I'm new here and looking for help.
I bought a baja dn250 buggy that someone could not get running. Thought it was a good deal and would be an easy fix. Can someone tell me what the rotation is on the motor looking at the drive belt? If I spray starting fluid in the carb and give it full throttle it seems to spit it out the card not suck it in. Thought it might be 180 out but I switched the timing and no difference. Can see intake valve open and close. The wiring is kind of a mess and looks like something happened and someone just put it back together there are like 5 green wires all soldered together and looks like crap. Any advice would be greatly appreciated I bought this for my kids and I cant get it to run.
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First thing to do is pull plug install wire and ground plug (threads) on engine and crank engine, do you have a bright blue spark and is it consistent? If so that part is good. Next pull valve cover and rotate engine by hand watching camshaft and sprocket until cam lobes point downward and 2 hash marks on cam sprocket are lined up with top of head. Use a skinny screwdriver insert in plug hole making sure piston is up. Now guide screwdriver with one hand while turning engine over with other hand 2 complete revolutions stooping when piston reaches top. ( turn engine, screwdriver will drop than rise than drop again than rise). At this point look at cam and sprocket making sure lobes point downward and marks line up with top of head. If good timing is OK, put valve cover back on. Engine still on TDC loosen the 2 adjusting screws, slightly move adjusters in towards each other than move out away from each other until you feel resistance. At this point you have 0 clearance now move each adjuster inward 1/2 of a mark. Now your valves are adjusted. If you have a compression gauge run a compression test. Top compression should be around 150-160. If all this checks out to be good than you know your engine is in good mechanical order. Next you need to drain the fuel tank and remove and clean if necessary, change the fuel filter. Pull carb, carefully disassemble and inspect, clean carb. Best is to use the dip (Berrymans; found at Walmart or most auto stores appx. $13.00). Also inspection of plug itself, black shinny carbon or gooey black means using oil, flat black powdery carbon means running rich, tan to brown is good. The green wires soldered are various grounds, just make sure all wires are bonded tightly. Check each wire and if any are loose re-solder and tape up. Use nothing but non ethanol fuel.
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I have checked all of the above and all is good. New fuel tank filter and carb. New plug as well. Everything checks out that's why I'm at a loss. Thank you for all your insight though great write up
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I'm pretty sure the rotation on the belt is CCW. Are you seeing a good blue spark when grounding the spark plug? A carb that blows instead of sucking usually indicates the intake valve is open/stuck or out of adjustment. IMO I'd go back and verify that the valves are actually moving or a spring isn't broke. Also check the intake manifold for cracks/holes or loose connections from the carb.
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My belt is going cw. Which I believe its spinning backwards. I am guessing someone put the wrong starter in or the wiring is wrong. The wiring is a mess and I don't have a good diagram that shows the wiring clearly. Someone obviously worked on the wiring but more like hacked it. My guess is the motor is spinning backwards and not sure why. Starters are cheap so might just get one and see
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If I remove the starter I can hook it up to 12v and get it to spin both ways. If i install it and try to reverse the wiring to get it to spin cw it just free spins
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What direction are the cooling fins on the variator?They should be scooping air, this will tell you the correct direction the motor should be turning.
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1 Attachment(s)
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It turns CCW
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Ok that's what I was thinking now just have to figure out why its turning backwards. Thanks for your help
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The only thing I can think of to reverse rotation of starter is, someone disassembled starter and assembled it with body reversed. with starter removed there are 2 bolts holding assembly together. The assembly has 3 main components. End cap (this is gear end), main body which holds internals), and brush end. If someone disassembled and reversed the main body this will reverse rotation of starter. Disassemble starter and reverse the main body should fix the problem. I had a customer years back who had a bad starter and replaced with one he purchased online. Engine now turned over but would not start. As I bumped over starter to line up timing marks to check if timing slipped I noticed engine turned over backwards. Replaced his new starter with another and all worked as should and buggy started. Some time later I had rebuilt a starter for a customers ATV but when I installed starter it turned backwards. I pulled the starter thinking I messed up with the new installed brushes so I disassembled the starter and everything looked as should be. After contemplating why I had a hunch to assemble flipping the main body. This reversed the magnetic pull on armature and starter rotation reversed.
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I ordered a new starter and see if that fixes it
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Put the new starter in and it just free spins fml
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Could there be something on the crank that takes a key or something that could be broke? Actually that doesn't make sense cause if it was broke it wouldn't spin the other way right?
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You have the starter and what is called a starter clutch. The starter clutch has a one way sprag which means one way it is locked the other way it spins freely.
The starter when engaged actually turns a double cut intermediate gear which than turns the ring gear on starter clutch which when working properly turns engine over. If the starter clutch sprag is bad the clutch will free spin and engine will not turn over. The starter clutch is attached to the flywheel which is keyed to the crankshaft so if key is stripped the engine will not turn over. With CVT cover and starter removed, look in hole starter mounts to and you will see the intermediate double cut gear. Using finger or screwdriver that gear should turn one way and not the other, if so the clutch is working. Next turn variator ccw (rotation of engine) watching gear through hole and it also should turn. Turn variator cw and gear should not turn. |
Thank you for the insight. Everything seems to check out. I thought the motor was trying to turn over backwards but I guess not. When looking at the drive belt it spins cw. The double gears you mentioned spin Ccw and freely cw. Guess I'm back at square one
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What kind of compression do you have?
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153 everything checks out but if I spray starting fluid in the carb it spits it out when cranking it. It will pop like it's trying to start. Thought it was the valves but they are good so I thought the motor was turning over backwards but guess not. I'm at a loss . Everything seems good I don't know what I'm missing
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It is important to know what the compression is. Knowing the compression reading will tell us where to or not to look.
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Compression is 153
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Sounds like your out of time or a valve is hung open.
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