Ex-500.com - The home of the Kawasaki EX500 / Ninja 500R banner

1 - 10 of 10 Posts

·
Registered
Joined
·
32 Posts
Discussion Starter · #1 ·
Over the winter I did a valve adjustment, took the carbs apart and "cleaned" them (they were fine) and did a few other maintenance items. When I did the valve check I remember some of the valves were a little tight but nothing extreme. With the carbs, I took things apart and put it back the way I found it. I drilled out the cap on the idle screws so I could do the FOG mod but set them back where they were (about 2 1/8 out).

I got the bike back together enough to fire up last night. Started easily and drops into an idle fine but sounded a little "off". Today I hooked up a set of vacuum gauges and they're reading low and bouncing all over the place (I'll try to link a video at the end of the post). I didn't do a reading before I took it apart (didn't have the tool at the time) so I'm not sure if this is a new problem. I rode the bike a couple times before I tore it down and it seemed fine. I haven't ridden it yet since getting it running. Somebody has hollowed out the mufflers on this thing, in case that's relevant.

If anyone has any ides or a place to start, I'd appreciate it. My compression tester is at work so I can't do that today. And I don't have an air compressor at home so I can't do a leakdown test. I don't suppose there's a way to check valve timing without pulling the valve cover back off?

Gauge Readings
 

·
Registered
Joined
·
1,377 Posts
all I can see is you didn't (choke down) the gauges, using the restrictors to stop the gauges fluctuating 10/15 Hg at tick over is fine. it's about where mine are (both bikes).
how can you balance the carbs, with the gauges over the place.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #3 ·
all I can see is you didn't (choke down) the gauges, using the restrictors to stop the gauges fluctuating 10/15 Hg at tick over is fine. it's about where mine are (both bikes).
how can you balance the carbs, with the gauges over the place.
I'm sorry, I don't understand what "choke down" means in relation to the gauges. Is there supposed to be a damper somewhere in the line? I had thought that maybe it was the tool (borrowed it from a friend who's never used it) so I popped the PCV breather hose off my truck and hooked it up to that. It read a perfectly stable 20 inHG. I'm used to working on car engines. A car of this vintage should have 18-21 at idle. So the low reading and the pulses were giving me pause.

I did wind up taking the valve cover back off and checking everything. The timing marks look fine (lines up with the head on the outside markings, bottom marks lined up with each other on the inner markings) with the "C" centered in the sight window. Can't count the pins between the camshaft marks without taking the guide off and I don't want to do that unless somebody tells me I need to. I don't have my feeler gauges at home but there's definitely play on the rockers when the valves are shut.
 

·
Super Moderator
Joined
·
6,552 Posts
Having a little side to side play in the rockers is normal.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #5 ·
Having a little side to side play in the rockers is normal.
Yeah, sorry if that was unclear. The play that is there indicates to me that the valve is not being held open when it shouldn't be and that there is appropriate valve clearance.
 

·
Registered
Joined
·
19,523 Posts
this engine has no intake manifold as such like multi cylinder cars , so no intake plenum to absorb the piston pulses. you must restrict the tube to the gages to make them replace the manifold to get smoother reading gages.

FOG
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #7 ·
this engine has no intake manifold as such like multi cylinder cars , so no intake plenum to absorb the piston pulses. you must restrict the tube to the gages to make them replace the manifold to get smoother reading gages.

FOG
Thank you. That is what I was looking for. And makes sense. Could you share a ballpark reading that I should see on this engine? (I'd phrase that as a "do you know" question, but I'm pretty sure you do :)) There are a set of tapered nipples in the kit but I was unsure of where those are supposed to hook up. There are no threads on the fittings to the gauges. Am I supposed to take the stock nipples off the carbs and install the tapered fittings from the kit? This is a cheap-y amazon kit so I'm not working with the latest and greatest here.
 

·
Registered
Joined
·
1,377 Posts
omg. this basic stuff. yeah your under a misconception your truck is the same as the EX it isn't. the truck has multi cylinder so the breather has constant vacuum. on the EX twin your taking readings direct from the intake of each cylinder so it pulses as the vac is switched off and on on each stroke. this makes the gauges erratic. to steady the needles you have to choke them down (reduce the pulses) to a steady stream.

depends on the gauges. the ones you have it will be that little brass knob on the connector turn it clockwise to reduce the pulses . and no you don't need any of the fittings just push the rubber pipe onto the carb ports (there not removable)
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #9 ·
omg. this basic stuff. yeah your under a misconception your truck is the same as the EX it isn't. the truck has multi cylinder so the breather has constant vacuum. on the EX twin your taking readings direct from the intake of each cylinder so it pulses as the vac is switched off and on on each stroke. this makes the gauges erratic. to steady the needles you have to choke them down (reduce the pulses) to a steady stream.

depends on the gauges. the ones you have it will be that little brass knob on the connector turn it clockwise to reduce the pulses . and no you don't need any of the fittings just push the rubber pipe onto the carb ports (there not removable)
Ok, calm down. I wasn't under the impression that it's the same as my truck. I took the reading from the truck to confirm that the gauges were functional and to get a baseline from a known good vehicle. I've never balanced carbs or hooked up a vacuum gauge to anything with individual carburetors. So there's a bit of a learning curve here. I saw something I didn't understand and didn't fit with my (not inconsiderable) mechanical experience. So I asked for help/clarification. You know, the raison d'etre of this particular board?

Anyway, turning the valves on the gauges seemed to have an on/off effect on the readings. But, again, I'm not using a particularly refined gauge set. I'll try again when I get things back together or maybe use a splice fitting as a damper. Thanks for the advice.
 

·
Registered
Joined
·
1,377 Posts
FYI and as an aside, the gauges you are using are atmospheric ones. that keep a constant air pressure of 1bar. (or whatever is around you) to keep the gauges accurate. (that is what the hole is in front glass) the gauge is just a brass tube when you apply vacuum the needle moves one way. when you add pressure they move the other way (dual function) but need choking to work correctly. (with the screw) mine on the other hand are oil filled so do not require a choke as the oil keeps the needles stable.

when checking the carb balance set the idle to around 1500rpm choke down the needles so there steady both dials should read the same. adjust them if there not then when stable rev the engine in blips both needles should rise and fall together if they don't but are the same at tick over then you have other issues (like a vac leak)
the dials are there for more than just for setting the carb balance there also a diagnostic tool also (but you have to know how to use them.
 
1 - 10 of 10 Posts
Top