1985 gpz 600 carb sync - KawiForums - Kawasaki Motorcycle Forums
 1Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 33 (permalink) Old 01-06-2019, 06:11 AM Thread Starter
Jr. Member
 
Join Date: Jan 2019
Posts: 16
 
1985 gpz 600 carb sync

Hi guys, im a noob here, but a pretty experienced d.i.y mechanic.

First things first, the bike has new rings, size 40 instead of 38 pilot jets and 3 turns, Fuel float height was set to 16.75mm instead of 17mm (slightly richer) , the float valve needle-tips are squished at the rubber tip not a perfect pyramid , And it did sit for months after the rebuild with the petrol cock left to prime and flooded the engine oil with petrol, but i caught onto that and drained the sump and reinstalled fresh oil, and installed an inline tap to the petrol cock to shut off when its not in use.

Valve adjustments were done when cold, not sure if need be done when hot, but they were not jammed open, i had clearances on all 16valves

The Bike runs pretty good, except for its erratic idle bouncing up 250rpm and down., so i assume now it must be the carb sync, they were synched by eye by me before i re-installed the carbies after i did the rings and valve adjustments..

Heres the kicker, I cant just plug off cylinders 3 and 4 and sync one and two together with a t-piece to a vac gauge. the bike wont start / or idle, it kicks over but wont start,


(all ports are blocked off at this stage) 1 and 2 with a T-piece to a gauge and 3 and 4 seperate lines that are blocked with a thick-screw.....And it wont start,

Then i switch it around and try and just see what vacuum #1 cylinder is pullin by itself, the other 3 vac-ports blocked individually,.. no go-er again,

Then i switch it around again back to stock with 1 and 4 synched up with its original hose and 2 and 3 to a T-piece as it is stock but the 3rd line that operates the petrol-cock diaphragm disconnected and plugged into the gauge, and it gives me a reading of about 15 cfpm and it starts/idles fine...

And when i connect 2 and 3 up like it is stock and then block the fuel vacuum line up with a screw and I then T-piece #1 and 4cylinders to the gauge it reads about 20cfpm vacuum,


Why cant I do each LEFT and RIGHT bank individually does anyone know?,

From what Ive been told by a mechanic you synch in #1 and 2 with its screw inbetween,
Tthen synch in #3 and 4 with its screw, then synch in the middle screw (between 2 and 3) obviously with a 4 vac-gauge setup,


But i cant even run the engine with its vacuum lines blocked , i have to run stock hose-routing, somethings up here, Ive sprayed starting fluid around the intake boots 'carb to head side' and nothing fluctuates so no leaks i assume, and i did spray a liberal amount....

Anyone with some helpful advice would be appreciated,

Am i running too rich with the richer+ leaking fuel bowls that it causes some issue or is the not being able to block off the vac ports separately other than stock factory setup something entirely different?


*bangs head

Last edited by JJ_GPZ_600; 01-06-2019 at 06:21 AM.
JJ_GPZ_600 is offline  
Sponsored Links
Advertisement
 
post #2 of 33 (permalink) Old 01-06-2019, 11:29 AM
bpe
Member
 
bpe's Avatar
 
Join Date: Dec 2018
Location: Atlanta,GA
Posts: 366
   
Garage
Are you not hooking up 4 gauges at the same time?

2006 EX500r
Purchased new in July 2006, 0 miles.
Miles as of January 2019 102,137 miles
bpe is offline  
post #3 of 33 (permalink) Old 01-06-2019, 11:51 AM
Jr. Member
 
bigbadbass's Avatar
 
Join Date: May 2015
Location: New York
Posts: 75
    
The mechanic advise you were given is correct, synch 1 & 2, then 3 & 4, followed by Left to Right bank

If i'm comprehending correctly???...why are you connecting to 1 & 2 **OR** 3 & 4.....why not connect vac gauge to ALL 4?

I recently did a ZX750 valve adjust (requiring pulling both cams) with zero issues synching.
Attached Thumbnails
Click image for larger version

Name:	zx7valves.jpg
Views:	29
Size:	170.2 KB
ID:	131291   Click image for larger version

Name:	zx7valves2.jpg
Views:	40
Size:	154.5 KB
ID:	131293   Click image for larger version

Name:	zx7valves3.jpg
Views:	17
Size:	113.3 KB
ID:	131295   Click image for larger version

Name:	zx7valves5.jpg
Views:	26
Size:	121.0 KB
ID:	131297  

'95 Ducati 900SS/SP
'07 Ducati SS800
'98 Honda VFR800 FI
bigbadbass is offline  
 
post #4 of 33 (permalink) Old 01-06-2019, 07:27 PM Thread Starter
Jr. Member
 
Join Date: Jan 2019
Posts: 16
 
Quote:
Originally Posted by bpe View Post
Are you not hooking up 4 gauges at the same time?

I dont own a 4-guage setup, just 2 gauges.


What I am implying though is the bike only wants me to test 1and 4 together or 2 and 3 together, and if i test 1and 4, 2 and 3 must share a common line , and if hook 2and 3, 1 and 4 must share a common line, If i alter any of those 2 pathways ...say to sync 1 and 2 together, then hooking up 3 and 4 to nothing at all but a capped tube -separate tubes. she doesnt run, and if i get wise and hook 3 and 4 up with a common tube (sharing vacuum) it still doesnt run.


It is an absolute nightmare.
Attached Thumbnails
Click image for larger version

Name:	carb_sync.jpg
Views:	13
Size:	68.5 KB
ID:	131299  
JJ_GPZ_600 is offline  
post #5 of 33 (permalink) Old 01-06-2019, 07:50 PM Thread Starter
Jr. Member
 
Join Date: Jan 2019
Posts: 16
 
Quote:
Originally Posted by bigbadbass View Post
The mechanic advise you were given is correct, synch 1 & 2, then 3 & 4, followed by Left to Right bank

If i'm comprehending correctly???...why are you connecting to 1 & 2 **OR** 3 & 4.....why not connect vac gauge to ALL 4?

I recently did a ZX750 valve adjust (requiring pulling both cams) with zero issues synching.

Nice bike , well done, I havent got 4way vac gauge and if i did, i doubt it would run because if 1and4 and 2and3 dont share the original common vac-lines she wont run,



its soooo annoying, ive inspected every hose for cracks and holes, nothing, must be some internal damage in the carby ?


, as my above post 2 and 3 share a T piece to the fuel tap from factory, so i just plug in the vac gauge with a double sided 1/4 inch plastic barb that comes with the vac-gauge and then join the gauges vac hose to the barb and then to 2and 3 t-piece setup, ............... the kit also comes with a t-piece barb so i cut the single tube joining 1 and 4 and put the t piece in the middle to the vac gauge,


luckily with further research I see for my 2nd vac gauge which is a hand pumping brakebleed kit essentialy ,..... that I must limit the ammount of vacuum going to that gauge as it jumps around like a yo yo, luckily... as i was saying I have a spare valve that i can restrict air flow which should fit the vac line with a bit of force and i can then have cylinder 1and4 hooked to a Tpiece and 2and 3 to a T piece and to two seperate gauges, but thats not the correct way to sync the carbs,..... its an actual nightmare.
Attached Thumbnails
Click image for larger version

Name:	20190107_111635.jpg
Views:	21
Size:	148.3 KB
ID:	131301  
JJ_GPZ_600 is offline  
post #6 of 33 (permalink) Old 01-06-2019, 08:27 PM Thread Starter
Jr. Member
 
Join Date: Jan 2019
Posts: 16
 
In the photo cyl 1 and 4 hooked to tpiece to large vac-gauge,


and 2and 3 to a t-piece to small vac- gauge
Attached Thumbnails
Click image for larger version

Name:	20190107_111635.jpg
Views:	15
Size:	148.3 KB
ID:	131303  
JJ_GPZ_600 is offline  
post #7 of 33 (permalink) Old 01-06-2019, 08:55 PM
bpe
Member
 
bpe's Avatar
 
Join Date: Dec 2018
Location: Atlanta,GA
Posts: 366
   
Garage
I'm no expert, but I don't see how that is going to get you a true 4 carb sync. You may have better luck going through the carbs getting everything back to stock, and replacing the worn parts before syncing them anyway.

2006 EX500r
Purchased new in July 2006, 0 miles.
Miles as of January 2019 102,137 miles
bpe is offline  
post #8 of 33 (permalink) Old 01-06-2019, 09:33 PM
Jr. Member
 
bigbadbass's Avatar
 
Join Date: May 2015
Location: New York
Posts: 75
    
Quote:
Originally Posted by bpe View Post
I'm no expert, but I don't see how that is going to get you a true 4 carb sync. You may have better luck going through the carbs getting everything back to stock, and replacing the worn parts before syncing them anyway.
Its not....you need each gauge directly connected to each cylinder...no "teeing" of any of the vacuum paths. Each carbs' vacuum paths are separate and do not interconnect downstream. If 1 gauge is Tee'd to any 2 cylinders...how would synch between those cylinders be possible at all? Think about it.

Look at my photo of proper 4 cylinder mercury synch tool....each tube connected to each carb...enabling synching 1 to 2....then 3 to 4....then L bank to R bank....resulting in perfect synch as pictured. Works every time....twin cylinder to 4 cylinder.

OP needs to follow standard, accepted service procedures written in manual, use proper tools and not try to reinvent the procedure to meet his convenience.

'95 Ducati 900SS/SP
'07 Ducati SS800
'98 Honda VFR800 FI
bigbadbass is offline  
post #9 of 33 (permalink) Old 01-07-2019, 02:30 AM Thread Starter
Jr. Member
 
Join Date: Jan 2019
Posts: 16
 
So yeah, just went and showed a seasoned bike mechanic the video of all 4 carbs blocked off individually and a no-start scenario, hes left scratching his head.



He said something along the lines of a XJ 650 (yamaha i take it?) once had a problem with the main shaft connecting all 4 butterflies leaking air somewhere in there on the seals between each carby, but Im left scratching my own head on that one as its his story not mine .


heres the link to the video i showed him, and you can see it tries to start with all 4 blocked off but fails instantly

Last edited by JJ_GPZ_600; 01-07-2019 at 02:34 AM.
JJ_GPZ_600 is offline  
post #10 of 33 (permalink) Old 01-07-2019, 06:17 AM
bpe
Member
 
bpe's Avatar
 
Join Date: Dec 2018
Location: Atlanta,GA
Posts: 366
   
Garage
It not being able to start may be a good reason to get the bike back to stock. A funnel would come in handy to put fuel in the fuel line.

2006 EX500r
Purchased new in July 2006, 0 miles.
Miles as of January 2019 102,137 miles
bpe is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the KawiForums - Kawasaki Motorcycle Forums 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