Re: ZXR 750 H1 in Green White and Blue
Posted: Sun Dec 08, 2013 5:10 pm
Well this alternator has given me some grief the last few months.
Once I'd established that the alternator didn't seem to be charging I needed to use the bike for a 60mile trip. So as the battery was charged I ran it without the lights on. It was starting to misfire at low RPMs. and finally stopped just 100yds from the house. Pulling the brake light on was enough to drop the voltage and I surmise the coils didn't fire.
It was only when I got home I realised I'd hadn't accounted for the electric fuel pump, doh! At least 60 miles was reasonable!
The belt was still going around, so it wasn't the belt that was buggered again.
I pulled the alt out, hooked it up on the bench and drove it with an electric drill, whilst it was all connected to a battery on the bench. I had to limit the rev's on the drill, as it would have blown the 10A fuse, so it was putting out the current and voltage was up at 14.5v.
So I stuck it back on the bike, which is a right pain. Tank, airbox and carbs off. Tho I later realised you can just lift the carbs/airbox up a little. The issue is you can fit the alternator from the side, but you can't see if the belt is aligned right. That pesky belt is £25. Now the belt, which had been new and gone hard in one part and had taken a 'set'. So the alternator would work fine for about 2mins, then stop charging. The belt was still going around.
So alt off again, back in the vice, I had it charging a car battery for 10mins, no problem. How bizarre.
Back on the bike it did the same as before, stopped charging at 2mins.
So a local breaker had a GPX750 one, which I was told was the basis of the ZXR motor in the H1 bike. So I bought that and guess what, it's very slightly smaller, 110mm between centres, the ZXR is 115mm.
So I found a guy breaking a fire damaged ZXR. He assured me the alternator was fine and it had a nearly new belt. So I went to buy it, the insides had got very hot in the fire and the wire was gone as it had melted. Most people were asking £40 for a used alt plus post, another tenner. So we agreed on £25 for this one as it had a new belt.
Once I swapped the wires over from my old one, and fitted it, it seemed to do exactly the same. Run for 2 mins and then stop.
By now I was convinced it was down to the belt tension, that after 2mins the belt was stretching slightly due to it getting warmer and as a result was a slipping. Although I've had it slip in the past and it screeched like a car alternator with a loose belt.
There's a special tool for tensioning the alternator available from Kawasaki. I decided to make one, it fits in the engine mounting bolt hole. Tension the alternator to 16nm and then tighten the mounting bolts. Once I did this it's seemed to have worked fine. Here's the tool. It's painted red as I was attempting to paint the NC front mudguard, I tell you 2k lacquer is a swine to get off, as I screwed up and put too much on.
Once I'd established that the alternator didn't seem to be charging I needed to use the bike for a 60mile trip. So as the battery was charged I ran it without the lights on. It was starting to misfire at low RPMs. and finally stopped just 100yds from the house. Pulling the brake light on was enough to drop the voltage and I surmise the coils didn't fire.
It was only when I got home I realised I'd hadn't accounted for the electric fuel pump, doh! At least 60 miles was reasonable!
The belt was still going around, so it wasn't the belt that was buggered again.
I pulled the alt out, hooked it up on the bench and drove it with an electric drill, whilst it was all connected to a battery on the bench. I had to limit the rev's on the drill, as it would have blown the 10A fuse, so it was putting out the current and voltage was up at 14.5v.
So I stuck it back on the bike, which is a right pain. Tank, airbox and carbs off. Tho I later realised you can just lift the carbs/airbox up a little. The issue is you can fit the alternator from the side, but you can't see if the belt is aligned right. That pesky belt is £25. Now the belt, which had been new and gone hard in one part and had taken a 'set'. So the alternator would work fine for about 2mins, then stop charging. The belt was still going around.
So alt off again, back in the vice, I had it charging a car battery for 10mins, no problem. How bizarre.
Back on the bike it did the same as before, stopped charging at 2mins.
So a local breaker had a GPX750 one, which I was told was the basis of the ZXR motor in the H1 bike. So I bought that and guess what, it's very slightly smaller, 110mm between centres, the ZXR is 115mm.
So I found a guy breaking a fire damaged ZXR. He assured me the alternator was fine and it had a nearly new belt. So I went to buy it, the insides had got very hot in the fire and the wire was gone as it had melted. Most people were asking £40 for a used alt plus post, another tenner. So we agreed on £25 for this one as it had a new belt.
Once I swapped the wires over from my old one, and fitted it, it seemed to do exactly the same. Run for 2 mins and then stop.
By now I was convinced it was down to the belt tension, that after 2mins the belt was stretching slightly due to it getting warmer and as a result was a slipping. Although I've had it slip in the past and it screeched like a car alternator with a loose belt.
There's a special tool for tensioning the alternator available from Kawasaki. I decided to make one, it fits in the engine mounting bolt hole. Tension the alternator to 16nm and then tighten the mounting bolts. Once I did this it's seemed to have worked fine. Here's the tool. It's painted red as I was attempting to paint the NC front mudguard, I tell you 2k lacquer is a swine to get off, as I screwed up and put too much on.
