Starting my '89 ZXR750 for the first time in 7 years, carb Q

[rexxxy]

Hi all,

About 7 years ago I bought a ZX9r, and retired my '89 ZXR750 to the garage. I could never bring myself to part with it, and today I am going to attempt to fire it up for the first time since around 2004.

My plan is to fit a new battery, change oil, plugs, filters, drain the fuel tank and refill with some fresh juice.

I suspect my carbs are full of garbage fuel, and presumably I will need to drain or at least get some new fuel into them.

I have been hunting for my copy of the workshop manual all morning, but no luck, so im hoping someone can point me in the right direction?

Also please feel free to offer any advice on restarting old Kwaka's.

In the past, when the bike had been sitting for up to 12 months, I just pulled the plugs, gave them a clean up, fresh fuel and a new battery and it fired everytime.

No plans to ride, it until I have given it a decent once over, but I want to know it will run before I plough more cash into it in preparation for RWC and re-reg.

Any help is appreciated!

[mike-s]

I would say strip carbs, replace oil, fuel and giving it a once-over ought to be enough. Was the battery disconnected or left connected? if disconnected it *might* still be ok and only require a trickle charge, but i wouldn't bank on it being ok.

I'd look at the tires as well, are they cracked or were they left to deflate? putting the bike on the stands may have help with keeping them ok, but chances are there's going to be a lovely flat spot on them.

[rexxxy]

Yeah carbs will be coming off for a tear down and clean up.

I have the worst luck with bike batteries, I havent even looked at it, from memory the battery was thrown out long ago.

I have just picked up filters / oil / battery and plugs.
The tyres have plenty of meat left, but they will be replaced prior to RWC.
I will measure the disks, I would say there is a good chance they are under. I do have spares though.
The forks are also pitted, I have a spare set in a box in the garage, but I havent laid eyes on them in 10 years, so I cant recall their condition.
The muffler is cactus, but I have a stock zx9 unit which im hoping to graft on.
Initially I want to see if it will go (no reason why not, except o-rings being shot in the carbs).
Thanks for the suggestions.

[mike-s]

Useless hint: If you'd had foresight you'd have drained the carby's prior to shelving the bike. Doesn't help us now i'm afraid.

Quite a bit of a to=do list for you there i see though.

[rexxxy]

The chances of me prepping the bike for long term storage lessened as the piles of crap required to move to get to the bike grew.

Im not complaining though, I enjoy working on the bike, and once it fires, I will be a happy man.

I just gave it a whores bath out in the backyard to get rid of years of dust and cob webs. Its air drying whilst I have a beer and work out who I lent my rear stand to!

[s man]

Just another little bit of advice, when the plugs & carbs are out, spray a heap of WD40 or Inox down the plug hole, & in the inlet track,then turn the motor over by hand. There could be a stuck valve, by turning it over by hand you will feel if the piston touch's a valve & can work to free it without doing any damage..
Hope this helps?

[rexxxy]

Too late for good advice now!
I gave each cylinder a squirt of WD40 when I was changing the plugs.
After topping up the oil and putting some fresh fuel in the tank, I let it kick over for about 10-15 seconds without spark + fuel, then plugged the leads in, dropped the tank back on and hit the go button, and it fired to life instantly.
It blew a bit of smoke for a couple of minutes but that calmed down soon enough.
Im pretty happy with the result. Its been a long day working on the bike. But good result.

But there is a problem, I started the bike with choke on, as per usual, no dramas, but when I went to give it a little throttle, it died instantly.
As the bike was now warm, I tried to start without choke, and no go, I then tried starting with a little throttle, nothing, then a little more, and basically I could get it to start and run at low revs with about half throttle applied, twisting the throttle to rev it up a little more, and the revs slowly crept up, not that instant rev.
Now Im just guessing as I have called it quits for the night, but perhaps I didnt run my HT leads correctly, and they are interfering with the throttle cables?

Any thought?

[rexxxy]

oh and seeing as I didnt mention it, I pulled the carbs down cleaned out some bad loooking red gunk in the fuel bowls.

[photomike666]

lack of revs sounds like a blocked jet? How long did you let it run for, these things sometimes clear up

[rexxxy]

I let it run for a couple of minutes.

Seems to run fine and rev find using the choke, not sure if its the same for all ZXR750's but I have to adjust the choke quite a bit as the bike is warming up, as it seems to have a mind of its own and the revs often jump up all of a sudden.

I should add that I could not get an air filter today from the shop, so there is no air filter in the airbox. The filter I pulled out was looking pretty ratty.

[rexxxy]

OK! It was doing my head in, so I just went out with the torch and I found the 3rd line which runs from the tank down the side of the block to a white / clear plastic bulb thingo, from there it runs another few inches of hose which has a plastic connection which appear to block the end of the hose.

Long story short, the connection on the tank was cracked and not sealing.

The neighbors will whinge if I start playing with the bike again, so I wont know for certian until tomorrow.

[Dafuzz31]

Yeah may wanna get the air filter replaced and get that bulb thingo and see if thats the issue.....good read...always interested in reading about bring back old bikes from the twilight zone. if u left fuel in the tank would be good to check for rust and other nasties lurking around.

[rexxxy]

The tank was pretty clean, I drained it, put a litre of fresh fuel in, gave it a shake up and drained it again.

I did the ring around today for an air filter, no one has anything in stock. They are quoting around 70 something bucks for genuine.

I hit up ebay and bought a K&N for $68 delivered from the states.

5 minutes after paying for it, I found another K&N for $10 less than what I just paid!
The bike wont be on the road for a while, and I wont be riding it, so I might slide the old filter back in for the mean time.

When I get home tonight I will fix up that vac line from the tank and see if it runs correctly without the choke. Also need to raid some boxes for front forks, rotors and whatever else I can fnd.

[MickLC]

Sounds to me like your pilot jets are still blocked.

The line from the tank just sounds from the description like it's the overflow or something, but I could be wrong.

[rexxxy]

Yep, I suspect your right.

I just had another crack at it, full of confidence that I had found the fault! But no go..
It seems to be running a fraction better, but I suspect thats just because its had a little more time to blow out the cob webs. It revs a little more freely, but close enough to wide open throttle and it didnt seem to want want to go past 4000 rpm, if that. And opening the throttle the revs are pick up really slowly.

Clearly there is a problem with it getting fuel. Im wondering if I should take it for a blast around the block before I pull the carbs off?

Still cant find my bloody workshop manual.