Throttle lag

**MSTRS:Me** · 28th November 2007, 10:25

Has anyone experienced the problem of opening up the throttle, only for nothing to happen for a sec or two, then WHAM! Full acceleration. Happened over and over for about 5 kms. Finally, held clutch in and 'taught it a lesson'. Problem disappeared.
No 'events' were logged on the computer and no warning lights showed on the dash.
Possible cause(s) may be dirty fuel filter, malfunctioning fuel pressure vacuum unit.
Mechanic has not come across this before. He has adjusted the throttle position sensor, cleaned the air filter and fitted new plugs.
It would be nice to have a definitive cause though.

**Crisis management** · 28th November 2007, 10:46

Has the warranty expired?

**MSTRS:Me** · 28th November 2007, 10:48

99 srad....long gone warranty

**98tls** · 28th November 2007, 18:55

Water in the gas?No idea really,if its carbed maybe its flooding?

**riffer** · 28th November 2007, 20:21

Check the jet needles. It sounds like you've got something stuck there and when the diaphragms are pulling in the vacuum but the diaphragms or needles aren't moving properly.

Actually, you know, a split in a diaphragm could give this problem.

I've had a similar problem on my RF, tracked it down to the throttle grip being a bit loose - I was winding the throttle on, and the throttle was actually spinning slowly in the grip. A little weird until I worked it out.

**MSTRS:Me** · 29th November 2007, 08:11

Um, it's fuel injected. Perhaps I should have been more specific, but thought the use of 'computer' and 'fuel pressure sensor' would be a clue?
My thought was water in the fuel as well, but that should have shown up in the computer as an 'event' in the injectors.

**Crisis management** · 29th November 2007, 08:22

All right, I'll try and be serious this time....

Throttle position sensor was my first thought but if it cleared up with "good thrash" remedy and has not re-occurred then maybe not. (water in the fuel maybe)?
The problem with electronics is the lack of consistency unless there is a total failure, intermittent faults caused by dry joints can be related to heat or dampness which makes diagnosis hard.
I would suggest drain the fuel system and replace with clean fuel, check all hoses for leaks (under pressure with the motor running) and give everything a good clean. Cleaning may make no difference to anything but gives you a good chance to have a close look at all the components for wear / breakage.

Failing this, keep riding and note any reoccurences........really helpful eh?

**MSTRS:Me** · 29th November 2007, 09:09

Originally Posted by Crisis management

All right, I'll try and be serious this time....

Throttle position sensor was my first thought but if it cleared up with "good thrash" remedy and has not re-occurred then maybe not. (water in the fuel maybe)?
The problem with electronics is the lack of consistency unless there is a total failure, intermittent faults caused by dry joints can be related to heat or dampness which makes diagnosis hard.
I would suggest drain the fuel system and replace with clean fuel, check all hoses for leaks (under pressure with the motor running) and give everything a good clean. Cleaning may make no difference to anything but gives you a good chance to have a close look at all the components for wear / breakage.

Failing this, keep riding and note any reoccurences........really helpful eh?

Yep to all that. Have dis- and re-connected all wiring plugs, and have a new fuel filter on order. When that arrives, the tank and pump will get cleaned out as well.

**imdying** · 29th November 2007, 10:10

TPS is a (admittedly) sealed wiper pot, it could get dirty and do this... or perhaps water in the fuel. Pump some out, have a look

**Mom** · 29th November 2007, 16:44

Originally Posted by MSTRS

Has anyone experienced the problem of opening up the throttle, only for nothing to happen for a sec or two, then WHAM! Full acceleration. Happened over and over for about 5 kms. Finally, held clutch in and 'taught it a lesson'. Problem disappeared.

Yep, long time ago, carb slides used to get stuck and then let go with "gay" abandon, not the problem here, I go contaminated fuel?

Originally Posted by Crisis management

All right, I'll try and be serious this time....
......really helpful eh?

Totally helpful dude.......LOL

Originally Posted by cowpoos

I am sorry I dissed you earlier, you young and vital speed demon you!

I should think so and all!