Bonneville America Forums Forums Technical Forums General Tech Well, she started, but...

Got it all back together finally. It starts! But it's backfiring like crazy. The idle is all messed up. The throttle at the low end is very spotty. If I can rev it over 4000 it starts to sound smooth, but not even near normal. Backfiring to the point of sounding scary. Also getting a burned something smell.

Brand new gas

New Tank

Carbs were just sprayed and cleaned, but only through the float bowl. I did not overhaul carbs.

Throttle cables are iffy. I reattached and tightened, but it could be off. I didn't mark where the nuts threaded to

As far as I know, the airbox is attached properly.

There is a little bit of Seafoam in the tank.

I used deep creep on the carbs

Anyone have any ideas before I tear the carbs off again? It HAS been sitting for a year. I thought a new tank and a cleaned carb would remedy that.

Sync the carbs, and back off the airscrews to 2 1/2 turns out as a start point. No body mentioned it, but you could have eyeballed the butterflies adjustment for similar opening (usually still close enough, unless you moved the screw) before you installed the carbs to the head. Also, be checking for air leaks on the intake side as that will cause backfiring.

Those dang vacuum caps, you need four new; shoot a bit of deep creep around the manifold joints to check for vacuum leaks there too. Your balance is likely out some but should be okay enough to get an idle happening, it's hard enough to move the adjuster screw when you mean to. And you probably have done fine tuning to do on the throttle cables...just take it a step at a time. Vacuum leaks first.

Vacuum leaks, if you had the slides out double check the diaphrams to be sure they are seated properly. The rubber caps and intake boots too. The boots are directional so be sure they are on the correct way if you had them completely off.

Also, it's easy to lose the little brass bushing that guides the needle down into the float bowl and not notice that it has dropped out. Don't ask me how I know.

I was using a screwdriver to guide the rubber over the carbs on the airbox side. Thought I was being careful but I'll check it out.

I'm sure I didn't reattach the throttle cable exactly to the point where it came off, and it could still be a little loose. The wrench I was using tightened them just fine, but I'm iffy about the bottom adjuster nut. Doesn't seem like an exact science.

If I am turning the air screws, I need to tighten them down all the way, then turn them back out 2 1/2, correct?

The brass bushings are definitely still there or at least they were when I put the bowls back.

Last question, no. Disconnect one plug lead and ground then turn the other mixture screw in until it runs rough then back out until it runs rough counting the turns. The correct setting is 1/2 way between thye 2 rough spots. Repeat for the other side. Then adjust the idle. The cable adjustment will only effect idle and how well they close.

Use silicon spray to ease the boots onto the carbs...not, of all things, a screwdriver.

The pilot mixture screws control fuel, not air.

I am thoroughly confused. What screw am I going to adjust? Is it called the air mixture screw or the pilot? Can I access it without pulling it apart again? I have not synced carbs before. I mentioned in another post that I haven't touched the carbs in 12 years since I rejetted them, and it ran great up until my accident last year. I am looking at a short tube on the outermost underside of the carb, one on each side. Those are the screws I believe I am adjusting.

Can I do this without Carbtuners? Or will I need to purchase one to do this right?

Best way to sync carbs is using mercury sticks or vacuum gages, BUT another way that gets them close is to get a piece of rubber tubing, approx 1/8" id. x 18" long remove air filters and put the tube into the venturi approx. 1" and listen to the pitch through the tube. Make sure you put the tube in the venturi's the same amount. Its an old timers trick and is better than nothing. I don't have carbs mines EFI.

I hate to admit defeat, but without a carb synchronizer and my limited knowledge of carbeurators, it may be cheaper to pay the local shop 90 bucks to do it properly.

I know I appear pretty clueless, but I never remain clueless long. Repairing a MC is a fun and valuable experience no matter what. But buying a carb tuner and whatever else I'll wind up purchasing right now is bound to cost me more than having the local guys (who I trust) do it right.

Anyone want to talk me out of it? I may just talk myself out. I'm just getting impatient and losing confidence in myself. And I don't want to keep chasing tools and money around town at this time.

At this point it's a good idea to take it to someone who knows what they are doing. Hopefully that way you'll only pay once.

Turning the screws didn't seem to make a difference one way or another. Something is wrong. Now when I turn the handlebars I get a little surge. I twisted the idle knob too much. I frigged it up. I don't think I'm gonna learn how to balance my carbs this time around. But I am going to save for a balancer and maybe get a junked carb to mess with. It's going to the boys, who actually know what they're doing and deserve the money. Not that I have it...

Still haven't called yet. I'm intrigued by the homemade manometer. I love stuff like that. Right now though, I feel defeated and kind of stupid. I followed directions, I tried, I failed. Whatever. I know more about my bike today than I did last Thursday.
It's been a frickin year, I'm itching to ride.

When I made mine I used 2 cycle oil so if it gets sucked into the carb it won't hurt anything. I also put a small ball valve at the bottom of the loop. That way I can open it slowly and if the balance is way off I can quickly close it again preventing anything from getting sucked into the engine. This home made tool is very sensitive and works great. You don't need to turn the balance screw much to make a difference, good thing too since that sucker is hard to get to. I take my tank off and put it up on a shelf with a long fuel line so it is complely out of the way.

You have to adjust the mixture screws one at a time. If they don't make a difference you may have clogged passages or need a different pilot jet or you have the butterfly so far open that you are not running off the idle circuit.

Yes that is the one. Not really affecting the idle. I definitely got lost with the idle knob and did not properly adjust the cables. At this point they are pretty screwy. Today I am only confident I'll make things worse. Tomorrow's another story but by then it will probably be off to the shop.

Don't feel defeated, you have learnt along the way and know more than you did a week ago. Bring it to me and i'll balance them for you and save the $90 for gas so you can enjoy the bike. I'm retired so any day or time is fine with me. Des.

It's possible that some orifices inside your carb could still have some blockage. Did you use any carb cleaner /q-tips ? You want to see shiny brass inside when you shine a light in there if they are freshly, mechanically cleaned.Make sure you can blow through the jets/or see through them. When working on carbs,best to sit at a fairly large empty table, so that it's easier to keep track of /organize all of the internals. Take Desmond up on his offer if you can. Feel free to make your own manometer as Ian described, and there are also many you tube videos on homemade manometers. As Ian stated, best to use 2 cycle oil just in case you do suck some in in the balancing procedure. The Morgan Carbtune tool is what I used when I did mine. Likely you will need the D -shaped tool to adjust your mixture screws, if your bike is 13 yrs old. We're here to help, tools, knowledge,labor. D'ont let a day's frustrat ion sway your confindance in yourself to get through this. But in the name of riding sooner than later, you might wish to enlist some help. Best wishes

Almost forgot, your throttle cables are binding as you turn your handlebars to the right, which is the surge you heard in your motor. Make sure those cables are properly routed. The problem can also be rectified by re-routing those cables to the right side of the frame.

They started the D tool with the 04 models, mine is a simple flathead. I didn't have my cables off of the bike. I think the surge is from me reattaching them to the carbs improperly. I think the adjuster nuts need to come way down. I'm pretty concerned about the idle knob too. I cranked on it a lot, trying to adjust the idle, then trying to get it back where it was. Adjusting the cable while it is attached is dicey. I'm either doing it wrong or it has to be adjusted off the bike. I did get frustrated yesterday but I still think I'm outgunned without a balancer and good carb experience. I knew the carbs were out of my skill set but I wanted to learn them better.

I'm wondering something. I used Deep Creep to clean my carbs. I just learned that the old "deep Creep" isn't the same as the new stuff. Apparently the new stuff is a penetrant, and the old stuff is just Seafoam in a spray can. Did I ruin my bike? Whatever was left in the carbs could've run into the engine and made a mess.

Can't find anything on this new Deep Creep stuff, except a few people saying it's great in carbs, but I think they are referring to the old Seaoam in a spray can which used to be called Deep Creep. Fiasco....

unlikely you did any damage.

tikiman, get it over here and we can fix it. Everyone on the site has their "own" way of fixing a problem me included. i work for free and have my own "mercury sticks" and anything else we may need. I hate to see a person in need of help and hesitant to accept it because they may feel they're imposing. I wouldn't offer my help if i didn't mean it. Des.

Des, it is really incredible of you to offer your time and effort to my bike problems! I would certainly take you up on your offer, but I have no way to get the bike to you. It will definitely not make the 90 mile journey. I can barely get it around the block without stalling. If I detach and send them to you, I would still need to sync them when I got them back onto the bike. I definitely attached the cables too ham handedly, and in my attempts to correct it, made it worse. Carbs are tricky. It'll take a few tries to get a better understanding of how to tweak it.

I don't have a truck, or anyone that would lend me theirs for a whole day. Still pretty new out here. Like I said, I can't really afford the shop, but it isn't a huge amount of $ and they'll come get it for me. Still haven't sent it off yet but they are supposed to come today. If it doesn't work out, I'll get in touch and try to figure a way to get the bike down to Fallbrook.

Well i guess you're North of me because 90 miles would put you in Mexico. I have a SUV and a bike trailer, so if things don't work out with the shop i can get it down here or just work on it at your place. If i go away for a day it'll give my wife a break from me. Hope things turn out good for you. Des.

That's an extremely generous offer, don't see how you could pass that up.

I did a bad job cleaning the carbs. I suspect it was the Deep Creep, and also me not disassembling it all the way. So for the future, DO NOT USE DEEP CREEP ON YOUR CARBS. Use Seafoam spray. Deep Creep is a penetrating lube spray. But it wasn't always! WTF!

Local shop deserves the business and they took care of me. She sounds amazing. But next time I'll do it myself. I just need to learn carbs a little better.

Ryk, Des, you guys are awesome. Expect more stupid questions from me in the future. On to the brakes now!

I'm glad you got it sorted.Nothing like being in the wind!

Fiddling with carbs is one thing, Brakes are not items to "learn" on. If you can have someone show you and guide you then ok. NO short cuts on brakes and cleanliness is of the utmost importance, remember your life depends on being able to stop.

Good advice Des, also helps to have a triumph/haynes manual on hand to reference. You will wish to fully understand reverse brake bleeding if you open up your system and allow air to enter. Bleeding the front brake can be tricky. Feel free to ask questions.That's what we're here for.

I am not learning with my brakes. I've bled my brakes and changed my pads exclusively with this bike. I've worked on auto brakes too, same thing just bigger. I did eff up the rear brakes on a caddy once, not knowing there was a cylinder in there. Had to take it to the shop for that one! I do most of the work when I can. So happens that the first time I wrench it in 5 years is to redo forks and mess with the carbs. 2 jobs I am not equipped to handle. I just bought a bleeder vacuum kit and I've never played with one of those before but It seems much easier than a wrench and pump 2 man bleed. I should be just fine! I do also have both manuals, the Haynes and now the Triumph shop manual, thanks to a friendly member here. I know I ask a lot of dumb questions but Im not THAT stupid... most of the time!

Sounds like you've got it under control, my son in law bought me a vacuum bleeder and it worked great. make sure you keep the master cyl. topped up though. i ran mine dry real quick but even if you do it's no big deal when using a power bleeder.

Oh yes for sure! I'm gonna use this opportunity to teach my daughter her first lesson in brakes! She gets to pour and wear goggles now. Damn I'm old...