.S. I take it #1 is firing ok, in other words your coil isn't starting to go?

[instigator]

[BanditsHigh]

We all do mate ... I was having serious problems with the clutch on my Mk1 B12, just wouldn't disengage properly ... eventually burnt the clutch out.

Tried everything, heavy duty clutch springs and eventually the heavy duty springs plus a standard one to keep the clutch going.

Eventually worked out why it hadn't been disengaging properly ... the lever pivot hole had ovalised (is that a word) and wasn't properly actuating the reservoir piston

[timjim]

the spark plug sockets are a nightmare..i ended up getting a Snapon 5/8" flexi soket(30 quid!! ),but its ace for getting the no 2 and 3 plugs out!!may be an idea to have a look at the coils..the left hand coil is for no 1 and 4 cylinder and the right for 2 and 3...good luck.

[Gawain]

You dont need to take the plug out to check for spark. Just take the ht lead off, stick any spare plug in and check for spark normally.

[instigator]

[teabag]

My GSX600F used to run rough when it was cold and damp, which I eventually traced to water down those nice deep plug holes. New HT leads with a good tight rubber seal on the plug solved it.
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NS125R = 2 years > GSX600F = 7 years > XR125L = 3.5 years > SV650S........and a Citroen Synergie HDI for the kids.

[NiteMare]