1983 xs400 - PROBLEM WITH STARTING - SILLY NEWBIE MISTAKES?

I picked this XS400 bike up last week, and it fired up with a boost, no problem. The bike was sitting for the past year with a half tank of gas. The guy turned the petcock to the 'on' position to get it going, so I'm assuming it was off during storage. I added a bottle of fuel injection cleaner to the tank also. I figured this would be good to clean things up...

I also changed the oil and oil filter. (there was a strong smell of gas in the oil). New oil seems fine, with little to no odour of gas. It fired up okay again. I then drained the fuel bowls (I thought it would be good to flush old gas) and now it won't start. I can hear the motor half turning, but it's not starting... It sounds like it wants too, but won't.

What did I do!? In retrospect I realize I shouldn't have added the injection cleaner, or drained the bowls, but rather asked for guidance.

Please help, Thanks.

 

Re: 1983 xs400 - PROBLEM WITH STARTING - SILLY NEWBIE MISTAK

And by the way, I've never owned a bike before... just ridden them. My wife always thought it would encourage my little guy to do 'dangerous' things... but I've convinced her that being responsible is the best example. So if my questions seem silly, forgive me - I've seen a lot of advice in the forums (I've been reading them for a couple of months now). I'm just not sure what specific action I should take.

Thanks again.

 

gas in the oil means stuck floats and possilby leaking petcock. you need a carburator diassasembly and cleaning

 

try turning the petcock to on or prime to refill the bowls. a shot of starting fluid may help if it's not flooded

 

Re: 1983 xs400 - PROBLEM WITH STARTING - SILLY NEWBIE MISTAK

Do I put the fluid through the air filter section, or right into the line that feeds the carb?

 

I've always removed the filter and shot the starting fluid in there.

 

Well, draining your carb bowls may have been either good or bad. Or both.
If you're lucky : your bowls are just empty. Turn the petcock to PRIME for about 30 seconds, then try starting it again. Use the choke and see if it runs. Return the petcock to the ON or RUN position regardless if it starts. If it started, great.. problem solved. If it didn't, then....

You aren't lucky : - you could have all kinds of gunk in your carbs. It's worth a shot of starting fluid sprayed into the mouths of the carbs through the airbox. Take the air filter out and spray starter fluid into each carb (3 or 4 seconds). try to start it. If it catches, you may just have dirty carbs. See any number of posts on this great board to clean your carbs.

You still aren't lucky - the petcock may not be letting fuel flow because (a) it's no good & needs repaired/replaced or (b) the filter screen in the tank just on top of the petcock is clogged. (remove & clean).

Good Luck. Where in Ontario are you ? There are lots of us here.. maybe we could help ?

Feel free to PM if you wish...

 

Last night I turned the fuel back on and the bowls are full, but no start. I've also noticed a small leak from the oil drainplug. The oil smells like gas again.

SO, then I pulled the sparkplugs this morning, and noticed that they are both black, sooty and oily. Of course they smell like oil and gas. I wiped them down and will clean them up later.

I'm going to try pulling the carb this evening if I can keep the little people occupied with something else.

Thanks for the advice, I can't wait to get this bike running!

By the way, I live in Toronto.

 

If your fresh oil smells like gas again, you have gas getting in there somehow... likely your floats are stuck, which could be why the PO had the fuel shut off. Either way, find the Carb Cleaning guide in the How-To section and have at 'er. With your 400, you only have 2 to worry about.

Good luck.

 

As suggested before you need to strip your carbs and clean, get hold of a manual and follow the instructions, it might seem complicated if youve never done anything like this before but its not that bad really, and above all the more you learn the more you save.

By the way, if your oil if smelling of petrol then DO NOT RIDE IT UNTIL YOU HAVE RESOLVED THE PROBLEM. Sorry for shouting but its bloody dangerous. Petrol vapour in an enclosed space is an explosion waiting to happen. Its a fairly remote chance that vapour in a crankcase would explode tbh but consider where your feet are in relation to the cases!

 

Use Ricks "carb cleaning the whole 9 yards" and "your carbs need to go clunk" guides.....
They have made a world of difference in my XS400K

I'm pretty sure the XS uses the same type of carbs, for a visual guide, check the gs resources website.... the carb cleaning primer there goes much deeper than you will need (the dissassemble the rack, for ease ot retuning you will want to keep them together)

1 tip, clean 1 at a time so no parts get mixed up as jets are often different left and right.

 

Re: 1983 xs400 - PROBLEM WITH STARTING - SILLY NEWBIE MISTAK

Thanks for the advice. I took the carbs out and disassembled piece by piece - separated per carb of course. The first carb (number one?) had sludge in it... I'm thinking that's a result of the injection cleaner I put in? The second was squeaky clean. They were both really clean except for those jets in #1. They are soaking overnight and I'll clean them tomorrow evening. I also drained the gas tank and am thinking I should check/clean the tank filter? I noticed the air filter smells like gas - is this normal? Oh, and they both go clunk.

 

Re: 1983 xs400 - PROBLEM WITH STARTING - SILLY NEWBIE MISTAK

You say the plugs were oily.
This would indicate blow by the piston.
May want to do a compression check.

 

Air filter would smell of gas because when the petcock fails, it floods the carbs which also gets the filter wet with gas and backs up allowing gas to run ino the intakes.

The petcock failing lets gas get into the combustion chamber and run thru the rings into your new fresh oil; the real danger here is to the engine with your oil being compromised.

Looks like a petcock fix and carb rebuild and sync

 

Re: 1983 xs400 - PROBLEM WITH STARTING - SILLY NEWBIE MISTAK

Well I tested the petcock, and flow stops when I turn the knob to 'on', but is activated by vacuum pull... I think I may have left it on PRI when the bike was dropped off out of sheer excitement. I hope that is the reason they flooded...

I cleaned up the carbs and put them back together, everything looks squeaky clean but I haven't installed them yet, because I still have gas in the tank and can't figure out how to drain it fully. I'm thinking I should jack up the back end? I really want to get the old gas completely out to minimize the risk of gunk flowing into the jets again. Then I can install and sync the carbs.

I hope I'm almost there...

 

My tank comes off with one bolt and then I can pull the petcock and kinda shake most of the gas out.

 

Yep, do as above and check your filter for the petcock while you're at it.
Then, use an old turkey baster, or antifreeze tester etc, to empty 99.9% of the remaining gas ....

Works great

 

i have taken the tank off anf flushed it with water then blew compressed air through the tank until dry, if compressed air is not available, put in a little bit of dry gas and let the tank set overnight to remove any extra water.

 

Well I took off the tank and flushed it good, blew the water out and refilled it with premium gas. Still couldn't get it to start, even with a boost. My buddy says the battery needs to be alive even with a boost. It did fire up with a push start... but was backfiring - which I think is because the plugs are not gapped properly. I've gotta clean and gap them. Man I am was so happy to hear her fire up. So I'm going to pick up a battery after work...

 

It's hard to get all the gas out even with the tank off the bike. Install an inline fuel filter before you try to start with those newly cleaned carbs. you would be surprised how much junk gets through the petcock screen.