I know I am way off the original topic now, but any idea why my bike jumps into neutral between 3rd and 4th sometimes. I am 100% sure it is not the standard neutral position between 1st and 2nd that it is doing. I have to intentionally shift it up extra hard and even then 25% of the time I hit a bla...

A little B-8 update directly from the NGK technician. The B-8 no longer exist. The auto parts stores do not "cross" it correctly. They will try to hand you a 2910 which is exceptionally wrong. He states that the B8S is the exact heat, thread, depth ect... NGK said I will have no issues wit...

I was having this issue about 5 years ago and ended up throwing a lawn mower plug in it. Are these the same as the standard B8?

B8es, B8hs

I just realized that I used an E3 Sparkplug and that was about the same time the knocking started. I read that a plug that is incorrect or "too hot" spark plug can cause pre-ignition (detonation) Does anyone know what plug I am supposed to run on the Ace 100 motor?

I forgot to mention that it only rattles when under a load. Never when in neutral

I did use the buzz box method but did not use a tdc or dial tool. I used the case marks and could clearly see that it was firing before the mark so I moved it to the case mark. Gave significant throttle response fix.

NEW Issue: Possible catastrophic failure soon. A very clear low rattle at low rps. I am 99% sure its the piston skirt hitting as I have had this happen to my other bikes in the past. In some cases in some motors I understand timing can make the piston shoot down as the rotation is still moving up an...

I made a flamethrower out of the inner spark arrestor. Clean now.

I am not an expert but in my research I hear many people say its Placebo Power to throw it on the fire once you get the choke points of the exhaust clear. They say you are talking about minimal performance gains but it looks cool and gives you a sense of accomplishment. I do not have the inner spark...

Was about 90% blocked. Didnt even know there was an insert in the muffler pipe. Pulled it out and it had about 1/2 inch of carbon on it. Wire wheeled it down and cooked it with a torch. I think the rest is pretty clear. Torch cleaned as much as I can in the muffler.

I am trying not to over invest. Just want it right. If it was a Super Rat or Super Combat I would probably throw down for plenty of performance upgrades.

Oh my goodness! Maybe 10 yr underlying problem found. The muffler appears to have a blockage. My father kept saying there isn't much in them to block it off typically, but it certainly is restricted. Runs like a champ with no muffler. Feels restricted blowing into it. This would probably cause the o...

As for the compression Leak Down Tester I grossly underestimated how hard it would be to keep 10 lbs of pressure not in the bike but in the tester. I tried to start with what I had laying around. Not worth saving a couple bucks. Here are the list of failure items for me and my leak down tester: *1/8...

I will get the pic of the plug up soon. I feel there has to be a failure in here somewhere. It ran perfectly for 12 min! Maybe something inside the muffler housing broke free. The "baffle"that is at the very end of the muffler held on by one screw was trashed 20 years ago when a younger me...

Final Results: Failure! Timing set and checked: Fixed hard cold start Carb thoroughly cleaned 3x: checked the float Pressure leak down test: Passed at 7lbs for 3 min and 5 lbs for 10 min. New Fuel: ethanol free 89 octane with 32/1 yamalube Took the bike out for a legit test drive. Running well, full...

I was 12 yrs when I bought the bike from my older best friend. Used my mowing money. Rode it like I stole it for 5 years. It only knew full throttle. Parked it when I moved out at 17 old. It actually popped 6 years after that when I was just testing how bad I had left it. 18 years of ownership I spe...

That was my old motor but i was sooooo upset I never even looked into it. I just pulled the motor and chucked it in a cubby in my garage. It hasn't moved since. If it was a head gasket another proven point that I should build that leakdown test asap.

RESULTS: Starts better, More pep, More bottom and top end power. I used the less sophisticated/less specialty tools/less accurate method of checking and setting the timing. Using the case marks and a buzz box I found it was firing significantly early. Set the timing and I no longer have the cold har...

I watched a video on the Compression leak down test for an ACE 100 a few years ago. I would be willing to do it but it seemed excessive to build the tools in order to test. You have to build seals for the exhaust and the intake, plug hole and install a valve and a pressure gauge (few other steps I c...

I am considering buying 4 or 5 jets to make myself a kinda tuning kit. I own 3 of these motors so it feels like its not a waste of money.

So I started this thread because of what happened to my original motor and after reading and learning from this thread I think I may have initially jumped to a few conclusions. I originally used "Bean oil" with this motor because I was also riding a kx250 air cooled 2 stroke and I thought ...

When I bought this bike over 20 years ago with the original motor we ran it for years on 30wt motor oil and gas mix. My father used to mix it by color in quart size glass mason jars. Calibrated eyeball technique. Brings back memories.

Ya. Took me a second also. The extra oil displaces the gas. Never thought about that before... Always learning. Thanks Ed

Because I now live at basically sea level that did not occur to me. When I live at 1 mile of elevation everything I owned had to be re-jetted. I didnt even know how to boil spaghetti. Great tip. I will look into buying some additional jets. THANKS CLARENCE. Is there a simple way with modern technolo...

Bullfrog: I must be naive to carburetor jetting. Admittedly I am not a mechanic but a pretty good part swap monkey. 20:1 is 2x the oil of 40:1 so my theory was more oil would lubricate better thus lowering temps. Thoughts? I also know that this is the factory Carburetor so other than another thoroug...

I use Yamalube 2R only.