89vfrrc24 Posted February 14, 2023 Share Posted February 14, 2023 Hello, my name is Carlos, im from Portugal. I am having a "big" problem with my lovely VFR. It's all my fault. Probably something I did during the replacement of my starter clutch. The process was done with some glitches. These glitches might have caused the problem. Flaws: a) put the starter motor washer in the wrong position, leaving the starter motor under pressure. I tapped the button a few times, hearing just one click. A user reminded me of the possible wrong position of the washer, so i ended up correcting the situation and the starter works without any problem. b) during the installation of the starter clutch, I touched the start button and observed a short circuit that i really don't know where and what cause that. Tests carried out so far: pulse generators ok only cylinder nr 2 turns off the bike when the pipe is removed all cylinders have spark (I don't know if at the right time) clean carburetors gas pump ok I leave some videos to help me. thank you all , Carlos https://youtube.com/shorts/85Umqiob8hg Link to comment Share on other sites More sharing options...
VFR750F3 Posted February 14, 2023 Share Posted February 14, 2023 Floats did you make sure they are working correctly. Is fuel pump working. Pinched fuel line. Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 14, 2023 Author Share Posted February 14, 2023 2 hours ago, VFR750F3 said: Floats did you make sure they are working correctly. Is fuel pump working. Pinched fuel line. Thank you. Yes, all the floats are working. I pull the fuel pipe that goes to the carburetores and the pump sends many fuel. Link to comment Share on other sites More sharing options...
VFR750F3 Posted February 14, 2023 Share Posted February 14, 2023 Oh I forgot the spring and diaphragm. Nothing torn and is it lined up correctly with the vacuum tube.. When you push on the slide does it snap back or not. Link to comment Share on other sites More sharing options...
Member Contributer jefferson Posted February 14, 2023 Member Contributer Share Posted February 14, 2023 Second above post. Hard to tell what you were doing with the throttle as that was out of shot. Was the stuttering because you were working the throttle back and forth? Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted February 14, 2023 Member Contributer Share Posted February 14, 2023 8 hours ago, 89vfrrc24 said: b) during the installation of the starter clutch, I touched the start button and observed a short circuit that i really don't know where and what cause that. How did you determine you had short? How did you fix this? What happened to cause short in 1st place? Link to comment Share on other sites More sharing options...
squirrelman Posted February 15, 2023 Share Posted February 15, 2023 a short will usually blow a fuse, so check all of them. were the carbs worked on recently ? the starter clutch you installed may be incorrect for your bike. compare the bumps along the outer ring with those on the starter clutch you replaced. Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 15, 2023 Author Share Posted February 15, 2023 13 hours ago, jefferson said: Second above post. Hard to tell what you were doing with the throttle as that was out of shot. Was the stuttering because you were working the throttle back and forth? Hi, thanks for the reply. The bike starts fine. After warming up, i try to open the throttle and the engine doesn't want to go up. The tachometer starts to show that behavior. Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 15, 2023 Author Share Posted February 15, 2023 11 hours ago, DannoXYZ said: How did you determine you had short? How did you fix this? What happened to cause short in 1st place? Sorry about the english, when i say short i mean like a spark or blown fuse, something flashed. Has i told you, i installed the washer in the wrong place and the starter clutch was not moving. I don't know if it was that... But the bike was running very well and it was only after this intervention that this behavior started 😞 Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 15, 2023 Author Share Posted February 15, 2023 10 hours ago, squirrelman said: a short will usually blow a fuse, so check all of them. were the carbs worked on recently ? the starter clutch you installed may be incorrect for your bike. compare the bumps along the outer ring with those on the starter clutch you replaced. The fuses are all great. The starter clutch was order from CMSNL, for that specific model VFR/K. there is no way to fail. Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 15, 2023 Author Share Posted February 15, 2023 14 hours ago, VFR750F3 said: Oh I forgot the spring and diaphragm. Nothing torn and is it lined up correctly with the vacuum tube.. When you push on the slide does it snap back or not. Didn't show any problem. and has i told before, never had problems with the fuel line. The only issue was the fuel filter that was cloged after sitting for some months. Notice that because i removed the gas tank, remove the fuel pipe that goes to the fuel pump and turn to on. no gasoline came out. Bought a new one from yamaha and after turn it to on, the gasoline started to pass. Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 15, 2023 Author Share Posted February 15, 2023 New vídeos testing spark. https://youtube.com/shorts/4fJmT50aCZo?feature=share https://youtube.com/shorts/q1LKGNCcluI?feature=share https://youtube.com/shorts/3xhbChCaqIw?feature=share https://youtube.com/shorts/YeLnJeTUlWU?feature=share I just remembered that the fuel in the gas tank is over 4 months old.... Link to comment Share on other sites More sharing options...
VFR750F3 Posted February 15, 2023 Share Posted February 15, 2023 Did you clean carbs after you replaced fuel filter or before. Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 16, 2023 Author Share Posted February 16, 2023 13 hours ago, VFR750F3 said: Did you clean carbs after you replaced fuel filter or before. Thank you. Cleaned the carbs after changing the fuel filter. I am hopping it's the cdi or i change the timming mechanically after pressing the stat button so many times with the starter motor badly fitted. I need to look for the TDC and see if the piston is on the top. Link to comment Share on other sites More sharing options...
VFR750F3 Posted February 16, 2023 Share Posted February 16, 2023 I still think its the carbs. Link to comment Share on other sites More sharing options...
Member Contributer jefferson Posted February 16, 2023 Member Contributer Share Posted February 16, 2023 2 minutes ago, VFR750F3 said: I still think its the carbs. I'm like you. I'm thinking the slides/diaghrams. Link to comment Share on other sites More sharing options...
Member Contributer Captain 80s Posted February 16, 2023 Member Contributer Share Posted February 16, 2023 3 minutes ago, VFR750F3 said: I still think its the carbs. It's almost always the carbs. Link to comment Share on other sites More sharing options...
V4 Rosso Posted February 16, 2023 Share Posted February 16, 2023 Have you tried getting rid of all that air that is trapped in the air filter by raising the fuel tank a little? Link to comment Share on other sites More sharing options...
89vfrrc24 Posted February 18, 2023 Author Share Posted February 18, 2023 Have noticed that the fuel pump doesn't prime. She only works with the engine running... What do you think? Can cause that problem? Thank you Link to comment Share on other sites More sharing options...
squirrelman Posted February 19, 2023 Share Posted February 19, 2023 On 2/16/2023 at 4:04 AM, 89vfrrc24 said: Cleaned the carbs after changing the fuel filter. could be your problem right there. your symptoms suggests that one or more vacuum slides are not rising properly to richen fuel mix with increasing rpm's. if you remove airbox and filter, with engine running you should be seeing slides rise and fall with throttle movement. its really hard to get old diaphragms properly seated in their grooves, so slides won't rise. do you have access to an air compressor ? you must try bypassing the pump relay as yours might have failed. Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted February 19, 2023 Member Contributer Share Posted February 19, 2023 6 hours ago, 89vfrrc24 said: Have noticed that the fuel pump doesn't prime. She only works with the engine running... What do you think? Can cause that problem? Thank you This is not EFI system with 3-sec prime and constant ON pump. It only pumps in time with ignition pulses to vary volume pumped based upon RPM. Verify pump is flowing sufficient volume: 1. drain each float bowl into separate containers. What are their volumes? 2. close bowl drains 3. manually run pump for 30-sec by jumpering pump-relay ON 4. repeat step #1 again. What is volume drained from each carb? Post 8 separate numbers You may still have electrical problem: On 2/14/2023 at 4:10 PM, DannoXYZ said: How did you determine you had short? How did you fix this? What happened to cause short in 1st place? On 2/15/2023 at 3:19 AM, 89vfrrc24 said: Sorry about the english, when i say short i mean like a spark or blown fuse, something flashed. Has i told you, i installed the washer in the wrong place and the starter clutch was not moving. I don't know if it was that... But the bike was running very well and it was only after this intervention that this behavior started 😞 Again, what caused electrical short and how did you fix it? Link to comment Share on other sites More sharing options...
Member Contributer Captain 80s Posted February 19, 2023 Member Contributer Share Posted February 19, 2023 6 hours ago, 89vfrrc24 said: Have noticed that the fuel pump doesn't prime. She only works with the engine running... What do you think? Can cause that problem? Thank you Working as designed. Pump only pumps if being cranked or running with the Fuel Cut Relay in place. Link to comment Share on other sites More sharing options...
VFR750F3 Posted February 19, 2023 Share Posted February 19, 2023 1 hour ago, squirrelman said: could be your problem right there. your symptoms suggests that one or more vacuum slides are not rising properly to richen fuel mix with increasing rpm's. if you remove airbox and filter, with engine running you should be seeing slides rise and fall with throttle movement. its really hard to get old diaphragms properly seated in their grooves, so slides won't rise. do you have access to an air compressor ? you must try bypassing the pump relay as your might have failed. Slides that is what I said also the float bowl needles are very important. I have been rebuilding VFR carbs for 32 years. I have learned quite a bit for trial and error. Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted February 19, 2023 Member Contributer Share Posted February 19, 2023 On 2/15/2023 at 9:20 PM, 89vfrrc24 said: The fuses are all great. The starter clutch was order from CMSNL, for that specific model VFR/K. there is no way to fail. Did you do what Squirrelman suggested?? Compare the Pulse Trigger bumps from the original Starter Clutch to the new one, make sure they are at exactly the same position and none have been bent or damaged with the install. Question for the carby experts????. Looking at Calos's original video. Can a carby issue respond as fast as the Tacho needle is displaying Or does this point to an electrical issue?? Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted February 19, 2023 Member Contributer Share Posted February 19, 2023 On 2/16/2023 at 9:05 AM, jefferson said: I'm like you. I'm thinking the slides/diaghrams. 6 hours ago, squirrelman said: could be your problem right there. your symptoms suggests that one or more vacuum slides are not rising properly to richen fuel mix with increasing rpm's. if you remove airbox and filter, with engine running you should be seeing slides rise and fall with throttle movement. its really hard to get old diaphragms properly seated in their grooves, so slides won't rise. do you have access to an air compressor ? you must try bypassing the pump relay as your might have failed. On 2/16/2023 at 2:04 AM, 89vfrrc24 said: Thank you. Cleaned the carbs after changing the fuel filter. I am hopping it's the cdi or i change the timming mechanically after pressing the stat button so many times with the starter motor badly fitted. I need to look for the TDC and see if the piston is on the top. On 2/16/2023 at 9:02 AM, VFR750F3 said: I still think its the carbs. very likely carb issue since 3000rpm problem occurred after carb work. Take video of your carb slides as you increase throttle. Vacuum increases with RPM and raises slide to add air and petrol. Does yours open fully like in this video?? Link to comment Share on other sites More sharing options...
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