Fueling grief at speed.

[Yoozy]

As far as I'm concerned, plugs, leads, coils, fuel lines, vacuum lines are all good.
Bike starts on the button, idles nicely, accelerates smoothly, is nice and even at slow speed, roll on roll off of the throttle is good. No problems at all.
I can batter it to about 70/80, and all is good until I roll off throttle and try to pick it up again, it hesitates like theirs a fuel problem, like needing to go on reserve.
The bugger was lovely before I started the rebuild, and the only thing I've done to the carbs is take the TPS off and refit it. I only took the TPS off to put some new bolts in as the old screws were a bit scrotey.
I'm sure I've put it back on exactly where it was before as you can clearly see marks on the mounting bit.
I've been out for a few runs and adjusted the TPS in tiny increments either way with no improvement really.
I've searched here but haven't found anyone else as yet with a similar problem, so what ya reckon chaps ?

[Con Rod]

to adjust the TPS you need to use the tachometre.

Have you set it like that??

Step 1: Turn the ignition to On.
Step 2. Disconnect the TPS plug
Step 3. Reconnect the TPS plug
Step 4: Obsreve the Tacho. It should swing to 4000rpm.

If it swings to 1000rpm or 9000rpm it is set in the wrong position. Adjust in tiny increments till you get 4000rpm

No, as for fueling at speed I found mine would not pull above 180kmph, turn out to be a dirty air filter

[fung]

Try cleaning out the tee piece strainer gauze......better yet,remove it and fit an inline hi flo filter

[Yoozy]

Keep em coming boys and I'll have a fettle tomorrow, looks like its gonna be lashing down all day so I can work through everything at me leisure
It'd carry on past 80 I'm sure, just not had a long enough stretch of road to try it yet. Doing me head in as it was spot on before removing the tps.

[dixonj]

Hi Yoozy I have had the same problem for over a year now tried everything. borrowed a set of carbs of tzx660 bike and now runs great thinking of sending my carbs to these guys http://www.jrs.uk.com/jrs/JRS_Home.html.

[Yoozy]

Ey up, I don't think its my carbs tbh. I've got a spare set and it does exactly the same thing with them on

[dixonj]

When running mine it would be fine until I gave a mitt full and then would encounter a flat spot when rolling on the throttle and sometimes it would go down to one pot as you say like it was going onto reserve I have borrowed a pals carbs last week and since done 200 miles with no problems even after a good blast up the motorway for twenty odd miles. Be interesting to see if you find out the problem.

[Yoozy]

Mad innit Its spot on until rolling off at speed, cough fart pop and then all is good again.




Giz them them good carbs then

[dixonj]

Yep does my fooookin head in

[cobbadiggabuddyblooo]

Not leaking around the inlet monifold rubbers at all?? Sounds possible that its sucking air

[Con Rod]

this should help

http://www.iwt.com.au/mikunicarb.htm

[Yoozy]

Simple thinking Cobba, I like that and it sounds possible
Nice one Con, even a complete bellend can understand them pictures

I had good intentions of sorting this out today, if only I didn't have a raging red wine yed ache

Better get the bacon and eggs out

[Gix]

get an airline on your tank breather..often overlooked and causes a very similar issue. Takes 2 secs to be sure

[cobbadiggabuddyblooo]

I had that issue with an aftermarket screw cap on the tank. Would get 160km out of the tank before it started playing games from full. Until I drilled the breather hole on the cap base larger so it actually could breathe. I would ride and every half hour just loosen the screw cap and release the vacuum inside the tank while at the lights.

[Yoozy]

Been all over it yesterday, checked all plumbing, cleaned all connections, rubbers are good etc and everything as far as I can see it ok. Massive sparks on both plugs. Even put an extra earth on the coils after sanding all the terminals and even took the powder coat off from behind the mount points. Went out and thought I'd cured it, it was better low down but same again at 70-80. Actually got worse then and I had to limp home.
Started rattling things about to check for loose wires and what not. Disconnected the right hand coil [brake side] and it made no difference, the bike still idled, bit rough because I've got the air box off. Reconnected it, no difference and disconnected the left side and bike cut out.
Could the coils be packing in when hot ?
I've not checked the tank breather, it has been resprayed so its a possibility.

Its mad, at speed its like their is an air or fuel issue, but yesterday it seemed more like an electrical fault. Fed up, dying to go for a propper rip on it