gpz750 troubles....

Hi. I'm james and i'm new to the forum and here's my problem..I recently bought a 1982 gpz750 that looked like a good deal but now i think i've been had. The bike started and ran great when i looked at it but now that it is home i have only gotten the thing started one time and when i checked the pluggs they were coated in oil. I've cleaned the plugs just to see if it will even start again but all i get now is just a lot of noise and a backfire every now and then. I have been told that the motor will have to be rebuilt but i am really afraid of how much that is going to run me. if anyone else has had anything like this happen please let me know something and how you handled the situation. Any and all help is greatly appreciated. thanks,
james

When this happened to me I just loaded up my shotgun with double odd buck and went over and blew the sellers head off. Just kidding, welcome to the forum it sounds like maybe you just fouled the plugs possibly from not being familiar with how you should start it. The first thing I'd do is go to the auto parts store and get 4 new NGK B7ES sparkplugs. How many miles are on the bike now? Also where are you located? There may be a member here close to you willing to lend you a hand. The 750's are pretty bulletproof bikes so unless it has a million miles on it already I'd take the needs a rebuild advice with a grain of salt.

nes, new plugs as Gringo said, also while you have them out run a compression check on the bike, that will tell you a lot as to the health of the motor, and make sure the battery is fully charged

well i hve tried new plugs in it and they all seem to quickly foul out and get covered in oil. and as far as the mileage that is unknown. I was unaware when i bought it that the spedo cable was not even hooked up to the odom. and it only shows 6029miles. it could have anywhere from 6029 to a million for all i know. And i'm located in the biggest little town in Arkansas..Bald Knob. you may have heard of us on the bevis and butthead movie. If anyone is willing to help i am in bad need of it, however i'm verry low on cash right now, so the cheaper the better. and the battery is brand spankin new.

Do you have a KHI (Kawasaki Heavy Industries) shop manual? This manual, while not curing your ills, will greatly aid in diagnosing what problems may plague your bike. If not, the manual is a free downloadable document but I don't recall the site (another member should be able to point you). But back to your bike...oil on the plugs can be a sign of major or relatively minor issues...I don't want to scare you off the bike. Take small steps...the first would be to check compression, as suggested by BSKZ650...but it will require you to beg, borrow, or steal a compression tester (inexpensive ones are about $30-$40:) ).

Here's the link for a manual.

kz.mbsween.com/

Welcome James. The 82 GPz750 is a great bike. I seriously doubt it has a lot of miles on it since a the speedo cable is relatively inexpensive and easy to replace. That being said what is the overall condition of the rest of the bike? That would give you a pretty good indication of how hard it has been used. What else do you know about its history?
As for your starting dilemna...Are you sure it's oil and not gas on your plugs? Are you using the enrichner circuit correctly? The reason I ask is mine would do the same thing crank and crank with just a few backfires. I ended up taking the carbs apart and cleaning them real good. Are you giving it gas at startup? You should not have to...
Let us know what your starting procedure is and if your choke is working correctly. It might just be rookie mistakes. That's what my problem turned out to be.
LUK

James so far you've gotten some really good advice. For what it's worth if you have a Harbor Freight store close to you they are going to have compression testers on sale starting April 5th for $5.00, I bought mine from there and it works great. If you end up going there you might also want to pick up one of their cheap multimeters it should cost less than $10.00 and is invaluable when trying to troubleshoot any electrical problems you may have.

Since you have already had problems it would be best to start at square one. The first thing I do when I get a new bike is change the oil and filter. It is by far the cheapest form of insurance you can buy especially when dealing with an older bike you don't know the history of.

i'll check with my neighbor for a compression tester...he does a lot of work on some sport bikes and i'm sure he might have one i can borrow. (thats about all he would be good for is borrowing tools...don't trust him enogh to let him work on my bike). And as far as the condition of the rest of the bike it is in pretty good shape. needs new paint but thats no big deal. The tires are new, and ther frame is in great shape, i haven't noticed any electrical problems except, i can't get the horns to work. As far as the history of the bike i have no idea except for i forgot to mention that it has been boored out to i think he said 815cc. oh and as far as it being oil or gas it looks and smells like oil, as far as i know it taste like oil but i'm not going to go that far to find out. as far as the compression goes what am i looking for the tester to say? And what exactly is the enricher circuit? AS far as when i try to start it i just choke and hit the starter, when it fires i back off the choke a bit and try again. I've owned and older honda (1973 cb500) kindof like this before and i started it the same way with no problems...well thats all i can really tell ya for now. Thanks for the help so far. Keep it coming. The more help the better.

How much oil is in the crankcase?
Is it all the way at the top of the window, or just up to the full line when the bike is on the centerstand (or standing straight up if no stand)?

well it was so low it was barely in the bubble but now it has been filled and is up to the top line.

Since you saw it running before you bought it, I assume it wasn't pouring blue smoke out the exhaust, right?

In that case it wasn't pumping oil into the combustion chambers at the time.

It takes a bunch of oil getting into the cylinders to cover the plugs in oil when just cranking it over, and I just can't think of any way that much oil could get into the cylinders from the motor just cranking it over. Especially all four cylinders.

So it seems to me like the oil is not coming from the motor, but through the carbs, either in the gas or from the air filter.

If it has individual air filters, take one off and look inside it (and the carb) to see if someone has over oiled it. If it has an airbox with filter, look to see if it's a K&N and someone over oiled it (look for oil in the bottom of the airbox as well).

Or someone dumped a couple of quarts (or more) of oil in the gas tank. You can disconnect a fuel line at the petcock and turn the petcock to prime to see if that's the case.

I have seen some worn out motors, but I have never seen one that would foul all four plugs with oil just by cranking it over.