Randys 85cc

I use premix 40:1 synthetic two stroke oil and premium gas. My oil injector tank has been converted to hold 50/50 water/alcohol, for injection thru the back of the air filter. Some times I experiment with 10% per gallon- toulene mix, zylene mix. This increases gasoline octane by 5 points. Only drawback is that these additives have a very high flammable level and cannot be used on cold or semi-cold days.. When the new motor is broke in. I will start making my own ''Rocket Fuel" A picture is worth a thousand words , so enjoy the pictures and feel free to email me (address below) if you have any questions with your bike. I am alway glad to help out fellow Honda Elite owners. Randy H

March 2005 100cc Stroker update

This is the third and latest revision to my 1993 Honda Elite 50. I took the 85cc cylinder and piston off, removed the stock crankshaft, and installed an 78mm x 50mm SEF Full Stroker Crankshaft. When the crankshaft was installed, I mated it to an SEF 50mm bore, cylinder and piston kit. This brought the cc's up to close to 100cc's.

I used a bunch of makeshift tools to split the crankcases. Honda has some great engine tools , but they are horrendously expensive. I used a dremel to expand the crankcase diameter to accept the bigger crank. I used the old crank bearings (sanded down to fit in the races by hand), to make sure the alignment of the new crank ran freely and did not hit any part of the crankcase. Then I expanded the scavenger port in the rear of the crankcase and cut a small relief in the front of the case for ample room for the con rod. I put in an aluminum plug where the oil injector was. With this big a motor, the injector pump is useless and I go with 50:1 pre mix. Since the case on these motors have no gaskets, I used Grey Moto Seal, on both Crankase halfs. I carefully pounded the new bearings I ordered, into the races, using a two pound sledge hammer and three inch wide washers as a strike surface. Then I used my home-made tools to insert the new crank and draw the cases together. I bolted the cases together and proceeded to put the motor together piece by piece.

I have never done this before, so I am praying it is going to work and not destroy the only 2001 motor I own. I completed the motor rebuild, fired it up and it ran great with the carb set-up I had on the old 85cc motor. The fan shroud fits very tight due to the stroker cylinder 3/4 inch higher cylinder. A small hole had to be cut in the rear fender , under the oil and fuel line and a relief channel had to be cut in the bottom of the helmet well, and spark plug access plate. When you sit on the bike, the shock compresses and the raised plug hits on the bottom of the helmet well. That is why a relief channel must be cut.

I have twenty miles on the engine and it runs well. I have learned that my 85cc racing pipe is too small for the 100cc engine and I am waiting on delivery of a proper pipe from VT cycles. in Hawaii. I understand that even the 52mm cylinder bore and 54mm bore, require their own pipes especially made for that size of engine.

The bike starts easy and has a low powerful 100cc motocross sound. It actually shakes on the kickstand as it idles. I have not adjusted jetting or gone on any high speed rides until the new pipe is installed. This is just the start of riding season in Washington state and I am going to break this motor in with a lot of patience (first 500 miles). My last revision of this bike will have the 52mm cylinder-(108-110cc's?), and of course, another racing pipe to match the cylinder size.

I have just figured out how to use my camcorder to record small email video clips with great sound. I have a few of the bike running. If anyone would like to hear a 100cc honda 50 elite stroker, just email me and I will send it. e-mail

All parts for the stroker were purchased from VTCYCLES.com in Hawaii.

I hope my bike revisions, helps some of you scooter fans.. Randy H

DougNote: While Randy accomplished opening up the crankase by himself, this is a critical operation and if you feel that the task is outside your capabilities, look into a local machine shop doing the work or ask the shop that sells you a stroker kit for a price to do the job. Simply splitting and re-assembling the crankcase requires a lot of special tools and care. I have , in the past, taken stripped down motors down to the local Honda motorcycle mechanic. They can crack the case, do the necessary work (install bearings etc) and re-assemble using the factory tools that make the job "easy". While I would feel capable of doing the work if I had the factory tool, the tools are expensive as Randy mentions.

April 2005- I just received a reply from Steve at VT cycles about the cost of disassembling the crankcase, modifying the Elite case for a stroker crank, shaping the boost port and re-assembly of the case. He estimated a price of around $125 but contact him for details if you're interested. I paid about the same price (labour only) simply to have the bare crankcase split, some main bearings installed and the case re-assembled at the local Honda dealer.

Update from Randy June 2005-

Doug:
Here are some pictures of my 100cc stroker, that took me many hours to tune. I have two new pipes, An SEF black pipe and the latest Phongeer Long pipe. On a scale of 1-10 in loudness, the black is an 8.5 and the phongeer is 7. The motor has plenty of power and is to an 80cc motor, what an 80cc scooter is to a 125cc moto cross bike. I am using a kitaco adjustable clutch, bando, thick racing belt. 1500 rpm yellow, main clutch spring. On my Oko 28mm carb, I enlarged the main jet from a 130# to a 135#. Then I set the needle valve position to neutral. My variator weights are all 8's and I am thinking of going 8,7,8,7,8,7 to increase the starting revs. I have done numerous "accidental wheelies" from take-off when racing cars. It is kinda of fun. I have sent pictures of the sef black pipe and the phongeer pipe that I own. Both require enlarging the rear bolt holes on the pipes to make them fit. I am also sending a picture of the modification , you have to make on the block, for the sef to fit. You need to file the edge of the front right ear, or the pipe will hit it and not fit right. I found using permatex gold and red high heat sealant, works great on these pipes, at the pipe/cylinder junction.

A stroker creates a lot of heat and Vibrates much more than an 80cc conversion. I used loctite on the head bolts, the rear wheel bolt, and exhaust bolts. The cooling shroud had to be modified to fit the higher cylinder and was raised by shims between the shroud and its base. I found that making rubber caps by the spark plug and shrouds along the lower rear edge and by the carb intake, helps keep the air flow where it should be. I hold the stock heat shroud together with plastic ties, and it works very well. A large hole has to be cut in the bottom of the helmet well to allow the spark plug top, free movement when hitting bumps.

I changed my primary transmission gears to 13x30 and promply spun a main bearing. I urge everyone to unbolt the transmission cover, drain the oil and fill with mobile 1 5-40 full synthetic oil. The transmission gets very hot with this motor. Reseal with permatex grey moto seal , which works great on all gasket surfaces. With these new gears the motor has good take off, good cruising speed, and a top speed of 70mph. Revs are the big factor in these motors. You need a certain high revs to keep the power up, for bursts of acceleration, and a high power band, when the back pully opens at mid speed. Low revs when the pully opens will bog the bike and acceleration will be very sluggish. Some guys run, all sixes or sevens in the variator to keep the revs high. I found cavitation problems (too much rattling) , with such low weights. I think a 787878 combination will work great, but I have not tried it yet. I have about 400 miles on the motor, my first hundred miles was done with belray normal oil at 50:1 to break in the cylinder. Now I use castrol or silkoleen half synthetic at the same ratio.

Engine is running well.This motor inhales fuel at a rapid rate. I am going to top the tank off, go for a long ride, refill the tank to previous level, and extrapolate how many ounces the ride took. Then I will figure out how many miles to the gallon the motor gets and let you know. For some strange reason, the starter engagement gear, connected to the kick starter, would vibrate out of its base and strike the crankshaft, making a ticking sound. Finally I just removed it and now rely on just electric start.

Both pipes have a problem with hitting the kick stand , while the stand is up, one the right side. I put some 1/2 inch fuel line over the right side kick stand, where it would touch the bottom of the pipe. My next project is to build a buffer on the underside of the motor, where the kickstand can rest, while riding and not touch the pipe. I am really trying to eliminate all unwanted sounds and bumps and vibrations, so I can really dial this motor in..

All in all, a stroker motor is worth every penny. They are loud , extremely powerful, and haul my 95 kilo frame around, like a rag doll. I hope you get your stroker running soon. I would add that shrouding for heat is a main concern. This motor vibrates so much, it even rattled the brass , threaded fitting , out of the spark plug boot!

Sincerely, Randall Hoffmann

DougNote: I didn't publish all the pics Randy took so if you want more, contact Randy at his e-mail address. He had some showing details of the cooling shroud showing the clearnce issues that he had to address with the 100cc's higher cylinder.

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