Hodaka 100-125 engine life

[Bill2001]

As a maintenance/preventative maintenance item, what is the service life of Hodaka engine components? Such as piston rings, bottom end (bearings? seals?) or clutch plates (a real variable!) ? I'd like to get a feel for when to split the case and check/replace the main bearings or (the biggie) the rod bearings.

--Bill

[hodakamax]

Hey Bill, Good questions. Of all the things mentioned I would think rings would be would be an item to check with a compression gauge perhaps annually or when a lack of power is noticed. Pistons/rings do wear out but will have symptoms such as noise and loss of compression. Normal service components seem to last almost forever in a well maintained Hodaka engine. Most Hodaka component failures today are from Father Time and/or abuse. These are antiques.

When splitting the cases it's standard to replace all the main bearings and seals which are relatively low cost. Checking the specs on the lower rod bearing as far as side play (which can be done without splitting the cases) will give you some idea on replacement options.

New clutch plates also last forever under normal service and can be ran to failure or at least to symptoms.

As always maintenance is the key. Periodic checks on timing, transmission lubricants, clutch adjustments, air filter and such will allow these little engines to operate for long intervals.

As for when to split the cases, The time is now if it hasn't been done for decades. Seals should be replaced on old engines.

Kinda general but I hope this helps!

Max

[Bill2001]

I had no idea how long they usually lasted, and what you say is much better than I expected. My Hodie is new-- new George Cone bottom end, the PO did new piston/rings, used and honed cylinder, new clutch plates. I've fine-tooth-combed the rest of the bike, replaced a couple of iffy components and have plans to do others "In a year or two. Or three."

But the bike is now zero'd-out on maintenance. And I'll go ride the heck out of it now that I figure it won't be wore-out in 3-4-5,000 miles. Can we have a yeee-haa ! ???

--Bill

[---]

I rode mine to death from 1971 to 1974, including countless hours of flogging it around Southern Illinois strip pits, and two times in the Daniel Boone Hare and Hound in 1973 and 1974. Until I killed the big end of the rod in the 1973 race, I was running the original Ace 100 engine, piston and rings, with only a sock air filter as modifications. Wild guess, maybe 500 hours of hard use, and failure was due to switching minutes before the race from petro oil to castor without flushing the tank and carb, not due to wearing out or other mechanical failure.

It depends on how it is built, how it is ridden, and how it is maintained. A wombat ridden sensibly will outlast you. If you scream it or try to race it, you can get a season out of it before it needs rebore.

[thrownchain]

Yep, use and maintenance. Taken good care of lasts long time, abused lasts a lot less.

[Bill2001]

I'm picky on maintenance. I'm thinking that good gas with good premix oil and the timing dead-on along with the carb set properly (mixture) are probably the #1 things to keep tabs on. And, really, those are basic maintenance items.

--Bill

[taber hodaka]

A good quality air cleaner, kept clean and serviced will do wonders. I don't hear it, but I will not use cheap low quality bearings. I only buy bearings made in the USA, Germany, or Japan. Back in the day I could get over two years on a bore, racing allot but I did change several rings.----- Clarence

[Bill2001]

That, too. The engine came with a new UNI air filter element, and, although it's too early now, I need to figure out whether to use a spray-on filter oil or use the traditional squeezed-out 30 wt oil. But that air filter is huge for a 125cc engine. You are correct about bearings-- it's false economy to use "cheap chinese junque" instead of a quality bearing.

One of the first things I did when I started going through this bike was change the gearbox oil, draining it into a fine-mesh "paint gun funnel" to catch any debris. Since the engine had a few "heat cycle miles" on it, this would be the best time to look closely. In addition, I drilled the drain plug and installed a small, powerful magnet. This will not only remove any ferrous debris from the oil, it will also give a degree of early warning if a component is starting to fail.

Speaking of which-- what type/brand of gear oil do we like?

--Bill

[taber hodaka]

On foam air filters I use 10 or 20wt oil squeezed out. I also grease the inside of my air cleaner. To some the spray on could be better, I still have some on my hands from using it three years ago, not really but it sure is sticky. The transmission oil needs to be non foaming and really good quality, you will get allot of good recommendations.-----------Clarence

[Bullfrog]

Several seasons of AHRMA racing can be completed on an engine rebuild IF - there is good air cleaner maintenance, oil changes, good fuel/oil mix, etc., respect for the machine when on the track, etc, etc.

I'm partial to Belray motorcycle transmission oil . . . partly because it is readily available from my local motorcycle dealer. I still like to support the local guy when I can.

I've always used something designed for oiled air filters (from the 1970's to the present time) OR chain saw bar oil (sticky stuff). I've never used standard engine oil for air cleaner oiling.

Ed

[hodakamax]

Clarence brought up a good point on using grease on air filter parts particularly on joints and seams. A few minutes on a dusty track with an opening to the outside will shorten ring and piston life to a few hours (or even minutes) instead of years. Air cleaner--Very important for long engine life.

Max

[---]

The grease is a good idea to trap dust that comes in contact with the hard parts before the carb. It doesn't catch much compared to total air flow, but some is better than none. Of course, if this bike is going to be ridden on the street, the grease is probably overkill.

I use spray on filter oil, and I use the filter cleaner spray to clean. It is very similar to garage floor cleaner. Both contain sodium metasilicate. I buy which ever is cheaper, usually the garage floor cleaner, and mix my own spray. I don't use gasoline or diesel to clean filters.

[Bill2001]

I removed the air cleaner assy to pull the battery box and redo the wiring and I reinstalled it today, paying much attention to air-tightness. The only thing I saw that raised a caution flag was the narrowness of the lip on the air cleaner body where the air horn-carb inlet fits. At just a little over 1/4" wide I'd worry about the air horn slipping off and letting unfiltered air into the carb. I may remove it and carefully bend part of that lip outward to give the wire clip something to bite against. Just being picky...

--Bill

[hodakamax]

Bill, that is an area of concern. The rubber boot fit to air cleaner is marginal at best. It get's worse when you've added a reed valve set-up and have to modify the rubber boot. I line it up by removing the outside cover and filter and pull them together with my finger. This is one of the places for the grease we are talking about. It works but there must be a better way.

Max

[dirty_rat]

The air filter bodies that I have already have a raised lip at the junction where the air boot attaches. It's not very big, but it does seem to hold the boot pretty well. And, as added insurance, as noted before, a little grease at the junction helps seal it even better.

[Bill2001]

The air filter element I have is a UNI 5002 with an appropriately-sized inner wire mesh basket. It all fits nice and snug and I think it will work out well. I typically use mineral spirits and 30-wt engine oil on foam filter elements, but this time I sprung for real live UNI cleaner and spray oil. We'll see how that store-bought'n stuff works..

--Bill

[Bill2001]

To continue with "Engine Life': Air Filter Maintenance". Even though the air filter is on my engine is new, I decided to clean it and prep it to zero-out _my_ maintenance of the bike. The filter element is a green UNI 5002, and always seemed to exude oil, so I had the impression that it may have been over-oiled.

I used the UNI air filter cleaner, which seems like a GUNK degreaser with steroids. I sprayed the cleaner on, worked it in and let it set for a few minutes, then washed it with water (per directions). The filter element seemed to be still a bit oily, so I washed it again with warm water and dishwashing detergent (my SOP on air filter cleaning on the yard eqpt). Seems a lot less oily, but that air filter oil is, well, tenacious stuff. I'll let the filter element air dry, then per the UNI spray air filter oil, spray the inside and outside, let set for a few minutes, then with the hands, knead the filter to work the oil into it. And last I'd do a light squeeze in a clean shop towel to remove any excess oil (as I do when I typically use engine oil on the foam filter).

Not a big deal, but as we say, a good air filter leads to a happy and long-running engine.

--Bill