Author Topic: Carb help please (Read 8894 times)

Loctite77 · « **Reply #25 on:** August 11, 2015, 06:21:00 AM »

So obviously you guys did not read the entire thread. I have already had them completely rebuilt by a professional. Albeit a poor one. They are already clean with all new hardware and seals. The guy just did a bad job. harisuluv is helping me tweak them in and finish The job myself. I do not have the funds to have been completely rebuilt second time. In the future I will most definitely be using him to rebuild my carbs though.

Yeah Son!

DaveBarbier · « **Reply #26 on:** August 11, 2015, 07:13:20 AM »

I think people are pointing to what you said about corrosion and crap in the slide bores. So, they're not completely clean. Who knows how well this hack cleaned them, so I think they're saying to make sure it's done RIGHT you could let Harisuluv do them and set the jets and needle height right. If you can't, no problem, money doesn't grow on trees, but if you could, it would be done right.

This rebuilder isn't named Elijah, is he? Carbjoy.com or motorcyclecarburetorrebuild.com? If so, throw them in a river. I had bad experience with that guy. He seemed to think blue loctite was a good slide lubricant.

flybox1 · « **Reply #27 on:** August 11, 2015, 08:06:25 AM »

Remove and clean your carbs.
set the air screws at 1 turn out
Relocate the slide needle 5th slot down from the top.
install #42 pilot jets
Install #115 main jets
(dont skimp on aftermarket jets. buy KeiHin only)

jetsrus is my go-to for new jets. good service and fast shipping.
siriusconinc is another choice.

Loctite77 · « **Reply #28 on:** August 11, 2015, 10:51:39 AM »

Thank you fly box. Lowered the clips last night going to try exactly what you have suggested. Thanks for the feedback everyone.

I'm going to email the guy and call him out and see what he says before I throw him under the bus.

Yeah Son!

Loctite77 · « **Reply #29 on:** August 12, 2015, 09:58:25 AM »

This morning I got the carbs back on the bike after lowering the clips to the bottom position. Bench sync them as best I could and set the air screws to 1/2 turn out. Went out for 10 minutes, MUCH better. No bogging when you roll on the throttle and no popping when you close the throttle. However for some reason #3 is now cold

and it was fine just a few days ago! I guess I'll check the plug first. Still planning on 115 mains when I get them. Listen to the video and let me know what you think, sounds a little rough to me but that is likely because 3 is not firing.

Yeah Son!

flybox1 · « **Reply #30 on:** August 12, 2015, 10:25:37 AM »

cold as in ZERO heat you can touch it with your hands, or just not as hot as the others?
Verify you are getting spark by holding the plug cap and put the plug threads in contact with the head, hit the starter button.
A dark garage helps.
If you have spark, its a fuel issue.
turn your fuel on, open the drain screw on #3, and let gas flow. 10-15 seconds. might clear some debris.
close the drain screw, fuel tap still on, take a block of wood or a rubber mallet and tap on the carb stay plate. this might free up a stuck float.
if #3 stays cold(er) than the rest, and with your current carb work, i'd still suspect a carb clog, stuck float, incorrect float height. remove and inspect your carbs again.

Loctite77 · « **Reply #31 on:** August 12, 2015, 10:41:02 AM »

Cold. I can touch it with my hand. Thanks for the tips. Headed out of town for a week now but I'll try this when I return. I'll have to pull the bowls anyway to replace the jets. Thanks brother.

Yeah Son!

harisuluv · « **Reply #32 on:** August 12, 2015, 11:58:00 AM »

Quote from: Loctite77 on August 12, 2015, 10:41:02 AM

Cold. I can touch it with my hand. Thanks for the tips. Headed out of town for a week now but I'll try this when I return. I'll have to pull the bowls anyway to replace the jets. Thanks brother.

That's weird. Hopefully it's something simple like just a clogged slow jet. Are you sure that it was running on all four previously? What are the chances it was running on only 3 before and maybe that was why it wasn't running right?

Loctite77 · « **Reply #33 on:** August 12, 2015, 12:12:59 PM »

It is weird. Last time I rode it I made a point of tapping all four pipes with my hand. They were all hot. I did notice that the float bowl gaskets seemed a little big, like there is extra material??? Maybe the number 3 gasket is rubbing the float and causing it to hang up??

Yeah Son!

harisuluv · « **Reply #34 on:** August 12, 2015, 12:37:29 PM »

some of the cheaper gaskets will swell when in contact with gas, it's possible. for it to hang to the point where it couldn't even open up... don't know about that. possible I guess if your float were kinda twisted out of shape. if there was fuel in the bowl, then i think it's safe to eliminate it that.

flybox1 · « **Reply #35 on:** August 12, 2015, 12:52:46 PM »

please invest in some proper, pre-shaped VITON bowl gaskets.
they wont swell, cause leaks, and they'll stay seated while you put the bowl on.

Loctite77 · « **Reply #36 on:** August 12, 2015, 04:24:51 PM »

Quote from: flybox1 on August 12, 2015, 12:52:46 PM

please invest in some proper, pre-shaped VITON bowl gaskets.
they wont swell, cause leaks, and they'll stay seated while you put the bowl on.

Will do. Thank you sir.

Yeah Son!

Gene · « **Reply #37 on:** August 12, 2015, 05:44:04 PM »

Quote from: flybox1 on August 12, 2015, 12:52:46 PM

please invest in some proper, pre-shaped VITON bowl gaskets.
they wont swell, cause leaks, and they'll stay seated while you put the bowl on.

+1 - lifesaver.

Loctite77 · « **Reply #38 on:** August 16, 2015, 02:49:55 PM »

Thanks guys. Making progress. Have new gaskets coming. Can anyone tell me where you measure from to set float height? There is the surface where the rubber seal sits and there is also a "shoulder" just inside the carb body that sits a little bit lower. Should I be a 25mm? I ask because maybe the fuel level is just too high and that's why fuel leaks when on the side stand.

Yeah Son!

flybox1 · « **Reply #39 on:** August 17, 2015, 06:51:22 AM »

with the float tang just resting on (but not compressing) the float valve, the tallest part of your float should read 25mm, as measured from the carb bowl mating surface.

Loctite77 · « **Reply #40 on:** August 29, 2015, 05:44:21 AM »

Thank you all for your help. Especially harisuluv for sending me the parts. I think she is running well now. Still pops a little when you roll off the throttle from higher RPM's maybe it still needs to go up a jet size? Currently at 115.

I emailed the guy who rebuilt them and he was unhelpful and unapologetic. He said "sometimes I make mistakes" but offered no help or partial refund. So.....don't use this guy....
http://cb750kfour.com

Here is his eBay listing
http://pages.ebay.com/link/?nav=item.view&alt=web&id=121743818946&globalID=EBAY-US

Yeah Son!

flybox1 · « **Reply #41 on:** August 29, 2015, 09:21:08 AM »

Good news!
If youre getting pop at decel with the throttle closed, richen the mixture screw by 1/8 turn incriments amd retest. You may be able to tune.it out thos way before diving.back in.for a jet change...

Loctite77 · « **Reply #42 on:** June 24, 2016, 03:39:26 PM »

So it's been a while since I have worked on and ridden the bike, obviously. Just recently replaced ALL electronics, including Pamco ignition, Ultimate coils, new iridium plugs and new plug wires. Took it out for a good test today, it still pops on decel on occasion and will still hesitate/pop when I really roll on the throttle and accelerate quickly. Are those two things a symptom of lean or rich?

I have not yet richen the mixture screw by 1/8 increments as suggested by flybox

Deltarider · « **Reply #43 on:** June 25, 2016, 01:33:42 AM »

Quote

I have not yet richen the mixture screw by 1/8 increments as suggested by flybox

Do.
And Is there a chance water has entered your fuel system?

Loctite77 · « **Reply #44 on:** June 25, 2016, 05:17:09 AM »

Quote from: Deltarider on June 25, 2016, 01:33:42 AM

Quote
I have not yet richen the mixture screw by 1/8 increments as suggested by flybox
Do.
And Is there a chance water has entered your fuel system?

Highly unlikely. It's stored inside and I have cranked and ridden it for a few minutes every few month.

Yeah Son!

Loctite77 · « **Reply #45 on:** June 25, 2016, 09:38:55 AM »

So I went out and did plug chops today. Here are photos. The first two are of 1 and 3 and the last blacker one is 4.

To me (and this is my first time doing plug chops) 1 and 3 look lean or dead on while 4 looks rich. I think I know the issue in that I have only bench synced the carbs, I don't have gauges. Could this possibly be the issue here? And do the first two photos look lean? I'm thinking I need to go up for 115 mains to 117.5 or 120??? I am getting hesitations from 3/4 throttle to full throttle. Thanks guys for any advice.

Yeah Son!

calj737 · « **Reply #46 on:** June 25, 2016, 03:03:05 PM »

1/3 look lean, but also look badly fouled around the threads. 4 looks rich and fouled. Fuel level issues?

Loctite77 · « **Reply #47 on:** June 25, 2016, 03:37:02 PM »

Quote from: calj737 on June 25, 2016, 03:03:05 PM

1/3 look lean, but also look badly fouled around the threads. 4 looks rich and fouled. Fuel level issues?

I'm not sure. I set the float heights when I rebuilt the carbs last year. What else could cause fuel level issues?

Yeah Son!

jodangler · « **Reply #48 on:** June 29, 2016, 03:06:53 PM »

I did the same conversion. I didn't mess with the needle, that seemed to complicated. What I have is 42 idle, 120 main, and I'm pretty happy. The bike climbs on the highway pretty good, no problems at 70, 80, 90ish;) I am maxed out on my air screw though so I'm thinking I might need to go to 122 mains.
I have 4 into1 exhaust and pods, CB750k6.

I do think you need to get ur carbs sorted out first before you tinker around with pods and jetting, and I know u had someone rebuild ur carbs but I wouldn't take his word on that, he might b dicking u around for a quick buck.. Or u might just need new plugs

Loctite77 · « **Reply #49 on:** July 05, 2016, 08:29:23 AM »

So yesterday went out for a hard 45minute ride, plenty of time at 70-80mph, near max revs. As I'm getting home and shift down through the gears I get a loud backfire as I let the clutch out to first, closed throttle. There is also regular popping under similar low rev deceleration with closed throttle. Unless I'm wrong isn't a backfire and popping from unburned fuel? Doesn't that mean I should lean maybe the mixture screw some?

Yeah Son!

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Author Topic: Carb help please (Read 8894 times)