I bought my first bike (a POS 2007 Baja Bv 250) recently just as something to learn on (got it really cheap). I have no experience with engines and am not especially mechanically inclined, but always wanted learn. It ran fine when I bought it but within a week it started jumping a bit on acceleration, then slowly lost power over 30 seconds while riding and sputtered to a stop. It started up a couple more times (after waiting 5-10 minutes each) and got me back to my house. At first it would idle for 30 seconds or so and then sputter and stall. Now it only fires up (catches) for a second sometimes but doesn't actually idle. I stripped down and cleaned the carb gas flows freely from petcock when both in the on and the reserve position. the carb had plenty of gas in the float bowls when i removed it so its getting gas. Battery is fine (ran low but i hooked it up to my car (without running the car) and it tried to start very hard so battery isn't causing the problem. I'm having trouble identifying where the spark plugs are to check them. Also, It seems that some tubes may have fallen out and I don't know where to to reconnect them (or if i even need to since some are likely overflow/vent tubes). Pictures: What is this cannister thing? fuel filter? emissions canister? One of the tubes possibly hooks up to the underside of the gas tank? These are the hookups under the gas tank. When I pulled the tank off neither of these nipples were hooked up to anything. Theres no label and theyre the same size. I think maybe the cannister tube goes to one of these. I'm not sure if a vacuum tube should be going to the petcock (I don't see a hookup for one). For now, only the fuel line from the carb is plugged in. This is the bottom of the carb. There are two hookups on the bottom (float bowl overflow?) that I currently have tubes routing to the bottom of the bike hooked up. There is also one larger tube on the top of the carb that i have routed down to nothing. Does this top tube need to be hooked up to something? Finally there is this much larger tube coming out of the intake manifold? Not sure if thats the right name. This tube also isn't currently hooked up. It has a lot of grease on the end of it. Thanks! i've spent the last couple of days working on it and have learned a ton about how engines work.
Well it looks like you have a major crack/ leak coming off your carb, (black piece on left of carb). That will allow un-metered air into the intake manifold. which will cause symptoms you are describing.
would this prevent it from starting up? There is another crack on the other side as well. I don't think these go all the way through. Additionally can I fix this via duct or electrical tape? I've read that the carb boots can be expensive or difficult to get the exact size. Parts aren't available for this bike. Also I still think something isn't hooked up right. currently nothing is hooked up to the 2 nipples under the tank, and all of the tubes (except for the fuel line) coming off the carb and don't connect to anything. thanks!
I agree, those manifold intake(s) are toast with those cracks. Looks like there are more to the left of the screw. It's a $17 part, so I'd just replace them than messing with tape... that will fail again. Left - Part # BV250-399 Right - Part # BV250-403 Might as well replace the entire assemblies. Look at Page 15.
Order the new part! In the meantime while you are waiting a some black urethane seal will let you continue tuning and testing. Just looking at the pics I would get some fuel line and an inline filter in there right away. With the tank off you should be able to see the spark plug boot right on top of the head. pull the plug, check for spark. If you have weak spark, start at the battery and clean terminals, then each plug connection leading to the coil(s) unplug one at a time and check the blade/bullet connectors for corrosion and fit. Fix as necessary, put a little dielectric grease in each connector to keep moisture out. Check spark again. If spark is good give it another try. You tore down the carb? Is it adjusted correctly(does it have a mixture screw)? Did you set the float level? This is where I would spend a little more time if you are sure you have good spark and Timing. The last 2 photos show the crankcase vent tube, oil will come out here if you overfill the engine as well.
If the carb was cleaned, it looks like you should re look at that. Find someone who can clean it ultrasonic. Some of those jets are very hard to clean. You might just replace the pilot jet. Good luck!
Can you please elaborate on: [MENTION=28038]TroyAG1[/MENTION] You tore down the carb? Is it adjusted correctly(does it have a mixture screw)? Did you set the float level? This is where I would spend a little more time if you are sure you have good spark and Timing. I took apart the carb and cleaned the pilot and main jet along with spraying every every crevice with carb cleaner. I was surprised at how clean it already was. I don't think I adjusted anything though. New spark plugs - fat blue spark. The spark plug is dry after trying to start the engine for a while though. Also, I was able to get it to start up for 5-10 seconds by using starting fluid into the carb air intake and then covering it up with my hand. Seems like no gas is getting through the carb in addition to potential vacuum issues. Its definitely getting to the float bowls as it flows freely when i unscrew the float bowl screw. What would cause no gas to get through to the top of the carb? [MENTION=29104]Smutny[/MENTION] - is that site reputable? I can't find baja parts anyway and am ok with spending around 50 on the carb boots, i'd just rather buy from a larger supplier. any advice?
Carb spray does almost nothing to clean a carb. You need to take the carb apart and either use Carb Dip or an ultrasonic bath to clean it. The other option is that you have a vacuum leak that is allowing air to come in post carb to the intake tract. Lastly, unless you have replaced the black rubber carb boots you are wasting your time. Honest.
[MENTION=31722]joblammy[/MENTION] I have no idea about the reputation of that parts house. You'd have to Google them and see if there are negative reviews or comments. You gotta roll the dice if you have a limited supply chain.. I buy stuff for my bike off of eBay, sometimes I score sometimes I don't. Have you contacted Baja directly? You could also look at manufacturing a replacement on your own. Pull the part and see what's all involved with it.
Simple Green makes a heavy duty cleaner, Simple Green Heavy-Duty Cleaner and Degreaser, that is pretty effective when diluted about 4 parts water to 1 part SG and letting parts soak for 12 - 24 hours. Non-corrosive so it doesn't eat stuff like Pine-Sol and is a lot easier to use and dispose of than dedicated carb cleaner solutions. You will still have to manually clean all the passages in carbs though. That is an area where an ultrasonic cleaner really shines.
I ended up ordering it from here: http://www.scrappydogscooters.com/253FMM_250_300_Twin_4T.html they're based in Las Vegas. Downside is that it's not specifically for my bike but i'm 99% its for the same engine.
If no one has said it yet. The two tubes on the bottom of the tank are 1 vent and 1 over flow from the cap. Both should vent down below the motor. If those cracks in the boots go all the way through, it might not start at all. Just sayin.
