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DB2SR - winter project turns into lockdown project
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hindsight



Joined: 13 Feb 2010
Posts: 66
Location: Central Scotland

PostPosted: Thu Apr 30, 2020 8:21 am    Post subject: Reply with quote

Thanks for all the encouragement guys, appreciate it.

DB1 860 wrote:
Wow Impressive, So Mike when You increased the bore to 944cc who's pistons and barrels did you use?


I used ST2 barrels/pistons, with the water cooling galleries in the barrels opened up to convert them to an oil jacket. This increases the volume of oil in the barrels, and should increase the ability to transfer heat (I think!).

Here's the ST2 barrels before the changes were made, marked out with red ink:



In the below pic - the top pair of barrels are ST2, with blue and red markings of the changes that were midway through being made, and the bottom pair are the original DB2/900ss units.



And finally - the access to the water cooling galleries (which were drilled out) was neatly welded up (not by me though, I was very pleased with the tidy job)



Using the ST2 barrels is a nice way of doing it, because it should leave plenty of material on the cylinder wall, if I should choose to get them further bored to a larger capacity, and the additional oil cooling available to them should allow that (it also means that I've got the original 904c barrels/pistons, should anything ever go wrong..). The disadvantage of course is that the pistons aren't particularly high-compression - but if I could easily replace the pistons in the future, if that became a priority.

2bims wrote:
Could you not get the settings from a Ducati ST2....which is 944cc and magneti Marelli fuel injected ecu?


Particularly given what I just said above, this is a great idea that I hadn't thought of. A proper tune would need a dyno and an AFR meter (or indeed to build that into the ECU), but the ST2 fuel map might well be a reasonable base position for comparison with what it's doing at the moment.


I've also done a little diagnosis on that odd air temperature sensor reading that I mentioned. Given my current configuration, 21C appears to be the value that the software will default to if there is an open circuit. I've also proven to myself that the ECU is working fine (it can be tested by disconnecting the ECU from the bike and simulating a connected temperature sensor then viewing the readings on the laptop) - so it would seem that I've probably got a loom issue on the bike or the sensor itself (I suspect the sensor to be good though..).

While I was writing this - I've also just had notification that the PCB fabricator has finished their work (*very* impressed at how quickly they work), so the new PCB should be on its way to me from China shortly.

But - whilst researching the proposed O2 sensor last night, I also now realise I've made an error in that part of the circuit, so I can't use an O2 sensor on this version of the PCB - darn. No matter though, plenty of other stuff to get on with!


Steve - On the forum side of things. I agree with you - I prefer these persistent forums, and very rarely go onto FB, except when I'm forced to. I realise that with FB being the more "accessible" option there is a smaller audience here than previous, but if there is sufficient interest, we could modernise it, possibly updating it to the latest version/features. That's entirely possible with the agreement/assistance of whoever does the admin and/or the owner of the domainname. Just putting that out there for discussion..

M.
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2bims



Joined: 03 Apr 2010
Posts: 6833

PostPosted: Thu Apr 30, 2020 12:28 pm    Post subject: Reply with quote

Updates or ease of loading pictures I'm fine with....but computers are like electrics to me....I use them...but prey they dont go wrong coz I wouldn't know how to fix...Maybe "Admin" aka Katy could though...who set up the forum and runs it...domain name etc

FB went a bit more "pants" recently...sure...you can upload 80 images in 5 mins....BUT...recently they've scrunched down the image sizes so they are a bit pants also...if you put up a word document...its illegible now on FB....due to file size being shrunk down so far......me likes old Skool anyhow.....and "large groups" meeting isn't allowed anymore so happy with the small band on here
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hindsight



Joined: 13 Feb 2010
Posts: 66
Location: Central Scotland

PostPosted: Thu Apr 30, 2020 1:04 pm    Post subject: Reply with quote

2bims wrote:
Updates or ease of loading pictures I'm fine with....but computers are like electrics to me....I use them...but prey they dont go wrong coz I wouldn't know how to fix...Maybe "Admin" aka Katy could though...who set up the forum and runs it...domain name etc


Can you send me contact details for Katy - I might be able to help out.

M.
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brian



Joined: 22 Aug 2011
Posts: 3484
Location: Australia

PostPosted: Thu Apr 30, 2020 1:52 pm    Post subject: Reply with quote

Just send a PM to (user name) Admin
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Current motorcycles - '99 Bimota DB4 #104, '96 Bimota SB6 #1165, Ď94 Bimota DB2 J #652, '99 Bimota DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, Ď94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, Ď61 BSA A10 650
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DB1 860



Joined: 23 Mar 2014
Posts: 134
Location: Sydney

PostPosted: Thu Apr 30, 2020 11:19 pm    Post subject: Reply with quote

:



Thanks for that Mike, My mechanic had mentioned using ST2 barrels as well with pistal or wossiner pistons.
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hindsight



Joined: 13 Feb 2010
Posts: 66
Location: Central Scotland

PostPosted: Fri May 08, 2020 7:50 pm    Post subject: Reply with quote

The PCB for version 2.0 arrived today from the fabricator (in China) - I'm very impressed how quickly these guys work.

Once I soldered on the various connectors and components, the result is a far more robust (and smaller) assembly than the prototype. Testing will get started at some point over the weekend, first on the bench to ensure that everything is working (or not!), then on the bike (hopefully).



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glened



Joined: 15 Aug 2013
Posts: 118
Location: Lancashire

PostPosted: Wed May 13, 2020 7:37 am    Post subject: Reply with quote

Hi Mike,

Intrigued and impressed with your DIYEFI solution. I have got a DB10 which on a good day runs ok not great just ok, however on a bad day she is a bitch. The ECU is an Athena, and as I understand it there was never an update to the map and it is starting to get more troublesome. Last year I was at Steves aka 2Bims trying to resolve some of the issues by swapping his lambda sensor for mine, when I was knocked of the bike. Bike ran like a pig from new, the dealer I bought the bike from is a personal friend of mine and had to fit a new ECU before they could get it running from new! However they could not the fuelling right as it was running very lean, as a fix to this the fitted a pair of "Fat Ducks" into the system to fool the lambda into richening the fuel mix. I have spoken to a number of people that have been recommended to me just get comments ranging from a flat no because the bike is so unique to the one that really gets me going "you couldn't afford to pay me enough" to write the map. So in essence I am curious as this may prove to my salvation. Do you propose to piggy back this unit with your original ECU or is it a complete replacement?

Regards Glen
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hindsight



Joined: 13 Feb 2010
Posts: 66
Location: Central Scotland

PostPosted: Wed May 13, 2020 8:53 am    Post subject: Reply with quote

Hi Glen - whilst doing some background reading, I just stumbled across your other thread from last year - sounds like a nasty spill, and I know that will have hurt badly: well done for coming through it, and still wanting to rebuild the DB.

The DB2SR ECU that I'm working on is a complete plug-and-play replacement for the original - the bike runs without the original ECU having to be connected. Reading through your history, I suspect that its likely that you've got an unseen fault somewhere (perhaps multiple faults, and potentially in the tuning map and/or software, rather than just component failure), but you can't get access to the ECU to diagnose it (or have it tuned properly).

I'd be interested in discussing further.. drop me an email - my email address is visible in the photo of the ECU, above. I'd be particularly interested if you happened to have had an electronic copy of the DB10 wiring diagram.

Mike
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welshlamb



Joined: 09 Mar 2011
Posts: 404
Location: South Wales , Nr. Abergavenny

PostPosted: Wed May 13, 2020 2:17 pm    Post subject: Slight deviation Reply with quote

Regarding using the ST2 barrels. Did you just swap the water inlet on the barrels for the oil inlets on the original air cooled DB2 barrels. Iím intrigued. I have some immaculate ss900ie barrels but cant use on my rebuild because of the lack of any external oil feed. Will probably need a new Nikasil job on my originals.
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hindsight



Joined: 13 Feb 2010
Posts: 66
Location: Central Scotland

PostPosted: Wed May 13, 2020 3:13 pm    Post subject: Re: Slight deviation Reply with quote

welshlamb wrote:
Did you just swap the water inlet on the barrels for the oil inlets on the original air cooled DB2 barrels


Yes - exactly




Quote:
I have some immaculate ss900ie barrels but cant use on my rebuild because of the lack of any external oil feed


The 900ssie didn't even have blanking plates over those ports, did it? does it still have a boss that could be machined?, or are they finned over? Either way, it's probably possible by an experienced machinist. Also - the oil drain on the 900ssie must be internal to the barrels as well (rather than external via that port and hoses), so that could be another route to look into - whether the existing cases could be modified to match the barrels.

M.
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hindsight



Joined: 13 Feb 2010
Posts: 66
Location: Central Scotland

PostPosted: Fri May 22, 2020 4:37 pm    Post subject: Reply with quote

It's been an interesting few weeks..


2bims wrote:

Could you not get the settings from a Ducati ST2....which is 944cc and magneti Marelli fuel injected ecu?


I recently managed to source an accurate map for a ST2 (thanks BB, if you read this!), so in due course I'll plug that into the ECU, and that will become my base position. But while looking at the figures it helped confirm something else that I'd suspected, but didn't know for sure.

The DB2SR runs Weber IW-042 (red) fuel injectors, rated at 200cc/min. The ST2 (and 888/900SSie/750SSie) runs Weber IW-031 (green) injectors, at 270cc/min.

If I take the fuel map for the ST2 and scale the injector duration up to compensate for the reduced flow on the Bimota, then it's clear that the injectors quickly run out of time within an engine cycle, particularly at large throttle openings and high revs.

I suspect this could well have been a constraint for the engine, even before I took it up to 944cc. Glad that I figured that out on paper before starting to more fully explore the tuning, there was nothing else for it, but to install some greens.. At least it'll reduce the maths required to translate the fuel map.


Reds and Greens


Greens installed

I've also made a bit of progress on the lambda sensor for fine-tuning the fuelling in due course. The lambda controller itself is an inline unit, to which the sensor plugs in. I've arranged the ECU such that it presents the O2 sensor connections on the ECU diagnostic plug that is installed on the DB2 loom (because the new ECU has both USB and Bluetooth, there is no real need for a dedicated diagnostic connector, so may as well do something useful with it!).


Diagnostic connector on loom - repurposed


Wideband O2 controller

This makes it much easier to connect the sensor, which is also picks up a +12v connection by an inline connection to the fuel pump connector, that way I didn't need to splice it into the loom either. Probably overkill, given that I'm only going to run with the lambda sensor whilst tuning it, but it's nice to do it right.

Separately, I had a bung welded onto the horizontal downpipe to accommodate the sensor, I was fortunate to have a local welder recommended that was still operating out of his workshop (Scotland remains in lockdown at this time). I was also fortunate to be able to position it out of the way, behind the crankcase so it oughtn't be too noticeable. If it bothers me in the future, I'll get another set of downpipes. The alignment of the bung could have been better in hindsight, but I think it's good enough.





Lastly, the next revision of ECU PCB is now on its' way to me, having been made in China. The one on it at the moment was a good first step, but it depended on an expensive specialist microcontroller, and I was keen to develop the design further so that the ECU software could run natively on a generic Arduino microcontroller: it also incorporates a number of other minor improvements and fixes over the previous version.
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brian



Joined: 22 Aug 2011
Posts: 3484
Location: Australia

PostPosted: Fri May 22, 2020 10:53 pm    Post subject: Reply with quote

Good progress mate. I do find this interesting but to be honest it does my head in Shocked. I do nuts, bolts, carbs, bearings, gears, heavy tools etc.... maths and electronics make my head hurt and fuel injection is in the same realms of electricity to me.... oh donít get me started on sparkies, theyíre a strange breed 😂. Keep up the good work 👍
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Current motorcycles - '99 Bimota DB4 #104, '96 Bimota SB6 #1165, Ď94 Bimota DB2 J #652, '99 Bimota DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, Ď94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, Ď61 BSA A10 650
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hindsight



Joined: 13 Feb 2010
Posts: 66
Location: Central Scotland

PostPosted: Sat May 23, 2020 8:36 am    Post subject: Reply with quote

Thanks Brian, although I do ok with nuts, bolts and bearings.. carbs have always eluded me and I struggle with them: the way my head is wired, I find them, well, analogue and imprecise - (which I fully admit is a nonsense view - someone with the level of experience that I clearly don't possess can set up a carb with the right needle/jet)

With EFI - I like the way I can calculate precisely the amount of fuel that I want to deliver in a spreadsheet, and use that to set up the ECU. But then... I have a long background in IT, and I realise that also makes me member of a particularly peculiar breed also.. Very Happy
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brian



Joined: 22 Aug 2011
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Location: Australia

PostPosted: Sat May 23, 2020 9:50 am    Post subject: Reply with quote

hindsight wrote:
Thanks Brian, although I do ok with nuts, bolts and bearings.. carbs have always eluded me and I struggle with them: the way my head is wired, I find them, well, analogue and imprecise - (which I fully admit is a nonsense view - someone with the level of experience that I clearly don't possess can set up a carb with the right needle/jet)

With EFI - I like the way I can calculate precisely the amount of fuel that I want to deliver in a spreadsheet, and use that to set up the ECU. But then... I have a long background in IT, and I realise that also makes me member of a particularly peculiar breed also.. Very Happy


I guess it comes down to what you know or what your willing to learn. I know nothing about EFI or electronics and donít really have the brain power or patients to learn. My mechanical brain needs to be able to SEE how something works, so understanding carburettors isnít too complicated, getting the fuckers to run right can be another matter altogether, mainly flatslides.

I must admit though.... the only fuel injected bike that Iíve ever owned (and still own) has never caused me any grief whatsoever.... just start and ride, every time. I canít say that about the other 11 bikes that are in my shed Rolling Eyes Embarassed
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glened



Joined: 15 Aug 2013
Posts: 118
Location: Lancashire

PostPosted: Thu May 28, 2020 10:44 pm    Post subject: Reply with quote

I enjoy this thread, as you know Mike I have a personal interest in watching what you are doing. The lamba sensor you are using for diagnostic purposes are you fitting just the one to the rear cylinder? or planning to run both? I like the information on the injector and the volume of fuel it will pass at a set level of pressure. Never had to think about it before, but it makes absolute sense. Could you alter the pump pressure? and how many variants of injectors do they use. Very interesting, please keep up the good and interesting work.

Glen
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