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99blackturq · September 21st, 2019, 05:52 PM

So, I do now think the prime suspect is a vacuum leak of some sort. I took the carbs off and put the rubber mounts on correctly this time, and the carbs seemed to be set in place a lot better. The rubber tubes aren't cracked and were way easier to get on when they were oriented correctly. I restarted the bike and it starts a lot easier, but it idles lower now and it responds to throttle a bit better too. Still relies very heavily on choke to keep revs up and start the bike.

I did also run the bike with and without a fuel filter. It was a new generic one I got from home depot but fit in place well when I first started working on the bike. There seemed to be no change at all from when I used the line with the fuel filter and when I used a straight line.

This is what makes me think it is vacuum of some sort. When the bike is idling I can take the vent hose off the back of the fuel tank (the oem plastic, I think, it's clear/orange and very stretchy) and nothing happens. Also, the airbox doesn't seem to be mounted in place very well and the opening to get to the air filter doesn't sit flush or ever seem to lock in place. While sitting on the bike with the seat off I can press the cap to the air filter into place and that also does nothing to make it run better.

Also, the fuel tank cap is aftermarket and does not seem to seal very well. The lid to the tank cap screws into place with an O-ring at the end so the actual part you take off to put fuel in seals well, but I don't think the whole assembly does. It's some anodized aluminum tank cap, gold. SSR brand I believe. I am missing one of the mounting screws so it is only held into place by the 7 screws I got from the previous owner.

I suppose I will send my petcock off to you, ducatiman, since that probably is my failure point. Not sure how to test if it's any good or not myself and you are the expert man.

The fuel in the tank is very new, and has a bit of fuel stabilizer in it, as per ducatiman's instructions when I got the carbs back from him.

Not sure when the valves were ever adjusted. I suppose I'll have to look into learning how to adjust them. I tried to get a compression tester from Autozone, but theirs didn't fit our smaller spark plug holes. Couldn't test compression but I did replace the spark plugs with NGK CR8HSAs, OEM spec and recommended by this forum. I didn't measure the gap, I don't have feeler gauges. I suppose I'll need some for the valves too.

I purchased this bike from Craigslist, in Austin. Some guy's dad had all the paperwork from the son who owned the bike. He had used it as his college commuter around 2014, it had an A&M sticker on the license plate when I got it. Damn aggies. The speedo cable was NOT attached and the odo read 5400 miles, he had the title and the title transfer form all filled out, the oil in the bike looked good and so did the coolant, it turned over so I figured I would take on a project. The only thing described wrong with it was a hole in the fuel tank, which was an easy fix. It's in the upper fairing screw mount so I figured he put the wrong screw in too far and punctured it.
Their house was really nice and in a nice part of town, the bike was in really good shape aesthetically so I thought he was being honest, and I still think that's true. This is all to say that I've never really spoken to the previous owner and I have no service records! Typing all that out has given me some introspective thoughts.

Still, there are less problems than I've expected. The bike came on Pirelli MT70 tires and the plastics are almost perfect. Seat is really nice too. The bike came with a cover and it was in a garage when I bought it so I don't think it's ever been seriously abused. I still don't regret this purchase because I've learned a lot already and basically knowledge is the only thing that really matters in the end. Enjoyment, too, I've had fun working on this and getting further. Yesterday in the neighborhood was great zipping around <35 MPH and struggling with my finnicky throttle, haha.
Anyways, sorry to turn this from an update post to a blog entry. Trying to be transparent. Much to think about.

September 21st, 2019, 05:52 PM	#9
99blackturq ninjette.org newbie Name: James Location: San Marcos, TX Join Date: Sep 2019 Motorcycle(s): 99 Ninja 250r Posts: 6	So, I do now think the prime suspect is a vacuum leak of some sort. I took the carbs off and put the rubber mounts on correctly this time, and the carbs seemed to be set in place a lot better. The rubber tubes aren't cracked and were way easier to get on when they were oriented correctly. I restarted the bike and it starts a lot easier, but it idles lower now and it responds to throttle a bit better too. Still relies very heavily on choke to keep revs up and start the bike. I did also run the bike with and without a fuel filter. It was a new generic one I got from home depot but fit in place well when I first started working on the bike. There seemed to be no change at all from when I used the line with the fuel filter and when I used a straight line. This is what makes me think it is vacuum of some sort. When the bike is idling I can take the vent hose off the back of the fuel tank (the oem plastic, I think, it's clear/orange and very stretchy) and nothing happens. Also, the airbox doesn't seem to be mounted in place very well and the opening to get to the air filter doesn't sit flush or ever seem to lock in place. While sitting on the bike with the seat off I can press the cap to the air filter into place and that also does nothing to make it run better. Also, the fuel tank cap is aftermarket and does not seem to seal very well. The lid to the tank cap screws into place with an O-ring at the end so the actual part you take off to put fuel in seals well, but I don't think the whole assembly does. It's some anodized aluminum tank cap, gold. SSR brand I believe. I am missing one of the mounting screws so it is only held into place by the 7 screws I got from the previous owner. I suppose I will send my petcock off to you, ducatiman, since that probably is my failure point. Not sure how to test if it's any good or not myself and you are the expert man. The fuel in the tank is very new, and has a bit of fuel stabilizer in it, as per ducatiman's instructions when I got the carbs back from him. Not sure when the valves were ever adjusted. I suppose I'll have to look into learning how to adjust them. I tried to get a compression tester from Autozone, but theirs didn't fit our smaller spark plug holes. Couldn't test compression but I did replace the spark plugs with NGK CR8HSAs, OEM spec and recommended by this forum. I didn't measure the gap, I don't have feeler gauges. I suppose I'll need some for the valves too. I purchased this bike from Craigslist, in Austin. Some guy's dad had all the paperwork from the son who owned the bike. He had used it as his college commuter around 2014, it had an A&M sticker on the license plate when I got it. Damn aggies. The speedo cable was NOT attached and the odo read 5400 miles, he had the title and the title transfer form all filled out, the oil in the bike looked good and so did the coolant, it turned over so I figured I would take on a project. The only thing described wrong with it was a hole in the fuel tank, which was an easy fix. It's in the upper fairing screw mount so I figured he put the wrong screw in too far and punctured it. Their house was really nice and in a nice part of town, the bike was in really good shape aesthetically so I thought he was being honest, and I still think that's true. This is all to say that I've never really spoken to the previous owner and I have no service records! Typing all that out has given me some introspective thoughts. Still, there are less problems than I've expected. The bike came on Pirelli MT70 tires and the plastics are almost perfect. Seat is really nice too. The bike came with a cover and it was in a garage when I bought it so I don't think it's ever been seriously abused. I still don't regret this purchase because I've learned a lot already and basically knowledge is the only thing that really matters in the end. Enjoyment, too, I've had fun working on this and getting further. Yesterday in the neighborhood was great zipping around <35 MPH and struggling with my finnicky throttle, haha. Anyways, sorry to turn this from an update post to a blog entry. Trying to be transparent. Much to think about.