atc 70 question

[nicholas]

I have an 85 atc 70. It starts first pull and idles great, but when I put it in gear it wont pull me. It just doesn't have any power. I took the carb off and it looks clean. Could this problem be realeted to the timing or bad point? Any suggestions would help. Oh, It does stay running when in gear.

[mdunn]

Does it rev up when it is not in gear? If everything seems fine when it is out of gear, is it possible that the clutch is bad and that is why it won't pull you, or does the engine just loose power when you give it throttle?

[nicholas]

It Bogs down if you give it gas when idling and it bogs when I put it in gear and give it gas. It has pulled me a few feet a couple times. The guy I bought it from said it ran fine until he parked it for 5 months. When he went to fire it up, these symptoms started.

[nicholas]

I can jack the wheels up and run through the gears. The wheels spin fine, but I guess the auto clutch could be worn?

[scooterroo]

go with a clutch upgrade on it. dratv.com has tons of parts for the 70's. they are becoming my favorite 70 parts connection.

[nicholas]

I don't want to replace the clutch if possible. could it be anything else?

[mdunn]

If it bogs down, it sounds like the main jet is partially clogged/blocked. Did you tear the carb apart or just the bowl? I would check and clean the jets and try again. Of course you still need to make sure the points are good and set properly.

[nicholas]

I don't know much about this 70, but I took the main jet out and blew air through it. Seemed clean, but I didn't stick anything through it. Any suggestions on best way to clean main jet out. Should I check anything else while im in there. thanks for the help

[mdunn]

If the jet itself is clean and there is nothing in the bottom of the bowl to get sucked up into the main, take some carb cleaner with the little red "straw" attachment and blast up through the main jet passage and other passages. Check the points for corrosion and/or being burnt also. I have an '85 also that has no trouble hauling my big rear end around...;')

[TRX250R87]

Does the 85 have points or CDI?

Check the pilot jet, main jet, fuel screw, and the rest of the carb. Also check the screen behind the petcock. Make sure the 2 lines coming from the tank are clear too!
ERIC

[james9r9r]

Yep same damm thing my 83 70 DID SO i GIVE UP...

[james9r9r]

i ALSO CLEANED AND REBUILT THE WHOLE CARB AND IT'S STILL A PILE...

[hancadam]

One of Mine did this when I first got it. After trying everything it was as simple as the air filter was to restrictive. Someone crammed a lawn mover foam in there. See how it runs with the air filter off.

[james9r9r]

Stick the smallest eletric guitar wire through the jets and make sure you can see in the light in both the side holes and from end to end...

[nicholas]

Hey guys, its been a while since i've had time to post. Well the air filter was wrong. It was an old lawn mower filter so I replaced it with an oem filter. Cleaned the carb until it was sparkling. Put it all back together and it finally started running. Not as good as my other one, but it was running and shifting through the gears. I thought it just might need to be ran a little to clean itself out. After riding it around through a full tank of old gas it never got any better. Put fresh gas in and still no better results. So I took the carb back off and cleaned it again. Let it idle for a little while, put it in gear and off I went. It seemed to run better. I shut it off and that was it. Now it wont run. sometimes it will idle but if you give it gas it dies. will not run in gear. I have checked everything I know to check. The only thing I think it could be is the points. They are clean, but aren't they supposed to open and close when you turn the moter over? They stay in the same position. I don't know much about the points, but just don't see how it ran good for a while and now nothing. anyone have any suggestions?

[300rman]

hmm, if it ran fine and just stopped all of a suden, the carb could have sucked something up. usually point problems start with a small irregularity here or there, and get worse over time. a sudden death of it could be the carb sucked some crap up.

also, try a new spark plug. that would cause it to die almost instantly.


and after it is back together and running, use some SEAFOAM gas tank treatment. it cleans the carb even moreso than you ever could be hand. and it cleans everything else too.

[PaTriker]

Clean those jets real well. I use a wire from a wire brush. I had same problem with my 70 and that was the cure.

[bigreddaddy]

Do you have a metal gas tank? Are you running a fuel filter? Check the gas tank cap vent hole. From what you have stated it sounds like there is still junk clogging up the jets.

[nicholas]

The points are not opening at all. Aren't the points supposed to open and close? How do you know when points are all the way open. Does it need to be TDC for the points to be open?

[990deere]

i have a honda 70 and its the same way i havent been able to fix it, i cleaned the carb 5 times now soaked it for 2 days run wire through jet, blew air through them too. i cleaned the points and replced then, changed plug , still no luck, it idles fine, starts fine, when you give it gas either in gear or out it just boggs down and wont stay running, you cant ride it wont pull at all boggs down soon as you gas it? i have tryed everything i know to down i think maybe its in the timing but how do you set it? where is the notch on the motor to make sure its TDC ?

[New2ATC]

I might be wrong but on a crf50 knockoff engine, if you take the cam chain cover off the head, on the cam gear there is a notch or a dot or some sort of marking on the outer edge, and another notch or marking around the cam gear on the head itself. Now at TDC I am pretty sure the marks should be aligned to be timed correctly.

[bigreddaddy]

The MANUAL states how to check the timing on the atc70. If I remember right at TDC the points should have a slight gap. Check with a feeler guage.

[Derek]

I had the same problem with my klt110 it was a carb issue. Just go on ebay and buy a cheap chinese carb for like $20 my klt runs like brand new now.

[ATCnut]

The points should open and close. One problem with a 70 is that the plastic wiper arm on the points wears off, and that changes the timing. The manual says to set the timing by setting the points gap, but you can also check it with a homemade timeing light. Basicly a flashlight with clip wires. If you have done the carb many times, I would try changing the points. You will want to get the correct flywheel puller, nothing will piss you off more than damaging the flywheel trying to get it off.

[nicholas]

Im going to replace the points and reset the timing. I'll let you guy know the results. Thanks for the help.

[330rRus]

I just bought a 84 70 , and I have done the same thing you have..no luck. Let us know how it tuns out. Good luck.

[nicholas]

Talking to a mechanic that works on 70s a lot told me to check the compression first. He said you really cant dial in anything else until your for sure you have good compression. Also, what I described to him he said if the compressions good and the points are good, chances are it has something to do with the cam chain.