Simplex 5 speed build

[pd]

Hmm , I can see the start of a new motorcycle company , centered on the new RickC-ycle design ( sidecar optional ) .

Pete .

[Ricks]

Those Phoenix bikes are really nice. I especially like the one with the girder front end on it.

[ndian22]

Pete if our nation was not so litigation crazy I might consider it, but why screw up a great hobby with work?

Rick the Phoenix is sweet as it is I like the flatter motor mount arrangement of the lower double tubes, the single upper tube on the Phoenix I see as a double tube in my design, as in the Simplex, but closer together since no saddle spring would be used. DOM tube at least .120 wall 1" used head to drops... steering head custom fab as well, but boxed in with steel plate similar to the Simplex design.

I'm liking the Harley double springer fork by Pat D. at Sportsman to round out the frame, but have two other fork designers in mind as well with sweet motorcycle springers, but lead time is in months for both.

Rick C.

[pd]

Pete if our nation was not so litigation crazy I might consider it, but why screw up a great hobby with work?

Rick C.

Good point .

Too many thinking 'the land of the free' means 'land of the free ride' .

Pete .

[ndian22]

Pete "free ride" sounds almost too nice how 'bout "free load"?

Are you located out of harms way from the lingering & widespread storms? It's really been a radical Fall storm season, even with the wildfires burning out West....what's next?

Still beautiful here in Indian Territory, so I've been riding a lot. The X-celsior Schwinn engine finally came to life during a short ride yesterday just before sunset. Just spun up to 6,500 rpm & kept going. Really caught me off guard, but I'm now certain the mods paid off on both motors. I'm pretty certain that the new reeds finally "flexed" 'cause the rings should have already seated, but I am satisfied with whatever combination came into play.

Both motors have some 4 stroking when relatively cool, but that mostly goes away after a good warm up & is only noticeable then for a narrow band at mid range, but now the application of more throttle blows right past it...smooth 2 cycle past that point after a good warm up.

Both motors are built up with almost identical mods, but feel quite different still. The X-celsior Schwinn has the expansion pipe and stock CDI and the Skyhawk has the "kit" muffler and the aftermarket performance "rocket CDI" the X-celsior is lighter...but final sprocket gearing is lower on the Skyhawk, it has 2" greater tire diameter that should offset  the 4 tooth difference. The Skyhawk is noticeably quicker off the mark and accelerates faster from any point in speed during cruising, despite the short, baffled exhaust pipe. I've tested the Skyhawk with the muffled "expansion" pipe on it and it runs even better with that setup, so I'm led to believe that the Rocket CDI on the Skyhawk is working really well?? Or it could be, & this is my favored opinion, that the long stroke motors small original design differences, including the tiny stroke increase are not really beneficial. Of course some motors just don't come off the assembly line quite right. Right now I'm happy with both motors, but the GT-5 Skyhawk is quicker & still my favorite version of the China girl engine. As the X-celsior Schwinn is ridden a bit more and the stock CDI module is changed out, along with some fine tuning on the carb jetting & plug heat range selection. I'll no doubt find more performance, but even if not it's quite peppy as is. Building additional power, past this point, is easy enough but low speed manners will suffer as will engine durability. I'm not going racing. I'm thinking output now somewhere close to 5 hp...from 66 cc, with full race mods on fuel maybe 11 hp in closed course race tune is close to the top hp wise for these Chinese weed wackers.

As a motor replacement on a Simplex? I'd say no even though the electric start version or the pull start mod would work for starting the clutch would not hold up well or be up to hauling the extra weight from dead stop with out significant gear reduction, modified CVT or light gearbox addition. I know better engine selections are already in use as replacements for the Simplex.

The China girl is a really neat little motor for bicycle motoring however & that's a good place to use them.  Rick C. 

[pd]

Rick ,

We've been fortunate to have had a Michigan type Summer and now Fall . So far , the storms have stayed away , thankfully .

China girls ... I have to wonder how a pair , say side by side , would perform in a Simplex frame . They might put out enough to accomplish some satisfaction .

Pete .

[ndian22]

I remember seeing a photo of inline CG but can't recall a side by side, dual pull clutch lever.   Don't recall the starting setup, but probably two independent pull starts as the electric starts were only recently introduced.  Build two up, at 5 hp each and there would be more than enough power. Inline arrangement would take some cosmetics to make it look decent though. Side by side they would look pretty cool.   Rick C.

[ndian22]

I really am addicted to modifying the 66 cc China motors. I found a case set and cylinder to use as a base (it's really not a kit) to build up a case inducted reed valve motor that has the potential of 10 hp + output, but I'm thinking I could  map the port timing toward the mild side and still get maybe 6 or 7 tractable street pony's out of it. It looks like the parts are a design copy of the Arrow team bike race motors, but I'd imagine I'll have a lot machine work to preform on the Chinese castings before I can use them. The parts set is under $150.00 and includes a reed valve and Kehin clone carb,gaskets, mod barrel, piston set and engine cases with bearings, no head or bottom end parts or assembly/setup instructions; definitely not a kit with much fitting and assembly required & of course no instructions or guarantees provided. Probably won't sell too many of these puppies, so I'm really not too sure why they would even bother with an attempt to market the parts,for the price I couldn't justify the time to machine the cases, let alone buy the individual parts. The carb, air cleaner and reed valve sell for $100. by themselves & that price alone is pretty dang sweet. So for me it's a no brainer. 

On the riding side the prospect of having a 7 hp, 25lb. motor, with a tiny installed footprint and one which has decent street manners; is an engine I can justify building...even if it falls short of my expectations as a street performer. I'm certain I can sell it as a bicycle race motor.  Rick C.

[pd]

So , there's a bicycle racing market ?

Must be an underground type thing , as I've never heard of such a thing .
I guess it's not too far fetched an idea . After all , bicycles have wheels and we all know were there are wheels there will be a race .

Pete .

[carryall]

There was a guy who commuted to work on his engine modified 18sp street bike next to our shop.  He had a 4 stroke engine with a friction wheel type set-up on a rear rack that moved him at over 50mph un-assisted.  Pretty nice little set-up.

[ndian22]

Pete SOCAL Motor Bicycle Racing is the group I 'kinda follow, nice tracks, good participation and organized structured events and classes. Many of the bikes are pretty awesome with qualified riders some pretty fast racing in the top classes. You might want to give them a look see. I just like racing but don't intend to actually get out there and mix it up. I'd probably be the beaver on the track & get out in the middle of the course and dam things up! Rick C.
 

[ndian22]

50 mph seems to be the ultimate goal of many motorized bike riders especially on the 66cc China girls. Going to a larger, more powerful motor & possibly adding a second or third speed to the drive line really makes more sense for actually riding at that sustained speed. The friction drive setups can work great, but it's hard to make them look very appealing. Of course 18 speeds does nothing unless he is pedal assisting, runs out of gas or breaks down, needs exercise etc.
There are however jack shafted shift kits available to mount an engine in the traditional frame location and that allows slick gear changes on the fly. I've not built one, but chain breakage can be a problem on the 18 thru 24 speed bikes even with top quality chain they are very tiny and won't handle much power for long.  My thought would be to eliminate the derrailuer 3 speed system up front along with the inside & outside chain rings (making a 18 speed into a 6 speed) then setting up the rear to run only three sprockets, spaced far enough apart to allow at least a high grade BMX chain to be used. By going to 3 speeds the chain line is kept much straighter with the remaining, centered, chain ring up front & eliminating as much chain angle as possible also decreases the likely hood of throwing a chain or breakage. A custom three speed cassette for the hub would be be the slickest way to do it right...probably take a lot of test time to make it all happen.  I think the higher quality models of Shimano shift systems could handle at least the weight of a BMX chain, possibly even a 415 size chain.  Just me thinking out loud again. Rick C.

[ndian22]

Paul you asked about clutch noise on the China girl engine in an earlier post & I later thought of something that is commonly associated with "clutch noise" & vibration that's caused by poor assembly & QC at the factory.

If you pull the clutch side engine cover and check the small 20 tooth bevel gear for "wobble" you may be surprised at how bad it is, and quite common, but it's easy to spot & correct by removing the slot head screw and spark plug then rotating the engine (some assistance here is nice...easier to check on the workbench) clean any excess gear lube to clearly see how the 2 gears run out. use a small hammer to tap down the high spot till you get them to run  true. That's part one. Then check the shaft for stand up, which is any amount protruding past the outside of the gear surface, it is quite common that the lock washer and slot head screw when torqued down properly will not be in contact with the gear itself. A thicker & sometimes larger diameter washer & blue Locktite is my simple solution rather than facing the shaft. A loose gear held in place solely with the Woodruff key will wobble, cause noise or worse. Check for wobble again after assembly and before adding a little gear lube, 'cause you may have to use the hammer again. Repeat till true.

I do this prior to install on every motor. It is a problem & besides not being proper it's really noisy and annoying. Good part is it's quick to check and easy to fix. Here's to a quieter running engine! Rick C.
 
 

[carryall]

Loose key was the cause of my last one also.  I ended up sanding down an oversized one to "tap fit" and it did work and run much truer causing both less noise and better clutch action.   I may build a motorized bike with my grandson one of these days so this info will probably come in handy in the future.  Thanks for the tips bud.

[ndian22]

Yes Paul a loose key is often caused as a result of the key bearing most if not all of the rotational load of shaft to gear.

Father/ Grandfather builds are special with boys or girls... a sort of Locktite for generations!  Rick C.