Help getting my bike running

allanrps

allanrps

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Hey guys,

I screwed school and tried to get my bike running today, but I ran into a couple problems.

First, I spent three (3) hours trying to get my brake lines filled, and the front brake line still wont fill :banghead:. I bled the master cylinder, which was bought new, and that worked, but when I put the hose on it just doesn't push fluid anymore. I have no idea what it could be. I tried different banjo bolts and seals. So it pushed fluid out of the outlet, then I screw the hose on, and now it won't push.

Second, I just put new oil in it, and now the oil light is on. I measured the oil to 2L, and the dipstick reads to the line, so I'm not sure what it is. All my other electronics work.

Finally, I put the carbs and exhaust on and tried to bottle feed it, but I couldn't get it to start. It should be in running shape (it was a month ago before I started working on it. Haven't touched the engine). I did replace the ignition coil screws with stainless, do those need to conduct? Also, I was bottle feeding it. Are there problems associated with that? The starter motor would just whir, I didn't hear any ignition or anything. Carbs are rebuilt btw.

Thanks,
Allan
 
Hi Allan, I was recently in a similar situation and with help from this wonderful site have made a lot of progress.

As for starting does it have spark? (mine needed new plugs before it even tried to start)
When you bottle fed it did you use enough gas to fill the float bowls? Did you put the air filters on? Did you plug both intakes on the carb boots if it is not connected to the tank? Is the battery charged enough? (If you have a kick start try using that rather than electric I've found it works a lot better on mine). You said the PO said it had 95 compression on both cylinders I believe it needs at least 120 to start but really needs to be in the 140-170 range...Definitely work on doing a compression test following the instructions in the service manual found in the tech section of this site. Hope that is any way helpful. I like your bike! Looks good.
 
As to the brakes, I would start looking on youtube for a nice how-to. Doesn't have to be xs400-specific, the principles of hydraulic brakes are the same on most bikes.

When you rebuilt the carbs something could have gone wrong.

Also +1 on what united says. Check for spark, check if the plugs are wet after trying to start the bike. Spray brake cleaner or starter fluid in the air intake to see if it'll run that way. Try to eliminate possibilities one at a time, and eventually you'll fix all your issues :)
 
the oil light should be on if the bike's not running btw ;)

once the bike runs, it should switch off
 
United, if that's true about the compression, then that's good news! the PO started it when I went to buy it:D. I'm pretty sure I filled the bowls. I squeezed the bottle until it started exhausting air rather than pushing gas, then filled it up again. Didn't pull the bowls off to check though. I'm darn sure that the carbs are in good shape. I had them apart for a good long time and took alot of care to put them back together clean and correct. But it is a possibility... I'll go down and check for a spark, I didn't do that before. Was so exhausted last night I barely made it to bed. They are new plugs though.

I didn't plug the intake on the other carb boot! I didn't think it mattered, which is pretty stupid now that I think about it. I'll do that

Haha I didn't know the oil light was supposed to be on... I did replace the oil filter though, so thanks for that.

Thanks a ton for all the help guys. I'll be back in 10 with an update!
 
Ok, so I just went down and tried her again. I took a plug out and verified that I am getting spark. Plug wasn't wet, but that's after sitting for the night. I also plugged the right carb boot. Jumped on her a couple times and tried the e-start but still got nothing. It is possible that I may have put the carb slide on backwards when I replaced the diaphragms, but I remember making sure they were on right, and if I understand correctly, that shouldn't even come in to play in idling.

And about the brakes, I watched a ton of videos and read a ton of literature on it, and it still took me stinking forever. I didn't know you have to bleed the master cylinder, then the hose, THEN the caliper, so I wasted an hour and a half doing nothing. But the rear brake is filled and bled and working. But I can't get the front to work. I think that the front hose may be clogged, as I tried to blow through it and got back pressure. But shouldn't the mc be able to push through it, if it is blocked? I mean it can stop a bike with the pressure.

Edit: checked the plugs after trying to start it and they were dry. Also, I forgot to mention, I rejet the carbs up a couple sizes and raised the needle because I went to a K&N filter (the filter wasn't on when I tried to start). I also turned the idle mix screws out some. If it were a problem with carb tuning, it would at least sputter, right? I'll probably go through them anyhow, at least that would make an easy fix. I can't put much, if any time into it over the next week though because I have alot of school work to do...
 
Last edited:
allanrps said:
Also, I forgot to mention, I rejet the carbs up a couple sizes and raised the needle because I went to a K&N filter (the filter wasn't on when I tried to start). I also turned the idle mix screws out some
Click to expand...

It seems you did too many changes on your carbs at the same time...So you have stock mufflers and pods, right? I am not a carb guru but I don't think it's necessary to go 2 sizes up.

Brakes - compressed air should be helpful, try to blow the hose through. As Scorp said, check your caliper piston.
 
Lucky8, for the carbs, I just put in the smallest size jet I had in the jetting kit, and I only raised the needle one notch. I read a thread somewhere on this forum about what the final jet sizes were for someone going to pods and a mac 2-1, and they had much more drastic changes. Also, the air filter isn't on it, so it should be pretty open flow right? I'll take another look at the carbs and maybe put the other mains back on. Not today though, I've really got to study.

Scorpio, I did already thoroughly go through everything in the brake system. The caliper unit is actually not hooked up, it's a hose problem it seems. I'll try to blow some WD through it.
 
Did you check both plugs for spark? Even if the plugs are new you may not be getting spark.

I thought the same thing when I started "even if everything isn't perfect it will run...just poorly" I've found that it doesn't really work like that. I had to clean the carbs three times and have good spark and a charged battery and found things that needed fixed after that. (It's been a lot of fun to learn so much about the bike though).

I'm not an expert but I think if you have no filters on then it is probably getting way too much air to start.

Just as a thought. When my clutch was not adjusted properly it wouldn't start nor make sounds like it was going to start.
 
I did check and both plugs have spark. Carbs have been dipped in chem-dip and pinesol, scrubbed, sprayed, and partially rebuilt. Battery is new. I figured that about the air filter, but the PO started it up for me without a filter on it, and that was with soiled carbs. Mine are jetted for some more air flow too, so I figured it wouldn't be a problem. The clutch seems to work. Motor turns freely with it out, and has compression with it in.

I probably did just do something dumb with the carbs. I put them together a couple weeks ago, I thought ready to put on the bike, but haven't been into them since. But the only idle related unit in the carbs is the fuel mixture screw right? Floats seem to be working, if squeezing the fuel bottle can give any indication. I'll play around with the idle mix screws some tonight.
 
i just went down and pulled the carbs off to check them out. Couldn't help it.... they looked fine. Screwed the idle mix screws to stock spec. I briefly checked the float height with a guy who knows his stuff, so I figured they were alright, but I don't have a digital caliper so I can't really double check. I do remember at first we were a little confused at where to measure it, so they could be off, but before us nobody opened these carbs up since they went on the bike at the factory, and it's only 1100 miles. I did see that the inside of the carb boots were moist with some gas, so fuel was getting through. So I'm kind of stumped. I've got fuel, I've got spark, and I've got an operational engine. Where's it going wrong?
 
It's very possible that I am flooding the carbs from pushing fuel past the float valve, but wouldn't I still get some type of ignition of the fuel after it went into the engine?
 
With the brass floats the correct height is 26mm not 32mm as per the manual. I have the brass floats and my bike would not start until they were near that number.

I really am no expert but my experience is that if the carbs aren't happy the bike won't start.
 
Went and checked the float height. Sure enough, they were a good bit off. Adjusted them to 26mm. Still wont start... For bottle feeding, I am plugging both carb boots, filling a bottle with gas, hole in the cap with a rubber hose running from fuel to carbs. Turn bottle upside down, make sure hose is submerged, let the fuel drip to the carbs till flow stops. Turn bottle upright, hose is submerged, choke carbs, kill switch on, kick it. I am getting a whizzing/whirring sound after kicking it or running the e-start. Is that normal? I've never started a bike, so I don't really have anything to go by.
Thanks for the help guys.
 

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