Dyno'd my Capo - it's running VERY rich.

[craig david]

My Capo has always given poor fuel economy (30-35mpg - UK gallons).
I suspected it was running very rich.

I got it dyno'd today at a main Aprilia dealer. It is indeed running very, very rich (the fuel/air mix drops off the chart which only reads above 10 by about 4000rpm - run was done in fourth gear).

The power curve is good (they even got me an extra 6bhp - now 85 bhp at the rear wheel - thanks to a new map). The bike is completely fine in every way except the poor fuel consumption. The Aprilia dealer were unable to solve the problem and the bike is still running really rich.

Any ideas what I can do to sort it or what might be wrong?
I'm thinking a Power Commander might be the way to go.

Any thoughts gratefuly recieved!

Cheers

[Ergo]

Cool info...thanks!

Year?
Mileage?
Mods?
Service performed/not performed?
Which Map?
History? (Always high consumption?)
Plugs? (Type and current condition.)
Air Filter? (Age and condition?)

:micah:

[craig david]

Cool info...thanks!

Year? 2002
Mileage? 9500
Mods? end cans may have been internally modified as they're quite loud
Service performed/not performed? serviced by non-aprilia agent, valve clearances done at 8500 miles
Which Map? previously and old one, now 'the latest' according to the Aprilia place I was at today.
History? (Always high consumption?) In the three months I've had it, yes fuel consumption has always been high
Plugs? (Type and current condition.) the recommended NGK ones - I changed them (plus airfilter) recently - made no difference. obviously the old ones were very black.
Air Filter? (Age and condition?) see above - 500 miles old! Genuine Aprilia item.

:micah:

I'ver seen lots of bikes dyno'd and I've never seen anything like this before - literally off the scale.

[ian-parkes]

Tim iam wondering if your bike has something causing it to stay in a cold start state ie still on choke . Iam not sure how the fuel enrichment system works for cold starting but it is a likely cause other than an air leak somewhere .

The mods on the exhaust etc should if anything make it run leaner .

The dealer didn't sound very helpful who was it ?

if they gave you the latest map then I was right your bike missed the map recall in early 03. that was the latest and only map for our non cat bikes . At least its making the right power now .

[craig david]

Good thoughts Ian.

I just rang the shop (Max Moto in Bury St Edmunds - seemed really good to be honest).

He said he thought about the cold start thing - but checked the temperature senders and they were fine plus there's no sign of this abnormal richnes on a closed throttle so this seems unlikely.

The map is 1105 - correct for a non-catalyst bike apparently.


He said the next thing he'd check is over-high fuel pressure. Anyone any idea how to do that?

[monoi]

If my past experience is anything, solving this rich condition should also increase the BHP...

I can see a trip to the dyno in my near future to check things out on my 05 as I also think its using too much petrol...for £20, its worth it !

[craig david]

Monoi - dynoing a bike is well worth it - it tells you loads about it.

How bad is your fuel consumption?

My light comes on at about 150 miles - I think this should be more like 200 if the bike is running correctly.

[Stu_O]

The map is 1105 - correct for a non-catalyst bike apparently.


He said the next thing he'd check is over-high fuel pressure. Anyone any idea how to do that?
Fuel pressure check is what I was going to suggest - it should be right at 50psi. There may be a factory gauge w/fittings for the Capo that your dealer will use. Another way would be to make a T-fitting to go between the tank and fuel supply line. Use quick connect fittings to hook to the bike and a threaded port in the center to screw in a standard fuel pressure gauge.

Look at the fuel return line where it exits the regulator on the left side of the throttle body. It takes a sharp bend back towards the right side of the bike at that point, and it could well be kinked. If it causes significant flow restriction, it'll raise the fuel pressure more than enough to cause what you're describing. Also don't discount the possibility of a restriction somewhere else in the return line, like at the QD fitting where the large hose joins the skinny one.

Stu

[craig david]

Many thanks Stu - excellent advice!

[CapoExplorer]

I am quite lucky in that Both I and my girlfriends dad both ride capos, so its great for comparison. mines 2004 and his is 2005. He does seem to get a little more to the tank out of his mile for mile, I have put this down to my tendency to try and wheely all of the time :) cant help it.. I get between 175 and 185miles to the tank where as he gets 180 - 200. I have have a max of 200miles.

I do seem to recall him taking this lead since he put on his staintune exhausts.

Does anyone know when the lastest map was released?

[juan lauda]

Keep us posted on how you get on.

[ian-parkes]

Tim like stu says the fuel lines could be the problem . I know you recently replaced the conector to the tank but did you do the other end that the reducer I sent you was for .
If you still have the original plastic conector on the pipe from the tank < the steel bound one > you could have a problem there , that one kinks really easy as the inner is thin plastic tube .

As I said to you before and air leak seems to cause the engine to go really rich , which surprised me untill I saw the effect on Joe's . He had ridden 300 miles on the motorway with the bungs removed from the balance tubes and the plugs were black and sooty .

As for fuel consumption I get about 160 - 170 before the light comes on . 16t sprocket and staintunes . The staintunes make no difference to the fuel used . I don't ride in town at all so 150 if you are in traffic may not be too bad . Its more a case of how much you get in after the light comes on , they probably all vary , mine takes about 17-18 litres. in general .

[craig david]

Good points Ian, thanks.

I haven't replaced the fuel return line connector with that one you sent me - the part you sent was excellent but I was nervous about making a good connection where the fuel lines leaves the injectors - If I get that wrong, it could pump loads of fuel onto the hot engine. I'm not sure I could do a good enough job.

It sounds like the fuel lines are the next thing to check so I might let a professional do it - apparently Taz who are local to me are Aprilia agents now so I might let them have a go.


As for tank range / mpg - I think I generally put in about 20 litres after the light comes on and I'm pretty sure I get 30-34mpg. I'd be happy with anything abive 40. The air / fuel graph on the dyno run shows something is very wrong!

Thanks for all the great advice so far - I'll keep you all posted!

[Northy]

Not sure how some of you guys manage over 175-180 miles to tank ,still not in that league, up to about 38 mpg and yes I think mines is running too rich as well .....so Dyno for it too.

Did notice some thing really werid the other night, smoke from the exhaust but I'd just turned the engine off ! OK could be exhuast gases from the engine but it going for about 3 minutes ...gentle whisp of smoke from one exhaust, so something was burning in the exhaust ??:WTF: ( unburn't petrol? ) .
So I started the bike up, the smoke goes , good ! .....I reckon she was just seeking attention !

Northy

[ian-parkes]

Northy that smoke is probably just steam . Unless you had the engine warmed up and rode fairly hard for a good few miles there would be some moisture in the exhaust this time of the year.

[juan lauda]

There's a chap in Harleston who is a trained Aprilia and Duc engineer who's gone solo. He is well respected and people are quite prepared to take their Italian bikes to him from all over the country. The name is Carl Harrison and his workshop no is 01379 852020. Give him a ring. Harleston is only another 25 or so miles further on from Max Moto. Carl could go thru all the obvious things - pump pressure, restricted fuel lines ect whilst you are there.
I got terrible mileage out of my rsv even tho the air/fuel ratio was in the right ball park ( I'm looking at the Dyno print out as we speak) and following threads on various forums on the subject everybodys fuel consumption differed wildly. There was no discernable average. I nailed a Power Commander on the bike and got a very definite improvement.I know your print out and plug chop indicate over fueling but have you considered modding the airbox and adding a tuneboy to make use of the extra fuel going thru the engine.

[Eastriding2002]

Not sure how some of you guys manage over 175-180 miles to tank ,still not in that league, up to about 38 mpg and yes I think mines is running too rich as well .....so Dyno for it too.


Northy


Northy,

You must be giving it some serious stick all of the time mate, ot it is indeed very fuel rich. I easily manage 180 to the light, sometimes more. I got 49 miles after the light once just to check how far I could go on "reserve", I hasten to add I was running in and had a spare gallon with me!! I was worried at first when the fuel gauge cheeses disappeared at an alarming rate, only when I filled up at 1/4 did I realise they weren't the full tank, but only down to reserve.

I'll be interested to see how my mpg goes when the warm weather arrives and riding is a little less sedate.

Andy T

[Northy]

Northy,

You must be giving it some serious stick all of the time mate, ot it is indeed very fuel rich.

I'll be interested to see how my mpg goes when the warm weather arrives and riding is a little less sedate.

Andy T

That's the problem I'm not (well not all the time :rolleyes: ) I'm convinced its to do with the cold weather as I was getting about 41- 43mpg in warmer times and giving it some. A week battery makes it worse (now using an optimate) and added to this I sure that my 10 mile run to work doesn't help.

I may have a new local aprilia dealer, who already has a dyno and preps lot of race machines......about a month ago he was in negotiations.I need to pay him a visit.

Northy

[monoi]

I get to about 145/150miles before the reserve light comes on.

LAst time, I put in 22.5 litres and it was 170miles.

I only do commuting, so lots of stops and starts. However, I went to Bimingham recently and it was about the same. Then again, I was close to 100mph all the way so who knows.

Only the dyno can tell me....

[Stu_O]

I get to about 145/150miles before the reserve light comes on.

LAst time, I put in 22.5 litres and it was 170miles.

I only do commuting, so lots of stops and starts. However, I went to Bimingham recently and it was about the same. Then again, I was close to 100mph all the way so who knows.

Only the dyno can tell me....I get around 30 mpg at 100 mph and 45mpg if I hold it down to 70. So your correct; the loud handle definitely affects fuel consumption, and that's why you can't compare yours to anyone elses unless you and he ride under the exact same conditions.

Stu

[juan lauda]

Stu, have you installed the tune-boy and if so did it make any discernable difference to mileage , better or worse?

[ian-parkes]

Stu you must be talkin smaler US gallons there.

Also with some people reporting worse fuel economy in the winter its time to look at how how the cold start (choke ) works and if that could be the reason .

[Leanit]

Stu you must be talkin smaler US gallons there.

Also with some people reporting worse fuel economy in the winter its time to look at how how the cold start (choke ) works and if that could be the reason .

Keep in mind that many cooler locales distribute a different formulation of gasoline in winter months, primarily for emissions purposes, I belive. Or maybe for something else. It's always 55-60 degrees F where I live, so I don't know the details.

- Matt

[ian-parkes]

Not heard of that here for petrol . Diesel used to be winter grade to stop waxing but I think its the same year round now .

I guess longer warm up time and short trips play a part.