Turns over, but won't start

[jakefromstatefarm]

Hi guys!

I'm rebuilding a 1979 xs400F. The electric starter worked for a few minutes before crapping out on me (although the bike never started), so that's a question I'd be thrilled to have answered. Could something have fried itself in the process?

I can get it a few gurgles out of it via kickstart, and even more by popping the clutch out of a rolling start in 1st gear. However, it sounds like it's not really trying to start.

My buddy says it could be stale fuel (regular fuel I bought a few months back). Not sure if that would make much difference. I also thought I could hear what sounded like a little air seeping out of the engine by the timing coil between strokes when kicking it over. Could a small leak be enough to prevent the engine from starting and running?

I'm a newbie so any and all advice is super appreciated.
Thanks fellas!

 

[BBS360]

You probably drained the battery trying the e-start. Doesn't take long.
Get a trickle charger and keep it topped up as you work on it.

When did the bike last run? Have you cleaned the carbs?

An air leak could easily prevent starting. Could be leakage from the spark plug.
Buy/borrow a compression tester and check your cylinder compression.

 

[jakefromstatefarm]

Is it okay to leave the trickle charger on it all night? That's what I was planning on doing and looking at it again tmrw. Hasn't ran in close to thirty years, as far as I know. I cleaned the carbs clear through a couple months ago. Are there any ways to check how carbs are performing without the bike starting?

Where do you recommend buying a cheap compression tester? Any idea what kind of compression reading should I expect?

Thanks so much!

 

[Old Mose]

There are many variables when it comes to engines not starting. The charger question depends on the battery in question and the type of charger used. As long as the battery isn't low on water and you are using a battery tender type charger, that should be fine. Gas these days isn't much good in general so you need to start off with some fresh fuel. 100% gasoline if it's available! If you can drain the carb bowls before adding the fresh fuel that would also be a plus. Are the plugs firing and does it have enough compression and enough vacuum to draw the fuel in on the intake stroke are some major questions!

 

[arfstrom]

My buddy says it could be stale fuel (regular fuel I bought a few months back). Not sure if that would make much difference. I also thought I could hear what sounded like a little air seeping out of the engine by the timing coil between strokes when kicking it over. Could a small leak be enough to prevent the engine from starting and running?

I find that ethanol fuel stales in about 3 days. If I use ethanol fuel, I need to drive the bike every two days. generally my experience is on the third day, I will have some starting issues like you have described. since my bike is running in good condition, I can start it like you described, push starting, putting it in gear. So in my opinion, don't hurt your self by trying to run with the bike.
The carbs will varnish fast, If you have been using ethanol free fuel, I have made though the winter, and a few extra months, and have the bike start on first kick. I did drain the fuel from carbs, since I knew it wasn't going to be fixed right away.

Air Seeping, I would inspect the carb boot, there should be one capped off, the other should have a line running up to the fuel tank petcock. I don't remember the last time I forgot that, I seem to think it will run, just crappy.. Also rememberer my boots were leaking, I found from Menards a Silicone self sealing rescue
https://www.amazon.com/Gardner-HTP-1010-Purpose-Silicone-Self-sealing/dp/B00004WLKT better discription at http://www.rescuetape.com/ i there is any difference between the two, I am ok spending 4 bucks for this at my local store.

Carb will be some varnishing going on day 3 for, so redo your carbs. I did the boiling lemon juice. vinegar is cheaper, and you get a gallon from one bottle.

Starter button failures, it happens all the time, (to me) Generally I chalk it up to atmospheric conditions, when its fine, its awesome, I have had to go into the button housing, and clean the connections, replaced the button, because the rim fell apart.

Trickle charger, it you buy a charger specifically designed for trickle charging, you can leave it on all winter. If you thinking of using a generic charger, read the owners manual. From the time I took my bike out of service last year, about August, to 3 weeks ago, my battery was on trickle charger. which I picked up of of amazon. This is typically used for storage purposes, will keep you battery from early fatigue, which will kill the battery sooner. (lack of a better analogy)

You home work:

• charge up the battery, (with what every you have)
• inspect starter button assembly
• buy some carb dip, or vinegar, follow the instructions posted here somewhere for carb cleaning
  • while ensuring there is not further damage to your floats, etc...

While researching, uses willem's thread, of Hows To's...
http://www.xs400.com/threads/a-bunch-of-how-tos-in-a-thread.10715/

 

[jakefromstatefarm]

WOW. You guys are incredible. Thank you so much!!

 

[jakefromstatefarm]

@arfstrom
I did a little more research on carb cleaning and something I read about sounds like a condition my carb might have. Rather than simply being crystallized remnants from old gas, it feels like the aluminum alloy is actually corroding a bit. The carb body feels ever so slightly like chalkboard and has a darker tint to it, rather than being cold, smooth, and shiny. Is this normal or do I have a bigger problem on my hands that may or may not be salvageable?

 

[MrStubb]

Hey Hi Howareya Jake!!! Sounds like you hit the mother load of advise from Arfstrom. He's a great wealth of info for us & not too far way either. 1 thing I found with my 80 XS400 is if the battery is a little under charged you will have firing issues. Given the fact that I think my coils are weak I will loose the right cyl if there's a charge issue. Another thing to think of is when you're inside your carbs make sure you thoroughly blow out each & every orifice. There's a couple that I missed several times before I got it right. Also on my bike I do have a bad thread for my right plug that will need some attention soon. You may also have an issue here since this one for me at least is difficult to get started strait since it's under the ignition pick up coil cover. You'll definitely get a slight hissing sound from that problem. Good luck Keep us posted on your progress. Oh like Arfstrom said stale fuel will give you headaches. Do your self a favor & get a load of good nonoxy premium. Mine seems to LOVE the stuff even if it's still not running right. Don't care what those greenies say Ethanol fuel has caused more issues than it's solved. Alcohol's for drinkin not for burnin.

 

[jakefromstatefarm]

BIG NEWS!!! After 5 months and a week of rebuild, the bike started for the first time since 1986! I cleaned out the carbs again, put nonoxy fuel in, charged it back up, and tightened my spark plugs a bit more. However, when running, it seems to be extremely lean. The little smoke that came from the exhaust was white, and it won't stay running on its own for long. It starts easiest if I've kicked it over a few times without the bike set to "run" so that some gas can build up a bit and/or I have my buddy spray intake with some starter fluid. I had to replace the old air filters with pod filters, and replaced the jets in the carbs with something slightly bigger than whatever it was that stock called for.

I'm a little nervous about the internal condition of the carbs (you might remember my earlier post about them corroding). When I was cleaning them back out today, some metal was rubbing off onto my fingers from the inside of the carb body. The vacuum slides still move like a charm and all the jet passages were unblocked, but I'm afraid the deteriorated/deteriorating carb bodies could be a real bad thing down the road. Unless this is actually normal or you guys don't think it'll effect too much.

Tomorrow I plan to mess around with the external settings on the carbs to see if I can richen it up a bit, but I don't have the feeling it will be enough to find the happy medium. I'd love to hear any advice you guys may have to work this out/do some more accurate troubleshooting.

Thanks guys!!

 

[jakefromstatefarm]

I couldn't get it to start tonight so I checked for a spark and now it's not sparking...
Battery reads at 12.4ish volts.
Primary and secondary coils all read correctly on my multimeter. Spark plugs also still in good shape...
Any ideas?

 

[jakefromstatefarm]

Got it to start again, it seems that the main issue is battery strength.

However, the engine turns off as soon as I let off the front brake - maybe some wiring is messed up somewhere?

Also, there's some loud knocking in the upper engine - probably a valve clearance issue. Anything else it might be?

 

[BBS360]

The bike's in neutral when it stops? You're not just stalling in in-gear?
It's unlikely but it'd be possible to wire the ignition through the brake switch. You'd only be able to start with the brake in and it'd die when you release.
You'll have to open up the headlight bucket and compare it to the wiring diagram.

 

[MrStubb]

Battery charge will cause issues with mine but I also agree that there's likely an issue with wiring. There's a lot of plugs & they're easy to get mixed up. Your knock bothers me!! Is it a lite clicking (valves) a lower tapping (Timing chain tensioner) or a definite knock almost like a block of wood ( Wrist pin Rod bearing piston slap). The last of which could be a serious detriment to your riding enjoyment.

 

[arfstrom]

Aluminum corrosion, I don't know enough to answer well. My thought would be "as long as it does not impact the seals or various passages, it might be fine, until it does. So it buys a breather time. Add pics of the corrosion, so we can help evaluation it., Kinda is just one place, on the bowl on the bottom away from the hole, or is it so bad its uncovering the rest of the holes.

If you dig thought the archives, you might find that you can seal the aluminum after the fact. I remember talking to a paint powder coating guy, and he said he has to do something to aluminum to keep if from corroding or something.

As a Minnesotan, we have a local bike bone yard near here. They have tons of carbs that have been take off of bikes, and placed into large crates. that is were I found my current float. bring your own tools, modest price. http://www.sportwheel.com/. Its just past the renaissance fields, next to the KOA.

So two options, get inexpensive replacement part,

Since your local, I work at the airport, you might see me buzzing by wearing a purple shirt over my work clothes. I have been driving the bike more frequently with the nice weather here.

Reviewing your last msg, that knocking noise you might want to check it out sooner than later, this is what happened to me.
http://www.xs400.com/media/albums/ohh-crap-fubar-valves.645/
I am sure I have thread about this, what Is not in the pic here, is that two nuts come off, and just one of the lifters pounded thought the inspection cap.

 

[arfstrom]

After reviewing this again, it reminds me of my first go around. You have the link in my albums, look in there should be a pic of my using clear hose to validate the floats are working. My symptoms were, I would work on the carb, put it in, it would start up right then. Then I would go to bed, come back sometime tomorrow, and it would not start. That was a bad float. Other signs was fuel smelling oil (crankcase, perhaps even flowing out the airfilter.)