Sportsman 200
- Thread starter sportscarpat
- Start date
Hey Pat, the valve cover on the clones already have a breather valve built into it. I was adjusting my valves and noticed it underneath the bottom. It's a one way valve. It only allows air to escape the block. So you have a choice of putting on a tube and letting it trickle on the ground, or you can make a glass vial catch can, which would be cool because you could see the rate of oil escaping the engine and pour it back in, or you could put a fitting on the back side of your air filter. As long as you re-circulate the oil/air mixture on the negative side of the Venturi it won't cause running problems.
what are your thoughts around having the manifold facing forward? this is what I was planning on doing, kind of a hot rod look versus the period correct laid back look. i think that manifold is awesome pat. curious about the exhaust...work in progress? Just looked like it was aimed at the oil fill. Looks great though. Are your exhausts tig or mig welded? hard to tell. beautiful Pat, very nice work.
I forgot you were running without a governor. Those numbers I gave were for the stock 3600 rpm. check out these links
speed calculator
Rawge's Mini Chopper Information Site - Jackshafts
ratio calculator
Rawge's Mini Chopper Information Site - Gear Ratio
As far as the oil goes I always used 3/4 qt just like cobra.
speed calculator
Rawge's Mini Chopper Information Site - Jackshafts
ratio calculator
Rawge's Mini Chopper Information Site - Gear Ratio
As far as the oil goes I always used 3/4 qt just like cobra.
Hi guys,
Lurker, thanks for the cool calculators. Easier than the way I figure it out. Running up to 8000 rpm changes speed calcs dramatically. It will still be a learning game for sure and I have a few sprockets to work with. I have a 52t and 44t for the rear to test the low speed and high speed nature of this build and will keep everyone posted as to what I find.
Tomgndallas, the exhaust is not finished in those pictures. With the intake I wanted it tucked back behind the engine but wanted to keep the intake short, also. I like the way it came out and can tell just by looking at it that it's going to flow nicely. Very smooth transitions.
Lurker, thanks for the cool calculators. Easier than the way I figure it out. Running up to 8000 rpm changes speed calcs dramatically. It will still be a learning game for sure and I have a few sprockets to work with. I have a 52t and 44t for the rear to test the low speed and high speed nature of this build and will keep everyone posted as to what I find.
Tomgndallas, the exhaust is not finished in those pictures. With the intake I wanted it tucked back behind the engine but wanted to keep the intake short, also. I like the way it came out and can tell just by looking at it that it's going to flow nicely. Very smooth transitions.
So, back to the exhaust. I wanted to go boardie all the way, short and loud, but felt the neighbors would like a more conservative approach. Here is what I came up with. I ran 1" stainless tubing off the head and back to a 2" tail pipe.
Sportsman 200 by Sportsman Flyer, on Flickr
Here you can see the business end of things. I decided to run down the bicycle side as not alot happens over here. I wanted to keep open access to the drive chains on the motor side and not hide all my hard work.
Sportsman 200 by Sportsman Flyer, on Flickr
This view shows how well it's all going to flow. Nice clean flowing turns into and out of the cylinder. The best thing about these four strokes is the endless possibilities for good old hotrodding.
Sportsman 200 by Sportsman Flyer, on Flickr
Eventually I'll go back and give the intake and exhaust a grained scotch brite finish to match the tanks, but for now it's mill finish stainless and colorful little tig welds. The cool thing about stainless is it will always be easy to maintain a nice finish, even on an exhaust pipe.
Sportsman 200 by Sportsman Flyer, on Flickr
Sportsman 200 by Sportsman Flyer, on Flickr
Here you can see the business end of things. I decided to run down the bicycle side as not alot happens over here. I wanted to keep open access to the drive chains on the motor side and not hide all my hard work.
Sportsman 200 by Sportsman Flyer, on Flickr
This view shows how well it's all going to flow. Nice clean flowing turns into and out of the cylinder. The best thing about these four strokes is the endless possibilities for good old hotrodding.
Sportsman 200 by Sportsman Flyer, on Flickr
Eventually I'll go back and give the intake and exhaust a grained scotch brite finish to match the tanks, but for now it's mill finish stainless and colorful little tig welds. The cool thing about stainless is it will always be easy to maintain a nice finish, even on an exhaust pipe.
Sportsman 200 by Sportsman Flyer, on Flickr
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I had a spare Whizzer exhaust laying around the shop so I borrowed the baffle. I cut my tail pipe to the same length as the Whizzer so I could slide the baffle inside. It bottoms out against the 2" x 1" reducer and then has one screw that retains it. Easily removed for more power!
Sportsman 200 by Sportsman Flyer, on Flickr
Here is how it looks mounted inside the tail pipe.
Sportsman 200 by Sportsman Flyer, on Flickr
Sportsman 200 by Sportsman Flyer, on Flickr
Here is how it looks mounted inside the tail pipe.
Sportsman 200 by Sportsman Flyer, on Flickr
that looks fantastic Pat. I really wish I had welding skills like yours. I especially wish I knew how to tig. I am interested in how much sound that will reduce. How did you make the trumpet part of the exhaust to adapt it from 1" to 2" ?
I remember reading this and saying, "yep, two more chances to screw it up". I am happy with the intake manifold but my exhaust was bugging me. Crossing over to the right hand side of the bike with a long 45 degree angle just didn't look right. My friend Carlos basically said throw that pipe in the trash. Trying to fit a street style exhaust to a race inspired bike is difficult if not impossible. My second attempt.
Sportsman 200 by Sportsman Flyer, on Flickr
Sportsman 200 by Sportsman Flyer, on Flickr
Sportsman 200 by Sportsman Flyer, on Flickr
It looketh good! Are you still baffling it?
Im thinkin that a baffle that increases some back pressure is a good idea.
I dunno if you guys have played around with jetting.
When I do jap bobbers with 250cc motors I usually swap out the mufflers.
I found that the stock mufflers were too restrictive, but get too close to an open pipe & you lose a lot of power & need to start from scratch with air flow & re-jetting.
But put enough baffling to create some healthy back pressure, & the engine seems to perform better than stock, with no rejetting. Put simply, jap 4 strokes (& I guess their clones) love some back pressure, & rely on a certain amount of it for performance.
Probably telling you stuff you already know but thought it worth mentioning anyway.
Im thinkin that a baffle that increases some back pressure is a good idea.
I dunno if you guys have played around with jetting.
When I do jap bobbers with 250cc motors I usually swap out the mufflers.
I found that the stock mufflers were too restrictive, but get too close to an open pipe & you lose a lot of power & need to start from scratch with air flow & re-jetting.
But put enough baffling to create some healthy back pressure, & the engine seems to perform better than stock, with no rejetting. Put simply, jap 4 strokes (& I guess their clones) love some back pressure, & rely on a certain amount of it for performance.
Probably telling you stuff you already know but thought it worth mentioning anyway.
I had a "dead" spot in the power band until I drilled out the main jet. I started small and worked my way up till I got a good plug reading and had lots of power where there was none before. I have the exact size bit I used in my build discussion. I am using my former China Girls muffler from the "Poo Poo" exhaust but with the rear cut off. Works well and is mildly loud but not too loud. Want total strangers to hate you in a flash, just run an open exhaust. Nobody likes "too loud" except the person that did it.
I reinstalled the Whizzer baffle. I bought my engine performance parts from AGK and based on cam selection they supplied a 22mm carb with idle and primary jets. I should be close enough to ride it around and get a feel for what needs to change. Actually looking forward to the tuning process! I plan to fire it off with the 52t rear sprocket, too, so I expect a sump puller! Things sure have changed since my first china engine kit on an old Schwinn........
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I think it will be a stump puller not a sump puller 
Man, yeah that sounds like it'll be a blast to ride.
Man, yeah that sounds like it'll be a blast to ride.
The gear ratios shouldn't be too hard to find the sweet spot. My drive chain runs 10t and 48t, so all you need to do is find the primary sizes front and rear.
Hey John,
I closely watched you starting your bike a couple weeks ago, but didn't see how you had modified your spool piece that you wrap the rope around. Any pictures? Anybody?
I closely watched you starting your bike a couple weeks ago, but didn't see how you had modified your spool piece that you wrap the rope around. Any pictures? Anybody?
You don't need a picture. Just cut it off and leave 3/4" remaining and drill a hole at 12 and 6 O'clock the size of your rope. You could probably get away with 1/2". You only need to go around it 3 times to get to velocity.
I'll drill my holes at 3 o'clock and 9 o'clock so people don't think I am copying you. Thanks John!
Pat, i bet you are riding this thing during the weekend! you gotta take some viddy if you do and post on you tube or flikr. i was checking out your latest pics...wow man, that thing is gorgeous. love what you did with the second exhaust. looks great.
