Talking out loud and hoping someone can direct my wayward brain.

Ulysses - fully warmed-up, riding at c.2000 RPM, 2nd/3rd gear, steady throttle - the bike hesitates/stutters. Not kangarooing but just hesitant/holding back. Bit like a brake with a random high spot but not as severe.

Like the lean stutters on a carb'ed bike.

Open the throttle and it goes very well indeed, so only a problem in town.

Bike is great to ride, this is just "character" although maybe once an hour it will miss completely and do a full "hiccough" if at this throttle/RPM.

Map is my own and is the best the bike has run since I bought it. Stock otherwise including exhaust and AMC is active.

Replaced plugs and leads, no difference.

Wondering if it could be:-

1. Too lean.
2. Too rich.
3. Fuel pump? Pressure tested 1000 miles ago, showed 47PSI (should be 49 but who knows how accurate a $25 gauge is?!)
3A. Fuel pump sock breaking up - blocks at low flow rate, folds out of way in high flow?
4. Throttle issue - sticky butterfly, a blocked something, leaky throttle plate shaft seal?
5. Ignition issue - coil, wrong advance (it's electronic IIRC so No.)? (Added better earths all round already)
6. ?????

Any ideas gratefully received - advice not to go too slowly will be ignored, I'm old!

Thanks in advance.

A

Over 200 views, but no views on the question.

Anybody got any helpful suggestions?

I know fuck all, but put a standard ecm back on it and try it

Hi there,

I had a similar problem on my 1125r with a standard ECU. It just wouldn't tick over steadily and stalled when I tried to set off.
I changed the the throttle position sensor and the other sensor (can't remember what it's called) but those made no difference. Tried another ECU and it fixed it immediately.

_________________
Ride Safe & Stay between the hedgerows.

They can be a bit hesitant/ lumpy at low rev's ( in town)
but as TOPGUMM has said, put standard ecm ( map ) back on .
Then do re set TPS and take it for a long steady ride for ECM to adjust its self .
afterwards check for fault codes and AFV . if abnormal readings then that would indicate a fault somewhere .

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Buell Ulysses XB12X 06/08

Maz had my 08 XT in for poor running, 12 months before I got it.
Next owner fitted a Remus can.
It was virtually unrideable around town.
I would pull the clutch in and coast as far as possible.
The plugs were white, AFV about 90.
My first injected bike, so I assumed the lambda was lying to the ecu making it run lean.
I was told plug colours mean nothing with modern fuel, and probably not the lambda.
So I got an earlier pipe and silencer to return it to standard(ish)
Then I decided it would be easier to change the lambda first.
Started it up with the seat off and there was a puff of smoke.
Had a look and saw a red spot that turned blue when I opened the throttle.
A look with a torch appeared to show a crack in the lambda boss weld.
Saturday morning, MOT booked so put exhaust putty on crack and did the usual two miles there and fifty home at quarter throttle and under 3000 revs.
It ran perfectly until a mile from home when the putty fell off.
I was told it is common for 08 pipes to crack.
Got the pipe off and found it had already been welded halfway round the boss and a new crack halfway round the pipe with two small round holes and the one I’d seen big enough to fit a medium size flat blade screwdriver.
Front pipe had a weld halfway round next to the flange.
There was a new 3” crack, longways halfway down the pipe that hadn’t started leaking yet.
Not worth welding, so I fitted the earlier setup, with a map from Pash.
Works fine, although disappointing for a 1200...
May not be relevant to your problem, and the rear pipe is hard to check, but you never know.

Anyone interested in an 08 black Remus can?

Thanks everyone, rode it to Sywell today and on the way back it was awful - much worse.

Can't believe it is tune related as it has run this tune for months OK. AFV is 99.7 all the time so I never changed it after that.

The previous tune might NOT have been the factory one - who knows, when the bikes are getting older/too many previous owners?

I have the old ECM (with another tune which may/may not be OE) so a quick swap might show a difference although - even if it shows a faulty ECM.

Unlikely to be a faulty ECM though as runs like a top with more throttle/revs.

Will check the Lambda weld - have a new lambda to fit already, as I'm a squirrel....

Update - did a TPS reset, feels better but not fixed, certainly less awful.

Swapped to spare ECM, did TPS reset again, no difference to other ECM.

So my thinking is it is possibly a worn throttle?

Or the TPS Sensor on the way out?

Or bad fuel (not if it goes better at higher revs, surely it would worsen?)

Too many variables here!

if bad fuel , then go for a ride and use it up or drain it ,then refill with good stuff ( ultimate , premium )
whilst doing a TPS reset , ( live data) check the value whilst opening and closing throttle, should be nice and smooth . if not could point to bad / worm TPS sensor .
also on throttle body , there is a small 90 deg vacuum pipe that is or should be blanked off ,little rubber cap , these can become perished and fall off .

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Buell Ulysses XB12X 06/08

Barney, thanks for that - my midnight musing was to check fuel next.

Will drain it out (hopefully any water will come first!) and replenish with fresh (but not too much in case I change the fuel pump - have a new one ready to go). Plus run some Redex through the system.

The Manual says replace drain plug - is that really necessary?

Like I said it feels like the "lean stutters" on a carb'ed bike, so at small flow, maybe the problem is more apparent!

A

Went to Northants V-Twin - Dave reckoned plugs (I've just fitted NGK, replacing NGK) - he said "fit Harley plugs"

Done that - still the same problem.

Not tried fuel yet as wanted to change one thing at a time. Will do that tomorrow when it stops f*ing raining.

May be the coil?

Getting urgent as I am (supposedly) going on holiday on the Uly next week - why do problems appear late?

A

Oh well, thought I'd check fuel pressure.

46psi steady but a bit low, may be the gauge accuracy? Maybe an old pump losing its mojo?

Stupidly, with high pressure still in the line, I couldn’t get the gauge off and in my efforts, I twisted the fitting and then the line to fitting joint started to leak fuel.

The manual clearly says to disconnect the fuel pump, run the engine to drop the pressure before disconnecting the line. I didn't……

Old bike, hardened rubber line, a tweak - then a problem.

Hard lesson to learn, bike not repairable at all until I sort this first.

I called this thread Psychotherapy…..maybe RTFM would be better!

A

we all fuck up , that's how we learn
no shame in it

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Feros Ferio

Have purchased (copy) Oetiker clamps to secure the hose to the fitting - I'll trim a bit off the hose to make a better connection.

I may even buy a new fitting in case the o-ring is the cause of the leak, Amazon has loads of the SAE J2044 fittings for 5/16" steel to 5/16" hose - lots of choice and some show 1/4" if nylon hose, but 5/16" if rubber hose.

Example - https://www.amazon.co.uk/AUTOHAUX-7-89mm-Fuel-Release-Connector/dp/B0BSDBRLLJ/ref=asc_df_B0BSDBRLLJ/?tag=googshopuk-21&linkCode=df0&hvadid=641663915718&hvpos=&hvnetw=g&hvrand=13239865108681551022&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045559&hvtargid=pla-2199775319212&psc=1&mcid=5c56c591c57733389f71382cc09df48b

Or Ebay - https://www.ebay.co.uk/itm/164492914906?mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5339017939&toolid=10049&customid=Cj0KCQjw6PGxBhCVARIsAIumnWYEAqL4vW8srEEOG0hWlRMV9EdzN7ALfEKaFBsVsGEhx36iAoCg6tEaAqSCEALw_wcB&gad_source=1&gclid=Cj0KCQjw6PGxBhCVARIsAIumnWYEAqL4vW8srEEOG0hWlRMV9EdzN7ALfEKaFBsVsGEhx36iAoCg6tEaAqSCEALw_wcB

Of course, none of this will address the original problem!

THEN I will replace the fuel pump - I have a new one from Rev-mo in the USA - that should give 49psi and I can move forward!