Reddit mentions: The best powersports carburetors

Not an expert, but

I'd focus on the drive train issues first, get all those tires working, might be a lost cause before going any deeper, but others will have to help with that, I take that kind of stuff to my mechanic.

Brake pedal could be that it's low on brake fluid, or one of the brake calipers is stuck.

My quad has a foot brake like that and a hand brake, but the foot brake only brakes 1 tire. That tire has two brake calipers on it's roter, one to the foot break and one to the hand brake. So the hand brake is all 4 wheels, and the foot brake is 1 wheel. There is a master cylinder on my hand brake and another on my right rear tire (foot brake). If my foot brakes master cylinder runs low or springs a leak, my pedal goes through the floor like in your pic but I'll still have brakes on the hand brake. It's like a double/emergency braking system. If my hand brake goes out I can down shift (engine brake) and lay on that foot brake to brake and not hit a tree...
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Fuel wise, it's likely carburetor being old. The carburetor should have a primer on it that injects gas into the carb when you press/pull it. Those generally have a diaphragm in them (rubber) that tends to go bad over time and cause a fuel leak.

If you can find a diagram of the carburetor that would help emensely.

Really though, you should take the whole carburetor off, take it apart and give it a bath in carb cleaner (no plastic/rubber in there) and clean all the jets out.

Also, they make rebuild kits for most carb's that come with all new jets, and pilot screw etc. See if you can find one. I typically just replace them all, easier and then I have spares.

Also, inspect the carb's vent hose and make sure it's intact and not clogged. Check the fuel line too, for damage/rot.

You should also remove the gas tank and clean it out. Take the petcock off and inspect the filters and valve, then clean the whole gas tank out so there's no dirt/bad gas in there.

Then check/change the spark plug(s). Before running it though, I'd check the valve clearance on the valves, guides on that online.

Once all that's done, it should run good and not leak gas.

Then you can address your other issues.

Pending how old it is, there are some parts I might replace just because:

• Voltage Regulator
  
• Starter Solenoid
  
• Starter
  
  If the current ones are working, call them spares.
  
  Starters and solenoids are cheap, voltage regulators OEM are expensive, but you can buy a few after markets pretty cheap to have spares.
  
  Tool wise, I can recommend at least the following:
  
  
• Wire/Brushes
  
• Jack/Lift
  
• Compression Tester
  
• [Feeler Guages] (https://www.amazon.com/gp/product/B000BYGIR4) You want these to go from at least .002 to .014 inches
  
• [Caliper] (https://www.amazon.com/Neiko-01407A-Electronic-Digital-Caliper/dp/B000GSLKIW/) If you need to measure float height, you want to be accurate.
  
• Angle Finder Useful for float height, as most carbs need to be held at a specific angle for accurate float height adjustment.
  
  Then your typical ratchet sets, air tools, impact guns, etc.
  
  And socket extensions (long ones) because getting to some things is a royal pita.

Sounds like you’re doing everything right, I have not hesitated to use a higher concentration of seafoam but it feels like a rebuild is in your future.

Rebuilding the Carbs isn’t difficult and YouTube is full of exact videos on how to do this probably for your exact bike too.

Having a nice, clean well lit work surface is important, Spread out a light colored towel to keep small pieces from rolling, disassemble and lay the parts out exactly as you take them apart, do them one at a time so you still have another carb for reference on how it goes back together. Wear nitrile gloves, good dexterity and saves you hands.

Examine the numbers on your jets so you can get a kit with the same exact parts in it, we don’t know if anything was changed in the past.

Use a good carb cleaner and a stiff toothbrush, not a wire brush. Put your float in a container with gas to be sure they float, take a pic and compare to how the other float floats, pretty important. In fact, taking many pictures along the way is highly recommended.

With two carbs, you may be able to sync them without tools, but a dual vacuum meter setup is the way to go, here’s one.

AlphaMoto Vacuum Carburetor Synchronizer Carb Sync Gauge 2 Cylinder Bike Cb Cl 350 https://www.amazon.com/dp/B004MSJ7C8/ref=cm_sw_r_cp_api_aFG0AbHHTVZK2

>A throttle body sync sounds quite in depth as well, but I will look into it.

It really isn't too bad, but is made infinitely easier by having the right tools. There are a lot of $5 solutions that folk use, but unless you really know what you're looking for then the majority won't be able to figure it out

I'm a huge fanof this device. It's not cheap, but it makes it super clear how your sync is looking. You can use it on any bike, including if you ever get a 4 cyl.

It's a bit of an investment, but still cheaper than having a shop do it. Plus I loan it out to friends for a 12-pack now, so it'll pay for itself many times over

Murray doesn't make engines, they just assemble and sell whole mowers. My circa ~2005 Murray has a Briggs and Stratton, yours has a Tecumseh.

Tecumseh TVS115-57052E to be exact. You should be able to get what you need with that.

Here's a nice parts diagram:
https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/tecumseh/4-cycle-vertical/tvs115/tvs115-57052e

And a carburetor, with gaskets:
https://www.amazon.com/632795A-Carburetor-Tecumseh-TVS-100/dp/B00YVW30Z0

I'm not an expert (just a DIYer like you), so maybe you can find just the gaskets elsewhere... but $12 for everything seems like a winner to me. Good luck!

Wait, cone filters? I wonder if the carbs have been rejetted to factor that in. If those cones are restricting air then that's why you're running rich. If the jets have been upgraded too large of a size then that's another reason. I'd find out what your stock carb's jet sizes are supposed to be, then I'd use an online calculator or ask a website that sells jets what size you should have given the mods you've got. And compare that with what you actually do have. So you're still gunna have to pull your carbs to check your jet values. You might even have a clogged air circuit in your carb bodies so cleaning is still imperative.

You could try making your own sync tool but if you have too strong of a vacuum then whatever liquid you're using will get sucked in. This is expensive, but a 'cry once buy once tool': http://www.amazon.com/Vacuum-Carburetor-Synchronizer-Carb-Gauge/dp/B004MSJ7E6

So is his buddy, I'm not sure if you need this for your carbs, I need it for mine: http://www.amazon.com/Motion-Pro-Carburetor-Adjusting-Tool/dp/B001DDH2ZY/ref=pd_bxgy_263_img_3?ie=UTF8&refRID=00QXJ3CH1BBWNM7K2FPZ

You could sync the side carb bodies with a regular screw driver and wrench, but once you move to the center 2 bodies that becomes almost impossible.

Here is a link to your manual that deals with the carburators: http://www.honda4fun.com/pdf_man_officina/pdf_manuali/CB350-400/CB350-400_04.pdf

I would take pictures and notes while doing this. There's not a huge wealth of information for 1972 CB350F carbs unfortunately.

You should register at this forum. Any questions you have they can help you out with: http://forums.sohc4.net/

I'd also pick up this ultrasonic cleaner from harbor freight: http://www.harborfreight.com/25-liter-ultrasonic-cleaner-95563.html Go to the dollar store, dollar general or whatever the cheap store in your area is called and buy a large bottle of LA Awesome and a gallon of diluted water. Stuff makes the dirtiest carbs come out brand new. Maybe be a total scumbag and return the ultrasonic cleaner for a full refund as soon as you're done with it. Should take a day to clean all the parts once your carbs are completely dismantled. Then spray a light hit of WD40 on the metal and polish it off with a paper towel to prevent corrosion.

This is another cool tool to have: http://cdn1.bikebandit-images.com/blog/images/2015/carb-cleaner-kit.jpg If you have an air compressor use a basket ball filling needle to blow all the passageways clean. Or a can of air. This goes without saying but carb cleaner will eat rubber, brake cleaner is almost as strong but safe for rubber.

Random tidbit here is an awesome trick for polishing the float needle seats on a carburator: https://www.youtube.com/watch?v=zlez_hdoWYk when they're dirty it can cause them to stick.

In closing this is going to be a good amount of work and money (Unless you return everything shamelessly) Rubber consumables on your carbs appear to be float bowl gaskets and a few orings, maybe some rubber fuel lines. Nothing too pricey.

Thanks.

After a few beers...

I pulled the trigger on it as well as a new intake manifold, a gasket, a Keihin carb, (I just bought a carb but could always use a better quality one). A gang of tools. This kit arrived as well as 3 different hi flow air filters due to some order confusion.

I hope all this, when installed and tuned, at least gets me to 38/40mph faster with good throttle response and is reliable. I'm not looking for top end speed so much.

This was just supposed to be something to learn how to 'wrench' on, but lately I've been wanting to fix it up all sporty like and actually use it as transportation.

Most 75 and 76 US spec 400Fs (400F0 and 400F1) have the flat handlebars as well. My 75 has them. Didn't think the US spec got the high handlebars and forward pegs till 77 (CB400F2).

I agree the starter switch is likely the cause of the headlight problems. The current for the headlight actually flows over that switch. Here's a link to a relay kit that will fix that.

Also the yahoo CB400f group has a set of pictures that show you how to repair the switch if its salvageable. You can also find NOS switches on ebay if you look hard enough.

Good Luck on sorting out the issues and getting it back on the road. I have a good deal of work to put into mine as well.

Some more useful CB400F links:

Electronic Ignition kit.

Honda Sohc4 forums

Honda Service Manuals and Parts Lists

3000 mile maintenance:

• Clean all carb passages -- Try this for badly gunked up carbs: Yamalube Carb cleaner
  
  May need to rebuild carbs if jets are badly varnished.
  
  
• Change oil & filter
  
• Change air filter
  
• Change spark plugs
  
• Adjust cam chain
  
• Check and adjust valve clearances -- need .002in feeler gauge
  
• Check and adjust points and timing (or replace with electronic ignition)
  
• Vacuum sync carbs --
  Carb sync tool
  
  
  
  11mm master cylinder thread on sohc4.net.
  
  
  
  
  
  

Seafoam is a stabilizer that can prevent the fuel from clogging the carb jets. But once a jet is clogged, it often requires actual scrubbing with a carb cleaner to break it up. Gasoline can become like solid paint lacquer. It can be cheaper to replace the carb on a scooter than the labor required to clean it. You can find them on Amazon for $20-30 like this one. You may have to know how to tune the new carb when you get it, but often it will work out of the box with the factory jets and settings. The one I listed has good reviews and has verification that it has an adjustable slide pin, which helps for tuning if needed. This carb is for a 150cc GY6 or GY6B.

Carb synching is pretty straightforward, and can be done with or without a carb synch tool. I have a CarbTune Pro as I wanted one that did not use liquid.

Without a carb synch tool, you can do a "bench sync." A bench sync means you remove the carbs and adjust the butterflies manually so they open at exactly the same time. You can accomplish this by either filling the carb (where the butterfly is) with gas / brake clean / etc. and adjusting the adjuster screws so when the throttle actuator BARELY opens, the fluid begins to drop at the same time. Alternately you can do it by eye, or use a thin piece of wire or something similar that's held by the butterfly while the throttle is closed and falls upon opening. The biggest issue you want to address is to get them both to open initially at the exact same time.

A carb tune simply helps you adjust this whilst on the bike w/ the bike running and you can verify things are good at various RPM ranges.

Is there an o ring on the back of the carb like this replacement one on Amazon? https://www.amazon.com/PANTERRA-100CC-110CC-REPLACEMENT-CARBURETOR/dp/B008ZI5EM8

If so, is it in good condition?


Could be running lean as well, which would be causing you to have too much air.

As far as I know most 50cc engines are bottom-mounted and 150cc engines are top-mounted so you will need to look for a bottom-mounted 150cc engine (which I think are rare) or do some modifications.

Depending on your budget there are some places that sell new 50cc engines with big bore kits already installed, I used to have a link to one that let you select all sorts of options using a web form with check boxes and they would send it all pre-configured but I can't find it offhand.

There are some videos on YouTube of people putting 157QMJ's onto TaoTao 50 frames, but it looks like a LOT of work to me requiring at least some machine-shop access or tools. AFAIK big bore kits tend to shorten the usable life of an engine, but I don't know by how much on average.

this is the carb that I just put into my 150cc with a 115 main jet. So far its working great. Eventually I want to go all out but that might be a year or two from now.

Seems like a fuel/air mixture problem. Firstly before you begin the process to reset everything to the way it is, make sure you have no air leaks between the carb and the engine and that the clamps are tight. Also check for cracks on the rubber boot that holds the carb to the intake port. Make sure you have a reasonably clean air filter installed as it will make tuning wonky without it or with a different exhaust.

1:Find your mixture screw, then tighten it all the way in until it wants to stop turning. Make sure to tighten it very gently as the needle can be damaged very easily. Then loosen it 2.5 turns.

2:Start the bike and keep it running for awhile until it warms up. You may need to hold the throttle and/or use the choke to keep it alive, but that's ok for now. When it's all the way warm, turn the choke off.

3:Adjust the big ol' screw on the side of the carb that pokes on the throttle arm until the bike idles nicely. If the engine is warm, the idle should sit nice and smooth now without needing to touch the throttle.

When the bike is cold it should start with the choke and may idle high until its warm and the choke is turned off. This is normal.

If this process did not fix the issue, I would suggest getting a carb rebuild kit and changing all of the jets and needle valves. It's cheap and is very easy to do. The jets or mixture screw may have been damaged from being over tightened or may be full of crud from old gas. While you are changing out everything, give it a good spray with carb cleaner and/or compressed air in all of the tight spots. Wear eye protection while doing so.

https://www.amazon.com/dp/B00GURJZZI/ref=cm_sw_r_cp_apa_yPAVzbWET8ACA This one. Basically all of the Chinese scooters have completely interchangeable parts, plus I have a moped identical to yours and this is the one I bought, fit perfect.

> Morgan Carbtune Pro

where do you think is the best place to purchase one? does this look right? https://www.amazon.com/CARBTUNE-PRO-4-W-Pouch/dp/B018UTHGPE

OEM is like $50-60. Is there an off-brand one that would work?
Something like this? https://www.amazon.com/CARBURETOR-ELECTRIC-CHOKE-125CC-SCOOTER/dp/B00E7871NA/

Do you think this one would work. I mean it looks pretty similar to the one currently in my scooter. The one in my baby has the tamper resistant screws, so buying a new one is much easier than dealing with those.

I use an old-school Uni-Syn Sync tool to balance them and then a Gunson Colortune to get the mixture set right. It actually seems to stay fairly well tuned and I only have to fiddle with them about once a year or so.

Sync Tool like this one: https://www.amazon.com/Uni-Syn-Carburetor-Synchronizer-Synchronizing-Balancing/dp/B073RPZKBX

Colortune: http://www.gunson.co.uk/products/Colortune

For sure man, thank you. The oil seal will be the last thing I check and only if the problem isn't resolved by the carb replacement and a good cleaning and probably a new belt. I'm looking at this kit if you have any input on it.

I have a set coming in for pilot and main. Cannot wait till they get here. If the tune calls for it, definitely going bigger!

Oh, and Here is the Amazon URL

I can't seem to find any airleaks. I've sprayed starter fluid all around where there could possibly be one while the scooter was running and I didn't hear any differences.

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Can you explain a little more what you mean about the throttle slide being impeded?

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And this is the carb I bought on Amazon. I have a 49cc IceBear. I still have my old carb, so what should I look at to compare the two to make sure the new one is correctly compatible?

You might have issues with the carbs not being balanced, god knows I’ve had em. If you do, there is a vacuum tool that makes balancing these things easy, invest. It’s worth every penny.

EMPI 5746 Universal SU / Bubble Type Carburetor Synchronizer - VW Dune Buggy Bug Ghia Thing Bus Trike Baja Down Draft / Side Draft https://www.amazon.com/dp/B003LIX3WK/ref=cm_sw_r_cp_api_i_bgrCDbN7TG7TD

Hope this helps
https://www.amazon.com/Honda-16100-ZF5-025-Carburetor-Be32A-C/dp/B00AJTYSNW/ref=cm_cr_arp_d_product_top?ie=UTF8

They remind me of tip cleaners used for welding/carburetors.

https://www.amazon.com/dp/B076HMF3DM/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B076HMF3DM&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=f52e26da-1287-4616-824b-efc564ff75a4&pf_rd_r=4VXEYMT6PJFT4FAHBYRK&pd_rd_wg=VYUU5&pf_rd_s=desktop-dp-sims&pf_rd_t=40701&pd_rd_w=ihA2C&pf_rd_i=desktop-dp-sims&pd_rd_r=42fefff4-b975-11e8-be59-db2f2d1fb2cc

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Same thing.

https://www.amazon.com/Carburetor-Cleaner-Torch-Welder-Motorcycle/dp/B076HMF3DM

Specifically a Uni-syn carb synchronizer.

https://www.amazon.com/gp/product/B00UCY60GW/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

I haven't taken apart the carb because I thought the fact that it was new means i didn't have to deal with it

Here is the carb if you were wondering

i would probably get a carb sync tool and go from there. are the rpms all over the place too?
edit: and how did you tune the carbs?

I'm sure you could do it without the adjuster tool but the tool makes it so incredibly easy. Here's a kit with everything you need for $50:

https://www.amazon.com/P1-Tools-Motorcycle-Synchronizer-Synchronization/dp/B07MJZ1RFB

Also, the vacuum test ports are on the intake runners, not the carbs.

And lastly, why aren't my comments showing up on the main thread? Weird.

You can take the float off and shake it to listen for liquid sloshing inside them. And here’s the tool...not this exact one but something similar. It’s a crude way, but it’s good enough.

Thanks! The problem is that the float bowl is putting pressure on the screw. I can reach the screw, but can't turn it because the bowl prevents it x_x.

I hooked up my gauge to cylinder 1 and no matter where I have the mixture screw the vacuum stays the same. The only time the vacuum changed slightly was when the bike reached operating temperature. I tried adjusting the screw again after this and it maintained a constant vacuum the entire time. No adjustments changed the vacuum - at least not at a level readable by the gauges. :(

https://www.amazon.com/gp/product/B004MSJ7E6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

That's the tool I'm using.