[FIXED[ new member: surging issues [FIXED FOR REAL]

[roasty_duck]

i have a co2 tester, one you shove up the exhaust, but i wasn't sure what it should read at? mine was saying 5.02 ~

it had 3 holes in the slides
it came with spare slides with 2 holes and i filled 1 hole in the front slide as suggested by superhawk owners and none of this has made a difference.

i have the £20 pilot tool so i can adjust the pilot but im not sure which way does what? does it allow more or less air or fuel?

bikes at 25k miles

the plugs looked like they have done maybe 1000 miles tops.
plugs are
dpr9eix-9 iridiums

[Squiffythewombat]

Blimey Squiffers where have you been hiding we haven't seen you for ages

Good to see you back though
Chris.

Cheers buddy - nice to see you too

I've been hiding as swamped with work, but now summers coming, i finally have a wee bit of time on my hands and a second bike to repair the main runner so life is good!

Hows you? It's nice to see some old faces around here!

Tony - HOLY MOLY I watched the video and looked through the images, you sir, are a genius! I would love to buy them but having bought an entire second bike the wallets a bit dry now. Pretty sure if you put them on the Facebook Firestorm page they will sell in mili-seconds though!

** end of thread hi-jack**

[roasty_duck]

Took the plugs out, checked plug gaps, gave them a good clean looking near new and went for a ride.

put my carbon exhausts back on, a lot less restrictive it runs much better with them however its still surging.

i had a play with the choke when riding it didn't seem to make much difference so im thinking it was in my head that it made it better.

i took it up to about 140 on a local dragstrip today... pulled the clutch in and revs settled, gave it a little rev and it seemed like it was bogging down the revs didn't want to climb.

made a little video warmed up revs up and down at idle too..



ordered a cbr stick pack, on its way from texas.
set of 4 so will have 2 spare.

Just questioning the balancing, its from the vacuum hose for the petrol tank and the allen bolt next to the front carb boot right? just checking im not balancing the wrong part

[grumpyfrog]

Mine did that all summer. Then it disappeared.
Bloody annoying it was too. I think it's just your time.

[tony.mon]

Co2 tester is no use here, that's just emissions measures.
What you need to measure is the air to fuel ratio, stoichiometric ratio to show off! Ideally around 13 to 13.5 parts air to 1 fuel.
A lambda sensor can derive this from the exhaust gas.
This looks more like an inlet side air leak to me.
Pull the tank, airbox and carbs off and check that the rear Carb is properly pushed into the mounting rubber. It takes all of your weight shoving down on it to seat properly.
While you're there fit the takeoff line to the front cylinder, just under the Carb inlet.
You'll need to cap it off or block it with a small Allen bolt and silicon when not in use.
Yes you use the rear cyl to tank vac line, but you'll need to keep the fuel flowing as well. If you just connect that link to a vac gauge the fuel stops flowing, so use a tee piece, again, block the open end when not connected.
Lastly, check all vac lines for splits and cracked ends allowing small leaks, and make sure the tips is plugged in on the side of the carbs.

[sirch345]

Blimey Squiffers where have you been hiding we haven't seen you for ages

Good to see you back though
Chris.

Cheers buddy - nice to see you too

I've been hiding as swamped with work, but now summers coming, i finally have a wee bit of time on my hands and a second bike to repair the main runner so life is good!

Hows you? It's nice to see some old faces around here!

That's good news work-wise I take it

I'm going on about the same thanks Toby

Chris.

[roasty_duck]

Co2 tester is no use here, that's just emissions measures.
What you need to measure is the air to fuel ratio, stoichiometric ratio to show off! Ideally around 13 to 13.5 parts air to 1 fuel.
A lambda sensor can derive this from the exhaust gas.
This looks more like an inlet side air leak to me.
Pull the tank, airbox and carbs off and check that the rear Carb is properly pushed into the mounting rubber. It takes all of your weight shoving down on it to seat properly.
While you're there fit the takeoff line to the front cylinder, just under the Carb inlet.
You'll need to cap it off or block it with a small Allen bolt and silicon when not in use.
Yes you use the rear cyl to tank vac line, but you'll need to keep the fuel flowing as well. If you just connect that link to a vac gauge the fuel stops flowing, so use a tee piece, again, block the open end when not connected.
Lastly, check all vac lines for splits and cracked ends allowing small leaks, and make sure the tips is plugged in on the side of the carbs.

Ah i did balance them properly then, i have fitted the adapter for balancing to the front and blocked it off.

ive been through loads of carb cleaner trying to find leaks yet i can't seem to find one, maybe im just being blind?

[roasty_duck]

Whilst im here, what other things could cause this...

plugs?
coils?
timing?
clearances?

Or am i purely looking at carb issues.

[VTR Phoenix]

I've just realised I put this in the wrong post.

Have you checked your air hoses and made sure a carb hasn't popped off, seal cracked? Pulling in too much air? Does it only surge when riding or will it surge just revving in neutral? If its just when riding check the TPS.

[roasty_duck]

when i bought the bike it was surging and the front rubber wasn't on properly, theyre now 1000% attached with no leaks and its still doing it.

im going to go through all my hoses today as browsing my spare set ive found a vacuum hose i don't remember plugging into anything when i put the carbs back together.

[VTR Phoenix]

can you post a pic of your hoses plugged in? Maybe there is a hose your missing or wrongly routed. Is your vacuum hose plugged into the fuel petcock?

[Squiffythewombat]

Update as I don't think he's seen this yet.... Vacum pipes deffo not fitted to bottom of carbs - I assume this would make a difference? Does anybody know the correct routing of this as some seem different and some have a T-bar extension?

[VTR Phoenix]

The pipe from the rear carb on the left goes to the petcock to create the vacuum to draw fuel, the T piece would fit to this pipe but that is solely for balancing the carbs. I would just run one pipe from the rear carb to the petcock for now to check. The front carb will either have a nipple or blank screw in place on the right. If it's a nipple then put pipe on and cap it.

[roasty_duck]

i have 2 air cut off valves on carb, front + rear, the rear goes from the shut off valve to the carb near the choke needle, the front does the same but has a T piece on it, with a piece of pipe connected to nothing..

Any ideas?

Not my image but its this pipe.



The rear vacuum hose that connects next to the carb rubber is connected to the fuel tap behind it and not on the nipple underneath where a lot of people put it.

the front have a balancing adapter fitted and blocked off.

[VTR Phoenix]

The front should be blocked off and not have a T piece. The rear sounds like it is hooked up correctly but that is the one that should have the T piece in.

Remove the T piece from the front carb air pipe and then cap the pipe off. Leave the rear pipe as is for now. Take the bike for a spin and see if that has cured it?