[boyfriday13]

Well, I got started and got some great help in the New Member forum so I thought it was time to move over to the R&M forum.

I have an '85 ATC 70 stock that's been sitting for a long time. Previously, the tank had rust and I used the PRO-15 kit on it. I pulled the carb and cleaned all. I have a carb re-build kit but I think the carb has all new stuff from before. Anyway, I cleaned it up good put it back together, checked the air filter. Checked spark and it looks good so I fired it up. It started and sounded fine, so I started to adjust the idle screw. After the engine warmed up some and while I was trying to dial in the carb, it quit and I wasn't able to get it to start again. I pulled the carb again and re-checked/cleaned the main and slow jets. Also re-checked the screen filter as it had a bunch of rust/dirt from before. I put a new plug in today and cranked it over with no luck. I adjusted the air/mix screw most of the way in and adjusted the idle screw all the way in and tried again. I got it to start and then it ran for awhile but was missing/sputtering when I rev it. Played with the air/mix screw a bit and then after it warmed up it quit again. Seems like it's getting gas, so I'm now thinking I should check the timing? Any ideas on if it's carb/gas related or a possible timing issue?

 

[Billy250X]

It's running out of gas.Maybe it needs jetted.

 

[shadetree]

yup..sounds like float is sticking..not letting enough gas in the carb..with the carb off..take the bowl off the bottom of the carb..hook the gas line from the tank back up to the carb..while you hold the float in the up position..slowly lower the float...as you do..gas should flow out..if it doesn't..then you got a restriction from your tank to your carb or float needle needs to be replaced or cleaned really good..after that checks out ok..re-clean your jets again..i know you said they were clean..but..if you get any..and i mean any small stuff inside the jets..it will stop them up..no matter how many times you clean them..it's a very good idea to have a inline fuel filter..spec a new one. hope this helps..keep us posted.

 

[boyfriday13]

Ok, thanks guys! I'll get on it and post back. One idea I had is that when I lined the tank I didn't plug the "out" tubes, I only capped them. Earlier I put some water in the tank and checked to see how it flows out through the tube and it came out fine from one and nothing from the other. I stuck a piece of wire into both and was able to run it in fine but I'm not sure if one is reserve and if I should be able to see flow out with a fairly small amount of liquid in the tank? I figure I can always tank the tank off the other bike and test to see if that's the issue.

 

[shadetree]

Ok, thanks guys! I'll get on it and post back. One idea I had is that when I lined the tank I didn't plug the "out" tubes, I only capped them. Earlier I put some water in the tank and checked to see how it flows out through the tube and it came out fine from one and nothing from the other. I stuck a piece of wire into both and was able to run it in fine but I'm not sure if one is reserve and if I should be able to see flow out with a fairly small amount of liquid in the tank? I figure I can always tank the tank off the other bike and test to see if that's the issue.

you just solved your own riddle..your bike is running out of gas..because it's set on reserve..which means..there isn't any gas flowing through that one tube going to your carb..if any at all..it's not enough..clean the lines out from your tank really good..check to make sure your getting gas from both tubes going to the carb when you switch the pet-cock from on to reserve..this should fix your prob.

 

[boyfriday13]

Here's the update: Put the new plastic tank from the other bike on, tried to start it with no luck. Pulled the carb and tried to follow Shadetree's suggestion for testing flow but I wasn't sure how to check it since the gas line connections come off with the bowl. Anyway, I had purchased a rebuild kit from DRATV some time ago so I went through the entire carb again. I put in new parts if I had them and cleaned everything again. Put it all back together and after a fair number of pulls it started. I was able to see results from adjusting the idle and played with the air/mix screw a bit. Starts right up now, idles fine and keeps running well even after it warms up. It was definitely a gas issue and may have been a combination of the fuel tank out lines being restricted and there still being some junk in the carb. Only thing I notice now is it's a little sluggish (slow response) if I rev it full. It hesitates or sputters just a little before opening all the way up. Seems like it's not all the time, just if it's been idling for a bit. Lastly, I put the old tank on my other 70 and it sure has a flow restriction. The other bike will stay idling but is definitely not getting enough fuel. Any tips on cleaning out these tank output tubes that have been lined with PRO-15? Or is it a lost cause...

 

[shadetree]

first thing i would do.is replace both fuel lines from tank to carb with new ones, second..put a inline fuel fliter on both lines leading to the carb, and if your bike is not rev'ing right..means your main jet is stoped up..or your main jet needle needs to be lowered..it's flooding the engine...take the top off the carb..push the throttle cable out from under the throat piston..then push the main jet needle out..on the main jet needle..where the c-clip is..move it up one notch..also ..your air/fuel mixture still could be out of wack..adjust the main jet needle before you play with the screw...oh...you may want to clean the points on the engine..remove the left upper side cover < two screws i think >..with a 10 mm socket..break the bolt loose..remove the point cam, with some fine sand paper..sand the points down alittle..watch how you take this off..it only goes back on one way..it's got a small tiny pin that lines up with the cam...if after you get all this done..you may also want to adjust the points..easy to do..there are two screws where your points are..they hold the point pick up down..loosen them a little..start your bike..while you rev it up..move this metal ring one way or the other..this adjust your timming..it may help with the rev part..hope this helps.

 

[boyfriday13]

Thanks very much! I think I'll do each of these, probably in order. I had replaced the needle and c-clip yesterday and put the clip the same as the old one on the 4th notch. Easy to change and test...I know there's some sand and maybe some dirt/corrosion in behind the magneto but I need a puller before I take this off and clean. Great tips, I can't thank you enough!!