K75S Vacuum Leak and New Clunking noise from transmission

[Jester]

Hello everyone, been a lurker on here for a while probably should have made an account and said hi before I ran into a problem and had to post here but alas here we are. I'm 24 Years old, bought my K75S as my first bike 2 years ago at 80000 miles and since then I've put on 2500 more and besides a stuck starter relay from a bad battery that I mended with a rubber mallet... and a new battery, I haven't had any issues. I'm just mechanically savvy enough to get into trouble and it appears to be what I've done here, probably wouldn't attempt a spline lube or opening the engine up but just about everything else Ill give the old college try.

Recently I had the brilliant idea to put the bike in quite a few pieces to replace the radiator fan as I noticed the bike had started to overheat on the parking lot that is I95 through Virginia. While I had the bike apart I had made the decision to do a few other things at the same time, I decided she deserved some new paint and new parts so I had the bike painted yellow close-ish to the 1994 Dakar yellow by a local paint shop. I changed the air filter, fuel filter, coolant, replaced my ripped/torn crank case bleeder hose and the fuel return line to the tank, my definitely warped front brake rotors and lastly my fuel injectors.

After reassembling the bike to a running state I kicked her on and she didn't wanna start at half choke from cold, which isn't that unusual for my bike so I kicked it to max and cranked it and it started right up, so I did what anybody does I revved the bike a bit and she sputtered so I revved it fully and it died. Bike would still rev and it got better when it warmed up but it was a noticeable lag on the throttle and it definitely didn't seem happy to rev. At this point, rather stupidly I reassembled the entire motorcycle because I am a fool. I think my logic was its probably just the injectors and I can get to those without the bike being completely apart.


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Pretty happy with the look though.   

At this point I started trouble shooting stuff found it to be running lean using the starter button test. I figured I had a vacuum leak. So I checked with some qd electric cleaner and somehow found nothing, still don't know how. Eventually I decided to replace the fuel injector O rings as they just didn't look the same size as the old ones when I compared them (I'm probably tweaking). After this I was some how no longer getting the rev increase while holding the starter, but the bike still was stalling when cold and still had a noticible lag when giving it heavy throttle, it was also still lacking power, but it was at least ridable once warm, albeit with a bunch of lag and a lot less power and the silent unnerving voice in my ear whispering that I'm breaking the bike by riding right now and I'm going to kill my baby. 

Injectors in Question were the Upgraded ones from Euromotolectrics - https://www.euromotoelectrics.com/product-p/finj523upgrade.htm

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After carefully reinstalling all the injectors  again in an effort to fix the lag the bike had the same problem but after going to an autozone on the bike I bought some starter fluid and this time I found a vacuum leak around I THINK the middle intake manifold. Part number 1 on this page
https://www.realoem.com/bmw/enUS/showparts?id=0572-USA-01-1990-K569-BMW-K_75_S_0563,0572_&diagId=11_1776

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The Culprit, I hope

I'm posting for one because I just cant tell if its cracked I know usually you have to remove it for these parts to tell but also I cant tell if Im losing my mind and it somehow still is the fuel injectors and the spray is just being slurped up by it as it goes by, I try spraying away from it or just on the injectors but they're close and anything near the middle gives the same effect so I really think it is the manifold but Im just so paranoid about tearing the entire bike apart again. I've tried re re installing the fuel rail and injectors again to see if I could get a difference to no avail same problem same leak I think... I'm hoping I'm not crazy and it is just the Intake but would love some verification from other brickers.

Secondly, and this is I really hope related, at idle when I am not holding my clutch I am getting a strange clunking noise from the transmission area, This is brand new, I am only noticing at idle and I am really really hoping its just some gear lash that is being amplified by the poor idle due to the air leak. I used a screw driver and my teeth to try to pin point the noise but I was getting it anywhere around the transmission / shaft drive, but it certainly wasnt coming from the alternator or engine.

I'm attaching a probably minorly upsetting video of me spraying starter fluid at the plugs and intake manifolds with abandon, a video of the lag on the throttle and a video hopefully getting the sound of the transmission. I stupidly did not attempt to pull the clutch in while getting the noise recorded BUT I assure you it quiets substantially upon being pulled.

Video of the throttle lag while the bike is all warmed up.


Video of the bike running while warm from left side (I can barely make out the thunking from this side of the bike)
https://youtube.com/shorts/QSmdQUHRD7s

Video of where I am pretty sure the sound is coming from (Sorry its a short, it wont let me change it because I filmed vertically)
https://youtube.com/shorts/eezcL0Prtz8

Video where I am spraying starter fluid around the injectors / intake manifolds. (Again sorry its a short youtube just likes to do it with vertical videos).
https://youtube.com/shorts/0--ryEOTYag

Id really hate to have to rip the entire bike apart to get to these intakes if its somehow the injectors but in my mind I know its likely I somehow wacked the damn thing or its just ever so slightly wedged from the airbox or when I was cleaning off the top of the motor I just did something to it in some way shape or form and damaged it but without any visual clues and after tightening the hose clamp with no success I turn it to the moto brick forum in the hopes of either ridicule at the obvious answer or reassurance Im not losing my mind and it is just the intakes. Either way I'm hoping its the intakes.

Some other peculiarities bike is running a k75 c ECU which I did not install and was there from the guy I bought it from, and there were quite a lot of connectors under the tank, just simply not being used?

Sorry for the thesis but I wanted to be thorough

Please be gentle I am held together by duct tape and friction.

[Laitch]

Sorry for the thesis but I wanted to be thorough

Please be gentle I am held together by duct tape and friction.

Surely you jest.

Get some narrow nozzles for your diagnostic spray can so you can be more precise with spraying. Just the red nozzle is all you need. GoFundMe should make short work of raising the funds.   


After that, spray the Z-tube that connects the airbox to the crankcase while the engine is running. It's located to the right of the rear most throttle body.


Remove the fuel tank cap assembly by carefully removing its four screw. It's resting on a gasket so be gentle with it.  Let us know the condition of the tank—clear fuel of varying degrees of black goo.

Remove the fuel filter and let us know if you can blow through it from the inlet side to the outlet side. If the rubber on the outside of the fuel hoses rubs off, replace them with SAE J30R10 submersible fuel injection hose. Right now, verify the hose clamps are tight around the hoses.

There's a lot to discuss about what you're doing but let's keep it simple tonight.

[Jester]

Thanks for the response! Seen you around the forum Laitch feels like Im in good or at the very least very experienced hands, thanks for having me.

Unfortunately I am up early for work and will be promptly passing out, I have used the narrow tips although it does feel I am just drowning the component with direct sprays but I shall make a new video with a more direct introduction of the starter fluid.

I replaced the breather hose in my reassembly, I have torqued the hose clamps down I hope enough, did try to spray it just not in the video didn't get anything from it but I will include in my tests for tomorrow as I didn't check it today so who knows maybe Its a ring around the rosey of causes or just a ton of different small ones.

As for the fuel filter here's where things get interesting. I did install a new filter it was the first thing I thought of after I reseated the injectors for the first time, I also re installed the old one afterwards to see if somehow I had installed the new one backwards or something or bought the wrong one. Both blow through "fine" from both ends but putting the old one on somehow helped the throttle lag although Im going to be completely honest it might have been something else. Tank seems to be in fine condition no floating gunk, when the tank was emptied I did notice a bit of grime stuck on to a wall around the very bottom but nothing I was particularly worried about and I have tightened the dickens out of the interior fuel lines none of which seemed to be in bad shape. I will put the new filter back in I will attempt to take some pictures of all the lines, unfortunately I think the tank is slightly full right now which should be a fun challenge to not ruin the paint, lots of towels I guess.

Fuel Filter I bought - Went for the cheap one? Kind of figured a paper filters a paper filter but maybe that's my problem? I mean It's probably placebo that the old one was better in the end so Idk I'm easily persuaded old filter had a bmw badge, after it wasn't working right I thought maybe it was different so I put it back in I guess.
https://www.euromotoelectrics.com/product-p/ff-859.htm

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As for the duct tape and friction it appears my taste in music cars and bikes has physically aged me as I am 24 going on 40 at least when it comes to my back and shoulders. But yes I'm young I'm fine, I did just have an MRI for a torn labrum though so fingers crossed its something else. I mostly just didn't want to get reamed if it was something so incredibly obvious and stupid, who knows maybe it still is.

Will update tommorow