**All work done by appointment only! Please do not remove your engine without making an appointment! Contact me here**

Thank you for inquiring on the Honda Minitrail motor restoration service.

Section 1: My Customers

Please keep in mind that I primarily cater to an individual who is interested in having an original engine restored back to factory specs to use in a very thorough minitrail restoration. What I don’t offer is a quick “freshen-up” consisting of a ring job & engine spruce. I don’t do that type of work and please do not ask me to perform an incomplete job for less money. My work is very thorough and the price reflects the necessary attention to detail and many hours required to get one of these little engines back to they way the ran and looked 40 or so years ago & to run for another 40 years. I perform engine restorations. I have some photos of an engine being tested on a test bike before it is to be shipped back to its owner that I will send along upon request.

Section 2: Carburetion

In my restoration service, I do not rebuild carburetors. I have done extensive testing on old carburetors & i have found that over time the original carburetors for these machines have become warped, worn, and clogged. No matter how “clean” you get these old carburetors, too often they will simply not work well enough to compliment the restored engine & will only serve to cause grief to anyone operating the bike or trying to get the bike to carburate properly.

All customer engines are run on a test bike before being shipped so that i can personally verify the ease of starting, transmission shift quality, ride quality and idle quality.

I cannot perform my testing with your original carburetor. I offer retrofit replacement carburetors which are the same one I use in my testing of your engine.

I strongly suggest that all of my customers purchase a carburetor kit for an older bike simply because it eliminates the very high level of grief that an old warped/clogged carburetor can carry with it. You can get your engine back perfect & tested from me & have nothing but grief with your old carb.

If you purchase one of my retrofit carburetor kits along with along with your engine restoration, I will test your engine with your new carburetor installed & ship the entire package back to you, tested, tuned & one-kick-ready.

If you are not purchasing a carburetor along with your restored engine, I will test your engine with my own carburetor to ensure that the engine will perform up to my high ride quality standards. If you have any running issues on your end & can’t come to a solution, you have the option of shipping the engine back to me & if it runs fine with my carb, you will be responsible for all costs incurred to ship it back & forth. It never happens, but i just need to not that detail. 

Z50’s

Hard Tail (for early model Z50’s like the K0,K1 & K2 that have no rear shocks)

One of my retrofit carburetor kits for any hard tail model Z50 includes the necessary air filter housing adapter pictured on the carburetor page. The intake tube must be shipped with the engine.

The kit will come furnished with a gray throttle cable.

Soft Tail (For K3 – 1978 Z50’s with rear shocks)

One of my all-Honda retrofit carburetor kits for a soft tail Z50 will include a new gray throttle cable.

Regardless of the type of engine you are sending, please send along your intake tube attached to the underside of the cylinder (it won’t get damaged in shipping there). Don’t use tape to secure it the intake tube to the engine. Use string/wire/rope & run it through the actual throat of the intake.

1979 & newer.

I sell a carb kit for this model, but it does not come with a cable because the bike came standard with a black external throttle cable, so there is nothing special about it.

I can get you a cable along with this kit if you like but it is no different than the original Honda throttle cable & can be purchased where Honda motorcycle parts are sold if you feel you need one.

www.dratv.com sells them according to your year.

Email for current pricing.

CT70’s

AI offer a new Honda retrofit carburetor kit for a CT70.  It comes furnished with a new throttle gray cable and a few additional parts necessary to facilitate the newer style OEM Honda carburetor I use in the kit. Installation of the kit will requires me to make a slight modification to the intake tube. Regardless of the model of CT70 engine you are sending, please send along your intake tube secured to the the cylinder (it won’t get damaged in shipping there). Use string,wire or rope to go through the throat of the intake tube itself & tie it to the engine. Don’t use tape to secure it to the engine, as it only makes a mess.  If you happen to be sending a CT70 engine and are not purchasing one of my carburetor retrofit kits, send your intake tube anyway, as I will modify it to accept the retrofit carburetor that I sell. This way, if you decide to go with my retrofit carburetor down the line, i can just ship the kit to you & do not need the intake tube to modify. The modification that i perform does not effect it’s use on the standard/original carburetor.

Section 3: Optimal running set up for CT70.

The CT70 carburetor kits I offer are jetted to run on a stock exhaust with no end baffle. These bikes are not horsepower kings to begin with & the muffler baffle not only kills the power but narrows the temperature range in which the engine runs well in. The bike is only slightly quieter with it in. If the end of your CT muffler has a rod about the diameter of a motorcycle wheel spoke in it, running diagonally across the end of the outlet, the muffler has a baffle in it. Will make the bike runs a considerably better.

The carburetor kits are jetted specifically without the baffle in. If you leave the baffle in, there is no guarantee that the engine will l run optimally due to the excessive back pressure.

If you can’t get the baffle out, a little heat from a plumbers torch right at the end of the exhaust will burn off the carbon in the area, allowing you to pull the baffle with a pair of channel locks or pliers.

Section 4: The need for proper carburetion.

I make very little profit on the retrofit carburetors & I only offer to sell them to satisfy the needs of my customers because i feel very strongly that the original carburetors should not be used.

Many perspective customers are under the impression that their carburetor is serviceable because the engine ran before they removed it to send it to me. When you receive your engine back from me, & you experience some sort of technical difficulty that can be traced to a problem with the original carburetor, I cannot assist in this area & can only recommend a new carburetor. I only stand by this policy because diagnosing & repairing problems related to the original carburetors could easily be a full time job in itself. If your carburetor has been well maintained, you may not “need” a newer carburetor but the reality is that no matter how good a shape an original carb is, the bike won’t as well or start as easily as it will with a new carb on it. I have several 30+- year old classic Honda Z50’s & CT70’s . They have all been switched over to the new carb simply because of the fact that they are trouble free & run better.

If your carburetor is at all suspect, i recommend a replacement carburetor kit ,as it no longer makes sense financially for the customer or myself to rebuild the original carburetors. If your carburetor is in good shape, great. Please consider my advice based on my experience so you do not feel like this customer.

Section 5: Z50 carburetor kits.

I have performed a great deal of testing with these newer carburetor set-ups and when installed, these bikes run better than they did with the original stock carbs. That’s simply due to better technology built into the carbs themselves.  The original CT carburetor varies only slightly in appearance since the updated carburetor’s bowl is round and it has a new-style plastic choke knob. The choke and petcock are on the left side just like the original.

Section 6: Retrofit Carburetor Kit Outward Appearance.

CT70:

The CT70 retrofit carb kit hooks up to the standard intake tube/intake manifold as well as the standard CT70 air cleaner canister. 

Here is a very good example of one of my kits installed http://www.motoenzo.com/images/customers_bikes/MikeM/hondact702.html

Many more examples of my kit installed on bikes can be found on my  Customer Projects page here

Z50 Hardtail & Softail:

Hardtail Carburetor Kits.

My Hard Tail retrofit Z50 carburetor kits are very close in appearance. The original carb kits had a different style of choke lever & my kit for this particular bike warrants the use of a rubber air filter adapter that is a Honda part.

You can see a pic of my retrofit carburetor kit installed on a Hard Tail Z50 on the carburetor page. If you are having a hardtail engine restored, and want a new carburetor, please send your intake tube. Unlike the later Z50’s , I can only modify the tube if you plan on using the updated carburetor because i remove the studs, drill the threads from the holes & use traditional bolts to hold the carburetor on. The modification will complicate the use of the original carburetor, so I will only modify a hard tail intake tube for someone who wants a new carburetor at the time of restoration.

Soft Tail Carburetor Kits.

Kits are nearly identical in appearance.
Section 7: What an engine rebuild entails

The remainder of the rebuild process entails the following:

Disassembly.  During the disassembly process, i carefully inspect every aspect of the engine & note any needs that are not part of the standard process.
Initial cleaning process. All parts are washed in an industrial parts washer. Any parts with a heavy sludge or carbon deposit are first soaked in a chemical bath to assure they are spotless.
Thread chasing. All threaded holes a thread chased. This includes the spark plug hole, oil drain hole. The spark plug hole threads are chased as well as every single hole on the engine (As depicted here)
Overall assessment. One the entire engine is clean & dry, i inspect every part & note any needs that are not part of the standard process. The need for threaded hole repair, welding of the engine cases or covers is undertaken. If any cooling fins on the cylinder head are broken off a new one will be fabricated & welded on to look original. This is a key aspect of my work. I can carry out work that would otherwise deem a part junk & in need of replacement.
Vapor blasting of bare aluminum parts. The cylinder head & engine case halves are stripped of all oxidation, dirt, grease, grime etc. They are refurbished to their original finish utilizing a relatively new process called wet blasting or vapor basting, which is NOTHING like bead blasting, sand blasting or (baking) soda blasting & has very key characteristics that make it the only way to retain yet restore the original surface. Wet blasting is the exact process currently used by Ferrari to obtain the very same bare satin aluminum finish on their vintage engine blocks. That finish is the same as your what your Honda engine had when it was manufactured. Please view this video that demonstrates the process & details of wet blasting.  https://www.youtube.com/watch?v=IC0FA2l79YE In short, vapor blasting does not tear the surface of the metal like any of the dry blasting processes. It does not fracture the media & imbed it into the metal because the media remains suspended in the surface tension of the water (the reason it hurts to do a belly flop into a pool is because of the surface tension of the water). The result is a finish that is not disturbed from original, yet is only clean. Any dry blasting process opens the pores of aluminum to some degree. The media becomes embedded in the metal & then has to be removed. Disturbing the surface during that dry blasting process re-starts & accelerates the oxidation process. Dry blasted metal also stains with the touch of a finger because the original “skin” that has formed on the cast aluminum over the course of the past few decades is now gone & is now porous.
Cylinder replacement. All original cylinders are discarded & replaced with OEM Honda new. The reasons for this are many, but to keep it short, the time it takes a lot of time to bore as many cylinders as i need turned around to go back on an engine. This, in and of itself, is a deterrent. Cylinders need to be replaced because they are either deeply scored, worn beyond spec., or have a pocket of erosion from sitting with no oil on the bare iron cylinder wall. By now, every engine i do has at least one of those issues. So, i simply discount the cost of the cylinder & use brand new one from Honda, removing any guesswork from the scenario. Nobody finishes a cylinder wall like Honda.
Cylinder painted. Even though the cylinder is OEM new, from Honda, the one thing they don’t do well is paint the cylinder. The paint on a new Honda cylinder is hastily applied, very thin & has obvious bare spots.  Once installed & run, it looks lousy in short order once the bare spots rust & the thin spots look dull. I strip the factory paint & apply a very high quality, high gloss fuel-resistant paint to all cylinders.
Engine covers refinished. The left (or, magneto/stator) cover as well as the right (clutch) cover of the engine are chemically stripped of their original paint, sanded, smoothed, filled & powder coated to match the original “cloud silver” that was applied to them.  I take a lot of time to smooth each cover & fill any gouges prior to power coating. The powder coat assures a durable, long lasting shine that is less prone to chipping or scratching.
Hardware. All of the visible hardware is either replaced with OEM new or nickel plated OEM Honda screws & fasteners with the exception of the 14mm hex cam chain tensioner  plug on the underside (hyper link), the exhaust studs (hyper link) & the oil drain plug (hyper link). I replace the original non magnetic oil drain plug with a very stock appearing magnetic oil drain plug. No, it’s not an OEM part, but if Honda could have installed a magnetic oil drain bolt back in the day, they would have. They work great. Any swarf from a rebuilt engine is caught during the initial oil changes & this has to be better than letting it float around.
Final clean. All parts are run through an industrial ultrasonic cleaner to ensure near-sterile levels of cleanliness during assembly. This machinery is very expensive & few in the world go to the trouble, time & expense of getting parts that clean before assembly. Ultrasonic cleaners are used in situations that require very clean working surfaces, namely surgical instruments & wristwatch/clock assembly, among others. Learn more on ultrasonic cleaning here http://en.wikipedia.org/wiki/Ultrasonic_cleaning
Reassembly. Upon final cleaning, the engine carefully re assembled.
Testing. Once the engine is complete, i install it in a test bike, hook up all the necessary ancillary items & test run the bike. I assure that all aspects of the engine are as designed from Honda. The engine must start with one the push of a hand on the kicstarter when cold. The engine must shift smoothly & idle properly. Lighting output is also checked at this time so that you can be assured that the electrical power output for the lighting on your bike has been verified.
Section 8: What parts are included in an engine restoration?

The cost includes the replacement of the parts and the labor listed below.

• Cylinder

•Piston

• Rings

• Piston circlips

• Shift fork guide pins.

• All new gaskets, seals and O rings

• *All new external engine hardware (see section 7 for exceptions)

• Clutch friction plates

• Cam chain (also known as timing chain)

• Both cylinder head tappet inspection covers (17mm covers)

• Cam sprocket cover (big round cover on the left side of the head)

• Spark plug wire guide & fixing screw (On the right side of CT70 cylinders).

• Carburetor overflow line guide (on the left side of the engine, forward of the engine cover).

• Ignition breaker points

• Oil dipstick

• Spark plug

• Crankcase breather hose

• Re-sheathing of stator wires to harness connector

Section 9: Supplemental needs not included in rebuild

Here’s a short list of items that sometimes require replacement, but are not included in a standard restoration because they don’t require replacement enough to be part of the standard process.

• Kickstart shaft ($45.00) The splines can be stripped or simply intact, but worn enough to warrant replacement. The kickstart shaft requires complete engine disassembly to replace. That being the case, i very thoroughly inspect the splines of the shaft so that if there is a hint of an issue, i replace it so as to guarantee no issues in the future.

• Shift shaft ($30.00) The most common issue with the shift shaft is that they are bent. Modern dirt bikes have folding shift levers. Back n the day, when the rider crashed the bike on the left side, the tip of the shifter really dug in & it was not unusual for the shift shaft to suffer. In mist cases a bent shfit shaft doesn’t actually cause a shifting issue. However, if the shaft is bent, i can’t reinstall it so i replace it or straighten it when possible, which is half the cost of a replacement shaft.

• Shift forks ($50.00 each) The engine has two shift forks. Shift forks are the most common item on the non standard list of parts, but they still don’t get replaced enough to be part of the standard rebuild. These can have accelerated wear if the engine was run out of oil or was operated with a clogged oil screen starving it of oil.

•Helicoil thread repair – any 6mm hole – ($10.00) Many times, these old engines have suffered at the hands of a backyard mechanic. Threads can be stripped & many of the holes are 6mm. I can heli coil thread repair any of them.

• Helicoil thread repair – 8mm underside step bar mount holes (upon inspection) – ($12.00/each hole). Many times, these engines were ridden for years with loose footpegs. This would wear out the lugs on the underside that the pegs bolt to & strip the threads. I can heli coil those threads. There are 4 lugs. Sometimes all 4 are fine. Sometime one or more can be stripped. 

• Helicoil thread repair spark plug hole ($25.00) The first thing people would check when their bike did not run was the spark plug. Upon re installation they would either cross thread the plug over over-tighten it. I have a specialty setup that i use to machine the park plug hole at the correct angle & use a special spark plug sized heli coil to repair the hole. The repaired hole with stainless steel threads is more robust than new, as is any heli coil thread repaired hole.

The above items are replaced on an as-needed basis. The need to replace these items varies from engine to engine & is usually dependant on how the engine has been cared for throughout its lifetime.

Section 10: What a restoration does not include.

These are items that hardly ever need addressing.

Crankshaft related items. The crankshafts are very robust & Honda uses them in 125cc engines. So your small 50 or 70cc engine is not wearing it out at all. Of course there are some instances when damage can occur, but it is usually brought about by human intervention. Sometimes owners will try to remove the stator/magneto & because they don’t have a impact gun will just tighten the nut on the crank by hand with a ratchet.  Eventually, the natural movement of the engine will eventually loosen this nut. A loose magneto on the crank will destroy the crankshaft.
Transmission related items.  The transmissions are also very robust. They too are used in much larger engine. Again, damage can happen, but it is extremely rare.
Section 11: Test Process

A key aspect of my restorations is that upon completion, you’re engine is installed in a test chassis & ridden for at least 15 minutes. During the test I personally assure ease of starting, shift quality, idle quality in neutral as well as in gear (automatic models), proper acceleration and deceleration aspects & steady cruise quality. Any and all adjustments necessary are made & rechecked before the motor is returned to you. This assures that the installation will go silky smooth for you & removes any question as to if the motor will work for you as it would for me.

My test process assures me that I can test the running condition of your engine before it is returned to you.

There are only 3 possible items on your bike that could cause your engine to run poorly for you, but not for me.

Those 3 items are:

1) Exhaust

2) Ignition coil

3) Carburetor

• The only way your exhaust could cause a problem is that if it were so dented or clogged so as to completely block flow. This would have to be a deliberate act & I have never heard of it happening.

• I have yet to see a Honda ignition coil go bad in my 30 years working on Honda motorcycles. They simply do not fail but it is possible and must be considered.

•  I caution against using your original carb. Attempting to use an original carb on a restored engine is the number one culprit of a dissatisfied customer. You can try to get away with it, but you’re on you’re own when it doesn’t idle, leaks, idle hangs up, doesn’t start or exhibits generally poor running condition. My engines perform as-new when you get them. They won’t perform as-new with an old carb, guaranteed.  Please be sure to that you have read the extensive information on this page with regards to how having a good carburetor is central to a good running engine.

The reason I am going through the possible scenarios is that you need to feel secure that your engine will be returned to you running like new. The best way for me to make you feel at ease is to describe all possible scenarios and assure you that they have been worked through. I stand behind my work & should you have some sort of issue with your engine, I will work through it with you to the point of resolution.

I don’t mind if you want to use your old carburetor as it may work fine. I am only assuring you are aware of the pitfalls that come with your old carb.

Section 12: What can be expected

The engine will be returned to you looking like a factory original engine or better. Engines do not get shipped unless they work as they were designed. I do not ship an engine back to its owner unless pushing the kick-starter by hand will result in the engine starting. This is so even the smallest of young riders can start the bike and learn to ride just like you did all those years ago. When your engine is returned to you it will look very close or identical to the way it was assembled at the factory. YOUR ENGINE IS RETURNED WITHOUT OIL IN IT FOR SHIPPING REASONS! You must put oil in it before operating. There is extensive information on oil that will be shipped along with the engine. Additionally, you can find more oil info here.

Section 13: Z50 & CT70/CL70/SL70 Engine Rebuild General Info

Standard engine restoration charges are $1000.00 for the following models:

3 speed automatic clutch CT70
Z50 any year
4 speed manual clutch CT70
CL/SL70 (Retrofit carb kits available. Please email if interested.)
• The overall restoration cost is a direct correlation to the quality of work you will receive, which is second to none.

I do not run a “core shop”. That is, I don’t send you someone else’s motor or motor parts back to you. What you receive back is YOUR motor, completely rebuilt utilizing all of my 30 years of Honda knowledge and experience. This will maintain your matching-number authenticity. I use all Genuine Honda parts where available in my standard restorations. Tested, tried-and-true aftermarket parts are utilized only in the very rare instance when & where Genuine Honda is not available, or when upgrading to power-up components.

Section 14: Determining additional needs.

Please be mindful that an engine that has had makeshift repairs or jerry rigging in some area will returned to stock specification. Any threaded hole that has been drilled out & tapped to accept a non-metric standard thread or simply a larger bolt/screw will be refurbished & it will all be returned to standard specification. I do this to ensure that your engine will be the same as when it when it rolled off the showroom floor, with no unusual work that could stump another ordinary mechanic years from now.

If there are an inordinate amount of additional needs, I will email you prior to doing any work.

Of the few thousand Minitrail engine restorations that I have completed, I have only turned away a couple of engines because it was not cost effective & simply buying a good used engine to start with was more cost effective.  In doing so i had saved those customer significant money.

One time an engine was brought to me after it had been pulled from a body of water. No internal or external parts were serviceable.

In another instance, a customer sent in an engine from a bike that had been parked under a gutter downspout  of his home for a few decades & the engine was regularly fed a continuous supply of water from his roof. The engine was seized & completely frozen, which is normally not that big a deal. However, that customer made an an attempt to clean the engine with a large industrial de-scaling power tool that is used to strip the paint off of highway bridges. He destroyed the engine cases & all of the external components it in the process. I think those are the only two customers that i advised strongly that they furnish another used engine for their project.

Somewhere in between a great running engine & a totally useless one is your engine as it sits with you. You may be able to get an idea of additional needs by looking at the overall condition so you can know what to expect. Most folks that send a really rough engine are not that surprised when I inform them that there were some additional needs.

Don’t bother cleaning it. I have very expensive cleaning industrial cleaning equipment & won’t complain at all no matter how dirty it is. Just make sure the oil is drained from your engine before shipping it.

Section 15: Deposit & Payment

If you would like an engine restored, please request the sheet that i email you so that you can print it, fill it out & ship it with the engine. I don’t have the sheet available on the site because it helps keep the spammers away.

You will see that on the shipping sheet, I ask for a deposit of roughly 50% with the engine, depending on your options chosen.

I ask for the balance upon completion of the job. Personal checks are fine for deposit & balance.

Section 16: Completion time:

All work is performed on a first come-first serve basis. Currently my turn around time is between 6 to 8weeks from when I recieve it. If you have any other questions, please e-mail me. If you are interested in sending an engine, please let me know and I will reply with the sheet you will need to fill out & ship along with the engine.

Section 17: Return Shipping:

Fed Ex ground is used to ship engines back, fulled insured.   To return an engine to Canada, i still use USPS but ground is no longer available, only air as of January 2012. All return shimpents to Canada are now automatically Priority Mail from USPS. The cost is usually around 170.00 US dollars as of 8/2015.

Section 18: Shipping punch list:

Please refer to this checklist  of helpful hints on how to pack & ship the engine.