Well it seems alot of the problem I was having was because the cap to my carb intake port was gone. Like an idiot, worrying about large things I overlooked something little. I replaced it with a cap we had in a cabinet. This AM the bike was hard to start (kick) again, and the elec starter was worthless. Can I ask what everyone uses to cap the port. Of course the other one is hooked to the vacuum line from the petcock. Thanks alot, have a great day!
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Intake ports (I think that's what they are)
- Thread starter zonk39
- Start date
Jacob
XS400 Enthusiast
There are vacuum caps available at the auto parts stores. If you have a short piece of vacuum hose you can stick a screw in one end and use that temporarily.
I use caps from the auto parts store with a spring hose clamp, just for fun.
Thanks alot for your input. 1 more stupid question. What size to get? Thanks again, and have a great day!
1/8"....I think. Smaller is better, they're rubber- they stretch.
Well I used a cap from an O2 tank at work. The same old problem came back. Starter couldn't turn over engine, kick start took 15-20 times when cold. It "missed" a couple of times when riding. Cleaned off the plugs (gently). Hoping to get a new valve cap (small) and put on it tonite. That has to be the problem. It worked great when I first capped it off. That couldn't have been a coincedence could it? Have a great day!
No now it was back to not starting if it was cold again. It has something to do with compression (or at least that what I think). When I finally got it started and rode it for about 30 min, I got home, turned it off, tried to start it again, and it blew the vacuum cap off of the carb inlet. Has anyone ever had that problem? have a great day!
jmd_forest
Bldg 1980 XS400 Cafe Bike
Blowing the vacuum cap off the inlet says backfire to me. Check you timing.
or leaky valves
I forgot to add one more thing I discovered yesterday. I can smell gas coming from hose that connects to back of carb on lt side. Tx again!
I am new to the motorcycle world but I would like to understand my bike as well as enjoy it. I just replaced the intake boots (thats what they were called on ebay where I bought them from) because my old ones were cracked and looked to be on their last leg. I noticed that I didn't have a cover for the vacuum line on one side of the old set; the right side, and the left one was capped off. It took forever to start the bike once it had been sold, lucky me. I am trying to figure out what the vacuum line does and how it might affect the bike's ability to start, or in my case not start... If someone can tell me what it does and what it should be connected to that would be a big help so I can get back on the road.
Other symptoms: Would not hold an idle, impossible to start, choke all the way in to finally start it, seemed to hiccup from time to time.
Thanks for the help!!!!
Other symptoms: Would not hold an idle, impossible to start, choke all the way in to finally start it, seemed to hiccup from time to time.
Thanks for the help!!!!
Well from my understanding of it. There should be a vacuum line that rins for the top of the petcock to one of the intakes. Then the other one should be capped off with a vacuum cap. The pupose is so that when the fuel is on the on or res positions, when the bike is running or started it pulls the diaphragm back in the petcock to allow fuel to be fed to the carbs. When the bike is not running, no vacuum, no gas flow (unless you turn it to prime). That is my understanding. There are alot of people on here that have far mor knowledge than me. Hopefully they will resond with an answer also. Good luck, I know how it is. Have a great day!
