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Discussion Starter #1
Hello everyone,

Hope all of you are well. I'm in need of some help regarding the Malossi big bore 182cc kit. I have the 182cc Big bore and the forcemaster 2 installed. The thing is, when the engine is cold it runs very well and the throttle is very responsive, but when the engine heats up to the normal operating temperature then the throttle doesn't seem to work when I turn it only a tiny bit. To easier explain this - When engine is hot and I turn the throttle 2-3 millimetres the engine wants to stall, but after that it revs up quick. I haven't got a clue what might be wrong. I'm using my stock exhaust and stock air filter and using map 1 on the forcemaster 2 (cylinder + forcemaster Malossi). When I first set up the kit I had to fiddle with the Idle screw on the air intake, because it used to stall after it got warm, idle ran decently but when I revved it after it heated up then it used to stall. After I messed with the iddle screw, Idling and revving seemed to be fine, then I went for a ride and noticed that the engine wants to stall as soon as I want to rev it slighty, idle works fine. Another thing I noticed was that the engine oil after the ride smelled really bad of gasoline, maybe its not getting enough air when its hot? Any suggestions to fix would help a lot. Please help me sort this issue. I doubt the iddle screw could have something to do with this, because the forcemaster injection is based off throttle position not the amount of air coming in. I beg someone to help me out with this.
 

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hiya and welcome to the forum :)

so the forcemaster 2 is the ecu which comes wiht the malossi kit, right? and that comes preloaded with maps for the 180cc cylinder? Is that a piggyback system or does it replace the stock ecu/cdi thing? Is there software with it which lets you look at and edit the maps like there is for the PCFC or Power commander V?

disclaimer: I'm just a diy tinkerer and I still have lots to learn and break plenty of stuff so please get 2nd opinions and verify things yourself where you can, but perhaps there's some ideas in here which might be helpful:

> The thing is, when the engine is cold it runs very well and the throttle is very responsive, but when the engine heats up to the normal operating temperature then the throttle doesn't seem to work when I turn it only a tiny bit. To easier explain this - When engine is hot and I turn the throttle 2-3 millimetres the engine wants to stall, but after that it revs up quick. I haven't got a clue what might be wrong.

it could be as simple as that the fuelling is a bit out on the low end for your particular motor so perhaps it's bogging/drowning in fuel a bit (or too lean, hard to tell from here). There's no such thing as a one-size-fits-all map so whatever they've put on the forcemaster ecu is gonna be just their best approximation, just liek the OEM map, and can't account for individual variations in the motor/build.

>I'm using my stock exhaust and stock air filter and using map 1 on the forcemaster 2 (cylinder + forcemaster Malossi). When I first set up the kit I had to fiddle with the Idle screw on the air intake, because it used to stall after it got warm, idle ran decently but when I revved it after it heated up then it used to stall.

ok, so I could be wrong but this is the first 180cc bike I've heard of still using a stock exhaust and the smaller opening in the back could quite easily be the kind of thing to mess with the low-end running. It might be possible to test this by removing the rear silencer. It'd be VERY loud but if you were able to remove it once the motor was warm you could potentially compare how the throttle picks up vs normal. If it's better maybe that's something which warrants further investigation (e.g. make the exhaust hole bigger perhaps). Though I'd have thought it would be more limiting your top end speed and just mean you have loads of torque low down, but hey, test (non-destructively) and find out.

>> because the forcemaster injection is based off throttle position not the amount of air coming in.

as far as I know the regular ecu has the TPS, RPM and Temp and that's pretty much how it decides the fuelling. Normally (on a carb motor) you'd have a choke mechanism which increases fuelling till the motor's warm and then it reduces to your normal "map". Presumably they do the same thing on the R125 but since it's EFI the ecu just edjusts based on the temp sensor.

Whilst my initial thought was it's probably downing from too much fuel at idle, if it runs better at the start (when there's likely more fuel) then runs worse when warm (presumably less fuel)...actually suggests it might be running lean. Either way - should be easy enough to test and see what happens. I would proceed gently - if it's too lean, making it drastically moreso and revving the crap out of it could quickly lead to the end of your piston but adjust a little, test a little and you should be ok.

There's trim screws for adjusting the fuelling on the forcemaster, have you tried adjusting those at all? It would be worth finding out what the adjustment range is on them beforehand so you get an idea of the sort of effect you're likely to have (on the PCFC it's +/-20%) but could be worth turning the low end one down (or up) a little once the motor's warm then rev and see if it's improved the pickup.


> Another thing I noticed was that the engine oil after the ride smelled really bad of gasoline, maybe its not getting enough air when its hot?

how are you establishing this? I've not tried smelling the dipstick after a run but i'd have expected there to be some smell of petrol - there's gonna be a bit of blow-by of fuel, vapours etc and whilst nto saying don't investigate, it's easy to get paranoid about stuff which may be perfectly normal just you don't tend to sitck your head in there to see whether it smells of petrol when it's all working great ;)

I could well be wrong but unless there's more oil than before or it's looking like it's thinning out you'd probably be into some pretty obscure & serious issues and in those situations you'd likely have bigger problems than it sounds like you do. Once it's cooled down again is there still the same amount of oil as before (i.e. it's not using/losing oil)? Does it still stink of petrol an hour or two later? I don't have an answer for this, just trying to think of things to maybe prompt a conclusion.

Hope some of this helps, there's others on here who know way more on the theory and engine building/ecu stuff (I do more trial and error) so maybe they'll chime in with some ideas :)
 

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Discussion Starter #3
I messed with the injection on the ECU, tried to add injection and reduce it, but that same problem is still showing. Could it be that the throttle position sensor is a bit faulty? Idle runs fine even when hot as crap with the cooling radiator fan spinning. but as soon as you hit the throttle a tiny tiny bit the engine wants to stall. You can hear how it REDUCES the RPM less than idle. Idle RPM runs faster than when you turn the throttle a tiny bit. if you blip it to 3-4k rpm you can hear that at the first millisecond the engine wants to stall and after that throttle range it revs up nicely. Another thing I noticed that as soon as the "low throttle stall" tries to happen the screen of the bike dims a bit at that exact moment. Also, if you blip it 2 times in a row the engine stalls sometimes. It's really frustrating. AND when it stalls it make a large grinding noise (not in the cylinder) it sounds like its coming from gear box or the starter, somewhere on that side of the engine. I spoke to a mechanic and he said that it could be that the coil is messing around. I also tried doing the same throttle blip test with the exhaust taken off and same results. So its not an exhaust issue. I tried the same blip test with the air filter taken out - same results. also after the whole engine cylinder swap the high beam stopped working, it was working before the cylinder swap. Another thing I noticed was that the starter really struggles to get the engine started even with the Battery near fully charged, there is like a 2 second delay before it starts spinning the engine and the whole screen dims as well. I think I said everything about the investigation I did. I'm really hoping that someone can help figure it out.
 

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Discussion Starter #4
I gave it some thought and I think that the throttle position sensor is the issue. Because I remember taking my grips off one time and they were glued fairly strong. I cutt some of the glue of the grips using a thing metal piece and then had to force the throttle on the handle a bit to get it off. The throttle free play became a bit more loose after that. Could it be that the sensor isnt picking up that lowesf throttle position sometimes and thats messing with the new ECU? this is just a guess. If some of you think that this could be the issue then please let me know.
 

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hmm, ok I don't know..and could be way off the mark but from what you're saying this does almost sound like an electrical issue. good to see you already tested without exhaust, filter etc.. so I guess it's not those things.

You only changed the cylinder, right, not the cam etc too (i.e. to one without the decompression mechanism) - that would make the starting difficult potentially.

>> AND when it stalls it make a large grinding noise (not in the cylinder) it sounds like its coming from gear box or the starter, somewhere on that side of the engine. I spoke to a mechanic and he said that it could be that the coil is messing around.

this alomost sounds like there's somethign fucky going on wiht the starter mechanism, that could give you the sort of grindy noise you describe but I don't really see how it could be engaging or causing that issue. As far as I know there's no solenoid on the starter like on a car (is there?), it's just a 1-way locking mechanism/gear isn't it? idkl I've not had the box apart on this yet, but that's how it is on the scooters.

>> also after the whole engine cylinder swap the high beam stopped working,

ok wtf? +1 for electrical

I guess the closest/only thing I can think of where mine exhibits any similar symptoms is if i forget to plug the rectifier in (just inside the frame by your left knee) but it sounds like you've been pretty thorough so that's unlikely...

I guess if it all worked before the cylinder swap and it doesn't after then either soemthign got messed up during the swap (e.g. soemthing broke or didn't get put back right), or the new addtions (ecu/wiring) caused the issue. I don't really see how the cylinder itself could cause those issues (though I'm happy to be enlightened if anyone has an answer)...
 

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Discussion Starter #6
I fliddled with the potentiometer screws on the ecu a bit. Increased 0-2000 rpm mapping by 10% more and the 2000-6000 rpm screw by 4% more fuel. Seems to be less jerky now but its still losses a ton of power when hot compared to cold. I believe its the mapping thats messed up. But It's hard to adjust without a dyno. Because I dont know if its too much fuel or not enough. I think I will take the bike to a diagnostics centre to set the fuel map.
 

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hmm ok that sounds promising. So when you say you adjusted the screw by 10% do you mean you moved the screw thru 10% of its available range of motion? or you adjusted the screw thru 50% of it's range of motion to give a 10% overall fuel adjustment.

I looked up the force master here ( https://www.malossistore.co.uk/force-master-2-electr-contr-injection-5514778-P ) and it says the screws do +/-20% so turning the adjustment screw all the way would still only give you 20% adjustment.

I mention this bc in places my PCV is giving over +100% duty cycle adjustment on my map and when I'm A/B testing maps I usually don't really notice any change smaller than 10%, so whilst we don't know what the figures "underneath" are for the baseline fuel curve for the map you have selected, you *may* be able to (or need to) be quite liberal with the adjustment screws.

So say the "map curve" gives you +40%, turning the fuel screw all the way up would still only get you to ~~60% so it seems like they screws are possibly just "trims" rather than gonna give you some crazy adjustments.

When I got my PCV fitted, the dyno tuning session was about £200 - quite expensive but the bike ran great :)

 

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Discussion Starter #8
Hmm.. do do you suggest ditching the malossi formaster ecu? That still doesnt clarify why its running so shit when hot. Do you do fuelling adjustments when the engine is hot or cold? I couldn't find a dynojet ecu for a 2015 r125, just up to 2013. The map that I selected should work as with the screws (potentiometers +20/-20% you only adjust it a tiny bit so it runs better. Either the map is way off of what its supposed to be or the whole ECU is faulty. Or maybe theres some mechanical/electrical issue with the bike thats causing this to happen. I couldnt get my head around it so on tuesday im taking my bike to a repair/ service/ dyno/ diagnostics centre to get it sorted. Because the lambda sensor should adjust the fuel/air ratio on different engine temperatures. Cant find a damn solution myself. The is SUPPOSED to run fine but not perfect with the map im specified to yse selected. Not be extra rich when its warm and super lean when its hot. Doesnt make any sense.
 

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honestly I'm not confident enough in any "diagnosis" at this point to really be suggesting any real course of action, unfortunately.

There's things you've said which suggest it could be an electrical issue (could have been introduced during fitting of the force master perhaps?), though the chances are if all else is as it was it's probably a fuelling issue. Could be a combo of both. I keep talking to people who've done the upgrade and have fuelling or other issues but they switched both the ecu and the cylinder out at once whcih means two sets of variables to deal with rather than one.

Whilst more by luck than judgement, the way I did it with running the PCV for a while before the cylinder upgrade (and having it dyno'd at the time of fitting the PCV) meant that she was *dialled* by the time I did the swap (blew the motor, 100% user error) I was only changing one thing: the cylinder, not then also switching to a new and untested type of fuelling too and possible electrical gremlins. Because of that adjusting the fuelling once I'd got the cylinder on took literally 10 mins to just go on the pc and add 40% fuelling onto my current map, and right away she went from sounding horrible to being perfectly rideable. I did my 600 break in miles on that map with no further modification.

Out of interest re the stuttering/bogging issue when you give it gas when it's warm, I wonder if it would be possible to test whether it's an electrical issue from the forcemaster by temporarily disconnecting the FM once the motor's hot. Idk if that's a particularly great thing to do with the motor running, so maybe stop and restart - I'd like to think that if not powered it would revert to allowing sensor data through rather than cutting it off... but if not the motor will stop/not resume till the FM is plugged back in. If it does keep running though and the FM is off, and it still does the bogging thing, then we can be pretty sure it's not the FM ecu, and if the bogging magically goes away then I guess it's definitely something to do with the FM (i.e. either fuelling or electrical)...either of those answers would be progress.

I don't know if i'd really want to run it long enough to get warm without the extra fuelling, hence suggesting doing it this way.


What your buddy said re the coil could also be a thing - if it was me, depending on my level of frustration by now I'd probably put a fresh spark plug plug, coil etc just to rule stuff out but I realise that's not always possible. But if it ran ok before and only suddenly started doing this since the upgrade then that's a pretty specific/coincidental time for a coil to develop a problem, hmm.

>> Because the lambda sensor should adjust the fuel/air ratio on different engine temperatures. Cant find a damn solution myself. The is SUPPOSED to run fine but not perfect with the map im specified to yse selected. Not be extra rich when its warm and super lean when its hot. Doesnt make any sense.

Ohhh.. I didn't realise there was a lambda probe in the mix - then, no idea how they interact and pretty sure the FM ecu has been around long before so whether it takes the lambda bikes into account, who knows but probably not? That could be doing allsorts of fun things to cause chaos, chikey.... so the FM could be pushing fuel in like crazy and the stock ecu could be correcting it all away. Maybe then you don't need the FM though, wouldn't the lambda just correct to 1.0, presumably it's a narrowband? Might be an idea to disconnect/unplug the lambda and see if that improves anything. Presumably it would revert to a baseline "limp home" map but might stop adjusting things on the fly so the FM can actually do its thing and you can maybe get the fuelling sorted.
 

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So reading this would start from simply going and doing emission test when hot and cold this would explain a loot when cold/hot perhaps there is in fact AFR issue, no need for dyno. Or if you want to go pro and think for future would straight buy wideband lambda with controller ~150e all in and test AFR and do tune up ;) , HOWEVER If bike have lambda then ecu will cut fuel , AGAIN however if you throw out FM and connect only via ecu with bigger cylinder ecu will go nuts and out of map range that will cause fault and limp mode. So coming to conclusion of this lenghty post there are 2 solutions to fix this: find propper bigger injector so ecu thinks that maps vs injection timing vs lambda match and no limp mode, this is quite problematic as finding proper injector is quite hard and more of guessing game you need emission tester/ wideband AFR module, OR just ditch all electronics ECU/FM and go with custom ecu cost is about 150e witch would recommend as this solution is much more versitile .You get this isse when hot as ecu is in closed loop and you get snow ball effect , ECU is trying to go stoich cutting injection timing, where FM is trying extend injection timing to fill in for bigger cylinder then lambda goes up so ecu cuts more injection thinking is to rich and in this moment all goes to hell.
 

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>> ECU is trying to go stoich cutting injection timing, where FM is trying extend injection timing to fill in for bigger cylinder then lambda goes up so ecu cuts more injection thinking is to rich and in this moment all goes to hell.

right - that's sorta what I was getting at but explained better. I'm guessing this is why we don't see much about the later bikes being tuned?

surely disconnecting the lambda would force it to revert to a limp-home map which wouldn't be ideal but at least it would be static (i.e. not constantly being adjusted by the lambda). No doubt you'd get an engine light but at least then you could trim the fuelling to compensate on the FM?

Re bigger injector - As far as I could tell the stock one is 100cc/min, the 180cc (cylinder) is ~40% bigger so potentially you could try a 140cc injector like this one for a tenner: https://www.aliexpress.com/i/32908052238.html?spm=2114.12057483.0.0.65185509POgqIx I have a 160cc one and I feel it's a bit too big.

>> OR just ditch all electronics ECU/FM and go with custom ecu cost is about 150e witch would recommend as this solution is much more versitile

is this the microsquirt like you've got? Do you have to make your own wiring loom from scratch? They always seemed like a good solution but pretty steep learning curve.

out of curiosity for my other motor/rig is there the facility to plug something like the auto-tune module (i.e. wideband plus little box which aims for a given AFR) on that setup? It's SO good on mine I'd like to replicate it but the PCV doesn't have control over ignition timing and we're gonna need that further down the line. Otherwise was gonna try and blend a powerspark into that mix. Does the custom ecu run off primarily off MAP like the big megasquirt or is it TPS+RPM+Temp like R125 stock setup? Presumably there's also stuff for handling boost-related fuelling?
 

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Disconnecting lambda is no go as will revert to limp mode but at big cost of fuel additionally spark advance will be retarded for safety so pointless.

For bigger injector is like playing guessing game so you need to buy good few to test and still you might not hit desired target and get limp mode as all depends if what you chose will fit in normal injection timing map and it wont be out of bounds for all RPM range so VERY dificult at least, as each injector has diferent quantity vs timing vs fuel pressure vs opening times of injector and it's not linear, and you have to keep in mind that fuel pressure has to play here as well so a loot to consider so you end up with generated costs of ~100e and still bee not happy where custom ecu is 150e and all can be done with few tuneups .

normal "Bikes" are tuned at level of ecu to some extent, where this r125 is lawnmover has ecu at level of strimmmer no point even touching it ;) And we do not see later bikes tuned as there is no point, as all goes custom ecu much faster solution and cheaper no need for special tools worth $$$$$ just to flash/read/modify where all can be done much easer with support of wideband and autotune.

No need to make loom from scratch all is there and connected to normal ECU just needs connecting to custom ecu fast and efficient just need to tell/teach custom ecu all sensors (very easy done) .

You can go with microsquirt but for r125 this is BIG overkill , you can defenitely find cheaper solution like rabbit project that will do same.

Yes there is auto tune works very good but for it to work you need to have setup with wideband that is best solution and yes all works.

MAP/TPS+temp like normal car/motorcycle , all do can be set to work of SD but still you need to emulate input from MAP so it's pointless its like giving healty person wheelchair and saying to him you will be using this from now on, when he can walk no problem.
 

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> Disconnecting lambda is no go as will revert to limp mode but at big cost of fuel additionally spark advance will be retarded for safety so pointless.

aah right, that makes sense.


>> or bigger injector is like playing guessing game ... bee not happy where custom ecu is 150e and all can be done with few tuneups .

also makes sense tbh


>> normal "Bikes" .. easer with support of wideband and autotune.

+1 for the gran turismo options. it's great to jsut be able to plug in laptop, beep boop, apply autotune trims or adjust whatever and off we go. Custom ecu would be better still bc adjsutment over timing and whatnot.

>> No need to make loom from scratch all is there and connected to normal ECU just needs connecting to custom ecu fast and efficient just need to tell/teach custom ecu all sensors (very easy done) .

excellent! is there a link/example of this you can point to pls? Is that what you're using? This sounds ideal for my project motor.

>> You can go with microsquirt but for r125 this is BIG overkill , you can defenitely find cheaper solution like rabbit project that will do same.

which are you using? Rabbit?

>>Yes there is auto tune works very good but for it to work you need to have setup with wideband that is best solution and yes all works.

awesome. I've been very impressed with the autotune on mine and one dyno tune is £200 so anythign whcih comes in under that is a win ;)

so presumably that's an auto-tune module you need to buy on top of the ECU? Again, links for any of this would be very helpful, especially if they're vendors you've had stuff from and are happy with. I'm guessing just plugging my dynojet one in won't work? ;) (goes via CAN bus). I have another wideband setup (LSU4.9) but it's a bit temperamental.

>> MAP/TPS+temp like normal car/motorcycle , all do can be set to work of SD but still you need to emulate input from MAP so it's pointless its like giving healty person wheelchair and saying to him you will be using this from now on, when he can walk no problem.

Great re MAP/TPS+temp, perfect. Sorry, what's SD?


In terms of the OP - this sounds like probably the best/only option too...seems like there'd be some messing about with sensors and calibrating but it doesn't sound like the FM/Powercommander route is really gonna work, nor would any of the other "hacks" to get around stuff. Custom ecu would give you total control and if thee's the option of an autotune box then GREAT bc mine (on the PCV) has done a great job so big thumbs up on auto-tune boxes from here. If you have the option of doing the same/similar as what someone else has done already (e.g. Misiozol) then that should somewhat flatten the learning curve towards making it actually work...

Thanks for the answers Misiozol, on the nail every one :)
 

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Autotune is a software feature built in in any of those MS/rabbit (no need to buy a thing) it works with narrowband as well but ONLY with stoich 14.7:1, all works best with wideband connected to custom ecu and with wideband then you can set afr 12.6:1 for power, I'm using MS and can tell you it's HUGE HUMUNGOUS OVERKILL for r125 would not do it again as there is no point to spend ~300-500e when same is for 150e tops and I have seen rabbit in action as well. For that matter there are at least half a dosen other good custom ecu's in same money buy I just can't remember their names :D

SD speed density ;) , and was thinking then about Alpha-N blending thats emulating MAP, was going ahead of my self :D

There are no links you just get schematics cut cables close to ecu and solder cables from new custom ecu no problem wire by wire (about dosen more less) quite simple it's not space shuttle :D. You have to understood custom ecu is all in one self contained setup, like any bike/car oem ecu but much much better and even can be set wirelessly (like mine) via bluetooth. That's ONLY way to go simple and efficient, times of power comander and other junk pigibacks are over as in same money you get much much more.
 

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so something like this?

https://www.tindie.com/products/ecumatt/rabbit-ecu-v12-populated-pcb-with-arduino-sockets/

where do you get the plugs and stuff to make the conversion cable? or do you have to start hacking your loom up to add a custom plug?

more info here by the look of it. I like the look of this approach for my other motor, thought it's kinda daunting as a subject at this point. I'm abotu to start on the build of the motor so I don't have to worry about custom ECUs just yet but will start learning more about it.

"Speeduino" was another arduino-based one I looked at before whcih also looked pretty good, though possibly still overkill? idk.

>> You have to understood custom ecu is all in one self contained setup, like any bike/car oem ecu but much much better and even can be set wirelessly (like mine) via bluetooth. That's ONLY way to go simple and efficient, times of power comander and other junk pigibacks are over as in same money you get much much more.

so you can do stuff like apply autotune trims and adjust ignition timing, or fuellign tables etc from your phone or tablet whilst out riding? that would be kinda mad :)

[edit]
AHA! cables, headers and plugs... I see hwo this fits together somewhat...ok. hmm
 

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Cut and solder, all can be done in matter of half an hour lets count cables on example r125

3xTPS \/ \/
3xMAP /\ common gnd on both
4xStep motor
1xCKPS - common gnd
1xSpark
1xGND
1x12V
1x12V after ignition
2xInjector

So whats the problem few cables :p

>>so you can do stuff like apply autotune trims and adjust ignition timing, or fuellign tables etc from your phone or tablet whilst out riding? that would be kinda mad

It's not mad thats normality, small 7 inch windows tablet + bluetooth mode and off you go all wireless modding on the go :D and if you add holder on stering you see all live data while driving kind of very extended dash :D
 

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Hell yes. Ok tbh that wiring doesn't sound so bad. I built the lighting loom for the trials from scratch so if that's all there is to it I should be good. Tweaking by tablet sounds spot on too :)

>> and if you add holder on stering you see all live data while driving kind of very extended dash

haha busted, I was actually wondering hwo I could see live data, just bc (I wasn't sure it's hitting the top cells properly.)

Thanks for the info! \o/
 

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Discussion Starter #20
I don't know. I took the bike to a diagnostics centre. We shall see what they say. Might end up getting a custom ECU lmao. Who knows. Cant wait for their reply
 
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