Thanks for your videos. I have 1983 Gpz750A. It was sitting for 11yrs before I bought it recently here in Australia. I followed step by step the same carby jetting and is now spot on. To help checking a/f ratio I fitted an oxygen sensor (a/f gauge) and is running to spec (max 14.5) keep up the good work
i ride this Bike a few years ago, 15 ore more. I sell it with two holes in the two middle Pistons. The adjustment of the caburators is absolut terrible. You think you fixed the cburstors, but a few weeks later you got the same issuse again. My Bike got rustpartikels in the fuel Tank. After 30 Miles at Highwayspeed here in Austria, 180 km/h+ , if got holes in the Pistons. When i buy an Retrobike again it will be the GPZ 750 Turbo ore the GPZ 1100 with the fuel injektion ...............Caburators, never again, they get you nuts, Kind Regards from Vienna/ Austria, Chris.
Love that bike, I tried in vain to buy a (custom green ) 750 Waaaay back when I was 20. Always lived that style & color.! Good for you keeping one alive...✌️
I am more into originality but the customer does have all the original red bodywork, tank and fairing. I like the green also but I’d rather have a green Eddie Lawson Replica. Thanks for watching and commenting.
Nice ! She's a totally different animal now. No stumble. Wonder if you just replaced the stiff heat cycled wires. Give it that little extra to make it 101%. Ticket machine.
Good to see the Kawasaki Bike from 80's. Younger generation like me get very rare chance to see such bike and Engineering put in. My Dad a bike and even he use to struggle with Carb setting right after cleanning. Looking ahead to see more such good content. Also appreciate hard work put in.
The solution is never having to clean them. That means, ride the things and keep good gas in them. 99% of my carb work is from engines, gas tanks, etc. that have been left sitting with gas that just goes bad. Frankly, I'm rather sick of doing rusty fuel tanks, luckily the last two jobs after this GPz had non-rusty tanks. Before, I had a run of I think 6 of 'em. Thanks for watching and commenting.
I just bought a gpz 750 and first day left the petcock on prime overnight and killed my engine, carbs, oil, spark plugs, and filter. Took me a week of hard work to get it running but your videos were a huge help when I was trying to figure out how to do anything (never owned a bike or done my own wrenching before) but now it runs beautifully! Thanks for the informative videos on this amazing bike.
Beautiful bike! I had a 84 gpz550. Same trouble when I bought it. Wouldn't rev. Some carb balancing and rebuilds and she pulled to redline. Still miss the bike. I'm older (and richer) now, I may buy another..
Good job sorting it out, I had faith in you! Brought back a memory of doing some carb work on my Z1000 and the thing wouldn't run above 5K. Drove me nut's trying to figure it out. Turned out a shop towel I left under the seat had been sucked into the airbox. The decel popping could definitely be related to the air injection system if it's still operational. You can test that by disconnecting the vacuum line you pointed too, leaving everything else intact, but you already know that. Great video!
Great job, hey everyone screws up now and again that's how we learn. Great man to own up to his mistakes, I have worked in many shop that would just keep replacing parts until they luck into getting it right. So ago great job. Thanks for the video.
Thanks. I screw up mostly small stuff but I have done some whoppers. Mistakes are inevitable however, how one handles them is the important thing. Motorcycle dealers are great at goofing up stuff and then playing the “Schultz” character from Hogans Hero’s, they “know nothing, see nothing!” Haha.
I had one that ran bad because there was a bit of crud in air passage to the main emulsion tube. I now have a spare water pick that I turn all the way up and blast out the little air passages when I have the carbs apart.
If the screw on tips of the spark plugs aren't being used, as seen at 9:35 in the video, the coils have to make 2 sparks/cross two gaps, one at the tip inside the cap, and one at the electrode. The effect is a stumble at higher rpms/roll on. The coils will pass individual field tests but weaken under load/over time.
Spark plugs caps ends of NGK plugs of that period are designed to not use the screw-on tops. There is a small receiving hole inside those caps where the lead attaches, that just has enough clearance for the threaded top of the plug, which are all standard by the way. Inside that hole in the cap is a tiny piece of spring metal that detents on the threads themselves as you push the cap onto the plug and securely attaches the cap/wire to the plug. So there is no gap there. There CAN be a problem if that springy piece breaks off and the caps are loose; but that's not the case here. Especially after replacing the caps with brand-new non-resister type. Thanks for watching and commenting.
interesting I have a older Ducat Parallel Twin 500 uses 105 main from the factory, I installed aftermarket magnetic trigger to eliminate the points, and running a pretty aggressive timing curve in the digital spark box, bike demanded a 115 main with the needles all the way up, probably could use a 120 also but for just cruising around town, and really getting on it once in while it's a different animal now than it used to be. Fuel quality almost demands more fuel today than from the stuff they had in 1984 at least 8-15% more
You raise a good point on fuel; generally, that's already baked-in my "gutwork" (a version of guesswork) when I pull out the jet drawer and start looking. I did ask the customer what fuel he had put into it, since my initial tests were on ETOH free and he said he put super unleaded in it. Frankly, I wouldn't use any ethanol fuel in a vintage bike unless there was no other fuels available. Down here, ethanol free is nearly on every corner. So fuel, yes, makes a big difference and something I am glad you mentioned because I never think about it out-loud that is. Cheers. Thanks for watching.
Be careful with electronic ignition. It’s either working or not, whereas the old points will get home spluttering when they start to wear out. I’d rather be limping home than stopped on the road, just saying mind!
So what is the reason for ANY resistors in the secondary circuit, sparkplug or inline? I can still get resistorless plugs for my bike and want resistorless caps also but can't find them. Can I go completely resistorless for more ignition power? 92 Honda 750 Nighthawk with DP8EA-9 plugs.
My understanding it is for ignition RF emission suppression. Caps are available but are like you said hard to find sometimes. I get them off eBay. Look for NGK LZFH caps.
2 and 1/2 turns is actual turns. Two 360 degree turns and one 180 degree turn. How most of us do it is, turn the flat screw 1/2 each turn, so “half, one, one and a half, two, two and a half.” I find that method easier to keep tract of.
Thanks for your videos. I have 1983 Gpz750A. It was sitting for 11yrs before I bought it recently here in Australia. I followed step by step the same carby jetting and is now spot on. To help checking a/f ratio I fitted an oxygen sensor (a/f gauge) and is running to spec (max 14.5) keep up the good work
I was just thinking about something like that how’d you install it and what equipment reads it? Do you simply use a scan tool?
i ride this Bike a few years ago, 15 ore more. I sell it with two holes in the two middle Pistons. The adjustment of the caburators is absolut terrible. You think you fixed the cburstors, but a few weeks later you got the same issuse again. My Bike got rustpartikels in the fuel Tank. After 30 Miles at Highwayspeed here in Austria, 180 km/h+ , if got holes in the Pistons. When i buy an Retrobike again it will be the GPZ 750 Turbo ore the GPZ 1100 with the fuel injektion ...............Caburators, never again, they get you nuts, Kind Regards from Vienna/ Austria, Chris.
Love that bike, I tried in vain to buy a (custom green ) 750 Waaaay back when I was 20.
Always lived that style & color.! Good for you keeping one alive...✌️
I am more into originality but the customer does have all the original red bodywork, tank and fairing. I like the green also but I’d rather have a green Eddie Lawson Replica. Thanks for watching and commenting.
Nice ! She's a totally different animal now. No stumble. Wonder if you just replaced the stiff heat cycled wires. Give it that little extra to make it 101%. Ticket machine.
Difficult to sell. Because the coils all test nominal under the parameters set forth in the service manual. Cost-wise. Thanks.
Good to see the Kawasaki Bike from 80's. Younger generation like me get very rare chance to see such bike and Engineering put in. My Dad a bike and even he use to struggle with Carb setting right after cleanning. Looking ahead to see more such good content. Also appreciate hard work put in.
The solution is never having to clean them. That means, ride the things and keep good gas in them. 99% of my carb work is from engines, gas tanks, etc. that have been left sitting with gas that just goes bad. Frankly, I'm rather sick of doing rusty fuel tanks, luckily the last two jobs after this GPz had non-rusty tanks. Before, I had a run of I think 6 of 'em. Thanks for watching and commenting.
I just bought a gpz 750 and first day left the petcock on prime overnight and killed my engine, carbs, oil, spark plugs, and filter. Took me a week of hard work to get it running but your videos were a huge help when I was trying to figure out how to do anything (never owned a bike or done my own wrenching before) but now it runs beautifully! Thanks for the informative videos on this amazing bike.
Thanks. Please consider subscribing. Glad to help.
Beautiful bike! I had a 84 gpz550. Same trouble when I bought it. Wouldn't rev. Some carb balancing and rebuilds and she pulled to redline. Still miss the bike. I'm older (and richer) now, I may buy another..
Bought a great-condition silver '84 GPz750 in 1989'ish. Of all the bikes I've owned over the decades, I wish I still had that one.
I wish I still had my 1967 Dodge Coronet R/T.... think about how much THAT would be worth today.
Good job sorting it out, I had faith in you! Brought back a memory of doing some carb work on my Z1000 and the thing wouldn't run above 5K. Drove me nut's trying to figure it out. Turned out a shop towel I left under the seat had been sucked into the airbox. The decel popping could definitely be related to the air injection system if it's still operational. You can test that by disconnecting the vacuum line you pointed too, leaving everything else intact, but you already know that. Great video!
That’s what the dang thing is called yea, Honda calls it one thing, Kawasaki another and Suzuki still something else. Thanks
Colour tuning the air screws on these fours instead of guesstimating makes a ton of difference.
Love that bike
Great job, hey everyone screws up now and again that's how we learn. Great man to own up to his mistakes, I have worked in many shop that would just keep replacing parts until they luck into getting it right. So ago great job. Thanks for the video.
Thanks. I screw up mostly small stuff but I have done some whoppers. Mistakes are inevitable however, how one handles them is the important thing. Motorcycle dealers are great at goofing up stuff and then playing the “Schultz” character from Hogans Hero’s, they “know nothing, see nothing!” Haha.
Exactly heat makes coils get weak n funky.
I had one that ran bad because there was a bit of crud in air passage to the main emulsion tube. I now have a spare water pick that I turn all the way up and blast out the little air passages when I have the carbs apart.
If the screw on tips of the spark plugs aren't being used, as seen at 9:35 in the video, the coils have to make 2 sparks/cross two gaps, one at the tip inside the cap, and one at the electrode. The effect is a stumble at higher rpms/roll on. The coils will pass individual field tests but weaken under load/over time.
Spark plugs caps ends of NGK plugs of that period are designed to not use the screw-on tops. There is a small receiving hole inside those caps where the lead attaches, that just has enough clearance for the threaded top of the plug, which are all standard by the way. Inside that hole in the cap is a tiny piece of spring metal that detents on the threads themselves as you push the cap onto the plug and securely attaches the cap/wire to the plug. So there is no gap there. There CAN be a problem if that springy piece breaks off and the caps are loose; but that's not the case here. Especially after replacing the caps with brand-new non-resister type. Thanks for watching and commenting.
interesting I have a older Ducat Parallel Twin 500 uses 105 main from the factory, I installed aftermarket magnetic trigger to eliminate the points, and running a pretty aggressive timing curve in the digital spark box, bike demanded a 115 main with the needles all the way up, probably could use a 120 also but for just cruising around town, and really getting on it once in while it's a different animal now than it used to be. Fuel quality almost demands more fuel today than from the stuff they had in 1984 at least 8-15% more
You raise a good point on fuel; generally, that's already baked-in my "gutwork" (a version of guesswork) when I pull out the jet drawer and start looking. I did ask the customer what fuel he had put into it, since my initial tests were on ETOH free and he said he put super unleaded in it. Frankly, I wouldn't use any ethanol fuel in a vintage bike unless there was no other fuels available. Down here, ethanol free is nearly on every corner. So fuel, yes, makes a big difference and something I am glad you mentioned because I never think about it out-loud that is. Cheers. Thanks for watching.
Be careful with electronic ignition. It’s either working or not, whereas the old points will get home spluttering when they start to wear out. I’d rather be limping home than stopped on the road, just saying mind!
it's amazing how just a small tweak like the jet size and a small item in the wrong place can totally screw up an otherwise great running engine
What a machine. Nice
So what is the reason for ANY resistors in the secondary circuit, sparkplug or inline?
I can still get resistorless plugs for my bike and want resistorless caps also but can't find them. Can I go completely resistorless for more ignition power?
92 Honda 750 Nighthawk with DP8EA-9 plugs.
My understanding it is for ignition RF emission suppression. Caps are available but are like you said hard to find sometimes. I get them off eBay. Look for NGK LZFH caps.
Intreated in a id oarb fuel mix screws. Mine says 2.5 turns from snug. DOES that mean a turn equls 180° or 360°?
2 and 1/2 turns is actual turns. Two 360 degree turns and one 180 degree turn. How most of us do it is, turn the flat screw 1/2 each turn, so “half, one, one and a half, two, two and a half.” I find that method easier to keep tract of.
Not a turbo 22:24
Never said it was.
try voltage regulator
Good point. Although it’s fixed. I’ll double check charging output though.