Topic: No start - troubleshooting help

[Bigmant]

How would you tell if the brakes are dragging? All brakes are new pads and brake systems. When I looked at the front brakes, the pads are not touching the caliper when just sitting off. And how would the floats control the engine not getting power on the road, but on the center stand it hits a high RPM just fine?

[newday777]

Get the wheels off the floor, IE on the center stand, spin the back wheel does it spin freely? Then put a jack under the motor to lift the front wheel off the ground slightly (just enough so it doesn't fall off the center stand)and spin it. The chain could be binding too.

The floats if not adjusted properly (too low) would cause starvation at speed using up the gas in the bowls......
Dirty carb ports or plugged fuel lines, improperly run fuel lines or aftermarket fuel filters, especially if run too low can cause it too.

[newday777]

After re-reading through all the posts in this thread to get the full scope of this thread to see if you had rebuilt the carbs or cleaned the tank of rust..... Did you clean the stock carbs and be sure there's no rust in the tank?

It appears looking through your other posts you have started that you had talked of getting the Yoshimura carbs, cam and exhaust early on for this bike(?) but left that thread hanging as to what you did on the build??? Same bike??? What did you do to the motor and the carbs, if the same bike?

[Bigmant]

After re-reading through all the posts in this thread to get the full scope of this thread to see if you had rebuilt the carbs or cleaned the tank of rust..... Did you clean the stock carbs and be sure there's no rust in the tank?

It appears looking through your other posts you have started that you had talked of getting the Yoshimura carbs, cam and exhaust early on for this bike(?) but left that thread hanging as to what you did on the build??? Same bike??? What did you do to the motor and the carbs, if the same bike?

Newday,

Wow! You even went back to see my other threads haha. I ended up not doing the Yoshimura stuff because I ultimately decided it was changing the bike away too much from what it was when my Dad took my Mom on their first date. So I left it mostly stock, with some cosmetic changes.

Motor is stock, but completely refreshed. Rings gaskets etc. Carbs are also completely ultrasonic cleaned all new parts inside. All new fuel lines, petcock etc as well.

As for the rear wheel, it does spin freely in neutral, but it doesn’t keep spinning when you push it by hand. Perhaps I’ve got something wrong there?

[newday777]

There will be some from chain friction.  Just has to move freely without brakes or chain binding part way round the circumference.
Standard rings without a bore over?(.25/.50)

[2wheels]

Just to be totally clear.  Your are driving down the street in first gear and the engine will not go above 3000 RPM.  (basically the engine is close to idle)  Is this correct?
And if you pull the clutch in the the engine will rev up.  Is this correct?
Did you check the spark plugs, a visual inspection to see if they all look the same?

[Bigmant]

There will be some from chain friction.  Just has to move freely without brakes or chain binding part way round the circumference.
Standard rings without a bore over?(.25/.50)

That is correct, standard rings, no bore over. Ok then the wheel should be good, it all moves freely.

[Bigmant]

Just to be totally clear.  Your are driving down the street in first gear and the engine will not go above 3000 RPM.  (basically the engine is close to idle)  Is this correct?
And if you pull the clutch in the the engine will rev up.  Is this correct?
Did you check the spark plugs, a visual inspection to see if they all look the same?

Sort of correct, it won’t get above 3k in any gear. I didn’t try pulling in the clutch to see if it would go above 3k, but when it’s on the center stand, in neutral it’ll go all the way to 6k+. The same is true in gear on the center stand.

Haven’t pulled the spark plugs since I just balanced all the carbs myself.

[newday777]

Standard rings without a bore over?(.25/.50)

That is correct, standard rings, no bore over.

Do a compression check. The bores usually egg-shape. Bigger at the bottom of the stroke.

[Bigmant]

Standard rings without a bore over?(.25/.50)

That is correct, standard rings, no bore over.

Do a compression check. The bores usually egg-shape. Bigger at the bottom of the stroke.

Could it possibly be a timing issue? I’ve timed it statically but not running with a gun yet. Just don’t see why it only can’t get above 3k under a load but on the stand it works great.

[Kevnz]

Even recheck timing statically. My 500 wouldn't rev past 6k even in neutral, went flat. I had set timing statically, but rechecked and found I either had made a mistake or it had moved, but carefully reset it and all good. I had to juggle points gaps to get it within the adjustment range on the plate, but gaps still within tolerance.

[newday777]

Standard rings without a bore over?(.25/.50)

That is correct, standard rings, no bore over.

Do a compression check. The bores usually egg-shape. Bigger at the bottom of the stroke.

Could it possibly be a timing issue? I’ve timed it statically but not running with a gun yet. Just don’t see why it only can’t get above 3k under a load but on the stand it works great.

Timing is a possibility but statically should suffice.
Also check the runout on the advanced shaft(#8, someone may have bent it trying to turn the crank with spark plugs in and too much compression).
The other possibility is the springs on the advancer could be stretched, so a timing light would show that. I think hondaman Mark says to cut the springs shorter to compensate if not advancing properly.

Again have you done a compression test since the rebuild? The standard rings may not be sealing at the bottom of the stroke.

[newday777]

Standard rings without a bore over?(.25/.50)

That is correct, standard rings, no bore over.

Do a compression check. The bores usually egg-shape. Bigger at the bottom of the stroke.

Could it possibly be a timing issue? I’ve timed it statically but not running with a gun yet. Just don’t see why it only can’t get above 3k under a load but on the stand it works great.

http://forums.sohc4.net/index.php/topic,155069.msg1775409.html#msg1775409

[2wheels]

Sort of correct, it won’t get above 3k in any gear. I didn’t try pulling in the clutch to see if it would go above 3k, but when it’s on the center stand, in neutral it’ll go all the way to 6k+. The same is true in gear on the center stand.

Haven’t pulled the spark plugs since I just balanced all the carbs myself.

I was just wondering if one cylinder is not producing any power (for whatever reason)  that would cause a significant loss of power.  The spark plugs would probably tell you if that is happening.
It may be a good idea to make a youtube video of you driving down the road.  Some people here may be able to hear the problem.

[Bigmant]

Ok gang, it is for sure the timing. When using the light gun, both were off. After fiddling with it for 3 hours today I decided to give it a rest. I’m not sure what I’m doing wrong, but setting the timing isn’t that hard. Here is my method so far, per the manual and this forum.

1. Set points gap. This is done by aligning the window to the tab, square piece, 90 degree mark whatever you call it. Set the gap to .012-.016.

2. Then using static timing set the 1/4 at the F mark.

3. Same for 2/3 at the F mark.

4. Start the bike up. Roughly around 850-950rpm idle, marks should be close using the light gun.

This is where it gets weird. My timing is off with the gun. So I go back and make adjustments that bring the timing closer to the F mark. However even when I get it close 1/4 will not hit the advanced tick marks at 2500rpm. The advance marks being the two “II” marks 20 or so degrees away from the F mark. As the RPMs increase, the timing remains at the F mark for 1/4.

Any thoughts?

[Kevnz]

Same result with 2\3? Sounds like your advancer unit is not playing the game, perhaps seized.

[Bigmant]

Same result with 2\3? Sounds like your advancer unit is not playing the game, perhaps seized.

Took the whole enchilada apart, everything looks good springs aren’t bound up, and it appears to open under centrifugal force as it should. 2/3 advance under increased RPMs just fine. So I’m not sure why 1/4 would lag.

[newday777]

Same result with 2\3? Sounds like your advancer unit is not playing the game, perhaps seized.

Took the whole enchilada apart, everything looks good springs aren’t bound up, and it appears to open under centrifugal force as it should. 2/3 advance under increased RPMs just fine. So I’m not sure why 1/4 would lag.

Check the spring tensions

[Kevnz]

+ agree with check spring tensions; if there's any slack before the springs start to engage, it's possible that you took up that slack when setting your static timing, which will put it out. My issue was just that, and just moving the plate around to time it was pulling the advancer around a bit too. Just needed to nip about 2-3mm off the end of the spring and tighten the loop. You can check it easily by removing the points cover and seeing if you can turn the advancer by hand, there should be resistance felt, no free movement.

[Bigmant]

+ agree with check spring tensions; if there's any slack before the springs start to engage, it's possible that you took up that slack when setting your static timing, which will put it out. My issue was just that, and just moving the plate around to time it was pulling the advancer around a bit too. Just needed to nip about 2-3mm off the end of the spring and tighten the loop. You can check it easily by removing the points cover and seeing if you can turn the advancer by hand, there should be resistance felt, no free movement.

Ok, so I now have a new timing shaft. I figured maybe I bent the old one using it to lift the crankshaft out during the engine rebuild. Still no luck with the timing.

Pulled apart the advancer unit, cleaned and relubricated it. It definitely operates WAY better and snaps back into position. So I think the springs are still good. I just can’t get the timing in no matter what I try. I’m wondering if buying a dyna ignition would solve the problem, this is literally the only thing stopping me from riding it at this point.

[bryanj]

Been doing these 40 odd years both in main dealers and for myself, ive used a strobe maybe twice, static timing is the way Honda tell you to do it BUT you need the gap at 14 thou then set timing to F and recheck gap as it alters when you move the plate, it takes a bit of fiagalling to get BOTH gap and timing correct but it can be done

[Bigmant]

Been doing these 40 odd years both in main dealers and for myself, ive used a strobe maybe twice, static timing is the way Honda tell you to do it BUT you need the gap at 14 thou then set timing to F and recheck gap as it alters when you move the plate, it takes a bit of fiagalling to get BOTH gap and timing correct but it can be done

I am now the proud owner of a dwell meter, and I am managing to get the timing closer but I still can’t get it spot on. Currently on 8cylinder setting, I’ve set the dwell to 23 degrees and 24 degrees. Both times, I can get 1/4 on the F mark, but then 2/3 run out of the ability to turn anymore. All set around 1000-1200rpm at idle.

Frustrating to say the least. I feel as though it shouldnt be this hard. Do the points need to be different gaps/dwell angle in order get it set right?

It’s frustrating t

[Bigmant]

Update!

So after reading a post from a few years ago on this forum about how TEC points are the way to go, I decided to slap them back on and see how they performed. Glad I kept them! Set them up with 24 degrees of dwell, and managed to get the timing pretty close. Not perfect, but close. Close enough for a ride around the block.

Bike actually did really well. Cleaning and regressing the advanced unit made a big difference and I can now pull through 3k RPM. And once it hits about 5-6k it really hits its stride. I now feel what I can only describe as a flat spot at 3k RPM that i will have to fix with a little carb tuning.

The bad news is, I came back, and found an oil leak that had covered the entire rear of the bike, decided to let the bike cool before cleaning it all up and fixing. Came back out and the rear wheel was flat. No puncture in the tire, but it’s leaking air out the spokes. So that’s a super bummer. Fixed the oil leak though!

So getting closer every day, I think I’ll raise the carb needles up to center, because they are currently 4 notches down. I have 120 mains, 40 idle, pods and a Carpy’s 4 into 1. After doing some reading if I move the needle up a notch or two it should help that flat spot. A stock air box would work better, but alas, this bike hasn’t had that, even before my dad got it in ‘76. So pods it is!

[bryanj]

It  must have a punture for air to leak out of the spokes! Your inner tube has a hole in it somewhere and i donr mean the one you inflate it through

[Bigmant]

Back on the road!

Fixed the tube myself, I was surprised it wasn’t that hard and now I have a new skill haha. Sure enough, the first tube was punctured near the valve stem. Super tiny hole, but that’s all it took. Fixed that, and installed a new Dyna S ignition system. Wow. The hype is real, in 45minutes I had it installed, and perfectly spot on to the advance marks. After fiddling with my old points for HOURS, it was a good feeling. The bike starts up, one try with barely any choke and idles very consistently.

I still have an oil leak that I need to figure out, and there is still a flat spot at 3000rpm that I believe I can fix with a carb adjustment. All that is for tomorrow though. Getting closer to perfection!