Need some Diag help. Running rich or valve issue? Or ignition? - Kawasaki KLR 650 Forum
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

 6Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 21 Old 01-11-2020, 09:54 PM Thread Starter
1st Gear
 
Join Date: Jan 2020
Posts: 15
Need some Diag help. Running rich or valve issue? Or ignition?

I just recently picked up a good condition 84 KLR 600 with 12k miles. I know I’m in the 87-07 650 threads but this seems to have much more tech discussions and it seems to be a similar engine anyways.

First let me say I’m quite experienced with working on engines and pretty thorough with checking and testing things so I have done even more than what I say but also don’t want to write a book with every single details - it seems to deter some people from reading/helping. Here is what is going on.

It is hard to start. It is running especially very rich on the pilot circuit. (After about 1/4 throttle it has plenty of power but not perfect then again the pilot circuit affects entire rpm range) Will barely idle on its own unless the idle speed screw is screwed in pretty much all the way and it’s very lopey/sluggish - Rev it and a ton of black sooty smoke comes out (supertrapp closed end muffler and has been on before with no issues). I have cleaned the carb in a heated ultrasonic cleaner. Cleaned every passage and verified flow everywhere especially thru the pilot fuel circuit including the air circuits in the front and also verified the choke/fuel enrichener is properly sealing. Also replaced o-ring for fuel screw since that was a little torn up. Spark plug is sooty black. Yes it’s proper plug. I have replaced spark plug wire and didn’t help. Carb float height is perfect at 17.5mm.

I have ruled out it’s not carb related. It runs better with fuel screw in all the way and the vacuum port OPEN - since it’s obviously running so rich (or not fully burning it) the extra air is helping lean it out.

Valve clearances at TDC are....
Intake - one is 10mm other is about 11-12mm
Exhaust - both are 15mm
These numbers are on the tightest range of the spec but still within spec technically.

Here is where I’m stumped....
If I hook up a vacuum gauge to the vacuum port at carb inlet port the needle bounces violently enough you can’t really get a decent reading. Ranges from 10inches of vacuum and 2psi of pressure (so avg of like 4in). I have a video but not sure if I can post it here since I just signed up.
Erratic vacuum readings should be intake valve related issue no? Since compression would essentially be blowing back backwards towards the carb and messing up the readings.

1.Could a bad cdi box do this if it was giving the wrong ignition timing?
KACR seems to be working properly
2.Anybody know the thread size for spark plug so I can do a leak down test?
3.As the engine wears does the valve clearances normally get bigger or tighter?
Cam/cup wear would increase clearance but valve/seat wear would decrease clearance so which happens more?
Engine has 12k miles and last thing to note is the intake cam mark is a tad ‘off’ when it’s at TDC. Not sure if it’s advanced or retarded but looks to be less than a tooth off - meaning if I move it 1 tooth over it will probably be even worse but just how it seems - no experience with this engine yet.
4. Is this normal or should both marks on cams be perfectly level with head casting?
I know changing exhaust timing is a common mod but that looks perfect since the marking is perfectly level with the head casting (and T mark aligned) but the intake cam is a little higher/lower.
5. Since one intake valve has a slightly different reading I’m thinking the issue might be related to this but I’m sure it’s also common things wear at different rates? for other reasons like manufacturing clearances, valve hardness, diff moon phases, things that can’t always be explained etc. loll
6. Should the valve clearances be adjusted for higher end of specs or lower or in between?

Thanks a lot for any input
I love the bike and trying to get her up and running so I can enjoy it!
My84KLR is offline  
Sponsored Links
Advertisement
 
post #2 of 21 Old 01-12-2020, 07:24 PM
OverDrive
 
Join Date: Nov 2009
Location: Lander, Wyoming
Posts: 6,013
OK, did you check the fluid flow thru the 3 low speed Transition holes under the bottom lip of the throttle butterfly plate? They get all of their fuel from the Pilot jet, as does the adjustable low speed mixture screw. I use a tiny wire bent 90 degrees to poke down thru them & back-flush out thru the pilot jet tower (jet removed of course).

Is the rubber face of the cold start enrichener plunger damaged? Plastic ferrel (choke nut) damaged? Choke cable sticking? Adjusted too tight?.

When all is proper with the carb, the butterfly plate will only expose about 1-1.5 of the low speed transition holes at about 1200rpm idle.

It is totally normal for the cam sprockets arrows to be 1/2 tooth Above gasket surface.

Valve tappet clearances Normally Tighten. I usually adjust to near Max Specs, or 1 shim size under (Never an easy fit on widest feeler). Especially on exhaust tappets, other wise too much ticking.

Spark plug is 12mm x 1.25pitch x 14mm long.

Normal compression test with valve cover still installed will probably be 77-124 psi like KLR650.
Engine compression in the KLR600 oem service manual is with the KACR DE-ACTIVATED, piece of fuel hose behind spring holding weights Open. 134 - 185 psi.

You would need a restrictor orifice smaller that you could drill to help stabilize a vacuum gauge on this large of single cylinder engine. Check the orifice size in the square cap of the vacuum fuel tap.
samuel likes this.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
pdwestman is offline  
post #3 of 21 Old 01-12-2020, 08:03 PM
Pretty in Pink, dunno why
 
Tom Schmitz's Avatar
 
Join Date: Feb 2009
Location: Redondo Beach
Posts: 7,834
Garage
I thought the issue was a missing jet needle 16017-1254. You know, that silver piece that falls out after you've removed the main jet holder, while you're not looking, and rolls under the bench and into the floor drain.

Tom [email protected]

“I decided I could lose nothing by the soft approach. If that didn't produce for me—and I didn't think it would—nature could take its course and we could bust up the furniture.” -Philip Marlowe

“'Why' and 'How' are words so important they cannot be too often used.” -Napoleon Bonaparte

Sting like a butterfly.
Noli Timere Messorem

Last edited by Tom Schmitz; 01-12-2020 at 08:06 PM.
Tom Schmitz is offline  
 
post #4 of 21 Old 01-12-2020, 08:42 PM Thread Starter
1st Gear
 
Join Date: Jan 2020
Posts: 15
Quote:
Originally Posted by Tom Schmitz View Post
I thought the issue was a missing jet needle 16017-1254. You know, that silver piece that falls out after you've removed the main jet holder, while you're not looking, and rolls under the bench and into the floor drain.

Well, I know that deff was an issue. I temporarily took a needle/jet collar from an 86 Kawi ZL600 that I have and put that in mine to see what would happen until I get my new proper one in mail. It ran totally different, in a good way but had some backfiring. Fuel needle was at 1 3/8 turns out so opened it another 1/2 turn (expecting to open more to be fully dialed in since has higher flowing exhaust) and it ran better and less backfiring. It was still backfiring during warm up (the more choke the less backfiring so telling me it needs more fuel or less air) but while slowly taking choke off during one of the backfires it stalled and since it’s so damn loud with the supertrapp muffler I called it quits so my neighbors don’t hate me more plus it’s only kick start and no fun to keep kicking over so switched to another project tonight. Also the collar from the 86 Zl600 from what I remember was a different part number so I’m sure it’s not running how it ‘should’ be anyways since it’s probably larger or taller or something. I will let it run longer tomorrow and see how she runs - I’m expecting to need to open the fuel screw open little more to be dialed in where it should be....plus the fact the carb it’s from, looks smaller so probably letting less fuel thru
My84KLR is offline  
post #5 of 21 Old 01-12-2020, 08:50 PM Thread Starter
1st Gear
 
Join Date: Jan 2020
Posts: 15
Quote:
Originally Posted by pdwestman View Post
OK, did you check the fluid flow thru the 3 low speed Transition holes under the bottom lip of the throttle butterfly plate? They get all of their fuel from the Pilot jet, as does the adjustable low speed mixture screw. I use a tiny wire bent 90 degrees to poke down thru them & back-flush out thru the pilot jet tower (jet removed of course).

Is the rubber face of the cold start enrichener plunger damaged? Plastic ferrel (choke nut) damaged? Choke cable sticking? Adjusted too tight?.

When all is proper with the carb, the butterfly plate will only expose about 1-1.5 of the low speed transition holes at about 1200rpm idle.

It is totally normal for the cam sprockets arrows to be 1/2 tooth Above gasket surface.

Valve tappet clearances Normally Tighten. I usually adjust to near Max Specs, or 1 shim size under (Never an easy fit on widest feeler). Especially on exhaust tappets, other wise too much ticking.

Spark plug is 12mm x 1.25pitch x 14mm long.

Normal compression test with valve cover still installed will probably be 77-124 psi like KLR650.
Engine compression in the KLR600 oem service manual is with the KACR DE-ACTIVATED, piece of fuel hose behind spring holding weights Open. 134 - 185 psi.

You would need a restrictor orifice smaller that you could drill to help stabilize a vacuum gauge on this large of single cylinder engine. Check the orifice size in the square cap of the vacuum fuel tap.
After many hours searching on this forum I verified the valve clearances do tighten up as engine wears so I plan on reshimming valves this spring.

Choke/fuel enrichener seal is mint, adjusted good, plastic collar is good also and planning to get that engineering brand one in future.

Thanks for info on cam sprockets, vacuum restriction (altho my KL600 doesn’t have vacuum petcock tho) and the spark plug threads - I still would like to do a leakdown test just out of curiosity.

I didn’t verify every single hole in carb bore with a wire. I saw fluid come out when I sprayed with carb cleaner from pilot jet end and saw a bunch of fluid coming out and it looked like all 3 holes were contributing together to make the one stream but will verify for sure next time I have carb off to put in the proper needle collar. Either way I was running super rich so figured even if one was clogged it shouldn’t be making it richer - only leaner
My84KLR is offline  
post #6 of 21 Old 01-13-2020, 11:07 AM
OverDrive
 
Join Date: Nov 2009
Location: Lander, Wyoming
Posts: 6,013
I believe the 'coasting enrichener' diaphragm cover (LH side of carb) has the same Very Tiny Hole as a fuel tap diaphragm cap, to stabilize the vacuum pulses. And that little diaphragm may need to be inspected for pin holes / ethanol rot. Be careful to not loose the spring or the Tiny Little o-ring which seals the vacuum passage between carb body & vacuum cap.

Maybe these 2 little items are part of your after-fire problems out of the tail pipe?

(IMO & experience 'Back-firing' is back thru the intake. 'After-fire' is after the combustion chamber, so out of the exhaust.)


Have you read this link? Care & Feeding Of The Keihin Carb

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
pdwestman is offline  
post #7 of 21 Old 01-13-2020, 12:28 PM Thread Starter
1st Gear
 
Join Date: Jan 2020
Posts: 15
Quote:
Originally Posted by pdwestman View Post
I believe the 'coasting enrichener' diaphragm cover (LH side of carb) has the same Very Tiny Hole as a fuel tap diaphragm cap, to stabilize the vacuum pulses. And that little diaphragm may need to be inspected for pin holes / ethanol rot. Be careful to not loose the spring or the Tiny Little o-ring which seals the vacuum passage between carb body & vacuum cap.

Maybe these 2 little items are part of your after-fire problems out of the tail pipe?

(IMO & experience 'Back-firing' is back thru the intake. 'After-fire' is after the combustion chamber, so out of the exhaust.)


Have you read this link? Care & Feeding Of The Keihin Carb
Yep I read that link and a few others floating around the forums.

The coasting diaphragm and the tiny o-ring seal is there and in great shape so is the slide diaphragm and springs for both. And the needle is under the plastic piece and the slide spring on top of that. No holes or rips or damage found. Next time I have carb apart I’m going to buff the slide with some light steel wool or something just to do it.

I verified with someone at a Kawi dealer that the needle collar from the zl600 is different than KLR so hoping that’s the main reason it’s doing the backfires and it sounded like it was thru the intake not exhaust. I’m going to start her up now and see what happens but really waiting for the new collar to come for proper results
My84KLR is offline  
post #8 of 21 Old 01-13-2020, 03:16 PM
OverDrive
 
Join Date: Nov 2009
Location: Lander, Wyoming
Posts: 6,013
If the exhaust header pipe is loose, cracked or has a bad gasket your engine will have after-fire out the tail pipe after being revved & quickly backing off the throttle.
Even if all carburetor systems are properly cleaned & metering fuel properly.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
pdwestman is offline  
post #9 of 21 Old 01-13-2020, 11:02 PM Thread Starter
1st Gear
 
Join Date: Jan 2020
Posts: 15
Quote:
Originally Posted by pdwestman View Post
If the exhaust header pipe is loose, cracked or has a bad gasket your engine will have after-fire out the tail pipe after being revved & quickly backing off the throttle.
Even if all carburetor systems are properly cleaned & metering fuel properly.
Header pipe looks and feels nice and tight. No obvious leaks anyway. When it was running rich it had no after firing. I should have new needle collar anyday now so should know if bike is 100% with new collar.

Anyone happen to know the I.D. Of the exhaust pipe where a slip on muffler joins? Mine is pretty damn loud with the supertrapp muffler. It probably needs to be repacked but need to check but probably would still like it quieter so looking at some baffles on eBay to stick in end of exhaust pipe then muffler slides over that. Or maybe slides in muffler inlet but either way it’s similar size. Anyone know the size? 51mm is what many of them are. Or have any other ideas to reduce noise without repacking or changing exhaust?
1984 KLR600 - I mention that cause I read exhaust is different than a 650 but not sure how.

I’m going to first take out a few discs of supertrapp and see how it sounds and feels but exploring other ideas
My84KLR is offline  
post #10 of 21 Old 01-13-2020, 11:17 PM
Pretty in Pink, dunno why
 
Tom Schmitz's Avatar
 
Join Date: Feb 2009
Location: Redondo Beach
Posts: 7,834
Garage
Quote:
Originally Posted by My84KLR View Post
...I’m going to first take out a few discs of supertrapp and see how it sounds and feels but exploring other ideas
Best thing you can do with a SuperTrapp:

Tom [email protected]

“I decided I could lose nothing by the soft approach. If that didn't produce for me—and I didn't think it would—nature could take its course and we could bust up the furniture.” -Philip Marlowe

“'Why' and 'How' are words so important they cannot be too often used.” -Napoleon Bonaparte

Sting like a butterfly.
Noli Timere Messorem
Tom Schmitz is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki KLR 650 Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome