Author Topic: No Combustion  (Read 1761 times)

Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
No Combustion
« on: April 01, 2019, 12:07:59 am »
So my project bike is turning into a neverending series of roadblocks. I can't get the bike to start and I'm desperate for any help. Here's hoping someone can help.

I'll try to keep the context as brief but thorough as possible. I'm doing a complete restoration of a 95 C10. I tore the carbs apart and cleaned them to look like new and replaced every rubber piece along with Steve's float bowls. Rebuilt J-box from Larry Buck and an almost new wire harness. Last week I hooked up an auxiliary tank and fired up the bike. It started with the choke but wasn't running very well. I tried adjusting the idle and it would stall out. I could only get it to run for about 15 seconds at a time before it would stall. I then saw gas coming out of Steve's overflow tubes. I drained the carbs and pulled them from the bike. I ordered new float valve needles from Murphs and when they arrived, tore apart the carbs. I replaced all the needles and discovered a bad float. I had a spare set of floats so I put them in. Put it all back together and then the bike wouldn't start at all.

I thought maybe it wasn't getting spark so I pulled all four plugs (brand new NGK plugs). Cylinders 1 and 4 plugs still look brand new like they never fired. Cylinders 2 and 3 plugs had carbon on them. I checked the cylinders and there was no standing gas so the overflow tubes did their job. So maybe the coil is bad? I followed the shop manual for testing the coils and the resistance was within specs for the coils and wires. Then I checked the coil pickup air gaps and they were out of spec. I adjusted them to .5mm, reassembled everything, and still no go. I went back in a readjusted them to .8mm and the same result. Then I used the multimeter and tested the coil pickup and it specs out. I have a spare coil pickup and swapped it with the same result. I also tested the ICU and it specs according to the manual as well.

The battery is brand new and the starter is working good. I hooked up the real tank as well including a Napa filter and a clear fuel line. I can see the fuel is getting to the carbs and I can smell slight gas fumes from the exhaust after trying to start it. But it just won't run.

Thoughts, ideas, suggestions? What am I missing?

Offline George R. Young

  • Moderator
  • Full Member
  • *****
  • Posts: 582
  • Country: ca
    • Concours 2001 Farkles
Re: No Combustion
« Reply #1 on: April 01, 2019, 06:42:52 am »
With the plugs out and grounded, do you see spark when cranking?

Are you absolutely sure that the pilot jets are clear?
65 CB160 (67-69), 69 350GTR (69-72), 72 R5, 73 RD350 (73-84), 82 XZ550 Vision (84-03), 01 Concours C10 (03-19), 89 EX250 (11-14), 00 SV650S (14-16), 03 SV650S (19-)

Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
Re: No Combustion
« Reply #2 on: April 01, 2019, 09:09:29 am »
With the plugs out and grounded, do you see spark when cranking?

Are you absolutely sure that the pilot jets are clear?

Thanks, I'll check on the plugs later today. I'm 99 percent sure that the pilot jets are clear.

Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
Re: No Combustion
« Reply #3 on: April 02, 2019, 12:32:56 pm »
So there is spark. I can see them firing with the out and grounded. So I guess I need to revisit the carbs...

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2739
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: No Combustion
« Reply #4 on: April 02, 2019, 02:36:42 pm »
do you positively have the correct spark plug wires, connected to the correct plugs?

sounds silly, but I have seen this many times here.....

L/H COIL TO PLUG #1 & #4
R/H COIL TO PLUG #2 & #3

30 YEARS OF KAW.....

Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
Re: No Combustion
« Reply #5 on: April 02, 2019, 05:03:28 pm »
do you positively have the correct spark plug wires, connected to the correct plugs?

sounds silly, but I have seen this many times here.....

L/H COIL TO PLUG #1 & #4
R/H COIL TO PLUG #2 & #3

Nah, it doesn't sound silly. I thought that same thing so I double and triple checked the connections to make sure I had them hooked up correctly. The wires still have the yellow stickers on them so it made it easier to double check the alignment.

Offline RFH87_Connie

  • Arena
  • Full Member
  • ***
  • Posts: 942
  • Country: us
Re: No Combustion
« Reply #6 on: April 03, 2019, 09:08:10 am »
Did you set the fuel height correctly in each carb bowl and then bench sync correctly (from reading MOB's article)?  This is very critical.  If they are off, it is probably making it hard to start and may be flooding them enough so it won't fire.  Also, a weak battery that spins the engine can still not be producing enough current to give you a good spark.  A good battery should spin the engine at a nice fast rpm.
“I can truly say I had rather be at home at Mount Vernon with a friend or two about me, than to be attended at the seat of government by the officers of State and the representatives of every power of Europe.” - George Washington

Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
Re: No Combustion
« Reply #7 on: April 03, 2019, 10:53:26 am »
Did you set the fuel height correctly in each carb bowl and then bench sync correctly (from reading MOB's article)?  This is very critical.  If they are off, it is probably making it hard to start and may be flooding them enough so it won't fire.  Also, a weak battery that spins the engine can still not be producing enough current to give you a good spark.  A good battery should spin the engine at a nice fast rpm.

I set the float bowl height to 17mm per the shop manual and visually bench synced the carbs. The battery was purchased from Battery+Bulbs less than a year ago and I have plugged into a battery tender. It spins fast but won't fire.

Offline gpineau

  • Full Member
  • ***
  • Posts: 201
  • Country: us
  • I am an organ donor
    • Things that keep me busy
Re: No Combustion
« Reply #8 on: April 03, 2019, 11:46:15 am »
So you checked and you have spark?  In my mind that says either timing or no fuel.

A quick test, is a shot of starter fluid into the air intake while cranking with the throttle wide open. 
If you indeed have spark then it should fire and run for a few seconds.
If it fires then that points to the carbs as the problem.
2 Connies, 2 Magnas, 1 Yamaha Vstar 950 Touring.
https://motostuff.shutterfly.com/pictures

Offline connie_rider

  • Full Member
  • ***
  • Posts: 1209
Re: No Combustion
« Reply #9 on: April 03, 2019, 01:33:36 pm »
gp beat me to it.
Easy way to see if your having carb issues.
But, suggest close throttle while cranking.
  On a CV carb the slides are closed anyway.

Ride safe, Ted

PS: Was the bike running prior to rebuilding the carbs?



Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
Re: No Combustion
« Reply #10 on: April 03, 2019, 06:13:46 pm »
gp beat me to it.
Easy way to see if your having carb issues.
But, suggest close throttle while cranking.
  On a CV carb the slides are closed anyway.

Ride safe, Ted

PS: Was the bike running prior to rebuilding the carbs?

Ted, I bought the bike as a non-running project bike. Prior to last week, I don't know when it was last running. Last week it ran for a few seconds and not well. I'll have to get some starting fluid to try starting it.

Offline BobCT

  • Newbie
  • *
  • Posts: 12
Re: No Combustion
« Reply #11 on: April 04, 2019, 04:43:21 am »
How many miles on the bike? Did you check valve clearances? How about air leaking in from torn or not fully seated carb boots?
Tough working on a bought non running bike when you don't know what the po might of done to try and get it to run.
You stated you are using choke(enriched), did you confirm that it is functioning at the carbs when you apply choke?

Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
Re: No Combustion
« Reply #12 on: April 04, 2019, 09:29:02 am »
How many miles on the bike? Did you check valve clearances? How about air leaking in from torn or not fully seated carb boots?
Tough working on a bought non running bike when you don't know what the po might of done to try and get it to run.
You stated you are using choke(enriched), did you confirm that it is functioning at the carbs when you apply choke?

The bike has approx. 50K miles. I tore the bike down completely (except for a motor tear down), painted the frame, and began a complete reassembly. I did a bent rod test and adjusted the valves to spec. I replaced all the coolant o-rings along with any other rubber parts that were showing age. The carb boots are like new and I double checked that they aren't torn and they are fully seated. The choke seems to be working properly as all the plungers open and close with the choke cable.

Offline Daytona_Mike

  • Full Member
  • ***
  • Posts: 778
  • Country: us
Re: No Combustion
« Reply #13 on: April 05, 2019, 08:00:45 am »
Sorry to hear about your issues.  We should eliminate what we can first and start with basics  (I know you checked this but maybe the green and black wires got swapped)
You should see a Green wire which controls coil #2 - those wires go from coil #2 to cylinders 2 and 3
the BK (I assume black) wire runs  coil #1 and those spark plug wires go to cylinders 1 and 4   (spark plugs wires seem ok? no shorting?)
The spark plug gap should be .028 with wire or spark plug gap tool  (not using feeler gauge) They come pre-gapped.. did you open the gap up?

Next lets do a compression test (throttle has to be wide open - all spark plugs out.) and see what we have before we fault the carbs again.
good luck. 
Lets us know so we can advise you further.

 Another test is if you have one of those thermal infra red heat sensor guns  to tell us which of the 4 exhaust pipes are getting hot and which are stone cold. It might help diagnose if you can get it running enough.
Also, you are a smart man to have installed overflow tubes.  You probably already saved the engine from major damage.

One more thing- get rid of that NAPA filter and try the petcock on PRIME please.
 
Have you verified the fuel in the bowls  and test the float valves (drop the hose down lower so more fuel fills the hose and then stops) with a length of clear tubing held next to the carb bowls?  The fuel level should stay right at the split where the bowl meets the carb body.
https://www.youtube.com/watch?v=PHuB1lyagKM

You said this:  I tore the carbs apart and cleaned them to look like new and replaced every rubber piece

  I can assume you did not change the  rubber diaphrams as those are expensive.  Please tell me you did not use carb cleaner?
Do you know how many people have cleaned the carbs to look like new and the engine will not run... a lot~! Are you sure you cleared all the jets/orifices? Assembled them correctly? You 'really really' need to KNOW these carbs to work on them.
« Last Edit: April 05, 2019, 09:35:20 am by Daytona_Mike »
If you still have fuel in the tank, you are not lost yet
Most motorcycle problems are caused by the nut that connects the handlebars to the saddle

Offline bigdt73

  • Jr. Member
  • **
  • Posts: 26
  • Country: us
Re: No Combustion
« Reply #14 on: April 05, 2019, 01:01:25 pm »
Daytona_Mike---

All good points, some of which I already checked. I've been following the Kawi shop manual for guidance along with this site (thank you all). I double checked the coil wires and everything is hooked up according to the shop manual and your advice. I cleaned the carb diaphrams with a solution of simple green and there are no tears or holes. I even polished the slides so they are super smooth and shiny. They slide smoothly and easily. Good point about not using carb cleaner. I also gapped the plugs using a wire gauge and most of them were already in spec.

Last week when I first tried starting the bike I was using a Motion Pro auxiliary tank that is either on or off. After it ran horribly and gas came out the overflow tubes, I pulled the carbs and changed the floats and float valves. Upon reassembly I used the bike tank on "prime" and the fuel was flowing freely through the gas line (clear tubing purchased from Murph's). I haven't tried a compression test yet but I believe it's warranted. I will need to get a compression tester.

Today I pulled my carbs again and tore them down, again. I pulled all the jets, the diaphragms, and the needles. I disconnected all the hoses and used carb cleaner and qtips on every surface. Then I used compressed air in every orifice and opening (approx 15-20 psi with a rubber tip). That brings me to a question about the carbs. In the attached picture, what role does the smallest opening play (the small brass orifice at the bottom of the picture)? The one without any removable jets or needle. When I ran compressed air through them, carbs 2 and 3 were fine but carbs 1 and 4 are clogged. No air passes through on 1 and 4 unlike 2 and 3. Is this causing the problem? The manual doesn't spell out their function nor does it specify what they are called.