
TPS -1
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- mangocrazy
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- Clubman Racer
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Well the gas analyser didn't work, we think because it is designed for a boiler running on light oil it's not calibrated for petrol engines, the CO readings were all over the place and wouldn't level out at all, but the readings were into the thousands not the 3.5% recommend by aprilia performance so back to the drawing board. Spoken to a friend who mots cars and bikes and he says there exhaust gas analyser for emissions should be far more accurate for what I need, so I'll need to make up copper adaptors to attach to the headers.
One thing that's got me wondering, is aprilia performance recommend setting the tb's as front 1.5 turns out and rear 3/4 out but on Gabros guide it says
6) set the bypass brass screws (TB's left side):
-> 51mm ad 54/57mm TB's generally needs different air bypass set-up: so try rear screw to one turn out from closed, front screw 1.5 turns out fronm fully closed for the bigger TB's, 2 turns out rear and 2.5 turns out front for the 51mm tb's.
Anyway that's only a base point. If the bike can't idle with the screws so closed, try openup 'em more. Try to keep the motor un-balanced with the front cylinder stronger than the rear.
Which would it be as I assume I have the 51mm's ??
Even setting the tb's to aprilia performance recommendations seems to have a nice smooth idle and picks up well.
One thing that's got me wondering, is aprilia performance recommend setting the tb's as front 1.5 turns out and rear 3/4 out but on Gabros guide it says
6) set the bypass brass screws (TB's left side):
-> 51mm ad 54/57mm TB's generally needs different air bypass set-up: so try rear screw to one turn out from closed, front screw 1.5 turns out fronm fully closed for the bigger TB's, 2 turns out rear and 2.5 turns out front for the 51mm tb's.
Anyway that's only a base point. If the bike can't idle with the screws so closed, try openup 'em more. Try to keep the motor un-balanced with the front cylinder stronger than the rear.
Which would it be as I assume I have the 51mm's ??
Even setting the tb's to aprilia performance recommendations seems to have a nice smooth idle and picks up well.
I bought one of those Gunsons gas analysers for cars etc and made all the adapters for the headers etc.
I was pretty chuffed that I'd made a good job of it .... until I tried to use it.
Readings were all over the place - a complete waste of time and money.

I was pretty chuffed that I'd made a good job of it .... until I tried to use it.
Readings were all over the place - a complete waste of time and money.

“Scientists investigate that which already is. Engineers create that which has never been.”
-- Albert Einstein
-- Albert Einstein
Not sure why you would want one cylinder to be stronger than the other, the idea is to balance them. I did mine not long ago and got them both steady at the 28cmHg mark. This was about 1.75 and 1.25 turns out on the front and rear respectively.Shetland Woody wrote:Well the gas analyser didn't work, we think because it is designed for a boiler running on light oil it's not calibrated for petrol engines, the CO readings were all over the place and wouldn't level out at all, but the readings were into the thousands not the 3.5% recommend by aprilia performance so back to the drawing board. Spoken to a friend who mots cars and bikes and he says there exhaust gas analyser for emissions should be far more accurate for what I need, so I'll need to make up copper adaptors to attach to the headers.
One thing that's got me wondering, is aprilia performance recommend setting the tb's as front 1.5 turns out and rear 3/4 out but on Gabros guide it says
6) set the bypass brass screws (TB's left side):
-> 51mm ad 54/57mm TB's generally needs different air bypass set-up: so try rear screw to one turn out from closed, front screw 1.5 turns out fronm fully closed for the bigger TB's, 2 turns out rear and 2.5 turns out front for the 51mm tb's.
Anyway that's only a base point. If the bike can't idle with the screws so closed, try openup 'em more. Try to keep the motor un-balanced with the front cylinder stronger than the rear.
Which would it be as I assume I have the 51mm's ??
Even setting the tb's to aprilia performance recommendations seems to have a nice smooth idle and picks up well.
2.5 and 2 on the 51's seems very rich to me as a start point. The idea is to run them as lean as possible without the revs dropping. There will be a point where you make it leaner and the revs drop significantly, wind it out a quarter of a turn from that and then fine tune the actual balance front to rear. I'd start at 2 on each, then winding a quarter of a turn until the revs drop. Then windnitnout a quarter, and then fine tune the balance.
That's what I've always done, anyway!
Highly likely you have 51's unless someone has modified the bike in the past.
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I can half sympathise, luckily I hadn't bought the machine, a friend supplied two gas analysers and both couldn't do the job we wanted. They are designed for domestic heating boilers though so I'm assuming that was the issue, I'm going to give the garage emmisons tester a try and if that fails I'll just have to basicly play with the trim pots and see if things alter, and keep pulling plugs and checking there colour.D-Rider wrote:I bought one of those Gunsons gas analysers for cars etc and made all the adapters for the headers etc.
I was pretty chuffed that I'd made a good job of it .... until I tried to use it.
Readings were all over the place - a complete waste of time and money.
Weirdly though, while we were tweeking the trim pots to see what difference they would make to the engine note, I twisted between 10-2 o'clock and it made no difference whatsoever, only when I slowly turned down to around 5 o'clock on the rear cylinder then you could hear her starting to become affected. But from what I've gathered from reading on the internet you should see a big difference with 1mm inputs. Pretty sure I don't have any vacuum leaks too. Without actually biting the bullet and heading down to the mainland for a tune up, it's bit of a dark art.
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Yea im pretty sure it's the 51's, when I bought her she was in standard trim all over bar the derestrict. I've been told you want a slighter stronger pull on the front as the rear runs hotter and probably could do with a touch more fuel to air for cooling purposes? Thanks for your tb figures, kinda helps confirm what mine should be at, it's difficult to decide when both Gabro and aprilia performance are both very well respected in there knowledge but the two seem to have different figures. I've gone with aprila performance's figures for the base setting and she definitely idles smoother than before, I just need to get a confirmation on what the CO levels are at via a gas analyser then the proof while be in the ride experience "or pudding" so to speak.Dalemac wrote:Not sure why you would want one cylinder to be stronger than the other, the idea is to balance them. I did mine not long ago and got them both steady at the 28cmHg mark. This was about 1.75 and 1.25 turns out on the front and rear respectively.Shetland Woody wrote:Well the gas analyser didn't work, we think because it is designed for a boiler running on light oil it's not calibrated for petrol engines, the CO readings were all over the place and wouldn't level out at all, but the readings were into the thousands not the 3.5% recommend by aprilia performance so back to the drawing board. Spoken to a friend who mots cars and bikes and he says there exhaust gas analyser for emissions should be far more accurate for what I need, so I'll need to make up copper adaptors to attach to the headers.
One thing that's got me wondering, is aprilia performance recommend setting the tb's as front 1.5 turns out and rear 3/4 out but on Gabros guide it says
6) set the bypass brass screws (TB's left side):
-> 51mm ad 54/57mm TB's generally needs different air bypass set-up: so try rear screw to one turn out from closed, front screw 1.5 turns out fronm fully closed for the bigger TB's, 2 turns out rear and 2.5 turns out front for the 51mm tb's.
Anyway that's only a base point. If the bike can't idle with the screws so closed, try openup 'em more. Try to keep the motor un-balanced with the front cylinder stronger than the rear.
Which would it be as I assume I have the 51mm's ??
Even setting the tb's to aprilia performance recommendations seems to have a nice smooth idle and picks up well.
2.5 and 2 on the 51's seems very rich to me as a start point. The idea is to run them as lean as possible without the revs dropping. There will be a point where you make it leaner and the revs drop significantly, wind it out a quarter of a turn from that and then fine tune the actual balance front to rear. I'd start at 2 on each, then winding a quarter of a turn until the revs drop. Then windnitnout a quarter, and then fine tune the balance.
That's what I've always done, anyway!
Highly likely you have 51's unless someone has modified the bike in the past.
I could ask to see where my friends trim pots are set as his bike just out of curiosity, but he's running a forza chip and the fuelling is probably different to what the Gabro chip is at, especially seeing mine is on map 2 for the open airbox.
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I'd been considering getting one after reading this:D-Rider wrote:I bought one of those Gunsons gas analysers for cars etc and made all the adapters for the headers etc.
I was pretty chuffed that I'd made a good job of it .... until I tried to use it.
Readings were all over the place - a complete waste of time and money.
:smt012
http://www.apriliaforum.com/forums/show ... -in-the-US
It seemed fiddly but possible.
Insert humourous comment here
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I am a happy happy man, had the bike for a 60 mile round trip to work and back.
Since setting the tbs to aprilia performance base settings and zeroing the TPS she is idling smooth, can happily come down the revs in a high gear....roll on the power and she's off like a stabbed rat, no horrible noises, just pulls.
Found myself cruising in top.... I thought this must be 5th but nope...sitting happy in 6th cruising away.
No more snatchy throttle response, and after treating her to motul 300v no clutch slip, and that's giving her some too. I even purposely held her in a lower gear with high revs and not even a hint of Clutch slip.
Wish I'd sorted her to run like this years ago. No idea what the co levels are at, might try and find out later but for now I'm happy, just going to pull the plugs now and again and check there colours.
Since setting the tbs to aprilia performance base settings and zeroing the TPS she is idling smooth, can happily come down the revs in a high gear....roll on the power and she's off like a stabbed rat, no horrible noises, just pulls.
Found myself cruising in top.... I thought this must be 5th but nope...sitting happy in 6th cruising away.
No more snatchy throttle response, and after treating her to motul 300v no clutch slip, and that's giving her some too. I even purposely held her in a lower gear with high revs and not even a hint of Clutch slip.
Wish I'd sorted her to run like this years ago. No idea what the co levels are at, might try and find out later but for now I'm happy, just going to pull the plugs now and again and check there colours.
- mangocrazy
- Admin
- Posts: 3944
- Joined: Thu Jul 17, 2008 3:24 pm
- Location: Sheffield, UK
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- Clubman Racer
- Posts: 306
- Joined: Sun Nov 06, 2011 4:29 pm