Dual carb adjustment

[voodoolord]

Im starting to put her back together. I have a Clymer manual and a small tutorial on synching the carbs there but was wondering if theres a easy and foolproof way of determining if their good. As many things were screwed up on this bike Im not going to trust that the carbs are right. They are out of the bike right now but will be going in soon so if you guys have any advice throw it at me ? Thanks.

voodoo

[Horri]

Just bend the arm that controls that adjustment so they both open at the same time,,easiest and fullproof..,,Couple of my twin carbers are set like that,,no issues using that method..,,I'll check out the airscrew situation and get back to you in a day or so if you aren't in any rush..Saturday here and I know the joker who supplies them likes fishing so he may be away today hiffing a line somewhere....

Edited October 21, 2011 by Horri

[thumpharder]

If you want to set them factory you want 5/16 inch between the arm on primary carb(the arm that hits the lever) and lever on secondary, 7/8 on the floats for 83, 3/4 for floats on newer up to 87. 1-1/2 turns out on screw and your ok to start, adjust screw as needed

[voodoolord]

ITS ALIVE!? Second or third kick she fires right up! I get a bit of fall off at full throttle though. I havent tried adjusting the air screw yet Ive just taken it around the property and up the road. Runs great so far though. I guess its down to fine tuning and tweaking her now.

[voodoolord]

Update, It ran great and I realized the choke was half on. If I take the choke off it wont idle. I have a hard time getting to the idle screw because its broke and I need a long needle nose to get to it but its turned in pretty far. I also noticed it seemed to almost stall after driving high speed on the road until I let off the gas. That makes me think the floats are too low.

Im running 55 pilot, 125 and 125 on the mains with the snorkle removed, stock pipe and factory air filter. I have a 122.5 main on hand which I think is stock, should I put that in the second carb? just trolling for Ideas before I tear it down again. By the way while the bike has power it doesnt have the wheelie power Ive heard of. Thanks for any tips.

voodoo

[thumpharder]

jets should be fine, idle air screw,or you need to pull the main jet out and the "jet holder" as honda calls it, it's really an emultion tube, the cross holes get plugged and also take a strand of wire from some 16-18 ga wire,or a strand from a wire brush and run it down the tiny holes in the throat of the carb, you know the bypass holes for idle and transfer ports.

I had mine off a couple times before I got it clean enough.

[voodoolord]

jets should be fine, idle air screw,or you need to pull the main jet out and the "jet holder" as honda calls it, it's really an emultion tube, the cross holes get plugged and also take a strand of wire from some 16-18 ga wire,or a strand from a wire brush and run it down the tiny holes in the throat of the carb, you know the bypass holes for idle and transfer ports.

I had mine off a couple times before I got it clean enough.

I completely disassembled the carbs and cleaned them with chem dip, compressed air and carb cleaner, I dont think thats the issue. Give me a call tomorrow and thanks Thump.

[HeadTrauma]

Since I saw it mentioned, don't set both carbs to open at the same time. With the stock setup, both carbs are open 100% at full throttle. Making the secondary carb open sooner will cause it to over extend at WOT and it will hurt response and fuel economy.

As for why it won't idle without the choke, look into the idle fuel and air air settings. The 125 mains are not the problem. If anything, they're a bit large.

[thumpharder]

The symptoms you mentioned, no idle and starving out tells me something I hate to bring up, I am going to put all my cards on a bad ACV (air check valve), the rubber diaphram, if you look close at it and see a spot on it, take a small single bulb L.E.D. flashlight like a key chain light and run it around the back while you look from the front side and see if any light comes through a pin hole.

That said, try the mix screw first, but if the screw doesn't do it, I'm betting ACV, when they are bad, your bike will run just like you discribe.

[voodoolord]

I'll check out the airscrew situation and get back to you in a day or so if you aren't in any rush..Saturday here and I know the joker who supplies them likes fishing so he may be away today hiffing a line somewhere....

Thanks Horri but Thumps got me covered. I appreciate the help.

[exdirtbiker]

I agree with Headtrauma... making both carbs open at same time is not recommended.

and the clymer isn't as detailed as this :

https://www.thumpertalk.com/forum/showthread.php?t=827613&highlight=

[scotteroni]

Your not really syncronizing equal fuel/ air delivery between two carburetors but more like coordinating the secondary carburetor to increase the volume of the fuel / air at the best time it's needed, seamlessly and smoothly. Like a two barrel carburetor on an older car. This is around or before (mid throttle position). Thats why the secondary throttle slide starts to lift when the primary is around 1/3 of the way up. The transition from single to dual carb operation In the stock form should work as designed without a flat spot or stumble mid throttle . If that occurs the secondary carb adjustment needs to be made to make the slide lift sooner or later. Any of the fellas in this thread with a manual should be able to give you factory specifications and procedure to do this. You really need a picture and the measurement to do this correctly. I only have the xl250r manual.

[voodoolord]

Man I need to get the factory manual. The funny thing is that my carb adjustment screw is the same one shown for the 84 carb with the lock nut not the one with the spring. I have an 83 for sure. Im wondering if someone replaced the adjustment screw or got a set of 84 carbs.

[MentalGuru]

Heres a couple of quotes of mine from a few weeks ago...

Google found me this Factory XL600R Service Manual. Each section of the manual is a seperate download. You need to use the "Shop Manual XL600R* (Inglese)" downloads.

http://www.hondaxl.it/manuali.htm

The XL600R factory manual is 23 downloads and well worth it.

I also downloaded the Honda Common Service Manual. I never seen it before, it seems to have some interesting info in it.

Just scroll down the page. ?

There is even a XL400R/XL500R Honda Factory Service Manual.

And people say there was never a XL400R made...

You can even download the Parts Catalog in English and Owners Manuals in other languages.... ?

?

[voodoolord]

Thanks I downloaded the manual. By the way you can go online and find pdf file mergers that let you combine the pdf files. I used foxyutils.com It made all 25 files into 2.

[voodoolord]

Ha! I Uploaded the whole thing to my android phone. So sweet to have the entire service manual in my pocket. Thanks again TNT.

[thumpharder]

So is that bike running yet ? see you have the manual now thats always good. Keep us posted how it's going

[voodoolord]

So is that bike running yet ? see you have the manual now thats always good. Keep us posted how it's going

Ya thump its running well and idling better but its still uneven. When I close the choke all the way I need to raise my throttle speed quite a bit for it to idle. When it warms up I need to drop the idle speed alot and its pretty hard to get it to idle consistently. As soon as it gets down to a certain speed it almost always stalls unless theres a little choke on. Its kinda weird. Im wondering if the stator might have something to do with it not idling well. Its funny though cause I can start it on the first or second kick every time. Im still waiting on a new pilot which should be here tomorrow.

[MentalGuru]

Ya thump its running well and idling better but its still uneven. When I close the choke all the way I need to raise my throttle speed quite a bit for it to idle. When it warms up I need to drop the idle speed alot and its pretty hard to get it to idle consistently. As soon as it gets down to a certain speed it almost always stalls unless theres a little choke on. Its kinda weird. Im wondering if the stator might have something to do with it not idling well. Its funny though cause I can start it on the first or second kick every time. Im still waiting on a new pilot which should be here tomorrow.

Set the idle for 1500rpm hot, no lower.

[voodoolord]

Ya I need to get a proper rpm reading. I need to check my Fluke and see if it does single cylinders.