Bike broke question

[Austblue]

Gents, my bike died on me today I've recently installed the elec advance unit and timed it and it was running fine then I fueled up with premium unleaded 98RON and barely got 2kms away and it started backfiring and died. I didn't have any tools available and a good Samaritan happened to pass by and offered to take it to his shop and despite having done all the work on it to date myself I relinquished and let him take it. I did manage to kick it over once more but it burbled and spat and backfired something terrible and then died after about a minute. I'm leaning towards some type of fuel delivery issue. I recently replaced the fuel hose because I believed that the original was kinking and choking the flow. I have the inline paper filter and stock vacuum petcock and even when on prime it isn't flowing into the filter which made me think perhaps the petcock filter was blocked but if I take the hose off it flows out freely and when running it does trickle fuel into the filter. I normally run regular unleaded which is 95RON but wouldn't have thought the slightly higher octane fuel would've put the bike out to cause this issue.

Summary of status of bike and work done by me:
81 special with original tank and petcock that haven't been serviced to my knowledge
150psi in both cylinders when checked last
Hugh's PMA
Pamco ignition and adv. with high output coil
650 central BS34 carb jetting kit -
Enlaged slide dampening hole
Titanium needle with clip in #3
#135 main jet
#45 pilot
Float checked and in spec
low speed mix screw at 2.5turns out
pod filters (http://www.mikesxs.net/product/15-0033.html) (I know I should replace these)
Rewired and running a 32k Mu capacitor
Original petcock not rebuilt.
Jama Mufflers which do have a bit of a leak where they join the headers.

I appreciate any assistance or suggestions that help. The mechanic is a local mod shop that generously helped out today - big shout to dockyard dragsters in mayfield (newcastle, NSW Australia). The owner offered to trailer it to my house and refused payment which I will now have the opportunity to pay him back for. I'm confident he'd sort it but having set the bike up myself I'm curious what the problem could be. I'd troubleshoot it myself but unfortunately I'm working away from home all year so time working on the bike is better spent riding it and I've not done much of that

cheers.

 

[jd750ace]

I don't know about Australia, but here in the states the premium grade fuel tanks don't cycle near as much fuel through them as the lower and mid-grade. This had led to water and debris issues out of those tanks occasionally. I try to get my fuel at stations with high turnover. Their filters get done more often, and the filling cycle churns up and disperses the impurities throughout the fuel load in the tank, so even if it's "dirty" everyone gets the same amount of dirt, instead of a couple of tanks getting a big dose. As far as I know, there is no re-circulation in the in-ground tanks at service stations.
When I was in the Army, we had remote re-fuel points in the jungle in Central America (if I told you where, I'd have to kill ya!) where we would fly in and shut down and the crew chief (me) would have to go set up the pumps and hoses and check the fuel in the bladder for water content. If the water content was above 10 PPM, we would connect the output hose to the input side of the fuel bladder, and use the pump to stir up the fuel and disperse the water out to an average value below 10 PPM before we could put it in the helicopter. Did not make the water go away, just churned it up into a lessor percentage per volume of fuel. This minimized the potential for icing to occur, which does not need cold temps to happen. The fuel system in the aircraft has over-dog pumps that bypass the excess and return it to the tank, acting as a fuel warmer as well, because the bypass fuel went through the heat exchanger in it's cycle. We don't get all that insurance in a gravity fed fuel tank on a bike, so a dose of water kills the fire. Just a thought. Hope your issue is as simple as a bad shot of fuel.

 

[rockhead]

With a vacuum petcock, there's a hose that leads from intake manifold to petcock to open it when the bike starts. Check that it's not kinked or loosely attached at either end. If it is, no vacuum at petcock, and it won't open.
Another idea is to check if the breather hose from the fuel tank is blocked. If it is, you end up with a slight vacuum inside the tank and fuel won't flow out. I've managed to do both of these at different times.

 

[Austblue]

The vacuum hose was on and I also tried running on prime which would take the vacuum hose out of play. I thought there may have been a problem with the petcock but as I said, when I took the hose off fuel flowed out.

Should my inline filter be filled when the petcock is set to prime?

 

[Ketis]

id check out the ground. If that came off, the regulator would just send 20+ volts to everything and fry the pamco

 

[rockhead]

I'm not that familiar with in line filters but there should be some fuel in there. It would depend on how much you filled up the filter when you put it in. Are the filters directional ? Are they a one way filter with a fuel in and fuel out end ? Maybe try to take the fuel hose off at the carb end and see if you have flow through the hose.

 

[Austblue]

The filter is directional and I'm certain it is on the correct direction. Due to being such a tight fit with the carb fuel intake nozzle being blocked by the frame I couldn't easily remove the hose where it joins the carbs but will suggest that the mechanic tries that to at least prime the line. I'm leaning towards either bad fuel or air trapped restricting flow.

 

[hotdog]

Drop your fuel lines at your carbs, set fuel tap to prime and see what happens, fuel should piss out. I would drain the tank into a clear container and check for water etc....
Have you pulled the plugs and grounded them to the head and checked for spark..?
These 2 checks will tell you what system you should be checking further.....

 

[Austblue]

Thanks for the help everyone. Unfortunately I'm working in Sydney and the bike lives in Newcastle so I let the mechanic take it and its in his shop otherwise it wouldn't get touched for a month. I also didn't take tools with me like I normally would because it had been running good and I was trying to be positive as it wasn't a test ride but rather a cruise out to meet family and friends for a morning picnic in the hunter valley. As such the simple checks haven't been done at this stage. Quite sad about it as I've done all the work myself and pride takes a hit letting someone else wrench on your bike

 

[Austblue]

I got word back that the pin had popped out of the advance mech unit. Simple problem with a simple fix that I could've done road side had I bothered to take tools. Fixed bike is good news though, time to put some miles on her and prove her worth!

 

[crescendo]

Don't worry about mechanic. He might be a professional. And he will definitely find and solve the problem of your bike.

 

[peanut]

I got word back that the pin had popped out of the advance mech unit. Simple problem with a simple fix that I could've done road side had I bothered to take tools. Fixed bike is good news though, time to put some miles on her and prove her worth!

thats a good ending and no loss of pride either...you did everything right.

 

[Dustproof]

Hi Austblue,

If you want to ride with another XS650, I live at Tuggerah. If your around this way, we could catch up and have a ride to Jerries for a coffee.

See ya
Noel

 

[Austblue]

Thanks Dustproof. I've not taken it down the coast yet but that'd be a nice long ride to do.

I picked the bike up from the mechanic and he hadn't set the timing so we did it on the spot by ear then I rode home and it wasn't pulling as hard but I knew that I had to re-time it with my strobe when I had time. Took it for a short ride down the hardware and it crapped itself on the way home. Mechanic had told me that he'd re-set the mech advance so that the weights were in rather than out and had done so by bending the tabs in which I didn't like but it was done so nothing i could do about it. Well the tabs didn’t like that so fatigued and let the weights go for it as you can see in the pics.





Luckily I was only 200m from home and Pete had sent me the copper cap so I had a lil picnic with my bike and got her sorted proper than got it home and set the timing. Mechanic had also said that my timing mark was out (Hugh’s PMA marked by me) which I disregarded as him being a nuffy Well sure enough I couldn’t get it to run clean with it firing on my mark so reluctantly pulled the plug to check my mark and confirmed that it’d shifted about 30degrees! I can’t explain how that’s happened given that the flywheel hasn’t been touched and I know the timing marks have been correct as I’ve done the timing myself off it a handful of times when going from initial tune to new mech advance to elec advance and then back to mech advance. Any tips?

$450 worth of work that lasted 20kms has restored my pride in doing my own quality (relative right )work. Had it back on the road in next to no time and I think it’ll be smooth sailing now *touches head*

 

[retiredgentleman]

That mechanic seems to know less than nothing about XS650 bikes.

Its always better to do your own work on these old bikes.

 

[peanut]

it makes me so angry when I hear about the mess so-called mechanics make of folks cars and bikes. Especially when we have to foot the bill for it.

I have done all my own wrenching for over 40 years until recently and the few times I've been forced to use mechanics they have either broken things or blown a head gasket or something.

Good to hear you sorted it yourself and its now rideable.

I love that seat, I particularly like the way you've managed to get such a cool look without chopping the frame or sticking bits of diy grp on the back. Your bike looks great.

 

[I am Carbon]

I agree with peanut 100%

 

[Austblue]

Gee shucks thanks peanut. That's actually the first pic I've put up because I wanted to get the bike looking nice before I put up build pics but I liked the look in that pic. I made the seat pan and had a local guy cover it to my wishes and the colour wasn't quite what I was chasing but its difficult to source good stuff here at a reasonable price. Main issue is that it'll mark up easy.

Keeping the frame as stock as possible is for a couple of reasons:
a) don't have the capacity or equipment to do the fab/welding myself
b) as its my first build I didn't want something that'd require engineering as that can be difficult in NSW for the uninitiated.
c) I like the stockish look!

I wont be painting her next year I think as I'm working away from home so not enough time to wrench.