Z750 Twin Forum

Hi Guys

I was just wondering if you were aware of the conversion of the carburetors from standard to GPZ500 carbs which are newer and more technologicaly advance. This is a cheap conversion that gives better performance and reliability

Cheers

KK

Hi KK,
we have heard of that conversion from the UK but I haven't seen one in Germany yet.
Are these carbs matching the B (wide) or LTD (narrow) inlet manifolds?
Any information about jet sizes and settings to get it run with a 750 Twin?
Cheers,
Michael

Hi Michael
Thank you for your question. Here in the UK we have had success with the GPZ500 carbs fitted with 145 main jets and 45 pilot jets and pods. The difference with centre's is about 1mm but they will fit happy when persuaded. Don't be scared. The main differences are

1. GPZ 500 carbs have 2 throttle cables like the B but unlike the CSR and LTD. If used on anCSR or LTD then a strong return spring may be wanted.

2. The choke on the GPZ carbs is on a cable so a choke knob will need to be mounted somewhere.

As you know the CSR and LTD models have 34mm carbs. The GPZ500 carbs are 34mm too so this is easy.

The carbs can be fitted to the B models too. You will need to use the CSR or LTD carb inlet rubbers. However there is a modification for this too. Suzuki 500 carb rubbers are nearly the same sizes as our twins. All you will need to do is fit a 10mm spacer between the cylinder head and the carb rubber.

I also believe the KLE500 and ER500 carbs will fit but i can not fully confirm this.

I am sorry if my English typing does not translate well. I/we are ignorant to speaking German. Michael please help here if you need too.

Cheers

KK

Hi KK,

after I read your posting I got curious and I bought the GPZ500 carbs on ebay and additionally I ordered a dynojet kit stage 3 because I have the K&N filters. Now I'm looking forward whether this will improve the response when accelerating. When the conversion is done I'll post the result.

Regards
Matthias

Sorry but I dont understand.

WHY will you change the original Cars to another Type - when you use the same Carb-Size and the same Carbtype with a membrane for low-pressure control??

:ka:

Manne

the possibilities for tunung are the same - and the parts for the original Carbs are available..
FOR real better carbs - you have to use another Carb-ype.. or / and other Size..

Carburettor racketeer directly headed, without membrane

Hi Manne,

we already talked about my plans when we where at the restaurant on the bike tour of the twin meeting last week. I'm just not satisfied with the acceleration response. When the reports of the other bikers that did the conversion are true it should be better then.

Greetings
Matthias

this is right - we spoke of it

but I´m sure - when there are some probs because the best adaptation of the carbs without air-box... you will need a engine test bench...

if you use other carbs with the same technik... the probs are the same....

I wish you good luck to get the carburetor setting

and Power and torque that you are happy.

Manne

Hi

The conversion is done to improve starting, running and performance. The 38mm B carbs are basic technology which was improved on with the CSR and LTD 34mm carbs. The GPZ carbs are improved technology again. I am aware of 5 conversions in the UK. All have made the bikes run better. Only one had a problem with engine flooding. I have those carbs now and the problem was cured by replacing the float cut off valve.

I am looking forward to reading Matthias's report

I understand only Railway Station... :ka:

Geht es hier darum, dass man die Vergaser der GPZ 500 ohne großen Umbau an die CSR hängen kann...und diese dann besser läüft?

Ja Kulle, genau darum geht es.
Wobei Manne anmerkt, dass er keinen Sinn darin sieht von der Größe identische Vergaser zu benutzen.