XS850 Restoration

First topic message reminder :

Having cleaned out a corner of the shed, I've finally started the work on the XS850.  Not much progress but I've made a start.  Pics to follow.

That will happen AFTER I have it working!

Not so good today.  Overhauled two of the carbs but had a disaster with the third - broke the support posts of the float.          I think the pin had been incorrectly inserted because it sure wasn't coming out.  But it did need to come out as this photo shows.  These are the needle holders for each carby - there is plenty of dried up fuel deposit.  The third one was just as bad as the other two but it cleaned up when I was examining it.  All three were replaced though with new parts supplied in the overhaul kits.  I didn't really find too much other gunk - just a light coating on most of the surfaces.  That carby cleaner is good stuff!   

I have found a new carby body on eBay and it should be arriving from the States soon!  Tools down until it arrives.

You have to be super careful with cast alloy. Maybe see if you can fix it with rapid fix its amazing stuff. http://www.rapidfixaustralia.com.au

Ta Reddog - I'll give it a go.  I hate throwing things out if they can be fixed.

Be very careful with floats.
Personal experience with a sticky float/needle in a Gemini.
Parked nose downhill. Fuel tank uphill. Float jammed up & allowed fuel to flow from tank. Overnight, fuel seeped past valves and filled up cylinders. Past rings and into sump.
Luckily, in the morning, the motor wouldn't turn over due to hydraulic lock. Fuel in the cylinders.
If you have one carb do this and the other two are fine, there's a chance that your motor will fire on the two and bend the con rod of the third, hydraulic lock cyl.
Personally, I would be patient and wait for the new part to arrive.
Keep up the good work, Ewok.
We never stop learning, do we?

You're traveling pretty well though mate. Keep it up.

Ta 2WA - I have to expect a setback or two, given it's also a learning exercise.

Ewok1958 wrote:Ta 2WA - I have to expect a setback or two, given it's also a learning exercise.

Hey, if that's the worst thing you come up against then I think you'll be doing alright.

My thoughts exactly Hammy (after a bit of initial frustration at what happened!).

Novelty number plate - thought I'd get a matching one for the TRX. What did we do before eBay?

Ooooooo!!!!
Sends a shiver up my spine.
I made a novelty number plate on a cnc engraver. Yellow plastic that when engraved revealed black.
I made it the same size as bike plate, rounded corners and everything. Even the border stripe. I was very proud of it.
"Volvo aware rider"
Yep, you guessed it. I wrote off a Volvo with my mint Gsxr two weeks after fitting it. She did a U-turn on the freeway in front of me. I obviously wasn't aware enough. Lol

Yours look the part, Ewok. Very snazzy.   

Well guys.  I reassembled the carbs and put the whole assembly back on the bike today and fired it up.  She ran beautifully (that's the good news) until I saw fuel pissing out of the airbox (that's the bad news)!  Mind you, it was still running sweet as even with the fuel dripping out.  I didn't run it more than 2 minutes as I was worried the whole lot might go up in flames, but it idled and ran fine over that time.

Any ideas on what might cause this?  Could the float levels be that badly out that it would leak fuel but still run fine?  Or something else completely.  I've no idea how the fuel could be getting into the airbox other than flowing out the back of the carbs - not sure if this is even possible but something is causing it.

Or do I call Spencer Mobile mechanic?     

Sound like float levels. Are all the over flows dropping out onto the floor?

I don't see any overflows rd - maybe that's why it's getting back into the airbox.

Sounds like a sticking float, or possible a float that doesn't - i.e. one might have a hole or split seam and is not actually floating.

barry_mcki wrote:Sounds like a sticking float, or possible a float that doesn't - i.e. one might have a hole or split seam and is not actually floating.

I agree with you Barry. Two out of the three carbs working well and their cylinders purring. Number three still running, but very rich. Fuel flowing back into the air box.

Nice to see that she fired up and ran sweet. Keep up the good work, Ewok.

Pull the plugs to check out which carb has the problem. 


A real carb (flat slide) looks like this



Notice all the hoses. Most of them are vents to allow fuel to flow and not bog the bike when hitting whoops or jumps

Good idea - I'll do that as soon as I can get to it - probably Sunday arvo if I don't do it crack of dawn tomorrow.  Thanks.

Start it up again and put your hand on each header pipe. One maybe cooler than the others. ie, not getting any fuel to burn.

Have you had a play with the old girl yet, Ewok?
Found the issue? 
Gagging for a video of her running down the street.  

Not yet unfortunately Bosco.  We're in the middle of some significant building work so I don't expect to get back to my garage until about mid-May.     
Cheers.

Well I put the carbs back on today and she ran again but there was still fuel running freely from the airbox!  Bummer.  The good news was that when it was just sucking fuel from the carbs (ie after I removed the tank) it ran as well it probably did from the factory.  Good throttle response, no hesitation at all.  Cycled it up and down through the gears nicely (a bit clunky) so the clutch and drivetrain (shaft drive) are good.  

I'm a bit stuck on what to do next.  Can't ride it far with just the carby fuel!  I'm still convinced it has to be a float bowl issue but they were checked by an old bloke who has a good reputation.

You might have to jury rig a funnel with a length of hose. 
Remove fuel tank. 
Fit the funnel hose to each carb individually and see which one keeps drinking. 
If they all only take enough fuel to fill their bowl, then it must be down to fuel line plumbing.

Good thinking Bosco but on the XS850 the duel fuel lines feed a common rail that sees all three carbs getting fuel from the two taps (one on each side). More head scratching....

That's what I mean. Remove the common rail and test each carb individually. This will confirm or rule out a float problem.