What am I missing ???

[sharky]

The bike runs fine on the bench....revs clean....no smoke etc...
When I try a test ride theres a huge lack of power/won't rev.
Checked all coil resistances and connections, spark jumps 6mm as per manual,float height set as per manual.
Carbs are jetted with factory pro kit for my bike, middle size main jet used. 2 x K&N filters, 4-2-1 and Supertrap can fitted, new Pingel fuel tap.
And yeah, yeah..lack of power,Yamaha etc etc...hahaha....:(

[EFE 1230]

Tried a spin without the filters??

[Cruisecontrol]

Vacuum hoses?

[sharky]

Weird......Cyl 1, slightly sooty plug....Cyl 4, white deposits and slighlty golden appearance to the metal surrounding the electrode...
As if 3+4 aren't getting enough fuel...
Gonna pull the carbs off again tomoro after work but first I will run the motor for a while and then drain each float bowl individually and measure the amount in each.

[Benz]

What about the airlines for the bowls?? If they're blocked,or kinked, would explain it....

[Docktor]

I had a pingel tap on mine first, worst piece of crap ever mate, Ya cant trust ya needle and seats at the best of times and with the pingel it got no vacuumn shutoff. I know its not ya problem but if ya do use a pingel turn the tap off after every ride. or better yet use a proper tap. and make sure ya vac line u not using now is blocked up and blah blah

[Large]

quote:Originally posted by sharky

The bike runs fine on the bench....revs clean....no smoke etc...
When I try a test ride theres a huge lack of power/won't rev.
Checked all coil resistances and connections, spark jumps 6mm as per manual,float height set as per manual.
Carbs are jetted with factory pro kit for my bike, middle size main jet used. 2 x K&N filters, 4-2-1 and Supertrap can fitted, new Pingel fuel tap.
And yeah, yeah..lack of power,Yamaha etc etc...hahaha....:(


Do you mean it runs fine with no one sitting on it- but when you ride it it's fucked?

What's changed? are you squashing a fuel or airline? Shorting some wire? Got your nuts in front of the airbox inlet?

[sharky]

Yeah, always turn it off doc....bought the first one as it was cheaper than replacing my leaking xjr tap.
After wasting money on a dribble flow hiddly tap I bought another pingel....it will be needed when he new motor is built.
All vac lines are blanked off...haven't got any tubes from the 2 over flow/vents on the carbies...but then never have had.

[evad]

Hey Russ, bummer!! Pull the drain plugs out of the carb bowls and rin them into a container and see how much fuel is coming through. Could be a breather blocked on the tank and you are getting a vac lock or debris blocking the fuel tap?

[_M_]

Had simular when the fuel pump power was disconected.

[TurboKat]

Check for rags in the inlet ports ;)

[sharky]

quote:Check for rags in the inlet ports


Checked ya phone for messages lately ??

[Deano]

what have you changed since it ran fine

when you say it runs shit what is happenin. cough and splutter, drop a cylinder or two, all 4 go out.

wouldnt be surprised if it is a plug issue. have you tried new plugs.

[TurboKat]

quote:Originally posted by sharky


Checked ya phone for messages lately ??

Just did, replied.

[sharky]

Well...velly interesting.....
Drained the float bowls today...into 4 matching containers...all 4 had as near as the same fuel level...however 1+2 had a good strong flow through the 3mm drain tube I used....3+4 dribbled...
Methinks the beer goes to Benz...got the carbs off...I'll work on 'em whilst watching Top Gear...great having a tv in the garage...

[evad]

so whats the go? Wasp nest?

[Deano]

you should also check that the drain is not part blocked.

do the same test with the float bowls off and operate the floats manually. use the same container and measure the amount of fuel that comes out in a certian time and see.

the float bowl drains can get a build up of red looking silt (easiest way to describe it)

you could also have a blocked main jet or something similiar. free reving will only use the pilot and abit of the needle.

also if you put the carbs back on and they still act up then take the filters off and watch the slide. you need to be able to see the position of the slide when the bike starts running shit. this will narrow down the section of the carb that is giving you issues eg- mains, needle, transitions.

while the carbs are out check the diaphrams aswell. could be a torn one or 2 that are not allowing the needle to rise.

what about the plugs, got some new ones. if so try with cleaned carbs and if no good replace plugs and retry.

[Benz]

I had the same shit happen to my slabby, ran good until I loaded it up a bit, then two carbs cut out............wasps nest in the end of one vent hose......

[evad]

lol, yeah I had the bloody wasps build a nest in the fuel line on my kx250..... really did my head in :D:D

[oldskool]

quote:Originally posted by TurboKat

Check for rags in the inlet ports ;)


BAAAAHAAHAHAHAHAHAHAHAHAHAHAHA! FUCKIN GOLD:D

[ninjaboy]

Don't get me started on fucking wasp nests!

[makaveli650]

too much oil on the air filters?, plug gap ? what you do to the motor? bloke i know bored/stroked his 750 4 honda n when the pistons came up they were just clipping the plugs n closing up the gap.

[davio]

quote:Originally posted by TurboKat

Check for rags in the inlet ports ;)
yer get fucked turbo ya cahn:D:D

[MONO]

ahh sharky had a customers bike like this free reved fine in the shop ,take it out on to the road ran like a dog .Checked a/f ratio, meter showed rich bike felt like it was starving . Lead to cap connections ( all tested fine off the bike on a meter)turns out at night under load to caps arked out to cooling fins on cylinder head and cracked cap unnoticeable to the trained eye but sure as hell it lit up like a christmas tree under load . Any way hope its some help btw hows that fuel line battle goin

[sharky]

Thanks for all the ideas and suggestions fellas...this is trying my patience...
Stripped and airlined the carbs today, checked all hoses and lines.
Checked the jet kit was correct (its for the 4 individual pods, I have a pair of 2 outlet pods as fitted to fj1200 legend cars, so barely any difference)
Fired it up...spluttered at around 4'k...took off pods and tried again...slides are vibrating up and down, rev'd it to 5k and held it there for a good 30 secs...no problems.
Now looking at refitting the airbox I made up (with out the tubing and coffee mugs)but using the K&N airbox filter.
I'll get some new HT caps tomoro....coil leads are moulded in but I have a pair of Dyna's....just need the leads....

[EFE 1230]

So who gets the beer???

[sharky]

No beer as yet mate....
Took it out today...after new plugs yet again....1+2 sooty, 3+4 look ok. Starts off reasonable upto 3k but after 30 secs of riding I come to a junction and she won't pull away...feels like its running out of fuel...
So I looked at the only other change...the exhaust....4-2-1 using mandrel bends and stock headers...
Put the nozzle of my heat gun into each pipe in turn (where the headers go)....4,3&2 gave instant 'fuck its hot' from the exit hole...1 was definetely slower to get to that stage.
Before trying each pipe I cooled my hand round a cold VB....purely in the interest of science of course...
Could this be the prob ? Number 1 is backing up and then choking number 2 ?
At the X point is a slight lip about 6mm wide as shown by the white line.....could this be the trouble ?
What do our great metal guru's think of the design ? Should it flow ok ?

Sold the stock collector anyway so now I need to find another quick to test the theory.....or just take a test ride on the downpipes....[}:)][}:)]

http://www.streetfighters.com.au/forum/upload/107290996135296.jpg

[EFE 1230]

I can't see how the pipe would be the problem, it looks the same as the yoshi 4-2-1 on my srad 600 although the "y" section is a little longer into the 1 section ...... and the welding is a little nicer.....

Have you checked the tappets? maybe you got a couple of tight ones?

The battery in good nick? maybe the coils aren't getting a constant current???

Fuck knows!!!

If all else fails ......BUY A SUZUKI!!!

[evad]

I recon using VB is a major problem :D:D
It must be fuel related, when it runs shitty is you open your fuel cap does it run any better? What happens if you put the choke on when it runs crap?
If you look at some of the car Exh manifolds they are much worse than your design and they still work.

[Deano]

dont think that exhaust is the problem.

what have u changed since it last ran fine?

[BANDITROD]

are you sure you are geeting a good flow from that new tank sharky i mean the tap is in the right spot cos if not the fuel will sit at the back of the tank while riding mate ...what you need to do is make sure your tank is full of fuel and then go for a ride i know someone that had the same problem just e few weeks ago ;)

[sharky]

quote:what have u changed since it last ran fine?
Modified the exhaust from 4-2 to 4-2-1, added the factory pro kit and K&N's.
Fuel supply is fine Rod, had 3 gallons on board.
It can't be electrical...or at least I would be suprised seeing that plugs 1+2 are different to 3+4...
I'm going to pull the jet kit out and go back to stock with larger mains...see what happens.
As for the exhaust I'm going to get a thermometer and test each pipe properley...ie how long to reach a certain temp....its weird how #1 doesn't seem to flow as well. Might see if I can modify it a bit to increase the flow.

[sharky]

Slowly sorting out the gremlins...
The exhaust has had the lip removed and welded up. Did actually make a difference...at least with the hotair gun test it did.
The 2 plugs sooty, 2 plugs clean was caused by 3+4 having dodgy HT caps...At least now all the plugs look the same.
I'm thinking its an electrical prob now 'cos it definetely cuts in and out. Next up are the dyna coils and leads.
Just going to do this by a process of elimination.
Fresh fuel...check.
Good flow....check.

[MONO]

got that sorted yet sharky . Have you put it on a gas analizer to get a base line , will it be ready for AFR ???

[sharky]

I've pulled the loom off as it needs tidying anyway and hopefully will find the misfire electrical gremlin while I'm at it.
IT WILL BE AT THE FOOLS RUN [}:)] even if I don't sleep 'til then[V]