jerky throttle pick up

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PeteL · #1 Post by **PeteL** » Sun Aug 24, 2008 8:58 pm

Just been out for a proper ride on my newly aquired Falco, great engine and corners beautifully. Even when warm, if I blip the throttle it kind of stumbles and then picks up...Is this just because its a big twin or is this abnormal? There is no error code showing and it pulls away and runs sweetly through the range. Its done 23000 miles and has service history to 19000 miles so its coming up for service. I was going to replace the plugs, oil/filter, check the air filter etc. Does it have a throttle position sensor or is it different with fuel injection/throttle bodies as opposed to carbs?
OR have I gotten too used to revving an inline 4?
Cheers
Pete

hornetrider · #2 Post by **hornetrider** » Sun Aug 24, 2008 9:27 pm

I've found mine rattle a bit if I crack her open below 3.5k rpm - but any more than that and its fine. Oh hang on you say blip the throttle - as in in neutral or clutch in? definitely no problems with mine doing that. someone more knowledgeable than I will be able to suggest things I'm sure

PeteL · #3 Post by **PeteL** » Sun Aug 24, 2008 9:33 pm

hi. when I blip it it stumbles slightly. Probably needs some service items, but wondered if this sounded familiar to anyone

HowardQ · #4 Post by **HowardQ** » Sun Aug 24, 2008 10:49 pm

It will feel very different after an IL4, takes a few weeks to get really aclimatised to it. After that IL4s are just boring, the Falco has much more character. It may need a service and a bit of setting up, but mine's never gone too far out of tune. I bought it just over 4 years ago with 6k on the clock and it's now got nearly 25k.
It chugs a bit like a Harley from low revs and you can feel every firing stroke from the big V Twin, it will also rattle and shake a bit, if revs are really low, then just goes out to over 10K.

With standard cans you will get a bit of a flatspot just before 5k, (like many bikes, this is the revs they do the drive by noise tests, so they get backed off). Some race cans and a K & N will cure that as long as it is fully de-restricted and the wire has been snipped on the ECU.
If you want to spend more money, you can go for a Renegade air kit and a Power Commander.

What I like about it is you get two bikes in one, you can keep it below 7k and ride it fairly relaxed but still quick using the torque, or you can scream it out to the top end if you feel that way.
Get used to it and I'm sure you'll get to love it!

D-Rider · #5 Post by **D-Rider** » Mon Aug 25, 2008 1:31 am

PeteL wrote:Just been out for a proper ride on my newly aquired Falco, great engine and corners beautifully. Even when warm, if I blip the throttle it kind of stumbles and then picks up...Is this just because its a big twin or is this abnormal? There is no error code showing and it pulls away and runs sweetly through the range. Its done 23000 miles and has service history to 19000 miles so its coming up for service. I was going to replace the plugs, oil/filter, check the air filter etc. Does it have a throttle position sensor or is it different with fuel injection/throttle bodies as opposed to carbs?
OR have I gotten too used to revving an inline 4?
Cheers
Pete

Hi Pete,

Yes it does have a TPS.
It can be checked out using the diagnostic mode (codes are -1,0,1). With the throttle fully closed it should read 0. I was realigning mine today. It tells you about this in the manual (download from Martin Pol's website if you don't have it already). It does say you can only adjust it if you are fitting a new one ..... not entirely true .....

Another thing to check is that your throttle bodies are well synchronised (another thing I was doing today).
You could also check the other usual things like plugs etc.

Now I was doing these things because I've a rough running problem too but it sounds a bit different to yours. I've a few more things to check on mine but if I can't solve it I'll be posting up about that one very soon. Basically on small throttle openings at 3000 rpm it's as rough as a badger's arse whereas below about 2900rpm and above about 3050 rpm it's as smooth as a baby's bottom ... it's that different inside and outside this band and the rev band is that narrow (it is now a bit narrower than it was before today's fiddling).

PeteL · #6 Post by **PeteL** » Mon Aug 25, 2008 6:30 am

Thanks HowardQ...I need to make the transition from inline 4 mode to V tiwin mode, I know, but after my ride last night, I'm almost there

D-Rider will check the service manual. Not familiar with the diagnostic options, are they in the user manual? Got lots of experience of overhauling carbs so FI is mysterious, new fangled and abstract to me

Thumper · #7 Post by **Thumper** » Tue Aug 26, 2008 8:07 am

All that D-rider has said but pay special attention to the front cylinder spark plugs often neglected as they are a little difficult to get at.
The falco plug caps are a little weak so make sure all the caps are fitted tightly lastly if your bike has standard gearing you may consider fitting a 15t front sprocket as the standard 16t this will make the bike more responsive at low speed.

PeteL · #8 Post by **PeteL** » Mon Oct 13, 2008 5:42 pm

Eventually got a chance to have a 'proper' look over the bike last night and found the cause of the jerky throttle pickup. Air filter almost completely clogged. Will replace but fo time being I removed as much crud as possible and blew it through. Also the chain slack was about 50mm so adjusted it back to spec 25mm. There is no baseplate to the airfilter in the airbox and the appropriate blue/green wire on ECU has been cut and properly sealed with shrinkwrap, so defo derestricted. Also adjusted all suspension adjustments back to factory spec. My ride to work today was amazing, no jerkyness at low speed, quicker pickup, more torquy and better throttle contol in the corners, well please. Suspension is much more forgiving too without being soft (I'm only 65kg).

HowardQ · #9 Post by **HowardQ** » Mon Oct 13, 2008 7:43 pm

Now you can start to really enjoy it !

PeteL · #10 Post by **PeteL** » Mon Oct 13, 2008 7:52 pm

Oh yes...this morning I was in my own sheffield motogp, in a very safe manner...of course

Aladinsaneuk · #11 Post by **Aladinsaneuk** » Mon Oct 13, 2008 8:24 pm

want to post up some pictures of your airbox?? something sounds not quite right there - possible home made evlo kit??

(if so, fun time - grab your vaseline and be ready to party!)

PeteL · #12 Post by **PeteL** » Fri Oct 17, 2008 4:19 pm

Sorry mate, missed your post.
Airbox looks standard gut with no restrictive baseplate ubder the filter....No 8 here...
https://www.apriliayorkshire.co.uk/cata ... =Air%20box
Cheers
Pete

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jerky throttle pick up

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