Modding my V4 for a right hand only rider

Bad starter?

Bad starter Definitely went through my mind for a while but I just kind of got to thinking that if it was a bad starter then it would fail to start more consistently or all the time but I haven't noticed The starter really changing in the cranking RPM other than when I 1st replaced the battery to the lithium that's in there now it definitely cranks faster than it used too but I'm not Leaning towards a bad starter at all. There is a guy who here on the forum change his starter To a higher power or higher kw rating than the standard one that comes in the 19 v4. I thought about upgrading to that moto corsa starter that he used but I just wasn't convinced enough that the starter was the problem to spend the amount of money that that starter costs

I’d try the upmap 1st, because that’s something you can use anyway and won’t be a waste of money in the long run.

See if that fixes it, then look for fueling issues if that doesn’t resolve it. Have you removed the evap stuff?

actually no i have not removed it, i was told it causes problems like stalling, but i never have that problem. it would not hurt anything for me to remove it and just do test i suppose, thanks for that one.

I did the complete air canister delete and started doing start tests sk well see if that changed anything .. alright I'm pretty convinced it's a mapping problem during startup based on air temp

I got the switch in from mouser .. Reused the black sleeve from another I had purchased incorrectly instead of tearing uo the original brake switch ..


Then solderedheatshrinked the old switches connector to the new switch...after finding the normally closed NC pair of wires ..and used 3m cloth tape to sesl in the ends of the sleeve ..the switch came out just a bit long but nothing major

The switched popped right in since it was made for these rear sets..no issue there


Here's it all went to .... ..I could not find 1 single damned drill that was sharp to make 2 holes for a ziptie to support and keep the wires from moving around at the side of the switch ..I ended screwing up the finish on this bracket. I had to just muscle a dull bit through it ..and here's the shiddy result ..I just stood there and laughed f it....its where it can't be seen anyway..but I know its there a&hhhhhhhhhhhhhhhhhhhh&hhhhhhhhhhhhhhhhhhh


I have 1 more mod to make to the rearsets and this is at least done... its super satisfying being able to track down the correct part for 21.00 bucks and making the part I need for less than 78.00 from the dealer which i would have had to cut up. the switch required no adjustment, the light activates just before the slack ends and it starts to actually apply pressure to the master cylinder. and i misspoke earlier, these particular switches from marquardt are IP67 rated, which is pretty impressive and im guessing its why they expensive

soooooooooo the carbon exhaust cover got super hot and the sections that hold the two halves together actually cooked and the inserts and carbon actually cooked black and disintegrated. LOL... so ill have to replace it with another type, i thought maybe it would be a problem, and now it doesnt make sense to spend 250 plus on another when i can find a good used factory for 45 bucks. but fullsix makes a one piece design.

i thought i was done with the tank vapor problem but far from it,
i opened the tank today after filling up and gettin home, and it sprayed all over the damn place

after riding in the heat, it will not start after sitting for 25 minutes
i did the following test 6 times to establish repeatability.
i completely removed the canister first then

after riding to the gas station to get it nice and toasty i got back home and
as soon as the fan comes on, i shut it down
at 1min 16 sec the tank starts to gurgle bigtime but its not boiling like i thought
only place bubbles can be coming from is from the fuel rail back towards and out the pump pickup
mu theory is that the heat soak is causing the fuel to vaporize in the fuel rail and then pushes back out the pump pickup causing the pressure and gurgling
when there is no air or fuel flow like during riding and the ram air effect.
the vapor pushes all the fuel out of the pump module and regulator..
the vapor line is not big enough to evacuate the vapors when its hot. maybe the charcoal was still causing backpressure

6 times with fuel lid closed
waited 25 minutes and it absolutely would not start
all kinds of gurgling and bubbling.
when i turn the key on i can hear the pump, but its running dry and will not pick up the fuel. no matter how many times i crank it.
on the 25th start attempt while cranking , i had my son open and close the throttle and finally it would starts to sputter and then stumble and crappily start
open the lid and wooooshhhhhhh still its building pressure.

6 times with fuel lid open
restart bike till fans come on then shut it down
with fuel lid open all kinds of gurgling and bubbling.
wait 25 minutes
then start, it will start but runs crappy for a second then clears up and is good to go

i did these 2 tests 6 times each alternating between the two procedures. and every time the lid was closed and let sit for 25 minutes it would vapor lock and not start unless we pumped the throttle then it would slowly come to life

every time i did the test with the lid open, it would start on the first or second try, run a little stumbly then clear up and run fine.
this vapor locking is not something i can do anything about, all of the fuel bits are under the airbox,
so i was at least able to reproduce the problem and i know its a heat soak problem.

every time i did it with the lid open, it would start relatively easily

with the canister deleted the pressure is still there but its alot less.
so the only thing left to do is buy the tuner and richen the lean areas, maybe that extra pulse width ill help get the air out of the lines during starting,
this is crazy. i know there is air in the fuel lines because when i turn the ignition on, looking in the tank i can see bubbles during the prime,
when its not vapor locked, there are no bubbles during the prime and when its vapor locked the pump has a higher pitched sound and a higher rpm....then once it starts to pull fuel i can here the pitch change when the pump gets a load on it,

it makes no sense, with the vapor line open to atmosphere the pressure in the tank should reach 1 atmosphere, but somehow its almost like once the pressure pushes all the fuel out of the pump assembly, its like the pump is kinda stuck between the pressure on top of the fuel and the pressure between the injectors and the pump. theres something strange at play and i cant figure it out,

the only fix i have right now is that the magic number is 20-25 minutes after riding, if im gonna stop for a drink or break, and im gonna be longer than 20 minutes, ill have to pop the fuel door as crazy as it sounds. to avoid vapor locking from the heat soak. unless i figure something else out. a tuner or a retune is not going to stop the vapor lock.
am i the only one this is happening to

i did the same tests early this morning while it was not as hot outside.
first i went for a spirited ride 15 minutes that consisted more of rpm to build heat..
came back same tests
let it sit for 20 minutes , i can hear severe bubbling in the tank, almost like boiling sound.
open the lid wooosshhhh fuel everywhere..
with the lid open i can see the bubbles keep coming up from the bottom of the tank..
try to restart... 25 attempts ..no joy.. held the throttle open with my hip and it slowly started to putt and the sound of the fuel pump again changed pitch when it reprimed.. after i heard that change in pitch, it started immediately ran rough for a second or 2 then cleared up.

went for ride again.
came back same test
open cap wooosshhhhh letf cap open
let sit for 25 minutes
still gurgling like before bubbling up from bottom of the tank
after 25 attempt to restart, first start failed second start attempt it started to chug and and sputter then cleared up and came to life again.

so this is 100 percent a vapor lock situation. does anyone know if this fuel system has a check valve in it. or should the regulator be preventing the backflow of fuel from the vaporizing in the lines. something has to be malfunctioning here.

or maybe the neutral or start map is way to lean, or maybe its a mixture of two problems. .. even if the map is superlean, this will not fix the vaporlocking problem and i should not having to leave the cap open to prevent vaporlock for the next start.

any input, guesses or hypothesis are super welcome,

only thing i can think of is to add more heatshield between the tank and underseat area where the rear headers are really close to the tank, and remove the airbox to see what fuel delivery lines or fuel rails i can add heat shield to to try to alleviate the heat soak of the fuel lines and rails after shutdown , although im not sure much can be done for heatsoak of parts

does anyone have pictures of the underside of the airbox or fuel delivery for the v4 i can take a gander at. before i take mine apart not knowing how its setup under there.

this may be a problem that may fix itself, well have to see , i completely forgot that winter and summer blends of fuel have differing RVPS thus differing boiling points and the fuel just may be boiling as well as vaporizing in the lines.
fuel manufacturers change blends for winter and summer. during winter up to 10% butane is added to raise the RVP making the fuel more volatile and able to burn easier which is required in cold weather. it can boil as low as 95deg F
summer blend is brought down to 2is% butane to be less volatile because of the high temps. and it could resist boil as high 395deg F
this could explain the ease with which the fuel could be boiling and vapor locking.
although im in texas, so i dont know how they would actually need to change the blend since we dont get all that cold
this all still does change the fact that this is a heat issue.
march-april the time frame that refineries start switching to summer blend. gas stations have until june 1st to switch to summer blend. only way to know is check the RVP.. or ask the station manager, some place dont switch summer to winter blend.
im just tossing another SWAG out there.

I can't understand why your bike is having this issue. It sounds to me like your vent line is non-functional; either blocked, kinked, or crushed. Mine was pinched between the frame and the electronics bay which caused the tank to pressurise and fuel to escape past the fuel cap.

i dont understand it either boss , i checked the vent line by using a smoke tester , i put smoke through the connector at the canister and i get full flow on the vent line from the canister connection up to the tank vent line. i even went as far as putting the fairings on and adding extensions at the bottom of the fairing and put smoke through there to see if maybe the installation of the belly fairings was maybe kinking the hoses somehow.. and still got good flow up into the tank and the to the drain area, the first thing i did before wasting time doing ant testing was to check the vent line

i will check the vent line again, just cuz im gettin smoke through there doesnt mean its not kinked and or restricted. i checked but its possible i missed it. but this till does not address the vapor lock..

Did you take the check ball and the valve out of the breather assembly in your fuel cap?

Anecdotally, I don’t think guys who run after market fuel caps have the heat related vapor problems.

There’s another breather check ball in the tail of the tank. I wouldn’t think offhand that’s it’s a source of trouble. It’s a bit trickier to inspect since you have to drain the tank or at least prop it up so the tail end is up.

The check ball in the cap was removed..as well as the checkball in the canister..but canister is deleted right now...please shed more light on the checkball in back of the tank...but I will try an aftermarket gas cap.im willing to try anything at this point

I was toying with the notion of stripping the paint off of my tank and giving it a brushed look. I got as far as stripping all of the components off, fuel pump, the tail breather etc. It was winter and I was bored.

It’s held in by a c-clip. Once you remove the clip you can pull the top of it out with pliers. It may help to let a little oil soak around the edges. You can see what the exploded assembly looks like in the parts manual. There’s a tube it connects to which runs up to the front of the tank. I presume to the vent line.

There’s also either an overflow or vent tube which is connected to the holes on the right side under the cap. If you’ve ever had the cap off you’ll know what I mean.

If you do decide to get an aftermarket cap, on @craig bush ’s recommendation, I went with a Lightech one. It’s wider than most of the ones on the market and can fit one of the Ripper gas nozzles which makes filling the bike from a gas can a breeze. If you go that route, make sure you get the right one for a Panigale V4. From the 1199 to the V4 the gas cap layout and bolt posistions are the same. Prior to the 1199 they are different.

i see the parts list on my parts book.. very interesting, i wonder what its function is...maybe this is whats malfunctioning in some way.. a piece of debris , when i took the tank out the first time, it had aluminum chips from the machining process, maybe there is a piece stuck in there. and its stuck open or closed hell i dont know, ill be taking the tank out anyway, ive gotten good a pulling the fuel out and removing the tank even with 1 damn hand at this point.
i think there are two lines for the venting system in the tank.. 1 goes from the hole under the right side of the cap, its going down towards the check ball you speak of...and then i think another line goes from there to the left side of the tanks exit vent port. im gonna buy an articulated inspection camera to get a good look in there i want to know how its plumbed.. i might be able to see the lines in the tank when i pull the pump module ,

i actually have a carbon gas cap that was a gift, but i didnt want to use it cuz the finish on the carbon was kinda shiddy, i will try that one first. but i doubt that the gas cap is the problem... there so much vapor from the boiling that its overwhelming the vent line, but i still gotta recheck if maybe its kinked, i checked it a while back but im gonna check again

thank a shitload for pointing that out.. and thanks for the heads up on the cap

No worries. I think the tail breather has to do with fuel sloshing forward under braking, so the tank can maintain a vent, but that's a guess.

Please post pics if you get an inspection camera in there. I'm curious as to how all the tubes are routed.

I had some vapor lock issues when I still had the EVAP and stock exhaust. Once I removed the EVAP, it cured the vapor lock, but I would get fuel dripping under hard braking from the vent/overflow line. I don't know which since they were plumbed together with a Y fitting. I eventually just routed it to a catch can. I think, and I'm not too sure since I never tested it, only observed it once, with the OEM fuel cap the catch can would accumulate some fuel. Some of the contents were water from when I washed the bike but it had a strong fuel smell. Since going to the Lightech cap, the catch can stays dry, even when I checked it after a track day. I only pass this on as an anecdotal observation, because again, I never really tested it.

ill get pics up for sure, always willing to pass on info.. and thanks for the info as well. it blows my mind that seemingly everyone elses problem went away when they deleted the evap. which is what i have done now as well. i have no catch can right now, its just the vent line and the drain line V'd together and going to the drain on the belly pan.
were supposed to be getting rain the next couple days, im gonna check the vent line for kinks, remove the tank. and pull the check valve and look for debris, get a camera in there to see whats up. if no change, ill change the gas cap out, then test again. if its still vaporlocking, the only thing i have left is to pull the airbox and add some DEI heat shielding between the airbox and engine cylinders, add DEI heat shield to the airbox and add DEI heat sleeve to the fuel distribution manifolds. i just dont know what else to do at this point.

i will be getting a woolich wideband tuner setup, but tuning is not going to do anything for vapor lock..

I'm doubting the heat is the issue, otherwise all V4s would be suffering with it. I blow air from the exit port any time I've removed the tank. I've found installing the tank can kink or push the hose into a bad spot and prevent flow (on the 1199 anyway)

My thoughts too. Everybody would having problem..not just me. thanks disco.. I will make absolutely sure the line is not restricted before i go chasing nything else

ok guys, the articulated borescope inspection cam came in, and this thing is cool and worth its weight in gold imho..LOL
so heres 3 vids. showing what i found and a vid of the piping for bpsfv4 and some of my theories as to whats going on.. yours re welcome as well



bear with me on this one, my theory on this vid is wrong of where the pressure is coming from..in vid 3 i think i got it right as far as where the pressure is coming from and whats causing the fuel spray with alot fuel in the tank and pressure buildup.




in this vid i think i got it right.


another think i plan on doing since i can see the fuel pump assembly now, is run the fuel down sufficiently and then get the cam down towards the assembly and see if i can see where the bubbles are coming from, i just realized this could be something as bad a a cracked plastic housing , faulty and or leaking fuel regulator