Triumph Rat Motorcycle Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Bike of the Month Challenge!
1 - 16 of 16 Posts

·
Registered
T595
Joined
·
146 Posts
Discussion Starter · #1 ·
So, we’ve put 10% on the fuel as per @DEcosse ’s kind suggestion (many thanks @RampantParanoia ), which has made a small difference to the low running under load. BUT it’s now a little more tricky to start, as per the video.
On the third start I applied a little throttle which choked it dead. On the 4th start I managed to get the throttle on and it’s always fine after that!
Before the 10% fuel MAP it started a little better and would accept the throttle after the second start. However, it’s never run to the 1500 on a cold start, which I understand it should.
ALSO, it’s still a pig to turn into 90 degree corners/junctions and also to ride at 30mph. It feels like you either need a gear down and ride it on a twitchy throttle above 2500 revs or turn it into junctions with the clutch in. There’s no option for a smooth, well controlled turn in any gear configuration.
Above 2500 it’s a perfect and beautiful monster - I really need this bike set up to ride…what’s wrong with it?
 

·
Registered
T595
Joined
·
146 Posts
Discussion Starter · #3 ·
Is that a cold or hot start?
Are both equally bad? One worse than other?

It still seems lean (both from not taking throttle at start-up and also the hesitation/surging/lurching description at low rpm under load)
Thanks for the reply…the starting behaviour is only when cold. After the bike has taken the throttle for the first time it revs freely.
 

·
Registered
T595
Joined
·
146 Posts
Discussion Starter · #4 ·
It’s still a horrible ride at constant traffic speed and when turning, whether hot or cold.
 

·
Super Moderator
Joined
·
22,136 Posts
For cold start improvement you would modify the 'warmup' table
Increase the A/F delta numbers in the bottom row at the applicable temps - each represents the delta from the A/F value in the main table (and is a negative number)
So below, there is zero delta between 74 to 130 - so it just uses the A/F value per that table
But for -10 to 64 it is subtracting that value from the main table value
e.g if main table is say 14.5, then at 14 deg it would become 13.75 (until it gets warmer and past that temp)
I would go at least +0.5 to those numbers (-10 to say 44)
(the bigger the number the more it subtracts - overall lower A/F is richer => increasing the value in the Warmup table is making it richer
Again, you would have to re-load the map after saving with the changes

760501



It’s still a horrible ride at constant traffic speed and when turning, whether hot or cold.
But that really suggests it is still lean even when warmed up - if it is jerking, lurching at low throttle setting, then you definitely need more fuel and need to add some more.
If changing to lower gear (to get the rpm up a little higher) smooths it out, that will suggest at what rpm and below you will need to further adjust it
 

·
Super Moderator
Joined
·
22,136 Posts
p.s. it dying when you open the throttle (passing more air) also says 'lean' - already not running smooth with throttle closed (which is really partially open) and opening wider creates instant even leaner condition hence the complete stall.

I don't recall - did you balance it while at @RampantParanoia
If not, you really need to get that done too
 

·
Registered
2000 Speed Triple 955i
Joined
·
992 Posts
No we didn't do the throttle bodies, Stuart said he still needs to tweak a few valve shims first.

When we changed the map I checked the sensors quickly and the coolant temp sensor seemed to be reading a sensible value, I also reset the TPS to be on the safe side. The CO was set to 6.3 or 6.1 from memory, I didn't change it.

I tried comparing the map that was on the bike to the one I put on and TuneECU said they're different maps so wouldn't compare, but they're both 9858. I manually compared all the tables and they're identical apart from the +10% fuel I put in. Not sure if that means anything.
 

·
Super Moderator
Joined
·
22,136 Posts
Did you compare the Flow Rate value?
And these are the original injectors for that model, right?
I would honestly get that balancing done - valve shims won't have any impact on that

I wonder how good the Fuel Pressure is? (FPR failures are rare, but leaks in the pump are not - so it could potentially be delivering less than 3 bar)
 

·
Registered
2000 Speed Triple 955i
Joined
·
992 Posts
No I didn't actually. Just looked, it's 383.6 for both. No idea on whether the injectors are original but I'd assume so.

I wasn't sure on whether valve clearances being out of spec, particularly on the intake, would affect the throttle vacuum? Or is it just not significant enough an effect?

I have a fuel pressure gauge so we can hook that up to confirm when we balance the throttle bodies.
 

·
Super Moderator
Joined
·
22,136 Posts
It's a pain to test the Fuel Pressure unless you have a gauge and a Tee set-up
But can certainly proactively take the pump apart and replace the filter and hoses and clamps - while it's apart you could replace the FPR but honestly, failures are pretty rare, so I don't think I would replace it without at least having an affirmed pressure problem (after refurbishing the pump assembly)
 

·
Registered
Joined
·
158 Posts
I may be a bit pedestrian but changing values with no data seems a bit mad. Surely the answer is to get it on a dyno or at least a lambda meter? Unless work has been done on the engine, you shouldnt have to deviate far from standard to get it to run ok.
 

·
Super Moderator
Joined
·
22,136 Posts
but changing values with no data seems a bit mad
It's not exactly 'no' data - the signature as exhibited by the running behaviour is clearly that it is lean in the low rpm zone.
But equally, putting it on a dyno may also be futile if there is an underlying fuel delivery issue (not saying there necessarily IS but at least it should be validated)
And it should also certainly be balanced (and the valve clearances were also mentioned)
You are not wrong however, it should ideally be tuned with a lamda sensor.
But adding fuel should not present any issues to the health of the motor.

Unless work has been done on the engine, you shouldnt have to deviate far from standard to get it to run ok.
This is a going on for 25 year old map, developed when fuels were VERY different (no ethanol for starters)
And there was never any O2 sensor on this model, with a purely manual trim adjustment.
So it's not unusual to me that it is lean now, given the OEM maps already started out that way.
 

·
Registered
Joined
·
158 Posts
Ok, if you say so but it doesn’t seem futile to me to see what and where the problem is, even if it won’t tell the cause.
Do these ecus have a fuel trim? And if so, can’t you just increase it until it runs better (or worse). If modern fuel is the cause, won’t it be lean every where.
 

·
Super Moderator
Joined
·
22,136 Posts
Do these ecus have a fuel trim? And if so, can’t you just increase it until it runs better (or worse).
Yes, but it's an idle trim - but what is difference between tweaking that vs adding more fuel via the table? - actually the difference is the latter gives you more scope to modify a specific range?

If modern fuel is the cause, won’t it be lean every where.
You might expect so, however these are already lean at the bottom end (to meet even the emissions std of the day back then) and is more pronounced at the bottom end.
 

·
Registered
Joined
·
158 Posts
Yes, but it's an idle trim - but what is difference between tweaking that vs adding more fuel via the table? - actually the difference is the latter gives you more scope to modify a specific range?
Don‘t know, I just assumed that it would be a faster turnaround to change one value and get in the ballpark. Then set the values in the table. And, for me, there’s the risk of missing a cell.
 
1 - 16 of 16 Posts
Top