Zzr1100 d4, bogging down under load

[dextersaurus]

Hello BCF

It's been a while.

I got a zzr1100 as part of a swap last year, was alright then had issues with electrics. It never ran quite right, always hesitating and a bit smoky due to a few oil leaks.

Anyway, took it off the road and stripped it, replaced the wiring loom, valve cover gasket, spark plug gaskets and various other bits and bobs. Had the carbs off and cleaned them up, set float heights, balanced and sorted out the weird and wonderful mixture screws as they were all over the place.

Now, I can't get it running right.

It idles absolutely spot on, and revs well sitting still, but as soon as I take it out on the road and open it up it hesitates and dies, then goes like jobbies off a shovel, then bogs down again etc etc. Like it's getting no fuel and/or too much air.

I've checked the diaphragms and theyre all fine, slides all move at the same time. I've checked for air leaks, can't find anything. I've checked voltage going to the fuel pump, showing a healthy 12v when running, and I've had the carbs apart again to clean the jets just in case I missed something

No improvement.

My next steps are to replace the plugs and HT leads and if that doesn't work, bypass the fuel pump to see if that's what's causing the issue.

Any other suggestions? At my wit's end - great bike when it's going but getting it going seems to be a major issue

Cheers

[Tracey Suntan-King]

Have you got any trousers on?
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Whether you think you can, or think you can't, you're probably right

[dextersaurus]

[dextersaurus]

I'm getting closer and closer to setting this bike on fire.

This place used to be great for help

[Easy-X]

[RhynoCZ]

Does it have ram air intake? Does the ''enrichment'' system work?
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Bhud]

[DJP]

Blocked fuel tank vent?

Blocked fuel filter?

Internally collapsed fuel line?

I had similar symptoms once from a blocked fuel filter: Sufficient fuel got through to let it idle and give a few seconds of full throttle and then it would run out again. As the fuel flow increased the crap would get sucked up and block the filter.
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Suzuki Bandit 1250
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That's http not https

[dextersaurus]

[mentalboy]

[dextersaurus]

[Fizzer Thou]

It sounds more like there is excessive air getting into the inlet because of the 'O' rings that seal the inlet manifold to the cylinder head.I have experienced this many times now.

One of the easiest ways to test is with the engine running,spray some WD40 around the inlets.When the engine revs change then you know where the air leak is

Not expensive either (joke....).Part number 92055

https://www.fowlersparts.co.uk/parts/3335264/zx1100-d5-1997-candy-amaranth-red-mica-gb/cylinder-head
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Just talk bikes.What else is there?

Always have a 'Plan B'

[mentalboy]

[Grubscrew]

I read your post with interest. I had a D4 with exactly the same issues, never did find out the problem.

I did all the usual bits, fuel cut off relay, pilot screw clean, valve gaps, plugs carbs flippin everything, still never ran correctly , same as yours......it seemed like a fuel/ air issue.......I even purchased a bank of vacuum gauges to try to balance the carbs. bastard bike...sold it on. However, chatting to a chap a few months ago and he’s suggested I should have looked elsewhere, ie the generator area/ stator etc, obviously by which time I sold it, but maybe that’s the place to look. Just a thought.
Frustrating it sure is.
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FJR1300/CBR1000F

[dextersaurus]

[mentalboy]

[Tarmacsurfer]

I run an 1100C, had a similar issue a few years back and it turned out to be a coil shorting under load.

I've since switched out to coil packs from a ZX9R, much tidier (not that you'll be looking under there much) and engine feels somewhat more responsive. Given I was running old leads on OEM coils that's easily explained.
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I'm immortal. Well, so far.

[dextersaurus]

WELL THEN

Had an interesting discovery this week whilst playing about with the bike trying to get it started.

It wouldn't fire, so I took the tank off and as I placed it down I realised the tap was still on reserve.... But no fuel was coming out. It's not a vacuum operated tap, so there's clearly an issue there.

The tap was definitely working before, but it appears to have blocked right up.

I took the tap off altogether and plumbed a line from one of the other nipples on the bottom of the tank (with a filter) and it started right up.

I'm thinking that this bloody fuel tap has been blocked all along and thats been the cause of all of my headaches!

[sickpup]

[dextersaurus]

So I no longer own this bike but did manage to fix if for the new owner. Turns out there was a blockage inside the tank where the fuel goes from the bottom of the tank up to the fuel tap. That was blown out with some compressed air and the fuel started pissing through.

So yeah, a blockage all along! It now runs perfectly and pulls well, powerband in every gear and so on and so forth 😂

[jaffa90]

Full marks to Easy-X then.