Im at a loss

Hey guys

First off, Valves have been maintained in spec over last two intervals, 3000 km from next service interval, looks like I'm diving into that early though

My 650 max was starting and idling a bit funky after taking it out of winter storage. It still had full power, but for the first maybe 5-10 seconds of running it would be missing on one or maybe two cylinders, had a somewhat lumpy throttle feel until I hit about 3000 rpm where it would spring to life and stay to life.

SO having some free time I decided I would go at my carbs again, thinking that my half ass storage procedures from the winter caused some varnish buildup. (Also hoping that the cause of my issue was some gummed up pilot or enrichment circuits).

Liberal use of carb cleaner and starnds of wire for those lovely little passages leaves me with what I feel are clean carbs. (wasn't bad when I opened it up in the first place, these carbs have been pretty well taken care of).

Bench sync? check! Fuel levels? 4mm below edge, check! Clunk test? Check!

I put the rack back on, hook up all my lines and cables, watch as the gas stops flowing while on prime (floats doing their job I should think)

I press the button and all I get is the engine cranking.

Check for spark? Good on all 4

I pull it all and do it again, still just engine cranking, not even a sign of combustion happening




Want to do a vac sync but cant get it to start

 

More info
- No gas in crankcase or air box
- fuel flows unrestricted on prime
- Not feeling any vacuum pull from the nipple that the vacuum line is attached to when I crank the engine

 

The float level is 2mm +-1mm so 4mm is too low.


FU

 

Mmmm, not according to the information overload hour

"Hitachi, all HSC32 series (all XJ650 except Turbo and 81-83 XJ750): -Fuel level measured via the clear-tube gauge: 3mm +/- 1mm (.12 +/- .04 inches)"

So I am still on the low end yes, but techincally in spec

 

Hmm I must be mistaken. But I think 4mm is still too low.

FU

 

How about the battery? Is it new, was it on a tender during storage? Might want to check battery voltage during crank and make sure it maintains a good voltage. 11.0V is good, anything below about 9.5V and the spark will be too weak.

 

Battery is good, got a good amount of cranking time out of it before it started to sound sluggish while cranking. It's on the charger now

 

Just because the battery turn the motor over doesn't mean that it has enough juice to start it.

 

Double check where you have the pilot screws set to.

 

it doesn't need to start to check your sync, just don't crank it too long. that's not your problem though. it should at least fire up unless your sync is way out in left field

 

Fully charge the battery and try again. I had the same problem in that the starter turned the engine fine, got spark on plugs, but no combustion at all. Fully charged the battery and it fired immediately. I don't understand how the battery can be strong enough to turn the engine and not provide enough power the the plugs, but that's what I've been told, and it sure seems to have worked for me.

 

Doesn't take a lot of juice to turn the engine over, but you need a good strong battery to kick a spark.

Try this though.....pull a spark plug and either spray a snort of starter fluid in, or a little squirt of gasoline. Put the plug back in and see if it fires........Try again with cyl 2. If it isn't firing with that, you go spark in free air but possibly not when in the chamber.

Also, when you take that plug out, look at it and see if it's wet or dry. If its' wet your drowning. If it's dry, you're starving.

Dave F

 

Thanks guys, I think the battery did it

Starts up, hangs at about 1500 for a second then races up to 6000.....investigating

 

My curiosity got the best of me since my Honda Rebel started with a battery that barely turned the engine over. As it turns out, the Honda has a CDI ignition rather than a TCI ignition. I've done a little reading on it but electrical stuff just puts me to sleep. However, apparently a CDI system with a capacitor doesn't take as much battery juice to create a spark. The capacitor stores the energy and gives a very strong but short spark where the TCI gives a weaker but longer spark without any storage, i.e. coming directly form the battery?? At least that's sort of what I got before nodding off to sleep. Now you know how little I understand about electricity. Anyone have an "ignition for dummies" explanation?

 

You've got the gist of it. Spark hotness and duration is determined by a number of factors that relate to combustion chamber design and compression ratio. TCI and CDI systems are just different methods for achieving the duration and hotness that the combustion chamber design calls for. Kevin Cameron goes into a lengthy and easy to understand explanation in his book Top Dead Center II.

 

After the hang ( up and running ), the race up the rpm's( warming up ) is good as long as you can start backing it down by slowly taking off the enricher lever. After a little bit you should mostly off, with the last little bit turned off shortly after you start riding, unless it's really cold out ..

If the rpms stay high without the enricher, you have an air leak. If the engine won't run without the enricher on, you have clogged jets.

Dave

 

I solved the rpm race, throttle cable was hanging up, adjusted and fixed that.
Not before I twiddled with the idle adjust knob to try fix it though, backed it way out thinking that was causing the high idle.

Now its firing on one cylinder when I start it, but won't catch on the others. Plug on the firing cylinder looks good, other ones are drowned in gas. Down go the pilot mix screws a half turn.

Now it tries to start at first but then just keeps firing on one cylinder as I hold the button, exhaust reeks of unburnt gas at this point.

Doesn't seem to matter which plug I swap into cylinder #1, that's the only one that's firing

Can't figure out why it won't catch on all 4

 

Engine sounded great when it was racing at 6k rpm, definitely was hitting on all 4 at that point

 

Glad you found the cable.

If your plugs are soaked, you may be flooding..... That could lead to a crankcase full of gas. Open the filler cap and take a sniff.

Could be floats, could be stuck needle, could be other issues.

Could just need some seafoam and clearing out of the older fuel---

Could be moisture-- seafoam will help there, too...

Could be you need new plugs...,

 

at this point, I would check the float levels with the carbs on the bike and see where they are at.

FU

 

I couldnt just leave well enough alone could I? haha

Left petcock on prime when i went for dinner....pool of gas, and yupp some oil, on the ground after

Looks like im doing an oil change too *facepalm*

 

Sometimes when you gas-soak the plugs, they're toast from then on. It's an easy fix (new plugs). Of course, after you fix the leaky fuel valves....... :-(

 

IF one flooded their engine with say a more than average amount of gas, how long could it potentially take to "dry out"? (is that what happens? I may be a little bit confused on what exactly has happened inside my cylinders)

My oil absolutely reeked of gas when I changed it, so I'm sure a decent amount got into the crankcase

Flushed the oil twice (once with 2 litres left from change last summer), once with brand new oil.

Engine still "chugging" while cranking and not starting.

Forgot to buy new plugs today *doh

 

Changing the oil will get rid of most of it. You might need to do a second one, but I've never found that to be necessary myself..

You don't really have a 'drying out' time

 

as the engine heats up, the gas left in it will turn to vapor and get sucked out the breather into the air cleaner and be gone. same idea as how they make the oil and gas

 

Exactly

 

I seeee

another possibly silly question

My new plugs have silver caps where the wires from the coils would attach, the ones currently in my bike have a thinner black pole with ridges. Do I just pull the silver cap off?

 

That's what I had to do with my plugs. Chacal also sells them FYI.

 

You will unthread the caps. It's done that way so one plug can be used in several different applications.

 

Just get a pair of pliers and unscrew them. The ridges are actually the threads.....

 

Also when your putting the caps back on the new plugs tighten them up and then just a touch tighter. I've had them rattle loose and the bike performance went down.

 

And she runs

After new spark plugs, resetting the float heights, and rebench syncing

Guess I messed up one of those steps the first or second time

Idles much better than before, starts with noooo throttle now. Im happy