One last problem: The carb! By FACE PLANT FOR LIFE (Read 1,924 times)

[tvnacman]

submerge a vac line in an ounce of fuel and let it suck it in . Sometimes it needs a little extra vacume to get it going . After it sucks the fuel in reconnect the line .

John

[Alleyoop]

Well we know fuel is getting into the carb bowl so that is good. Do this after cranking it over and not starting pull the plug and see if it is WET with FUEL or DRY.
That will tell us if something else is wrong.

Also when you have the plug out STICK it in back into the BOOT CAP and hold the plug against the VALVE cover and crank it and see if it is sparking. You should see a nice blue spark.
Alleyoop

[FACE PLANT FOR LIFE]

The spark plug is 100% dry (no fuel), and has plenty of spark when placed up against the valve cover. Could the carb be really just clogged up and not letting ANY fuel get to the engine?

[Alleyoop]

Great!! now we know fuel is not being drawn out of the carb. Does your carb have an ENRICHER on it?
If so that alone should feed fuel unless it is not working. If it has a Fuel Ratio Mixtue Screw turn it clockwise until it stops and turn it Counter CLockwise 2 1/2 turns and see if it then gets some fuel.

Also how long has the carb been sitting on the scoot without running? The Pilot jet and ITS PASSAGE could be clogged.
Can you take a picture of the Carb Area and hoses BOTH SIDES OF THE CARB.
Alleyoop

[FACE PLANT FOR LIFE]

Well, we have got a theory going, actually. Remember when I said we had our suspicions that we (and by we I mean my dad) may not have installed the head gasket? It's starting to look a bit more plausible. What doesn't make sense it that it seems like it has compression. The weird part is that when the starter is cranking, the exhaust lets out a puff of air AND sucks in at the same time (pulling your finger into it if it is sufficiently close to the exhaust). The carb was just taken apart the other day and the jets are perfectly clean, and I already turned the air-fuel mixture ratio screw in and then out roughly 2 1/2. The enrichener may or may not be working.

[Alleyoop]

Very cool that could be it, it is loosen compression. You can test the compression if you have a gauge if not take the plug out STICK your finger in the hole nice and snug and HOLD THE THROTTLE WIDE OPEN and crank it. If it has descent compression it will LIFT your finger off the hole if you just feel some pressure LOW COMPRESSION and not creating enough suction to draw fuel from the carb.
Alleyoop

[Deleted]

Mar 19, 2014 16:56:47 GMT -6 FACE PLANT FOR LIFE said:

the exhaust lets out a puff of air AND sucks in at the same time (pulling your finger into it if it is sufficiently close to the exhaust).

this is probably your issue. did you time it right? check timing and dont crank it again til you do! if your timing is off you may have already run a valve into the piston! make sure you check this!

[fj12rider]

Take the air filter off the bike and when you crank it over stick your hand over the back of the carb . This will do 2 things , increase the fuel to air ratio and dump a load of fuel into the barrel , but not so much that it'll flood. Check that you have both a spark and compression first of course, but this is how I start all the bikes I've had sitting around a while that won't start and it works every time . Check that your choke (enriched I think you say in the states) is getting hot . If it's not getting hot it's not working , it works by getting hot and melting the wax in the top allowing the choke to close once the bike is warmed up . It won't stop it starting but it will make the bike run rough as a tramps arse if it's not . Is it 2 stroke or 4 stroke ?? 

[FACE PLANT FOR LIFE]

Alleyoop is probably right about the compression. We ordered another gasket just now, we will get it disassembled and replace whatever gasket (if any) that is there. I'll make sure to check the valve timing as well, but I wasn't there to supervise the reassembly (my dad might have tried to crank the engine with the timing chain off for all I know..not that he would, but you never know, things happen!). Any instructions on making sure the valves are lined up like they should be?

[tvnacman]

Look at them see if there are any marks on them and the piston .

John

[Alleyoop]

Any instructions on making sure the valves are lined up like they should be?

Take the valve cover off.
1. Rotate the motor BY HAND and bring the PISTON up to TOP DEAD CENTER.
2. At this point the CAM SPROCKET should look like In PIC #1.
3. Also at this point the Flywheel and case pointer should be pointing to the LINE next to the "T" Mark on the flywheel.
like in PIC #2.
Alleyoop

PIC #1:


PIC #2:

[FACE PLANT FOR LIFE]

Just thought I would pop in and say we finally got it running. It was NOT the carb in the end. The cylinder gasket was RUINED. If we hadn't ordered the whole set of gaskets, we would never have taken the time to look, but the cylinder gasket was torn in two. Everything is back reassembled and it starts and runs great. Time to put the plastics on (oh joy).

[Alleyoop]

FANTASTIC!! good job guys
Ride safe
Alleyoop

[jvino]

Carbs can be tricky I am with kz on this one don't touch unless you have to but in your case you have to. Sounds like the float is sticking if it is leaking fuel. Put together gentle you might have to take it of a couple time to adjust before you get it just right good luck.

[jvino]

Glad to here you got it going Alleyoop knows what he is talking about. that's fantastic hope you enjoy riding it and the whole 3 dollars it takes to fill.