ZXR 750 H1

Hi Boys and girls,
I am new to this forum, although I have a question already, I have a ZXR 750 H1, yes a 1989 model, not the usual thing you see on these pages going by what I have seen in the threads.

I have a problem that is driving me nuts, fuel problems, I think, below 4K the engine boggs down and sometimes stops above that it will rip your head off, any ideas? I have tried fuel cleaner I think it has made the problem worse.

Mark

hi mate
and welcome

some more facts pleeze...
your H1..has a can or not? whose?
has modded jetting???
any other engine mods??
last service was when?
replaced the fuel filter recently??


cheers

Has a stock pipe, serviced 2 months ago, similar problem , I have not replaced the fuel filter, I would trade the thing but I have thrown too much money at it, the mechanic did say the carb slides are worn, I don't want to ask how much a new set would be worth !

Welcome Mark n i have no idea, but I'm sure the clever Canically minded guys will help you out.
Cheers Brett

Has a stock pipe, serviced 2 months ago, similar problem , I have not replaced the fuel filter, I would trade the thing but I have thrown too much money at it, the mechanic did say the carb slides are worn, I don't want to ask how much a new set would be worth !

thanks Mark

You have answered your own question....
Worn slides will give you exactly the symptoms you are experiencing.
the hestitation.. stumbling and poor fuelling at low revs
then as revs rise, followed by normal "rip ya arms off" acceleration'

guess you may have to start saving....


ciao

Checked the cost of a new set of carb's $2700

Worn "slides" or worn "slide holders"? (throttle needle slider holders... throttle slider clips... whatever you want to call them).

I don't know the internals of ZXR's carbis (since I haven't got mine home yet ) but I imagine they're similar to other carbis in that "carbi slides" is refering to the top needle slides, where the needle is held inside a ceramic (or something like ceramic) cylinder by a fairly soft plastic clip/plug, which then hangs on the diaphram lifter... or am I totally wrong?

Hopefuly I'm right, coz a set of the plastic slide holder thingies will be cheap, hahaha (and cause the symptoms you describe).

EDIT: surely 90% of a ZXR has carefuly designed wear-points, such as soft plastic bushings (or slider holder clip thingies, haha) that you can replace cheaply. New carbis would probably be overboard unless you've modded, rusts, or trashed the bike.

James

I agree with James
the carbs are repairable, you don't need a new set
ask your mechanic to quote you ...on fixing 'em
(not replacing 'em)


ciao

Hi Mark and Welcome. $2700 is bullshit for a set imho.

Have a look at these for example.

http://cgi.ebay.com.au/ws/eBayISAPI.dll ... eName=WD2V

Do some home work and then go bidding.

I agree with James
the carbs are repairable, you don't need a new set
ask your mechanic to quote you ...on fixing 'em
(not replacing 'em)


ciao

If "slides" was refering to the throttle needle slides that I'm think of; surely Mark (maybe with some help from another ZXR owner) could do the work himself? Then maybe seeing a mechanic to balance the carbis back up.

Here's article on "throttle slide holders" for my spewzuki (I'm learning some KSRC forum lingo ) Across 250.
http://across.jlid.com.au/index.php?tit ... er_Holders

The ZXR has 4 carbis (as apposed to the Across's 2 dual carbis) but the concept and layout will be similar.
Worn "throttle slide holders" give the symptoms you describe on most carburated engines and should be one of the first things you check.

Even if you get no success it never hurts to have a squiz

An Across usually gets around 5,000k's out of it's slide holders (which is crap), my Across gets around 3,000k's (because I'm mean to it). No idea what to expect from a ZXR but definitely not 15 years-worth.

Thanks for all the iput, what I can't understand why it does not do it all the time, it was crook before a trip to Canberra, had the carbs cleaned out, two weeks later crook again !

aaah more info....

Mark
you have dirt or shitty fuel getting into the carbs
my money is on crud getting in and stuffing things up

carbs will need a clean out and so will the lines and the tank
and a new filter.....

Thanks again, I will buy a filter tomorrow, rip of the carbs clean the suckers out, Q/ what about the tank dump the fuel? what do I clean / or coat it with to stop the rust if any ? It would be a pity to get rid of it, it my be old, but it is still sharp, unlike me I am just old.

Cheers,
Mark.

Hey Mark,
a bit of a bright note for you, I had a ZXR750 J1, when I did the timing chain it was found that the cams were stuffed( pitted to hell and lost the hard coat) and that the carbie slides were shot.

Won't bore you too much with the other deatails (cept to say if you can get a set of RR cams you'll love the result), but a place here in Adelaide(Renew-Bike) completly overhauled and rebuilt my carbs for $470.00 (including parts).

In fact the whole job (cam chain, tensioner, carbs and a second hand set of RR cams 9000km old) only cost me $1300.00 and when it was finished she felt like a new bike.

Forget this $2700 B/S you can get way better.

Electrical problems don't generally cause a spluttering effect, so it would have to be fueling. And as most have already said, this is something I would be 97% certain is a carby problem.

For a bike of that age, they probably have not been touched since new. Time for an overhaul, either you do it yourself or pay someone to do it. You'll have plenty of change from $2700...and you probably wont believe how good your bike is afterwards.

While you are at it, replace ALL fuel hoses as these can degrade on the internal wall, sending bits of black crap all through the fuel system. Fair bet some of them would be original equipment...