Alright everyone, I really do hate asking for help but I need to try to figure out what's going on with my carbs and I don't have friends/mechanic/anyone local to me that can I can have look at it and see if they can point me in the right direction.
I rebuilt my carbs, all new rebuild kits from RPM, soaked the carbs, ultrasonic cleaned, blew all the passages out and ultrasonic cleaned them again, blew the passages out and dried them before putting back together. I'm confident in the cleaning, rebuild and float height.
I synch'd the carbs and am confident in that. I do have gauges and got all of the carbs even at idle and when throttle is open.
Put them on the bike, checked for vacuum leaks by spraying fluid around everywhere - there were none.
New plugs, gapped correctly
Bike started fine and idled fine, had some hesitation off of idle so I messed around with the needle and ended up raising it one notch (RPM's are adjustable). I tried lowering it first but it seemed to make it worse.
Messed with the air mixture screws, started at 2.5 turns out, went to three, seemed worse, backed it back down to 2 I think and everything seemed good. Slight hesitation off idle but not bad at all.
I finally get to go try riding it, it started okay, idle was low even after it warmed up, more than just a little hesitation off of idle, started to pop at the exhaust after revving when the rpm's start coming back down. When I actually took off it was so sluggish it was pitiful. I decided to just go around the block at this point, when I would take off from a stop sign I had to give it so much gas and feather the clutch just to be able to get it going, almost like I was taking off in 3rd gear (I wasn't by the way), when I pulled in the driveway it died before I got it to the garage. Haven't tried restarting it yet.
Does anyone have any idea where to look? Where to start? Any needle/mixture setting recommendations? I'm in northern Arkansas and the bike does have a Vance & Hines 4 into 1 exhaust.
Thanks in advance for any tips or advice
What air filter are you using and what pilot jets, air bleed screws and main jets are you using in the carbs?
Good morning, according to RPM's website it has 110 main, 155 air pilot jet and 42.5 fuel pilot jet.
Air filter = K&N filter and it looks like someone took a router to the side cover for more airflow.
I would put a pic of it on here but I still don't see how in the world to post pictures
I need to go to a 112.5 main don't I? What about the pilot jet? Stock or go to 45mm? Or am I way off in my thoughts?
#112.5 mains, #42.5 pilots, 155 air bleeds, needles at middle clip. 2 1/2 turns out idle mixture screws. Set cold idle at 1k rpm. Good start.
Did you replace your manifold O rings? You should have.
Double check your float heights? Low float measurements = higher floats = rich.
Verify floats, Get some clear tubing and check your fuel levels in the carb bowls.
Good seal on your slide rubbers? Slide drop test: Lift each slide with your finger, then drop them, they should all slowly drop uniformly.
The rule is, when your cold idle is fine but hot idle is too high, you're running rich.
Did you do the throttle blip test?
Hanging RPM = too lean
RPM drops low then slowly returns to idle = too rich.
Keep at it, you'll get her running right....cheers. Pat
Quote from: Pat Conlon on June 08, 2025, 11:20:35 AM#112.5 mains, #42.5 pilots, 155 air bleeds, needles at middle clip. 2 1/2 turns out idle mixture screws. Set cold idle at 1k rpm. Good start.
Did you replace your manifold O rings? You should have.
Double check your float heights? Low float measurements = higher floats = rich.
Verify floats, Get some clear tubing and check your fuel levels in the carb bowls.
Good seal on your slide rubbers? Slide drop test: Lift each slide with your finger, then drop them, they should all slowly drop uniformly.
The rule is, when your cold idle is fine but hot idle is too high, you're running rich.
Did you do the throttle blip test?
Hanging RPM = too lean
RPM drops low then slowly returns to idle = too rich.
Keep at it, you'll get her running right....cheers. Pat
Thanks Pat, I did replace the manifold gaskets, I'm going to get the new mains ordered tonight and get them on the way here. I'll double check the float heights also when I have them opened up. As far as checking the float height, depending on where I read, some just put the carbs upside and measure, another says to hold them upside, tilt to a 45 degree angle and measure, another says to hold them upside down and tilt to 65 degree angle and measure (which is what I did). What is the correct tried and true way that you have found and done? I'd rather hear it from someone on here who has done it with favorable results. Thanks again for the help.
Jason
Rotate carb body until the float tab just touches (but not compresses) the float needle.
Just thought i would give an update if anyone was interested. After a 3 week hiatus to Kansas for work on 2 days notice, the new jets getting lost in California somewhere, luckily the replacements made it here just fine, I got it back together and am quite amazed how strong it runs for a 36yo bike. I was surprised. I went with the 112.5 jet, raised the needle one clip, and am leaving it alone. I'm quite happy. Thanks for all the help, not only with me but to everyone that you all help out.
Yo let's see a pic of that 1988 zx10
Well, how in the world do you post pictures in the message? I couldn't figure it before either. If there's a way, please write it out in crayon so I can figure it out please. I'm pretty simple.
You have to hit the reply button then you can drag over an attachment
I tried, said the picture was to big. Not sure how to change a picture size.
ok no worries, those old ZX10's were awesome can't believe one is still out there
I you figure it out add in the RS250! As an owner of a RZ350 (+4/+4 421cc) I do love me a good 2 smoke.
I make low resolution copys of my pictures by sending them in a text then downloading the low resolution version of the picture from the text.
Quote from: captaudi on July 16, 2025, 12:05:17 PMI you figure it out add in the RS250! As an owner of a RZ350 (+4/+4 421cc) I do love me a good 2 smoke.
I wish I would've kept my Kenny Roberts edition. I regret selling it all the time. I to love a good two-smoke
My '96 RS250 Loris Reggiani Edition
'88 ZX10 - I think I may repaint it(keep it factory colors and scheme), clean it up and maybe take it on my trip next year to TN and back. 2,000-2,200 mile roundtrip. That thing is pretty comfy.
Quote from: T Legg on July 16, 2025, 02:51:45 PMI make low resolution copys of my pictures by sending them in a text then downloading the low resolution version of the picture from the text.
I do a screenshot and trim it down.
Quote from: 81Delorean on July 16, 2025, 06:29:50 PM'88 ZX10 - I think I may repaint it(keep it factory colors and scheme), clean it up and maybe take it on my trip next year to TN and back. 2,000-2,200 mile roundtrip. That thing is pretty comfy.
So nice!!!
So nice!!!
[/quote]
Thank you. I got a killer deal on it from a guy up in Missouri who needed money for his sons legal issues. $1,000 Well worth the 8 hour round trip drive to me.
That bike is worthy many times that! How's the zx10 ride compared to the FJ I never rode one
Suprisingly it's lighter than the FJ, stable, comfortable to me, suspension is soft but fine for normal riding. Power is there when you need it. All in all I'm pretty happy with it.
Nice stable man! I would love to take either one a rip. I always wanted to try a ZX10, I had a GPZ900A2 back in the day. And the Aprilia would just be a giggle.
Thank you. i do like the ZX10, had a 1996 ZX11 also for a couple years. Got a good deal on it also but it wasn't like I remembered it being when I was young and it just never grew on me. Sold it to a guy in Delaware (?) who has an exotic car dealership and a nice collection of bikes.
For trips, I wouldn't take the RS250. It's fun to ride, handles spectacular but thirsty and light, wouldn't be great on a trip but would be excellent on a short track.
I have always had a fondness for Kawasaki. I think it's because the bike I learned to ride on when I was 10 was a 1974(?) Kawasaki F11 250. Whish I had another one just for the memory. I have considered starting a collection of early Ninjas of all displacements but I don't have room and the wife wouldn't be particularly excited about it.