Need help starting after rebuild

[Ajf]

I'm having trouble starting an ace 100 engine. It has a fresh bore hone and piston from roger lippiatt. I replaced all bearings, gaskets and seals. The points are set at .013". The gap between flywheel and lighting coil exciting coil are set at .01". It has great spark and compression. It has an nos ignition coil and I also tried 2 other used coils. The fiber washers look like they're in the right place. Tried several different ngk b8s spark plugs with gap set at .025". I can't get it to pop. Tried some premix in the spark plug hole. Tried some starting fluid in the air opening on the carb. Any ideas? Am I overlooking something? Any help is greatly appreciated.

[bobwhitman]

Sounds like no spark; check carefully. Does it have a key; if so disable that and try with only the blue & black wires connected.
Bob

[Ajf]

Thanks for the reply. There's no key. It's not mounted to a bike. It just has the blue and black wire plug. I put a steel rod in spark plug lead and it looks like nice strong spark jumping when I bring it close to the head.

[Zyx]

Assuming that you tried the spark plugs outside the engine and laying against the head to verify that you had spark, the only item mentioned that is only half done is the ignition timing. Setting the gap on the points doesn't set the timing, it only approximates it. It should be close enough to run, however, but the only correct way to set timing is electrically (or if you are good at it, you can set with a dial indicator).

May we assume the premix is fresh? What are you using and at what ratio? Has a spark plug come out of the head wet with fuel after trying th start (not from putting gas straight into the spark hole, but letting it draw from the carb). When you say it has great compression, what is the compression?

Internal combustion engines need three things, spark, fuel, and compression, in order to run. When supplied at the right time and in the right amount, it will run well. Everything you have described so far suggests it will run. Aside from verifying it is getting fuel through the carb, the only variable I see is timing. Setting to 0.013" is a starting place and can put your timing out by five degrees easily, which is why the book says gap,between 0.012 and 0.015. That is actually a broad range. You need to verify that the points break open when the timing marks are aligned. The gap ends up being whatever it is depending on the blend of parts used. Points vary in their dimensions by small amounts which can change the needed gap.

We had a bike at Hodaka Days that was doing the same thing, would not start unless pushed. Gap set at 0.013". When we put a timing light on it, it was quite a ways off, advanced. Advancing the timing can make them a bugger to start.

[Zyx]

The fact that it is making spark means it isn't the key or the harness or the coil or the condenser or whatever. Verify spark with a known good plug, not a steel rod or screw driver. Now that you know you have a spark, you need to know if your plug makes spark, and when it sparks. Everything else may be deemed good for the moment.

[Ajf]

I haven't verified the spark plug but I did try 3 different nos plugs. I will try that next. I set the points with the left mark on the case. I've rebuild small horizontal engines and know you want the points to brake at a certain amount before top dead center and you can adjust it by rotating the stator plate. I'm unclear how to adjust timing on the hodaka. I just went by the marks. I used an ethonal free 40:1 premix from autozone.

[viclioce]

I think the 40:1 mc may be a bit weak but it should still start with that mix. I mix 32/1 for my 125. If you set the points to start opening at the left mark you may have the timing advanced too far. I would set it to open about 1/3 the way to the right of the left mark and try it again.

Also pull the plug and hold it (with your hand grounded) to the top of the head where you can see if the plug sparks. You should be able to see the spark arc across the gap. Reducing the gap from .25 to .23 can make the spark jump across easier too. If the plug fouls easily, then the spark won't arc across. It will find its way down the insulator. So if the plug gets too wet, you need a fresh, dry plug. Don't give up!

I had he same issues with my 125! My problem was the woodruff key on the crank wore out and the flywheel wouldn't stay in the same place each rotation until I replaced it. So check that as well! Good luck and keep us posted. Tell us everything you check and what you find! ; D Victor

[Ajf]

Ok. I have nice strong blue spark jumping from plug to the head when I remove the plug. Back to the timing. If I put the mark from the flywheel to the left mark on the case and set the points at .013 with feeler gage is that good enough to start it? I have an meter and a dial indicator if needed but it's unclear from my book how to adjust the timing. I'm very frustrated. I am very thankful for the responses. I just want to hear it pop.

[hodakamax]

The left hand mark is TDC. Points should break on the right hand mark. I brought up Timing the Hodaka for you.

Max

[rtboone]

Greetings

Did you put a rag in the intake or exhaust to keep the internals clean during your build?
Did you remember to remove same rag? It's not uncommon to forget this detail. At least once.

Tom

[Dale]

To answer your question, yes, setting the points to .013 at the left mark should be fine to get you started. And, the point gap is the only adjustment to be made for your timing.

[Ajf]

Thanks everyone for the help. I set timing with a meter and same thing. It still won't fire. I guess tomorrow I'll get a compression gauge and make sure there's no loss of compression. It's a fresh bore/hone that's was bored and honed to the new piston/rings. Maybe a leak from cylinder gasket or base gasket. I'm not sure. Still can't believe it's giving me so much trouble. Even if there's a carb issue it should still pop with fuel in the spark plug hole, right?

[viclioce]

Yes. It should pop with fuel in the cylinder unless the timing is advanced too far. Try setting it between the two marks. See if you get a pop or two there! And did you check the woodruff key on the crank? ; D Victor

[Firehawkmph]

Is there anything plugging up the exhaust? My modern bike that I ride (Suzuki rmz250) doesn't like to fire after I give it a bath and forget to take the rubber plug out of the exhaust. Won't even pop.
Mike Hawkins

[Ajf]

Yes. It should pop with fuel in the cylinder unless the timing is advanced too far. Try setting it between the two marks. See if you get a pop or two there! And did you check the woodruff key on the crank? ; D Victor

Ok I'll try adjusting the timing. I did check the key and its on the flywheel keyseat. The key is worn a bit and there's minor movement.

[Ajf]

Is there anything plugging up the exhaust? My modern bike that I ride (Suzuki rmz250) doesn't like to fire after I give it a bath and forget to take the rubber plug out of the exhaust. Won't even pop.
Mike Hawkins

Nothing plugging the exhaust or intake. I have the u shaped ace 90 loop on it at the moment there is no exhaust just the loop. Would it not pop with the expansion chamber not installed on it?

[Zyx]

With an open exhaust tube, it will run fine, sound like a big chain saw, and pull about as well as one -- not very but that's not your problem here.

Your flywheel should have a mark on it in the form of a scribed line, and may have "F T" as well. On the engine case there are two marks maybe an inch apart. The left most mark, toward the front of the engine, is your timing mark. The points should just break open when these two lines, the flywheel and the left timing mark, are aligned. Setting the points to a gap only puts you somewhere close. If you have a multimeter, you can look for continuity between black wire and blue wire. Continuity means points are closed. No continuity, points open. Adjust the point gap until points go from continuity to none when marks are lined up. That sets the timing. Guessing at some point to the left or right of the timing mark is just fishing for something you can't use.

Sounds like you have a good spark. Set the timing and that part is good.

And I am curious about the flywheel wiggles a bit because the key is worn. Surely it does not do this now, when it is all together. Woodruff key or no, the flywheel should not wiggle, period. If you are not sure you got the key in the slot in both crank and flywheel, pull it and verify. Without a key the flywheel will bolt up anywhere within 360 degrees and you will never find timing. It has to be keyed flywheel to crank, and it is easy to push the woodruff key out of the slot when assembling. Check this, otherwise, you are wasting your time trying to get the timing right.

Then, all that is left is the intake system. Your carb has to supply fuel. You are remembering to depress the starting lever on the carb, right? New plug, lever down, no throttle, give it a try. With the lever down, don't use the throttle. It is tempting, but don't. If it doesn't start after five or ten kicks, pull the plug. Is it wet??? If not, it ain't getting fuel. Yes you can squirt some down the hole, but all that does is flood the engine. It may pop, it may not, and it may just foul the plug. If you must squirt something down the hole, do it sparingly.

Frankly, Autozone does not sell two stroke motorcycle oil, unless you are getting Lucas, which is expensive, and even then I wouldn't do it. The oil you showed is for chain saws and string trimmers, and 40 to one is correct for such devices, but not for your bike. Get real motorcycle two stroke oil from a bike shop, mix 32:1, and move to the next step. However, that is. It what is stopping your bike from running. It will run on straight gasoline, it just won't run for as long as you want it to. What you have is more or less safe to use, but not optimal at all.

Make sure fuel is getting into your float bowl. I think your carb has a main jet access in the bottom or side of the bowl. Pull it. If gas starts running out, put it back. If crap and water start running out, shut off the fuel and pull your carb.

With a newly rebuilt bike, it isn't likely to be compression, so I would put that at the bottom of the list. I am thinking no fuel, or timing is off.

[Ajf]

The flywheel key was a little worn. It had a little side to side movement until it was seated. After it was seated it was fine. I pulled a key from another ace 100 I had sitting that looked better. No issue with the key at all now. The can I had posted is actually a premix not just oil. I just grabbed it to try and fire the engine. I will look at the carb tomorrow. I have 2 other carbs but they are in pieces. I'll try and post some pictures tomorrow. Thanks again.

[viclioce]

Ok I'll try adjusting the timing. I did check the key and its on the flywheel keyseat. The key is worn a bit and there's minor movement.

If the key is worn and the flywheel wiggles you may not be able to set your timing accurately enough. Replace the key and make sure the flywheel is torqued to specs.

Then check your carb. As AZ said, check the main jet, but also check the pilot jet as well. If the pilot jet is dirty or clogged, the bike won't start because it won't get enough fuel. Pilot jets get dirty easily especially if the carb has not been cleaned and rebuilt.

I put a different pilot jet in mine because it was running too rich. Soon after replacing the pilot jet it got clogged because I was using castor oil and letting the fuel sit in the tank too long without running it. Get a good, synthetic 2 Stroke oil and mix it 32:1 and with the carb cleaned out try again! It sounds more like a not getting fuel issue since you're getting spark on the plug. ; D Victor

[Dale]

I am going to give my 2 cents regarding the timing marks. When the scribed line on the flywheel aligns with the right most mark on the case, your points should break open. This is where you can use a meter, light or buzz box to tell that your points are indeed opening as these 2 marks align. Once the flywheel mark reaches the left hand mark on the case, your points will be somewhere between .012 and .015 gap.

Setting gap alone will get the motor running and probably running well. However, it is best to use a device to verify your break point and then even better to use a timing light to verify afterwards.
Dale

[Zyx]

Dale is correct. I said left mark, I meant right mark. Right hand mark is the point break.

The premixed fuel could be fine. 40:1 is a bit light for air cooled motorcycles IMHO. Without knowing what kind of oil is mixed with the fuel, it's hard to say if it's worth using. I have seen premixed fuel at the local Honda dealer, and the cost per gallon makes me think we are living in Greece. Some use it because it is consistent and because the stated octane rating is higher than pump gas, but unless you are in the top three internationally on some circuit, I don't think the fuel is cost efficient. Just sayin'. It should run on it.

With the key way issue resolved, about all that is left is fuel delivery. Could well be clogged passages, clogged pilot, failed start circuit, or just dirt in the passage going to the float needle.

Hate to ask, but have you verified the throttle slide is free to fall shut, and is not jammed open? Really hard to start with full throttle, not to mention interesting if and when it does. Make sure the slide is aligned with its locating pin, otherwise, WFO.