no clue on what to do

[brianhenry]

i have a 85 atc 70, it will not start, i have relaced, coil, plug multiple times, points, condensor, i have fire, fuel, compression, and i pull on the thing for hours and still
wont start, the point gap is right, timing is right on, the plug has fuel on it, the only thing i am not sure of is compression, i dont have a fitting that goes that small, i had it running this past sunday, i rode it down the street and back and parked it and now nothing, i got it to back fire a couple of times but that is it, now i cant get it to do anything, i realy need some help :mad:

[thefox]

Have you tried a new spark plug? Simple I know but try it, I speak from experience.

[200x Basket]

gas and a match :) most likely low on compression. check the valves and see if they are too tight.

[oldtime3wheeler]

My 83' 70 did the same thing the other week. Put a new plug in and it fired up on the first pull.

[83_200e_rider]

whats the oil lookin like

[brianhenry]

i just bought 3 new spark plugs today and tried them all, i changed the oil a week ago it had been set up for 6 years

[brianhenry]

200x basket
how do you check the valves

[ducati998]

to check the valves is very simple ----1) bring the piston to top dead center and if u check your flywheel your timeing mark should line up with a slit in the case.. then take the valve caps off your settings should be .002 intake and exhaust 3)--you set the valves both together very very important your 70 has to be on compression stroke to set valves. When this is done and still nothing make sure your valves move freely when u pull your 70 over and either valve is stuck open or closed.

[200x Basket]

get a manual or print one off line.

[brianhenry]

thanks alot i will try setting the valves tomorrow, i just found a manual on line, one more question were do you find a comression tester that small, i am a ford mechanic and all my fittings are to big

[Gag_Halfront]

You can find compression testers with a tapered rubber tip that you simply press and hold into the spark plug hole. It's not high tech, nor is it the most accurate thing on earth, but then these little one-cylinder motors don't require a very high degree of precision just to fire.

I used to have two of the rubber tipped ones. I don't know where I got them, but I have a hunch a fella could find one at Sears.

You might want to drain out some gas. If it quit running overnight you could have gotten condensation in the tank and have a little bit of water at the bottom of the bowl. As a rule, I always top off the tank before I put a machine up for the night. Bikes with steel tanks are fairly susceptible to condensation issues. I still do it on the bikes with plastic tanks just for good measure.

Will it fire if you spray in some "Crack in a Can" (ether)?

[bigreddaddy]

A quick way to get a general idea of compression without a tester is to pull the plug, put your finger over the hole and yank the starter and see if your finger pops off the hole. Whats your spark look like, bright? What did your plug look like after you ran it?
Also, the plug is probably getting soaked if your pulling it that much. Clean the plug after about 5-6 pulls if it doesn't start.

Check the condition of your on/off switch. I would think your compression is probably okay if you have had it running recently though you still need to check it. Is it flooding? Have you cleaned the carb recently? Air filter clean, choke working?

[Vealmonkey]

You never said if you checked for spark. I would check my ground wire from the coil and make sure it is secured to a decent-clean ground. Next, did you have the starter switch in the on position? Might sound crazy but I've seen it done. Do you even have a starter swtich? I've seen that happen too. If you have the switch on but no spark, You can connect the wires going to the starter switch to each other, jumping out the starter switch and see if that makes a difference. If those things make a difference, and you have your points and such set correctly, I would check the magneto coil to see if it is connected properly or making power. Heck, it could be as simple as a previous owner hooked up 2 wires wrong, so, you might want to check your wire connections too.

[brianhenry]

i checked the valves, exhaust was good but intake was tight, i adjusted to the right specs, i had good fire yesterday but now i can only get one spark every so often, the kill switch is not hooked up, and the choke is working, compression will blow my finger off the hole so i guess it is ok, how do u test the magneto

[bigreddaddy]

I would use a VOM (volt/ohm meter) and check the wires coming from the magneto/pull start. See if your getting a reading every time your pulling starting it. If not then its most likely a coil/magneto. If you get a constant reading then start troubleshooting. You can also check the plug wire this way. I don't know how your checking spark, but its difficult to check it by yourself without an electric start and no meter. And, as stated above, CHECK YOUR GROUND WIRE CONNECTION.

[brianhenry]

i have a friend help me check for spark, i am getting an irratic spark, only once or twice a pull, i have checked the ground and even cleaned it again, i just tried push starting and it would putter for a second and then that is it, the manual said the coil is between 8-9ohms, my coil tested at 9.71ohms, it is about 2 weeks old, what do you guys thing

[bigreddaddy]

Seems like your getting spark man. Its starting to sound like a fuel problem. Pull your fuel line off the petcock and let the gas flow out into a container for a minute or two to see if there is a steady flow. Make sure your air filter is clean. If you don't have a fuel filter and your tank is rusty/dirty then your carb jets will just keep getting plugged up.

[brianhenry]

fuel is flowing good, i just had the tank cleaned and installed 2 fuel filters, one for res and one for primary, im about to blown the thing up

[bigreddaddy]

Get the fitting for your compression tester and check it so it can be ruled out as the problem. They should have one at any auto parts store.

[bigreddaddy]

One more question about the spark. Is it a fat blue, or dull, or what?