Flat height settings 1996 bandit 250 (GJ77A)

[imthatguy]

Does anyone happy to know what the correct float height is for the later model bandit 250's (GJ77A model), mine does not want to start and I suspect it may be related as Ive tried literally everything else..

[F5 Dave]

That won't affect things enough to make it fail to start, unless perhaps fuel is pouring out the overflow pipes.

Give it a squirt of ether (startyabastard or equivalent), or brake cleaner in a pinch, down the airbox (filter removed). Report back.

Oh yeah, have a rag handy to smother any backfire flames. Just in case.

[andrej168]

Would start with the basics
Check for spark and compression. If you have that, Dave's advice will make bike cough couple of time and maybe start.
How has bike been sitting?

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[imthatguy]

I just realised I wrong flat not float height, sorry about that!

Ok so some background would probably be helpful, this has been a problem bike for about 5 months now and Ive never managed to start it off the starter button ( It WILL bumpstart fairly easily ). Compression is ok, around 120psi over the 4 cylinders, if you squirt some carb clean in the bike will clearly stutter and cough like it wants to start but thats about it.

When I first picked the bike up it had no spark, narrowed that down to a missing resistor in the ignition, and finally the gapping of the crank sensor, now we have consistent (although relatively weak) spark at all times when turning over. All other electrical systems on the bike check out.

As too the carbs, Ive gone over them with a fine tooth comb and cleaned / reset them, fitted new washers etc etc. Float height is a bit hard to set, but as you say, and I assumed, it shouldn't really stop it starting.. All the jets are clean, emulsion tubes clean, no tears in the diaphragms, mixture screws set at 1.5 turns out (though Ive tried anything from 0 - 5 turns out.

Bike had been sitting for about 6 months before I picked it up.

Edit: If you bumpstart the bike it will run, although fairly badly, definitely needs tuning but that would logically come after being able to start it

Edit 2: Have replaced the plugs before anyone suggests that

[Akzle]

vacuum leaks

[F5 Dave]

OKfor giggles, bump start it then put a meter over that battery and see what voltage it is putting out. 13.5-14.7 ok. Above or below =bad.

Check the heat in header pipes when it first starts. Do some pipes get hot and some not?

[imthatguy]

vacuum leaks

Nope, nothing connected past the carbs and near new carb => block rubbers, all hoses replaced

[imthatguy]

OKfor giggles, bump start it then put a meter over that battery and see what voltage it is putting out. 13.5-14.7 ok. Above or below =bad.

Check the heat in header pipes when it first starts. Do some pipes get hot and some not?

Reg / Rect isn't connected at all atm but when connected getting 13.8v

They are all warming at roughly the same temp, also when its running its does idle evenly, its not missing

[Akzle]

Nope, nothing connected past the carbs and near new carb => block rubbers, all hoses replaced

ya so, grasshopper

[FJRider]

Edit: If you bumpstart the bike it will run, although fairly badly, definitely needs tuning but that would logically come after being able to start it

Edit 2: Have replaced the plugs before anyone suggests that

The ability to bumpstart it suggests a bad battery. The starter motor is sucking all the power. Try first putting jumper leads from a good battery power source and try the starter motor again.

Small bikes are easily affected by small things .. so check plug gap. Check all power connections are clean and tight (including battery terminals).

[imthatguy]

ya so, grasshopper

Well Akzle, whereabouts would you suggest I look for a vacuum leak?

[imthatguy]

The ability to bumpstart it suggests a bad battery. The starter motor is sucking all the power. Try first putting jumper leads from a good battery power source and try the starter motor again.

Small bikes are easily affected by small things .. so check plug gap. Check all power connections are clean and tight (including battery terminals).

Have actually run seperate wires for the ignition system to eliminate the loom so its not that, swapped out the bike battery for a big ass car battery today for the lol's but the issue persisted. It sounds keen to start, its intermittently kicking but its never catching for long enough to be self sustaining.

Plug gap was checked when i swapped the plugs..

What effect would tight valves have? I had another bike awhile back that was incredibly hard to start and ran like shit until the valves were opened up a bit, but it did at least start..

[Akzle]

Well Akzle, whereabouts would you suggest I look for a vacuum leak?

everywhere.

i might also suggest (based on "it runs rough" and "[you've] done 'literally' everything else")
that you're running way too lean with no airbox, and that the either: the carbs arent even close to balanced (did you bench set them?); or there's one or more pots not doing what it should.

also, weak spark outside, will probably equal no-spark under compression.

[Akzle]

. It sounds keen to start, its intermittently kicking but its never catching for long enough to be self sustaining.



got choke, nigga?

[Drew]

If you can see spark, it's normally ample. However that is not always the case. If you've buggered around with the pulse generators, the issue may well be there and in the timing.

How have you got it wired up? Could be a shit connection breaking down with the wires you have.

I once experience similar issues with a bike, and it turned out to be broken wires in the loom at the steering head. Fuck did that take some time to find.

If there is good compression, I reckon it's not valve clearance.

[FJRider]

Bike had been sitting for about 6 months before I picked it up.

Edit: If you bumpstart the bike it will run, although fairly badly, definitely needs tuning but that would logically come after being able to start it



Is the fuel fresh ... these days fuel goes "off" quite rapidly .... check also fuel supply and vacuum lines/valves from the tank. This includes the filter inside the tank at the outlet for gunk.

I'm still sure it's power related though. Look and listen for shorts on the HT leads. Run it in the dark and if there is a short ... it will (usually) be obvious.

Were the plugs you put in .. new .. ??


Reg / Rect isn't connected at all atm ...

????? ... Had these been removed before you got possession of the bike ???

[imthatguy]

everywhere.

i might also suggest (based on "it runs rough" and "[you've] done 'literally' everything else")
that you're running way too lean with no airbox, and that the either: the carbs arent even close to balanced (did you bench set them?); or there's one or more pots not doing what it should.

also, weak spark outside, will probably equal no-spark under compression.

Everywhere has indeed been checked haha.

Shouldn't need the airbox to start, I (tried to) set a friends bandit 250 to run with pods last year and even that idled fine.

They are bench balanced, and yeah Im going with none of them doing what they should ;)

Finally I think your possibly right re the spark thing, but I don't really know what else to do about it. Coils, leads, caps are all we'll within tolerance and work fine on another bike. CDI has been replaced as has the crank sensor (and regapped correctly). All new wiring has been run direct from the battery..

Also re your comment below, thats with choke on, without choke it just turns over and occasionally whimpers :laugh:

[imthatguy]

Is the fuel fresh ... these days fuel goes "off" quite rapidly .... check also fuel supply and vacuum lines/valves from the tank. This includes the filter inside the tank at the outlet for gunk.

I'm still sure it's power related though. Look and listen for shorts on the HT leads. Run it in the dark and if there is a short ... it will (usually) be obvious.

Were the plugs you put in .. new .. ??



????? ... Had these been removed before you got possession of the bike ???

Yep just bought new fuel on Tuesday, no gunk anywhere, carbs, tank, fuel lines are as clean as a bleached anus.

Im inclined to agree, but no shorts! Leads and caps are within tolerance.

And yeah haha, though Im tempted to go and buy another new set of the next heat range and try that tbh

Reg/Rect was just disconnected by me because I was trying to reduce the number of variables in play at once

[imthatguy]

If you can see spark, it's normally ample. However that is not always the case. If you've buggered around with the pulse generators, the issue may well be there and in the timing.

How have you got it wired up? Could be a shit connection breaking down with the wires you have.

I once experience similar issues with a bike, and it turned out to be broken wires in the loom at the steering head. Fuck did that take some time to find.

If there is good compression, I reckon it's not valve clearance.

Yeah that what I figured, and it'll jump a good 8mm to get to ground so thats all good.

Ive literally run seperate wiring for all the ignition components so it can't be an issue in the loom, and Ive done a continuity test on my own wiring.

I actually took the rocker cover off last night but as you say theres plenty of wiggle room on those valves, they certainly aren't being held open..

[imthatguy]

Is the fuel fresh ... these days fuel goes "off" quite rapidly .... check also fuel supply and vacuum lines/valves from the tank. This includes the filter inside the tank at the outlet for gunk.

I'm still sure it's power related though. Look and listen for shorts on the HT leads. Run it in the dark and if there is a short ... it will (usually) be obvious.

Were the plugs you put in .. new .. ??



????? ... Had these been removed before you got possession of the bike ???

Interesting note re the fuel going off btw, it seems to depend on the bike. Most of the time the kawasaki will start first pop after sitting for 6 months, but if the bikes already having issue it just adds insult to injury

[Drew]

It's gotta be timing then. At least, that's the next place I'd be looking

[imthatguy]

It's gotta be timing then. At least, that's the next place I'd be looking

How could the ignition timing be out? The crank position sensor can't really move, and it has a inner tooth on the cog itself to ensure it cant be reattached wrong.
You mean the actually valve timing? Ill check it, but I can almost guarantee that rocker cover hasn't been off because, I spent a good 20mins prising it off last night

[Drew]

How could the ignition timing be out? The crank position sensor can't really move, and it has a inner tooth on the cog itself to ensure it cant be reattached wrong.
You mean the actually valve timing? Ill check it, but I can almost guarantee that rocker cover hasn't been off because, I spent a good 20mins prising it off last night
Let's address the carbs first Mibbee. I'm back pedaling now because I have a vague recollection that the pulse generators don't mount to a plate. If they do however, make sure said plate is not mounted backwards.

Float height is easy enough to set. The needle should land right about the time the top of the float is parallel with the bowl mating surface. Check the spring tension in those little fuckers too. Make sure they can support the weight of the float, when you slowly turn the carbs upside down.

[imthatguy]

Let's address the carbs first Mibbee. I'm back pedaling now because I have a vague recollection that the pulse generators don't mount to a plate. If they do however, make sure said plate is not mounted backwards.

Float height is easy enough to set. The needle should land right about the time the top of the float is parallel with the bowl mating surface. Check the spring tension in those little fuckers too. Make sure they can support the weight of the float, when you slowly turn the carbs upside down.

The floats are set as suggested, and have checked the float needles too. The carbs don't actively leak, so Im going to say they are working more or less correctly (given the actual floats rest at the same height).

The CPS does indeed mount to a plate, but there is only one side of the place the actual sensor will attach too (as in fit on), and theres only one way the entire assembly will fit in the bike so theres really no way it could be wrong, that I can see

[F5 Dave]

You say you tried to start it with carb clean. Might not be the right stuff. Try brake clean or better yet starting spray.

The GSXR400 I can't seem to move from my lockup (I'll have to go forage the parts myself at this rate) was a bit of a prick as I rebuilt the spare carbs the owner had as originals seized up. Any rate the donor carbs are the same except they had hidden the vacuum tap hose inlet where the gsxr doesn't. Plugging that helped immediately.

[Drew]

You say you tried to start it with carb clean. Might not be the right stuff. Try brake clean or better yet starting spray.

The GSXR400 I can't seem to move from my lockup (I'll have to go forage the parts myself at this rate) was a bit of a prick as I rebuilt the spare carbs the owner had as originals seized up. Any rate the donor carbs are the same except they had hidden the vacuum tap hose inlet where the gsxr doesn't. Plugging that helped immediately.There's an idea.

[F5 Dave]

Scarily its akzele`s