Like a challenge? Try and solve what's wrong with my Bike.....

[boonbuilt]

Hi Guys! be so appreciative of some advice here!

Right...... basically my bikes been sitting for about 2 months (XS400 1980). 2 months ago it was running like a dream as it had just had a service and was ticking over fine.

Come back from uni to find my bike wont start at all. Bloke who serviced it said it needs new points, but as its starting I wont need to get new ones for a while.

As it won't start i got some new points and they seemed to be sparking really nice, but the bike still won't start.

What i've checked so far is, both sparks are arcing, points sparking, new battery (on trickle charge), compression is fine, new condensors, fuel line's unblocked, fuel tanks been cleaned out, carbs were cleaned out 2 months ago. petrol is getting to the right hand side spark plug but not the left. Although surely if petrol is getting to one side- it should fire up one cylinder?

I've tried to bump start and it seems to splutter and gets to 2000 revs but just won't fire!


any ideas? suggestions? HELP!!

 

[Scorpio1963]

Have you tried starting fluid?

 

[boonbuilt]

yeh, ive tried it a good few times and it does nothing. I cant believe it as it starts just about anything!

I've also tried the fluid whilst bumping it and also from stationary.

 

[bentwrench]

1980 DOHC with points?

Doesn't sound right... can you post a pic of your bike?

 

[boonbuilt]

Yamaha XS400 1980

 

[boonbuilt]

Bentwrench i think you're right- i cocked up its no DOHC.

 

[ECP89]

Check to see if the plug wires are mixed up. I had that on my bike, fuel; spark; and compression but could not get it started. Swapped the plug wires and it was running within seconds. Easy test to do.

 

[boonbuilt]

Hey man, yeh I've tried switching... Also my fuses are all ok too and have been checked, it must be electrical problem though right? Thanks for the replies so far guys!

 

[abobber91]

Id thoroughly clean the carbs again if they haven't been touched in 2 months. Fuel thats trapped in the passages can gunk up over time. Lots of carb cleaner and compressed air.

Electrical problem sounds unlikely if you got the bike to sputter, and assuming all lights came on etc.

Also make sure the slide diaphragms are good (no unevenly bending spots or holes..)

 

[drewpy]

seems weird you have points on such a late model.

your problem is the condensors have failed or not connected properly that's why the points are sparking.

 

[Scorpio1963]

Yeah it was either 1980 or 81 yamaha switch to electronic ignition.

 

[Keithp]

Well you know the basics. Fuel spark and compression. You have verified the spark. What were the compression numbers? And clearly you have some fuel problems since you are only getting it to one side. Start with a carb clean. Take everything out. Clean clean clean and see if you are getting fuel evenly. If you know you have proper fuel and spark then it's either compression or timing. I'd love to know the progress. Any current updates?

 

[Scorpio1963]

Check the fuel bowls of each carb and look at the float level.Also take a small tiny needle and poke them through the idle jets inside the venturi.

 

[Keithp]

Check the fuel bowls of each carb and look at the float level.Also take a small tiny needle and poke them through the idle jets inside the venturi.

Good call. I had a float needle that was sticky and would either not let fuel through or would stay open and dump fuel out the carb! Damn you e85 fuel! They say it start turning to gel if not used within 30 ish days!!

 

[Scorpio1963]

Glad I was able to help solve your problem.

 

[xadmp]

to do all this..do you need to take the carbs off?

 

[willem]

Yea you should take off the carbs. That's not so hard, even I can do it

On my '89 DOHC that goes as following:

Turn off the fuel cock and disconnect the fuel line, take off the tank (one bolt under seat). Disconnect throttle cable and starter choke cable (starter choke cable is clamped on with a screw on mine). Loosen the inlet and outlet rings around the rubbers connecting to the air filter and towards the engine (4 rings total). Remove bolts connecting the rubbers to the cylinders.
Now remove the three bolts that hold your air filter body in place so you have some wiggle room. Take off the left side rubber between your carbs and cyclinders and slide the carbs out to the right. There is fuel in the float chambers (=fuel bowls) so that will come out if you turn the things sideways, be careful not to spill it on yourself/your garage (my friend was covered in it )

Then with the loose carbs you can take off the float chambers at the bottom and clean everything out on that side at least. Take a very thin needle to poke through the idle jets, the rest is pretty self-explanatory.

 

[Drewcifer]

Update? Vroom? Happy bike?

Drewpy, it's never the condenser (think of House saying It's never Lupus. tee hee)

Dave, don't start!

 

[16VGTIDave]

Never say never...