Hello Guest User,

Please feel free to have a look around the forum but be aware that as an unregistered guest you can't see all of it and you can't post.

To access these 'Registered Users Only' areas simply register and login.

GPz1100B2 Carb Conversion problems

Need help restoring, building, or finding then try here.

Moderators: KeithZ1R, chrisu, paul doran, Taffus

Message
Author
User avatar
Richard L
100Club
100Club
Posts: 177
Joined: 19th Jan 2012
Location: Heidelberg, Germany

GPz1100B2 Carb Conversion problems

#1 PostAuthor: Richard L » Sun Jan 27, 2013 6:36 pm

I've just wasted the last two weekends attempting to simplify my B2 by fitting Mikuni CV34 carbs instead of the over complicated injection system .
The bike was running ok in November before snow put an end to riding ,and the carbs I got from my brother who had them on his B2 for a few weeks to test them . The problem is it misfires spits back through the carbs backfires and cuts out ! I think I have checked every possibility but my question is do you need 1000J/R inlet rubbers or are the GPZ ones (different part no ) ok ?
Anyone had similar problems ( carbs have dynojet stage 3 and K and N's)
Richard

User avatar
z1bman
Hardcore
Hardcore
Posts: 4227
Joined: 3rd Mar 2010
Location: WORDSLEY WEST MIDLANDS

#2 PostAuthor: z1bman » Sun Jan 27, 2013 6:46 pm

CARB RUBBERS ARE THE SAME. IF IT WAS RUNNING OK IN NOVEMBER I WOULD SUSPECT SOMETHING ELSE LIKE ELECTRICAL? POSSIBLY A COIL OR SPARK PLUG/ CAP

User avatar
Taffus
Moderator
Posts: 4159
Joined: 30th Aug 2007
Location: .21 club

#3 PostAuthor: Taffus » Sun Jan 27, 2013 6:55 pm

yep agree with the above, I had the same problem and eventually it went on to 3 cylinders. switched the leads over and the fault moved so thought the coils had gone.
Ordered a new set from Jeff and whilst I awaited their arrival, prepped the bike, when I took the offending coil off I found the connection in the coil was corroded. Did a quick clean up and all has run smooth in this area since
(\__/)
(='.'=)
(")_(")Image

User avatar
Richard L
100Club
100Club
Posts: 177
Joined: 19th Jan 2012
Location: Heidelberg, Germany

#4 PostAuthor: Richard L » Sun Jan 27, 2013 6:59 pm

I thought that too. I have already swapped plugs , coils , CDI , advance /retard , retorqued head, raised needles , blanked off a third of K and N s ( as per instructions for misfire) stripped carbs twice etc etc . Next weekend I might have to refit the injection just to double check but that is such a drag .
With ref inlet rubbers pattern items are often for both but genuine kawasaki
are different no's and prices ( courtesey cmsnl.com )

User avatar
Al
Hardcore
Hardcore
Posts: 2233
Joined: 21st Oct 2007
Location: Farnbronx Sin City N.E. Hants

#5 PostAuthor: Al » Sun Jan 27, 2013 7:00 pm

There were some early J rubbers with a notch in them and then they were superseded.

Look inside the rubbers and you will see a little raised bump.

CV's are difficult to get right with individual filters ( pods or ram airs) they really need the original airbox to generate enough back pressure / resistance to lift the slides correctly.
That said, if the idle mixture is set correctly they will pop and spit back untill fully warmed up. Does choke even them out or kill the idle?

Use a set of vacuum gauges to set the balance of the four chokes with the engine stone cold. Bend the tangs on the choke bar but make sure each choke assembly is correctly seated with the choke lever off.

If they were running well on youre brothers bike it may be that he has different valve timing to you. They are also sensitive to different induction vacuum levels.

AL
1981 J1

User avatar
Pigford
Hardcore
Hardcore
Posts: 13314
Joined: 2nd Jan 2006
Location: North Dorset

#6 PostAuthor: Pigford » Sun Jan 27, 2013 7:21 pm

Have you checked the coils are getting the FULL +12v :?: The kill switches are also often a source of grief :|
And on the 7th day... Zeds were created!

User avatar
Richard L
100Club
100Club
Posts: 177
Joined: 19th Jan 2012
Location: Heidelberg, Germany

#7 PostAuthor: Richard L » Sun Jan 27, 2013 7:31 pm

Thanks for all your suggestions .
I did forget in the original post to say that it only really runs with choke
but when it has warmed up it will tick over a bit until you rev it and then it pops back and cuts out .
In answer to the coil voltage no I haven't checked that yet it will have to wait till next weekend cause I am doing all this outside in snow and ice rain at the moment !
Richard

User avatar
Al
Hardcore
Hardcore
Posts: 2233
Joined: 21st Oct 2007
Location: Farnbronx Sin City N.E. Hants

#8 PostAuthor: Al » Sun Jan 27, 2013 9:30 pm

I did forget in the original post to say that it only really runs with choke


First position of the choke pulled out or full choke pulled out?
If its full choke pulled out that allows it to run then its definitely running weak.
Have you glued the steel base plates of the rubbers onto the head?
I glue them on with the screws loose and tighten the screws the following day or after.
Another problem with individual filters is that there is no support for the carbs.
Have you any splits in the rubber parts?
They eventually part company where they are bonded to the base plate.
Might be worth looking to see if the filters are obscuring the air jets in the carb mouths as well.

If you cant get it to idle nicely within the range of adjustment of the air screws you can set a new datum for the airscrews by raising the fuel level in the float bowls.
What is the fuel level in the float bowls at now?
Best to do this with it running on or just above idle.
I use a piece of windscreen washer tube on the float bowl stubs which also allows you to see any accumulated water droplets and general smolge.

Image

http://s254.photobucket.com/albums/hh86 ... v%20level/

AL
1981 J1

User avatar
Richard L
100Club
100Club
Posts: 177
Joined: 19th Jan 2012
Location: Heidelberg, Germany

#9 PostAuthor: Richard L » Sun Jan 27, 2013 10:06 pm

Inlet rubbers are genuine kawasaki and only 6 months old (no tears or cracks) and I did glue them on like you describe and the carbs are supported by a bracket from the top tube of the frame. Bike fires up on full choke and sounds good , then on half choke rus ok just won't rev cleanly and when it starts to misfire it will no longer tick over or run at all. Removing the K and N's completely makes no difference.
Fuel level will also have to wait till next weekend !

User avatar
zed1015
Hardcore
Hardcore
Posts: 2319
Joined: 2nd Nov 2005
Location: Somewhere between Scunny and Goole.

#10 PostAuthor: zed1015 » Sun Jan 27, 2013 10:29 pm

Sounds like fuel starvation, restricted fuel supply, clogged fuel filter etc.

I bet if you leave it a while it fires straight back up ok then exhibits the same symptoms all over again.
Last edited by zed1015 on Sun Jan 27, 2013 10:50 pm, edited 1 time in total.

User avatar
z1bman
Hardcore
Hardcore
Posts: 4227
Joined: 3rd Mar 2010
Location: WORDSLEY WEST MIDLANDS

#11 PostAuthor: z1bman » Sun Jan 27, 2013 10:39 pm

HAVE YOU TRIED A NEW SET OF PLUGS FROM WHAT YOU ARE SAYING IT MIGHT HAVE SOOTED /FOULED THE PLUGS

User avatar
davejames
Hardcore
Hardcore
Posts: 1255
Joined: 22nd Dec 2001
Location: Northwich, Cheshire

#12 PostAuthor: davejames » Mon Jan 28, 2013 8:09 am

I found Denso's to be so much better than NGK's although I know not everyone agrees :wink: Unlikely that it would foul the whole set in one go, would be more likely to run badly on 2 or 3 ??
Feng shui................my arse

trekker-zed

#13 PostAuthor: trekker-zed » Tue Jan 29, 2013 10:53 am

Had a similar prob years ago on my b2 turned out to be fuel restriction. The filter looked fine but didnt pass enough fuel. Filter changed, solved.
Prob no help to you but never know.
I too removed injection ( that worked perfectly and did great mpg ! ) and fitted cv carbs. Could never get them to run properly spent ages on them. In the end i fitted a set of spangly new Mikuni flatslides and everything was fab. That was bout 20 yrs ago and they are still fab.

zmaxmotorsports
Regular Poster
Posts: 96
Joined: 9th Jan 2013
Location: louisville ne

#14 PostAuthor: zmaxmotorsports » Tue Jan 29, 2013 12:36 pm

I had problems with a new gpz1100 back in 84,after playing the dealer game I ditched the injectors and installed 29 smootbores on it and never had a problem again.
Im not sure what brand of carb cleaner you guys can get over there but Ive had really good luck over here dumping a big can of sea foam brand carb cleaner in the tank and riding the wheels off of things,the stuff really works for cleaning trash out of carbs :wink:
Ive never had any kind of luck with those cv style carbs,if you have pods or differant cams or theres a cloud in the sky theyll be a tuning nightmare! :lol:
10-72 (build date)z1/2-74 z1s/2-75 z1s/77 1428 turbo/77 1170/78 1170/74 z1 1385 turbo nitrous project/80 1000ltd 1327 z1 clone.........
That ol kaw was fast on the draw
Outgunned suzukis and outrunned the law


Return to “Bike Help”

Who is online

Users browsing this forum: No registered users and 20 guests