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Throttle hesitancy.

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Stevex View Drop Down
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    Posted: 20 Sep 2021 at 14:00
Gen 1 Tuono; owned for about 8 years, oem air filter, modded collector, FR200 chip, Giannelli end can. It's always run superbly and had the O2 levels checked on one of Griffs travelling workshops a few years back. Nearly 2 years ago I re shimmed the heads.
So, the last couple of outings I've noticed some low rev hesitation about 50% of the time, but didn't take much notice of it. A few days ago I was in mid range rpm and it appeared to miss a beat, as though the ignition had been cut for a milli second. It's never done that before and there's been no repeat.
Today I took her out and the low rev hesitation is still there, but on a couple of occasions where I opened her up higher into the rev range the engine appeared to stagnate, I just didn't feel the normal kick in the pants you usually get. Again, it wasn't all the time, the next straight I went down a gear and opening it up and she was back to normal, good acceleration.
Do these symptoms indicate the need to get the pump out and replace/clean the sock/fuel filter?.
I've never had it out but it appears the PO has, as there is some sealant around the pump mating surface.
People say I don't know Jack Sh1t; but I do, he lives next door.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowman Quote  Post ReplyReply Direct Link To This Post Posted: 20 Sep 2021 at 14:43
Vacuum pipes on throttle bodies would be my first check, never had it myself but have read about it ?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Spoonz Quote  Post ReplyReply Direct Link To This Post Posted: 20 Sep 2021 at 16:32
Fuel or ignition related possibly. Maybe fuel filter or something as silly a loose batt leads. Process of elimination really. 

If it were a gen2 vac pipes would be on the list but unlikely for a gen1 for that big a miss at varied revs. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wigginsjp Quote  Post ReplyReply Direct Link To This Post Posted: 20 Sep 2021 at 18:19
I’d definitely pop the pump out and have a look yes. 

Can be sure the teabag filter will have gummy substance on it and cleaning it out can only help. Whilst you’re there check the hoses etc for leaks 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 20 Sep 2021 at 19:10
Thanks all for the info.
Can the tea bag be cleaned or should it be replaced?
Are they available as a separate part?
Any recommendations for an after market filter or best to stick with
Oem?
People say I don't know Jack Sh1t; but I do, he lives next door.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ajaycad Quote  Post ReplyReply Direct Link To This Post Posted: 20 Sep 2021 at 20:23
I had almost the same identical problem on my Gen 2. Last winter I gave it a full service which included changing the canister fuel filter. This means removing the pump assembly. I didn't change the tea bag filter at the time. When putting the pump back in, I used Honda sealant, and more than was really required. I then started getting similar symptoms as to what your having only worse. I removed the pump assembly to find that the  tea bag filter was covered in black gum from the Honda sealant, so the engine was effectively being starved of fuel.
I replaced the pump and tea bag filter as an assembly (genuine aprilia new old stock) used the recommended Loctite sealant more sparingly this time, and it cured the problem. I do very occasionally get a very slight misfire, as if the ignition is cut for a millisecond, but I popped in to see Griff a month ago as I was in the area, and he reckons its a tuning issue.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2021 at 13:27
I see Griff has the fuel filter and pump gasket; what clamps have you used when replacing the filter?
Just removed the pump; I've read about a 'tea bag' / strainer but can't see anything obvious. 
Is it under the black plastic housing that's mounted to the base flange?
Thanks in advance.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wigginsjp Quote  Post ReplyReply Direct Link To This Post Posted: 21 Sep 2021 at 14:28
Originally posted by Stevex Stevex wrote:

I see Griff has the fuel filter and pump gasket; what clamps have you used when replacing the filter?
Just removed the pump; I've read about a 'tea bag' / strainer but can't see anything obvious. 
Is it under the black plastic housing that's mounted to the base flange?
Thanks in advance.

Yes Steve. 

Unscrew the black plastic piece and it’s under there. 
You can replace if you wish but I’ve found fresh fuel, a tooth brush will suffice 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2021 at 11:28
Stripped the pump and found very little contamination, once the petrol evaporated it just brushed away like dust.




Found this, but I don't think it's a problem. I take it the wires go straight through, so as long as it's not leaking it's OK?


Once I get the new filter I'll cut the old one open to check it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanG Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2021 at 13:44
Is it just me or does that potting look very suspect?

Classic failure point right there by all accounts


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2021 at 14:00
Originally posted by IanG IanG wrote:

Is it just me or does that potting look very suspect?

Classic failure point right there by all accounts



Definitely cracked Ian, but it doesn't go too deep and this is just a bung so the wires can exit the tank, no? There's still a lot of uncompromised material in there, but I have thought about putting a layer of aircraft fuel tank sealant on it for belt and braces. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanG Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2021 at 17:08
Well,yes and no.  The potting seals the soldered eyelets from any fuel ingress and potential corrosion resulting,and that's a known failure point even when the potting looks to be ok.

Given you're having issues already I'd be carefully digging in there while considering ordering a new short harness.

At least that short part of the loom is still available although not cheap.

There was a lengthy debate on the other forum a while back considering the best way round this issue and iirc the recommended potting compound was very expensive if you don't have any to hand.

Even if you do I'd be wary of just filling the cracks without digging down onto the connectors to check on their condition,but then I'm ultra cautious about things that could potentially involve electricity and petrol carried just above a hot exhaust pipe even if the risks are very,very low.

If you do have some decent potting compound how about just replacing the joined speaker wires with heavier duty cable instead?  
I'm sure I've read the joined oe spaghetti is right on the edge of current carrying capacity when new and heavy duty pump use could benefit from heavier guage .

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2021 at 18:45
So theres a joint in there, not just straight through wire?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanG Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2021 at 19:43
I believe so,different models different number of wires and methods of joining.

I think someone on here (Spoonz maybe?) posted up a fractured joint and I think that was a soldered eyelet?   Just found other models Capo Nord at least that have this type 



Tbh I'm not sure what connection it'll be but I'm quietly confident there will be an internal join



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Spoonz Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 2021 at 20:51
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 2021 at 09:49
Hmm, that defied logic...why would they?
You're right Ian, expensive to replace, £92.
I'll dig out to the bottom of the cracks and do a continuity and resistance check on those wires.
If all is ok, I'll cap the top off with sealant. 
I guess this fault would stop the bike dead, so hopefully I've caught the breakdown of that block before it's got to the joint.
Spoonz, what did you use to re build up that block?
Thanks for the pics.
People say I don't know Jack Sh1t; but I do, he lives next door.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Spoonz Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 2021 at 19:05
Originally posted by Stevex Stevex wrote:

Spoonz, what did you use to re build up that block?
Thanks for the pics.

3 bond sealant but only because it was to hand. Anything that holds the wiring fairly firmly in place and seals it up should do the job. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 2021 at 10:20
Gasket and filter arrived from Griffs place in a day Clap
Just waiting for new Oetiker clamps to arrive now.
Re sealed the top of the wire block, resistance and continuity all good.
People say I don't know Jack Sh1t; but I do, he lives next door.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stevex Quote  Post ReplyReply Direct Link To This Post Posted: 25 Sep 2021 at 14:11
Replaced the filter and put the pump assembly back together again.
Use Oetiker clamps and made a set of forming pliers out of an old pair of mole grips, worked brilliantly.
I was a bit worried that everything looked a bit clean and fuelling might not be the problem...until I opened up the old filter.


The loose bits are from the plastic outer I cut into, but the element looks horrible and I'm hoping this is the cause.
I'm not sure how long that filter has been fitted, but the PO has removed the pump before so I'm guessing about 10 years-ish if he replaced it or 17 years if he didn't.
Giving the sealant time to cure then I'll stick some fuel in it (if I can find any!) and take it for a run.
People say I don't know Jack Sh1t; but I do, he lives next door.
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