Well onfinialy got it to start today after it’s been sitting for a year when I bought it.And when I heard it start for the first time I can’t express how happy that loud a&&ss bike made me and my son.My question is though when the choke is all the way open it runs but when I cut the choke off it cuts off can the carb guys tell me where to start looking as what it could be thanks
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Question for the carb. Pros
- Thread starter Stick14ya
- Start date
Sounds like you need to clean the carbs. The choke provides an auxiliary rich mixture for the bike to start and run on when cold. Switch it off and the bike reverts back to running off the idle or low speed circuit. Sounds like yours may be plugged. It's a mistake to try and run or start a bike, any bike, that has sat for a long, long time, like a year or more. Most of the fuel in the float bowls has evaporated and left behind varnish and gummy deposits. Trying to start it sucks that crap into the carb jets and passageways, plugging stuff up. You end up making a minor problem worse. What was a float bowl in need of cleaning now becomes the whole carb and all it's little passageways and jets.
I do have one more question as this is the first case that I have done any work to the two brass it looks to be vacuum tubes that is coming off of the bottom of the carb boots is that the vacuum lines or and over flo lines and if so where do the hook to I tried to find some pics of it but didn’t see any thing.here’s a pic of what I’m talking about thanks Chris
Attachments
Those are vacuum ports and when you install the manifolds, face them up, not down. They're there for vacuum hoses to be run to the vacuum petcocks to power them. If you don't have vacuum petcocks, you won't have vacuum lines attached to them but they must be capped or you'll have a giant air leak. Here's one with a vacuum hose attached (orange hose) .....
..... and here's one capped .....
..... and here's one capped .....
The intakes can only be mounted in 1 of 2 positions, mount them with hose barbs facing in the upmost outward pointing position not inward and down. Only running with the choke on is pretty indicative of a lean condition at idle. This can be caused by a couple of different things, first is the bike not getting enough fuel. Plugged idle jets are a common culprit. A good rule of thumb when cleaning carbs is just when you think you have em clean, clean more because their not clean yet. Second is a vacuum leak, this lets in to much air and in turn also causes a lean condition. By opening the enrichners/turning on the choke you introduce more fuel allowing the bike to "run" with a vacuum leak. Vacuum leaks can be caused by leaky intake boots, carbs not seated in intakes properly, vacuum hose barbs, slide diaphragms, carb tops, throttle shaft bushings, loose clamps. Take some ether (starting fluid) and spray it around the possibly leaky areas, the idle will climb if it sucks in the ether. What kind of carbs are you working with BS38's, BS34's VM34's? What kind of air filters? Some aftermarket pod filters can block off air bleed jets in the venturi mouth and cause problems.
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Ether will cause a strong response when it hits a vacuum leak, but be very careful with it. I use it, but I keep a bigass beach towel in a bucket of water and a fuel rated fire extinguisher handy in case the ether ignites. Use a straw and hit each problem area (boot joints, throttle shaft ends, choke valve covers) with a light, short burst.
Good advice, ether is pretty flammable stuff so do be careful with it.
Ok good advice I have bs34 carbs and I don’t have the air pods hooked up yet just wanted to start the bike to make sure I had everything hopked up right on it I’ll install the pods and check and cap the barbs off off the boots after I finish cleaning them good then let you know what I find thanks for the advice
Are the hose barbs open right now?
Yea I’m on my way to my garage and take some pics but yes they are open and not plugged.Also rusty is the best place to find air pods for the bs34 carbs I found some cheap ones on eBay but don’t know if I trust them
Don't get the cheapo pods, they're junk. You want UNI foam pods, for your BS34's, part # UP4229 or UP4229ST (dual layer) .....
For oiling them, don't use the special foam filter oil, it's too thick and can clog them. Just use a simple 50-50 mix of gas and motor oil. I bought a bottle of the cheap Walmart brand straight 30wt. to use specifically for this .....
For oiling them, don't use the special foam filter oil, it's too thick and can clog them. Just use a simple 50-50 mix of gas and motor oil. I bought a bottle of the cheap Walmart brand straight 30wt. to use specifically for this .....
Your intake manifolds are mounted incorrectly. You want the brass barbs facing up and towards the outside. You also appear to be missing the tin covers that fit over them. They won't hold up long like that before splitting.
These need to be capped off with vacuum caps, with these open you basically have a massive vacuum leak. If you're running a vacuum petcock one needs to be capped and the other needs to go to the vac port on the petcock. Also your intakes are upside down.
Yep, that’s correct.
