Main Menu

Hydraulic-ing

Started by pinholenz, November 20, 2015, 04:45:52 PM

Previous topic - Next topic

pinholenz

I've seen mention of the problem of Hydraulic-ing somewhere, in reference to carb problems and flooding.

Occasionally if I stall the XZ (say, stopped at a junction when I forgot to change down), then I have a real problem starting the bike. Inevitably I have to wheel the bike over to the side, let it stand for 5 minutes and then it turns over fine and fires up.

I can only guess that stalling has sucked petrol into the cylinders and that it has expanded in the hot engine so that the starter has too much resistance. The starter motor really struggles to turn the engine over, whereas under other circumstances it spins fine.

Any thoughts or suggestions other than "LOL, don't stall you idiot!"?
Only one '82.5  eXtreme Zen 550

jefferson

If it was hydro locked it wouldn't turn over at all. Might the starter be hot and thus the extra resistance be from that and cooling off for that time lets it cool to where it will crank fast? That would be my guess.

Blake

#2
90% this has nothing to do with your carbs.  It's your stator or voltage regulator.  This is a long standing issue with "hot starts."  Check your electrical system.


Cliffnotes:  Stator or VR is dying, running the bike for a while runs down the battery enough that it has a hard time starting, bike wont start.  You let the bike sit for a while, things cool down, it starts right up. 
"At first it's like a new pair of underware... Frustrating and constrictive.  But then, it kind of grows on you..."

Re-Vision

I don't know with any certainty what is causing your problem but I remember when first getting my bike of killing the engine at a stop sign and how embarrassing it was pushing to the side. Several minutes later it started. Had the carbs cleaned and no more starting problems.   BDC

The Prophet of Doom

There are a ton of things that cause hard hot starting.  Can I add poor valve adjustment to the list of likely possibilities. 

b_racuda

Last summer I had problem with gas tank cap, it was so corroded inside that the bike was stalling at the red lights. The problem only occurred when the bike was hot.

pinholenz

#6
Hmm. Take your pick.. Nothings too simple with the 'ol XZ!  When she has stalled and is hot, the starter struggles to turn the engine over.

Increased starter resistance when hot sounds feasible. I ran a new heavy guage wire back to the starter relay a couple of years ago when I rebuilt the starter. It certainly helped improve general starting performance. Apart from turnover rpm, how can I check the current being drawn by the starter? I have a voltmeter installed on the bike, but not specifically on the starter circuit. Would the voltage drop on hot versus cold starts be sufficient to point to a starter problem?

I'm pretty confident the Mosfet regulator/rectifier is OK, as is the stator. (But I do have a new (used) SH775 ready to install when the weather turns.)  The bike always starts from cold within 5 seconds of cranking and I always have a visual check with the voltmeter installed to see what its charging at. I don't use a trickle charger between rides.

Carbs have been overhauled and she is running without any stumbles. But I could do with a new air filter and the carbs haven't been off for a while now - but how would that affect crank speed?

Next time this happens, I will try taking the gas cap off in case a vacuum has built up - but I cant see how that would affect the cranking either.

And thanks for the valve clearance reminder POD. STILL haven't done it. The thought of having to take it off the road during this lovely summer and maybe not riding for 2 or 3 weeks while I source shims or, (heaven forbid), gaskets,  is too stressful. (BTW any news from your CNC man about a batch of shim tools?)

Only one '82.5  eXtreme Zen 550

The Prophet of Doom


I should have read more carefully...Carbs, valves, spark plugs lead etc can make it a bugger to start, but I can't see how it would make cranking slow.



I'd suggest trying to isolate it to battery /charging, cabling or starter motor itself using jumper cables and a car battery. Do you need instructions for this?


If you end up suspecting battery then a load test at a battery shop is your best bet.  Cabling, then make all nice and shiny, and not forgetting your earth.  If starter motor then a teardown or I can send you a loaner.




Still waiting patiently on word on the tool :-)




pinholenz

Thanks very much for the offer POD.

I have jumped the starter in the past (when I had drained the battery) by running a car battery negative to the bike battery and then touched the positive lead to the starter terminal with the ignition turned on. A bit sparky brutal but worked a treat. Is that what you mean?

Load test first makes sense, then, take it for a hard ride ending up at the car to see if it spins over easier on the car battery or  the bike battery. Is that the idea? Then take it from there.... Thanks.
Only one '82.5  eXtreme Zen 550

The Prophet of Doom

Electrical issues are a pain in the arse.  Resistance goes up drastically with temperature, so something like a marginal earth lead can start to flake when it was working fine cold.

The idea is to zone in on the problem without spending any time, money or trawling into a shop.
Do the easy/cheap/quick stuff first.

You can eliminate the battery from the equation by connecting the car battery to the XZ battery with jumper leads.
You can eliminate the wiring from the equation by using jumper leads direct from the battery to the starter.
You can eliminate the positive side just by running a jump from the battery earth direct to the starter case.

You only need the effort of a load test if jumping from the car to the XZ battery fixes the issue.

Wear safety glasses for the sparks - having these dug out of your eyeballs is no fun at all - I can tell you from first hand experience. Also you can use two sets of leads so you aren't sparking on things you care about.