won't take throttle at 2k revs

[mcyoungy]

My Gen 1 ha developed a problem. It won't take throttle at about 2k revs. Feels like a misfire, but slipping the clutch gets it through and away.


Is this likely to be Exup or TPS?


Goes fine otherwise.

[eddie]

check under seat that what ever you have stored there has not blocked air box

[Falcon 269]

Is this likely to be Exup or TPS?

Possibly.  

When you say 'developed' do you really mean it's only just started to happen or you've only just started to notice it?

I'd start by checking the EXUP - never wasted time on a Gen 1 - and experiment with TPS setting after that. 

Advance the spark slightly by rotating the TPS unit so that the tacho reading bounces between 5 - 10k rpm.  Or try Ivan's engine-running method (see Pat's Site) ... it has the same effect.

Mike

[mcyoungy]

Thanks fellas

I collected the bike on Saturday and it didn't do it.


Rode it for the first time since then today. All good for the first 70 -80 miles then I noticed a couple of times going round a junction it started to feel like it was missing. By the time I'd done 120 miles it was doing it every time I came to a stop or walking pace traffic. Couple of times it cut out altogether.


Just checked the TPS and it was reading 10k with a closed throttle. Adjusted it to 5k now. Is that not ideal?


Checked the Exup and the servo is certainly moving. Will have to get on the floor to check t'other end.


Maybe it's crap or water in the fuel so I've given it a dose of Pro-FST.


Nothing added under the seat and the air intake doesn't have any mice or other creatures nesting in it.


 

[Ghoti]

I had something similar on an old car, but I had just left the choke on a little  . I am sure you are not that stupid and it show much earlier than 70 miles.

[mcyoungy]

It would............... maybe I am!

[Falcon 269]

Just checked the TPS and it was reading 10k with a closed throttle. Adjusted it to 5k now. Is that not ideal?

Yes, by the book but no by experience.   The stock timing takes account of poorer quality fuel worldwide, I reckon.  The bike will take - and appreciate - a bit more advance on 95 octane fuel.  So, bouncing between 5 - 10k is a good setting.

The partial choke call is a good one.  Certainly worth confirming. 

Likewise, the possibility of crap in the fuel system.  If the FST and a fresh tank of fuel doesn't cure it, maybe drain the carb float bowls but be very careful tightening the drain screws as it's easy to overdo it and crack the float bowl.  Those can't be bought separately ...

Another possible cause of a misfire could be plugs or plug leads.  The caps take a firm press to push fully home.  Also, consider unscrewing the plug leads, trimming 1cm off the end and refitting.

I'm sure you'll assume nothing, just because the dealer said he did a long pre-delivery service ...

[mcyoungy]

Mike how did you know what was wrong with it????????????? Are you watching me over the fence?


Balanced the carbs - what a jolly jape that was. They were way out and probably not been touched since leaving the factory.


While I was doing this the vacuum on No.1 cylinder dropped to zero intermittently. So I removed the plug cap and...... it came off in my hand. Cut off the end of the lead, replaced the cap tightly and hey presto! No more misfire, and super smooth.


Exup is all good. Choke too. TPS set to book.


Also cleaned it after the soaking I got yesterday. Looks, sounds and runs a million dollars.


Thanks for the tips.

[Falcon 269]

How did I know?  I didn't ... just shot-gunned ideas at you.  

I hope you trimmed the other plugs leads the same way.

Glad it's sorted.

Mike

PS.  Carb synch way out, huh?  How many cups of coffee got drunk during that intensive dealer pre-delivery, I wonder.  Honestly, they're worse than politicians ...

[mcyoungy]

yeah I know............... can't complain too much though - new tyre, battery... happy now