The Hodaka Club Forum

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’d still put it over a fire! You’d be surprised what will burn out of it! And a quick spray of black high heat engine paint will make it look new again! Victor

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 arrestor piece and I am not willing to pay for a new one. I feel with the inner arrestor missing I may want some restriction in flow. This is of course not a race bike.

I have burned 3, or actually 4 pipes so far. One pipe was the wrong model & got repainted & sold because it didn’t fit. Everyone of them loosened up old oil, carbon deposits and 2 of them actually became flame throwers for awhile. Just saying, never underestimate..... Victor

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

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 and create a rattle. If you read above: motor was new. Compression is over 140 lbs. I did advance the timing a bit to match up with the case marks. Bike has more power now. Jetting is better as I went to a 100. Bike not over revving. More torque. Don't think its possible the crank bearings could go with just a dozen hours max on the motor. Open to any suggestions. Getting exceptionally frustrated.

You might want to consider using a different method of timing the motor. Most precision requires using a buzz box or for a few bucks, a TDC tool and timing wheel is a decent and more accurate method. Also consider pulling the head and inspecting the dome for signs of detonation and while in the jug, double check clearance. Hopefully, what you are hearing is something loose on the bike that just so happens to resonate with the engine at low rpms. Motor mounts would be a good place to start and go from there. Idle the bike on the side stand and make a careful inspection. Hope a simple fix is in store for you.

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.

the case marks should serve you fine. Or point gap. -----------Clarence

There are people who are frequent contributors to this forum who are infinitely more knowledgeable than me so for what its worth, try not to let frustration take over. Trust me when I say I've been there but the truth is, these are reliable bikes and the problems are inevitably identifiable and repairable. I ride a 52-year-old one to work every day and it runs flawlessly. I had a problem similar to yours where it made a horrible noise under load and the only problem was my improper shimming of the clutch disk. Hang tough and someone will drill down on the problem and set you on the right path to remedy - they sure have for me on countless occasions.

The rattle that you are hearing under load very well could be pre-ignition or detonation, and as you say could lead to engine failure. There are several sources of detonation including advanced ignition timing, low octane fuel, lean condition, etc. Any or all of these can lead to overheating and failure.

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?

NGK B-8 is standard

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

No. not the same at all! They are all different lengths and you can damage the piston by using an incorrect length. You can Google NGK plug charts to learn what the numbers and letters mean.

Look up the specs for your Hodaka and use the correct NGK plug and keep lawn mower plugs in lawn mowers.

Just to expand a bit on what Dale offered, spark plug selection is critical to the proper and safe operation of the engine. Two of the basic features of the spark plug that determine its appropriate application are "reach" and "temperature". Reach pertains to the threaded portion of the base of the spark plug. Appropriate "reach" is engineered into the cylinder head so that the firing tip of the plug is optimally positioned within the combustion chamber. If a plug of inappropriate reach is used, one of two bad things can happen . If a plug with an inappropriately long reach is used, the piston can strike the plug which may hole your piston. Too short reach leaves the firing tip up in the threaded portion of the dome of the cylinder head rather that in its proper position within the combustion chamber leading to inefficient combustion, carbon fouling, loss of power, and potential damage to the threads. The temperature designation of the plug refers to the heat dissipating properties of the plug. This is primarily a function of the length and thickness of the insulating nose of the plug. A "hotter" plug is designed to dissipate less heat thus retaining more heat in the plug. A "colder" plug works oppositely. Heat retention is important for proper combustion and the burning of carbon to lessen carbon deposition and plug fouling. If a plug that is too "hot" is used, the retained heat may be great enough to spontaneously ignite the fuel irrespective of proper position of the piston in the cycle (detonation) resulting in major engine damage. A plug which is too "cold" can result in carbon fouling and loss of power since the thermal properties of the plug are inadequate to burn off carbon deposits. The bottom line here is to use the proper plug for the application. For an Ace 100, this means using an NGK B-8. They are cheap. I've found them costing less that a dollar apiece when purchased in a box of 10.

. . . AND the NGK's are very good spark plugs. I've been using them since 1969.
Ed

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 with the B8S and they are in stock at most Napa Auto Parts store. I will let you know if this helps with the detonation .

This is true. The NGK charts show that the "S" after the heat range number denotes Standard electrode. The length is denoted by an "E", "H" or the absence of a letter. You have the latter. It would be a correct plug.

The manual states B7, B8, B9 for the 3/8 head. Check the manual. For racing the manual lists B 8N to B 12N. The manual also lists plugs and racing plugs for 1/2 and 3/4 heads also along with a conversion chart to Champion, A-C, Auto-lite, Bosch, KLG, and Lodge. --------------Clarence

Aaaaaaand, NOS B-8 plugs are frequently available on fleabay.

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 blank spot. Only messes up when shifting up not shifting down.

Your shifter mechanism is out of adjustment or showing the effects of excessive wear AND/OR the control shaft spring on the magneto side of ball receiver is partially collapsed (probably due to the extra stresses on the spring caused by being out of adjustment or excessively worn). Effects of being out adjustment almost always initially show up with 3rd to 4th shifts or 3rd to 2nd shifts.
Ed