Sportsman 200

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sportscarpat

Bonneville Bomber the Salt Flat record breaker
Jun 25, 2009
1,839
471
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california
Time to throw my hat into the ring on the clone engine builds. I have been quitely working away on a new personal build using the 6.5 hp Honda clone engine as a power plant. This build is an evolution of the current chassis design used on my Racer and WZ builds, and will use most of the same components, but the engine and drive system will be completely new. These engines are right around 200cc so that is where the "Sportsman 200" name comes from. I have to give credit to Lurker, CCC Jeff, and Cobrafreak John for paving the way with running the clone engine cylinder in the upright or vertical configuration. Once I saw that and the running clone powered bikes of CCC and Shane of AGK I knew I had to have one.

The build has been progressing along and here it is in it's current state still resting in the frame jig covered in brazing flux. Good old turn of the century brazed and lugged frame design.


Sportsman 200 by Sportsman Flyer, on Flickr

This is a close-up shot of the engine mount tacked into place in the frame and the engine mounted up. Engine is running centered in the frame to maintain an overall balanced package. I tied the mount into the seatpost frame tube, the bottom bracket housing in both vertical and horizontal directions to reduce potential twisting moments, and then into the down tube. I ran the engine base parallel to the seat post frame tube giving the engine cylinder about a two degree forward rake in the frame.


Sportsman 200 by Sportsman Flyer, on Flickr

Here is a detail shot of the finished engine mount assembly and the mock up I used to test fit to the frame. Mount is CAD designed and laser cut to insure accuracy, then placed into the frame and squared up off the frame jig to assure proper chain alignment. The three pieces of the mount are tabed and slotted together so they self align and interlock before welding. Very easy to assemble and maintain alignment through the tig welding process. I like how the main backbone of the mount looks kind of like a big bowie hunting knife. I will try to keep this thread updated as the build continues.


Sportsman 200 by Sportsman Flyer, on Flickr
 
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brett7777

brett7777

New Member
Aug 19, 2011
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Auckland, New Zealand
that engine looks good in that frame. man there's a lotta good stuff comin outta your shop Pat.
so when you say Honda clone, are these a Chinese version of one of the Honda motors? which Honda motor is it a clone of?
 
Lurker

Lurker

New Member
Jan 29, 2010
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Pittsburgh
Wow Pat that is going to be so cool! This bike is going to be every thing I wanted my last bike to be but never was. It will be nice to see one of your beautiful bikes with the 4stroke engine and sound. I never could stand the sound of a 2stroke.
 
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sportscarpat

Bonneville Bomber the Salt Flat record breaker
Jun 25, 2009
1,839
471
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california
Lurker said:
Wow Pat that is going to be so cool! This bike is going to be every thing I wanted my last bike to be but never was. It will be nice to see one of your beautiful bikes with the 4stroke engine and sound. I never could stand the sound of a 2stroke.
Click to expand...
Hi Lurker,
You guys paved the way and gave me plenty of design ideas. After seeing Jeff and Shane at the track and hearing these four strokes run, I was sold. They sounded like little Harleys. Not a twin cylinder sound but definately a thumper. I will not be running a CVT on this build.
 
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cobrafreak

New Member
Feb 16, 2011
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sacramento ca
This is good news Pat. This really is a nice engine to work with. Because you are not going to have a CVT, you are going to be single speed, right? You really must put the ARC billet con rod in and heavy duty valve springs in so you can get the engine into 6K territory or you won't have a good speed range. The stock con rod was not designed to go above 3500 rpm. The stock flywheel looks good but the magnet for the magneto will fly off at high RPM, so you will need to upgrade that to a performance cart item also. It would be cool to make the coil for these engines adjustable either by a wrench or even by lever so you could advance the spark. The stock setting is 0 degrees, the racing set up's are 4 and 8 degrees advance. This would help it have "legs". Don't forget the oil drain plug position or you won't be able to drain the case all the way each time. Looking forward to this one for sure.
 
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sportscarpat

Bonneville Bomber the Salt Flat record breaker
Jun 25, 2009
1,839
471
83
california
Hi Cobra,
I have a big box just stuffed to the brim with all kinds of go fast candy straight from AGK, including a nice little billet connecting rod, tiny little cam and valve kit, and other pieces. My two disk Bully centrifugal clutch just rolled in today, too. Very nice part. My drive system? I'll get to that part pretty soon. Those pieces are still being machined!
 
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sportscarpat

Bonneville Bomber the Salt Flat record breaker
Jun 25, 2009
1,839
471
83
california
My brother came by the shop today to lend a hand with my engine build. We have both been building V8 engines since high school, so felt right at home tearing into these little four strokes. I called Shane at AGK and he fixed me up with all the necessary engine components. The quality of the parts is impressive. I am not going for all out hp, but am looking for good solid reliability.

Here are all the parts. Billet rod and flywheel, flat top piston, Mikuni carb, valves and valve springs.


Honda Clone Engine Build by Sportsman Flyer, on Flickr

Here is a stock valve next to an aftermarket valve. The new valve has a nice undercut swirl pattern to it and is machined for the upgraded springs and keepers.


Honda Clone Engine Build by Sportsman Flyer, on Flickr

Here is Rich lapping in the valves.


Honda Clone Engine Build by Sportsman Flyer, on Flickr

We had to fab up a quick little valve spring compressor.


Honda Clone Engine Build by Sportsman Flyer, on Flickr

This picture shows the bottom end going back together.


Honda Clone Engine Build by Sportsman Flyer, on Flickr
 
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sportscarpat

Bonneville Bomber the Salt Flat record breaker
Jun 25, 2009
1,839
471
83
california
I have decided to run a centrifugal clutch on this build and went with this Bully twin disk design. It is a pretty impressive looking part to say the least. I have heard the disk clutch locks up smoother than a shoe type centrifugal clutch. Guess I'm going to find out.


Honda Clone Engine Build by Sportsman Flyer, on Flickr


Honda Clone Engine Build by Sportsman Flyer, on Flickr

Here is the flywheel side of the reassembled engine. Looks better already!


Honda Clone Engine Build by Sportsman Flyer, on Flickr

The clutch side of the engine. Primary sprocket is mounted inboard between the clutch and the engine case.


Honda Clone Engine Build by Sportsman Flyer, on Flickr

Here is the front view of the engine showing the new flywheel and clutch. I got out the cutoff wheel and removed all the extra engine casting projections. I wanted a nice clean look.


Honda Clone Engine Build by Sportsman Flyer, on Flickr
 
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culvercityclassic

Well-Known Member
Sep 27, 2009
3,115
177
63
Culver City, Ca
I was very impressed with the quality of the motor and how nice the ports were in the head. It brought me back home working on this motor. The last motor I built was a GM stroker 383 for my Chevelle.
 
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itchybird

Member
Nov 4, 2009
316
6
18
SF Bay Area.
These are amazing motors for the money, we paid right around $125 shipped for the basic motor. It's amazing what you get for the money, these are a high quality four stroke with very high quality castings. But because the basic motors are limited to 3600 RPM's, they do need some tweaking for higher RPM use.

As Pat said, the initial focus of the build was to improve durability for higher RPM. A quick call to Shane at AGK and we had everything we needed. Anyone considering a clone motor build up should check the AGK website -they have it all. Most of the parts are very reasonably priced and Shane is a big help to sort thru the options.

First up, a billet flywheel and connecting rod -these are quality pieces. Since we had the motor apart, we upgraded with a stock Honda flat top piston, replacing the dished piston that came with motor. This gives a nice little bump in compression ratio. We chose a longer rod - 0.01" longer than stock. This puts the piston slightly higher in the bore which will give another little bump in compression ratio without decking the head. To finish off the bottom end, we went for a performance cam -nothing crazy, just enough to warm things up a bit.

With the bottom end buttoned up, we turned our sights on the cylinder head. When we tore down the head, I was amazed at the quality of the casting, these are nice little motors right out of the box! Nonetheless, I spent about 15 minutes or to better blend the port transitions in the valve pockets, but left the ports themselves alone. From there, we replaced the entire stock valve train.

First up, stiffer springs to handle the increased RPM and higher lift cam. We went ahead and upgraded to stainless valves, but went with stock size. The stainless valves have longer stems which allow more lift. We upgraded to the aluminum keepers and stock Honda lash caps. I hand lapped the valves and liquid tested to ensure the valves were sealing properly. We finished the package off with chromoly pushrods which add strength and reduce deflection. After a good scrubbing, we bolted it all back together.

For our effort, we should have a very durable little motor. That is if you consider 200cc little.
 
silverbear

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
These motors look like the new wave. Hard to argue with the price, availability of upgrade parts and power. I consider 200cc a big motor for a bicycle framed build. You guys did a nice job on the mounting setup. The bar just got raised again...
SB
 
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