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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: BBQ_SqaureD on June 11, 2023, 12:02:32 PM
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Hey all! Just bought a BMW 75kt.
Decided to join here, hopefully 🤞 I can get it running again!
This is my first dip into the motorcycle world.
Rode it once and the fuel pump died, replaced the pump and filter along with numerous hoses. It runs now. But not very good! Hoping that someone can point me in the right direction?!? I’ll upload videos of my issue.
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Welcome!
Has it been sitting idle for a long time? If it has, throw some Techron fuel system cleaner in the tank and take it out for a couple long rides. After a couple tanks are run through the injectors, the engine should be running better.
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I’ve dumped the old fuel out. There wasn’t much in it, but I have put fuel cleaner in it. I did mess with the throttlebody screws. Rookie mistake figured that out after I shouldn’t have touched them. Before the fuel pump went out, it was idling at. 1,200rpm didn’t seem right.
I put a carb tuner on it
https://youtube.com/shorts/TY7CKlqdYZ8?feature=share
No matter what I do it won’t run right.
Edit. I don’t really think it ever sat long the original owner drove it quite a lot.
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Send the fuel injectors to Mr. injector.
http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/fis/fis.htm
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Actually cleaned them out. Major difference! But I will still send them out! There wasn’t any fuel coming out of 2 and 3 soaked em. They woke up the bike
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Update. Injectors came back! They were definitely clogged!
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Thanks for the update; please keep us in the loop.
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Ran great! First time. Went for a second ride. Back to cutting out
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Be sure each spark plug wire's terminal is firmly connected to its spark plug. The wire cannot be wiggled or removed easily if it is connected correctly. Inspect each plug to verify its gap is correct.
What you also can check right now is the condition of the z-hose—a hose connecting the crankcase to the air box on the camshaft cover side of the engine. See the attached photo from Euro MotoElectrics. If it’s cracked and leaking, it will make the fuel mixture too lean resulting in the engine’s cutting out and often being hard to start. Leakage of the throttle body manifolds can also cause that, but checking those can come later.
There is more to verify in your future because you have "messed" with the throttle body screws but these two are a good beginning and might get you reliably rolling again, if the correct planets align.
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Thank you! I ordered a couple of new things for it. One by one! I’ll eventually get it going
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https://youtube.com/shorts/NquDdyPpVic?feature=share
Here’s its current state. I’ve begun to wonder if I should have passed on it! This is my first motorcycle! And I’m starting to get discouraged with it!
I also carb cleaned everything to make sure no leaks. No changes
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Do I need to drop the motor to access the air box and to replace the entire throttlebody, since I have a replacement sitting here
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No. Why are you replacing the throttle bodies? Download the BMW K100/K75 service manual here (http://www.motobrick.com/index.php?PHPSESSID=c9384debac5dcc9dfd4be865eb22b2c8&topic=11014.0).
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No. Why are you replacing the throttle bodies? Download the BMW K100/K75 service manual here (http://www.motobrick.com/index.php?PHPSESSID=c9384debac5dcc9dfd4be865eb22b2c8&topic=11014.0).
Process of elimination. Wanting to take it out and check behind everything. Because I’m at a loss at this point. Plus I’m wanting to replace the rubber even though it looks good. Just a preventative measure
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Unless you know what you're looking at and know how it works, I don't recommend that course of action. The process of elimination can be done more easily when you have the engine in and running no matter how rough it's running.
Good luck with your Brick!
For greater understanding, read the document at the attached link.
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Thank you for the advice and the upload.. I did notice. The fuel tank only had 3 lines hooked up. Fuel return fuel to the rail line and then the vacuum one from the block.
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Clogged injectors tell me that there is a bunch of crap in the fuel system. You need to find it and get it cleaned out.
Have you changed the fuel filter?
Are you absolutely sure there is no shit in the fuel rail? Did you clean it out while the injectors were getting cleaned? You may have just reclogged your injectors. The rails on idle bikes have been known to rust from the water absorbed by ethanol gas.
Is there any dirt laying in the low parts of the fuel tank?
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Clogged injectors tell me that there is a bunch of crap in the fuel system. You need to find it and get it cleaned out.
Have you changed the fuel filter?
Are you absolutely sure there is no shit in the fuel rail? Did you clean it out while the injectors were getting cleaned? You may have just reclogged your injectors. The rails on idle bikes have been known to rust from the water absorbed by ethanol gas.
Is there any dirt laying in the low parts of the fuel tank?
Tank is spotless, cleaned it out at work. But never thought about the rail itself.
But yeah I replaced the pump and filter. Along with the hoses
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I’m wanting to replace the rubber even though it looks good. Just a preventative measure
If they have been proven not to leak, money would be better spent elsewhere. I can send you my PayPal address; personalized prayers are available at low rates.
Learn how to do a basic tuneup while the thing still runs before it's messed up further.
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Take the rail apart and soak it in white vinegar for a day or so. What comes out after the soak will give you a clue as to your problem. While it's soaking you can try cleaning the injectors out again.
The fact that the bike ran well right after you had them cleaned and then got bad again sounds like they got plugged while you were running it.
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I went ahead and bought new injectors. But I will have these cleaned again for spares. But I will definitely soak the rail. Thank you for the suggestion.
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About that hose running from the tank to the crankcase, it can cause problems and has been modified in countless Bricks. Read the attached service bulletin.
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About that hose running from the tank to the crankcase, it can cause problems and has been modified in countless Bricks. Read the attached service bulletin.
that’s why I was just going to replace all the remaining rubber. Including the fuel pressure regulator.
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that’s why I was just going to replace all the remaining rubber. Including the fuel pressure regulator.
My statement in Reply#14 sums up my view of the situation. Good luck with your Brick.
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Worth a shot at least, it’s soaking this morning. At this point I’m willing to try anything lol
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What’s next?
https://youtube.com/shorts/f2FnPgYJmi8?feature=share
https://youtube.com/shorts/f2FnPgYJmi8?feature=share
https://youtube.com/shorts/tbRAmAtUrK4?feature=share
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Here’s the plugs as well
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When you say you fiddled with the throttle body screws, did you mean the brass idle air control screws or the throttle butterfly synchronization screws(these are on the linkage between throttle bodies and marked with blue paint)?
If it was the idle air screws, you can get back to a decent adjustment by first removing them one by one and cleaning the bore they screw into with carb cleaner. Then screw them in until lightly bottomed and then back them all out 1 1/2 turns.
Your spark plug doesn't look all that bad, seeing as how you really haven't been able to get any extended run time on the engine. The engine looks like it is running a little fat, but that may be the result of not maintaining normal operating temperature for any length of time.
One common problem is the engine coolant temperature sensor. A failing sensor or dirty/loose/corroded connection will make the fuel injection control think the engine is cold and enrich the mixture. With the engine at operating temperature, the resistance between contacts #10 and #13 on the engine control plug should be about 250 ohms. A cold engine will read about 2500 ohms.
About the rail: when the soak is done, pour out the vinegar in the rail through a coffee filter to catch whatever comes out. Do a good rinse with lots of water and if you can, blow it out with compressed air followed by a rinse with 91% isopropyl rubbing alcohol to remove any water that may still be in it.
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When you say you fiddled with the throttle body screws, did you mean the brass idle air control screws or the throttle butterfly synchronization screws(these are on the linkage between throttle bodies and marked with blue paint)?
If it was the idle air screws, you can get back to a decent adjustment by first removing them one by one and cleaning the bore they screw into with carb cleaner. Then screw them in until lightly bottomed and then back them all out 1 1/2 turns.
Your spark plug doesn't look all that bad, seeing as how you really haven't been able to get any extended run time on the engine. The engine looks like it is running a little fat, but that may be the result of not maintaining normal operating temperature for any length of time.
One common problem is the engine coolant temperature sensor. A failing sensor or dirty/loose/corroded connection will make the fuel injection control think the engine is cold and enrich the mixture. With the engine at operating temperature, the resistance between contacts #10 and #13 on the engine control plug should be about 250 ohms. A cold engine will read about 2500 ohms.
About the rail: when the soak is done, pour out the vinegar in the rail through a coffee filter to catch whatever comes out. Do a good rinse with lots of water and if you can, blow it out with compressed air followed by a rinse with 91% isopropyl rubbing alcohol to remove any water that may still be in it.
Thanks for the tip. And yeah I messed around with the brass ones
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That is good news. You can get back to a usable balance doing what I suggested. Don't ever touch the screws with the blue paint. They are set up on a flow bench at the factory, and you don't have the equipment to get a really good setup for them.
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That is good news. You can get back to a usable balance doing what I suggested. Don't ever touch the screws with the blue paint. They are set up on a flow bench at the factory, and you don't have the equipment to get a really good setup for them.
Thank you. As for the coolant sensor, is there a aftermarket option? Or do I have to use the one from
https://www.euromotoelectrics.com/TEMPSENS-K197-p/tempsens-k197.htm
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Don't buy the cheap Aliexpress one it doesn't work. It did work on the 16v Brick. This was a few years ago.
Regards Martin.
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Test the one on the bike before you start spending money on a replacement.
The one from EuroMotoElectrics is okay. They sell good parts.
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Getting ready to test it now. Before buying a new one. Also going to call the local bmw shop to see if they have one instead of waiting until mid next week whenever they open this morning..
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https://youtu.be/uAoneCMpZSQ
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Ohm on cold was around 4? I replaced it.
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Was that 4 ohm measurement across terminals #10 and #13 on the big plug? Your 4 ohm reading is unusual in that normally when the sender fails the resistance goes higher not lower.
Have you removed the sender from the bike? I would suggest putting it into a pan of cold water and reading the resistance from the pins to the metal case of the sender. Then heat the water and the sender and measure the resistance again. The cold water reading should be 2500 ohms dropping to approximately 250 ohms as the temperature approaches 200 degrees F.
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Question?
What are theses two for?
And yes. Around 4.2 ohms when tested off of the pins.
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Your photo is of the oil pressure switch that turns on the oil idiot light on the tachometer.
Where on the temperature sender did you get your reading? That resistance would tell the engine control unit that the engine has melted. That temperature would be well above the point where the engine would do an overtemp shutdown that would prevent the engine from running.
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What’s next?
Still running bad, new coolant sensor helped for a few minutes until it warms up.
Mass air next?
Bad ecu?
Pins from the new sensor show within range.
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What’s next?
A valve clearance check/adjustment, a throttle body balance with a manometer made with Snapple bottles or otherwise, and a CO adjustment. :laughing4-giggles:
(https://www.motobrick.com/gallery/4/1601-200623120059.jpeg)
(https://www.motobrick.com/gallery/4/1601-200623120245.jpeg)
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No key or anything. New problem???
https://youtube.com/shorts/8NS04-0C5Lk?feature=share
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You put the positive from a battery on the + terminal on the starter and ground the negative. Of course the starter is going to crank the engine.
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Figured. Rookie move. Change the sensor again. Tried everything. I’m giving up. Probably will post it under the for sale. Someone else can have a project. Could be something simple. Could be something more. But I don’t think I want to mess with it.. last resort is taking it to a local shop and having them mess with it. But I don’t want to spend another 2 grand on it.
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Problem solved! Finally!!!!!!! But regardless I went ahead and bought a second bike in case it decided to break down again.
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So, what was the problem???
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So, what was the problem???
Even though I had the injectors professionally cleaned. Decided to take them out again, sent them to a different company. Locally… they were bad. Once they get warm enough they start pulsing differently. Bad windings is what I’m told.
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Thanks! Looking forward to more updates on your progress.
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Thanks! Looking forward to more updates on your progress.
Definitely! Thanks for all the advice as well. If everything goes smoothly. Even though it’s probably not everyone’s taste, I bought it to turn into a Cafe racer. I’m not a huge fan of the style it’s currently at I just don’t care for the huge windscreen.. but I will make a new post with the updated and pictures once I start.
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Update. Rode her around 400 miles. I absolutely love it! The ride is amazing!
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Definitely! Thanks for all the advice as well. If everything goes smoothly. Even though it’s probably not everyone’s taste, I bought it to turn into a Cafe racer. I’m not a huge fan of the style it’s currently at I just don’t care for the huge windscreen.. but I will make a new post with the updated and pictures once I start.
Once you get it running reliably, go out and do a week of 600 mile days going somewhere you would like to ride. I think that will show what the RT is all about. If you are a wandering horizon chaser who has to know what's on the other side of the hill or the other end of a canyon you will love what you have been lucky enough to find.
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Once you get it running reliably, go out and do a week of 600 mile days going somewhere you would like to ride. I think that will show what the RT is all about. If you are a wandering horizon chaser who has to know what's on the other side of the hill or the other end of a canyon you will love what you have been lucky enough to find.
Absolutely above 600miles and legal now! I really enjoy this bike!
Now it’s time to start painting it.