Simplex 5 speed build

[pd]

Rick ,

I know I've read what you do to your China motors . I thought I bookmarked that post , but I guess I was dreaming , because I can't find it .
Could you please post a link to that post ?

Pete .

[ndian22]

Pete I'll do you one better and take a few photos of the internal mods to the jug, case and piston of a reed valve setup with a third transfer port and piston port window.... as compared to a milder engine with just the basic skirted and ramped piston, with enlarged and matched ports and transfer ports slightly enlarged and smoothed.

I've also found a couple of motor sources that feature balanced cranks and use grade 8 head bolts, so I don't bother with doing this myself anymore. Also the decks are accurately machined so that step is no longer necessary. I also use copper head gasket. Buying a good base motor is the most important step in the whole process as some of the kits are pure crap to build on. I'm not about touting vendors, but I can PM the ones I buy from cost about $125. to $150. short block with basic mods so fifty or sixty dollars more than unknown vendor block & worth it to me.

I use the SHA Dellorto slide carb and 6 cc aluminum aftermarket heads, bigger the better for cooling more than for power, though power is increased, NGK plug & solid copper wire, after market ignition on the performance motors that retard advance at high rpm (opposite of 4 stroke theory) depending on the exhaust used the highly modified engines come on pipe at 8,000 to 9,500 rpm with 12,000 to 13,000 topped. No matter how well these motors are built they won't live long operating at plus 10,500 rpm, but fun to run up for a short burst.

I run a 48 tooth final sprocket and 26" tire so I'm really geared low on the bike I spoke of in the previous post and it pulls well from dead stops and pulls long hills well without overheating, super dependable. I really like these little motors and don't usually build out for max power, but it's pretty easy to double stock power with minor mods and triple with more mods and much tuning. I don't have a dyno and don't necessarily believe vendor claims, but know it takes several extra hp to get past the true stock mph limits on a kit bike.   Rick C.

[pd]

Rick ,

I'm looking forward to your 'tutorial' .

Pete .

[Bob53]

Rick, PM me with the vendors and mods. I'm going to try my hand at a china girl on a vintage bike. From the hours you've clocked on yours it sounds like you definitely have the bugs worked out. I'm still going to try and come and visit when the summer cools down and slows down. We're just 2 hours from you. Bob

[carryall]

Whatever bike you decide on, make sure the bikes strong enough to handle the vibration and stress.  I had to solder the lugs on my old Western Flyer and even then it flexed at higher speeds.

[Eric]

 Hi  Just looking at the picture,why so many spokes in the front? wheel compared to the rear.   eric

[ndian22]

Great looking Flyer! You discovered the greatest problem motorizing a vintage bike frame or an inexpensive modern frame from a box store...strength, especially if the bike is to be used a lot and the rider is a full grown adult (supersized) on rough roads at higher speeds etc. I either build my own frame, like my Simplex, from the best materials and properly re enforced or carefully select a new classic frame design to build around. I often add gussets etc. to these as well. Not all frames are good candidates just because a motor will fit, but as you show in your Flyer build a very nice build can result with ingenuity and work. There are old bike frames that can withstand the transition to motor assist safely, but many require a bit of enforcement.  Rick C.

[ndian22]

Rick, PM me with the vendors and mods. I'm going to try my hand at a china girl on a vintage bike. From the hours you've clocked on yours it sounds like you definitely have the bugs worked out. I'm still going to try and come and visit when the summer cools down and slows down. We're just 2 hours from you. Bob

Will do Bob, have a safe trip to Portland. It would be a pleasure to have you drop by any time. We have an excellent outdoor Fall festival and car show in October that is very beautiful and draws several thousand visitors each year. Lots of vendors and food and the setting is a large public park very pretty & restful setting. Rick C.

[carryall]

Why so many spokes?  LOL, Long story short, they were leftover from another job and, they looked kinda cool and were really strong.  Speaking of the little china motors and modifications, what have you done about the weak and really noisy dry clutches on them?

[ndian22]

Now that's a great question. I've tried a bit of  everything to quite things down in the clutch area and no real solution, though the heavy aluminum billet cover helped some. I've had great life from the clutch's themselves & have yet to change the little pads on any of the motors, this amazes me cause I pull from dead stops and usually don't pedal assist using the 48 tooth rear sprocket but with the 44 tooth I do usually help with the pedals a little. I'm a buck 75 in weight & big guys probably can't get away with unassisted dead stops without a lot of clutch slip and I'm positive the little dry clutch can't take much of that kind of abuse.

Wish I had some magic trick for you but the clutch is really small & needs some babying in order to survive. Good news is pad sets are less than ten bucks and are quick to change out.  Rick C.

One of the drive train mods I always make is to throw the rag joint sprocket set away and use the Manic type sprocket hub adapter setup. Of course it adds $70. to $100. to the cost but saves the spokes and warped wheel the rag joint will eventually cause.

Rick C.

[carryall]

Hey Rick C (NDIAN22)  I forgot to mention a suspension system I did on a sidecar you could consider.  I modeled it off of the plunger type rear  suspension system I had on an old chopper I built long ago.  It was simple and had approx. 4" of travel.

[ndian22]

Very nice, simple design & looks great as well on the cycle frame. I'd think 4 " of overall travel sufficient for a car suspension as well. I like the compact size & it's just quirky, vintage look is appealing too. Thanks for sharing.

Rick C.

[ndian22]

Just a few photos of my Schwinn Excelsior Autocycle project I've been working on a little this Summer, not yet completed but I'm riding her while completion is underway. I'm a believer in prolonged break in routine especially on inexpensive motors that are routinely clearanced rather tight... burnished in place. I ride 10 or 15 min. at slower rpm while continuously the speed, almost zero idle time. I allow the engine to cool to the touch before repeating. This ride routine is practiced over twenty or so rides, until the motor starts to show some life as it frees up. Initial startup can be taxing even though pre-lubing the cylinder bore and manually turning the motor over a couple of dozen times helps.

I also find some of the clutch assemblies are frozen in place during the shipping & storage phase which makes one fear a locked up motor...it has always been the clutch in my experience. Just another basic example of 2 stroke design and quite simple to work on or with. I've had quite good fortune with them, but they still have their quirks.  Rick C. 

[pd]

Looking nice , Rick .

Pete .

[ndian22]

Thanks Pete got the rear fender mounted, Excelsior/Schwinn brass head badge And a small cylinder leather tool bag mounted and just waiting on the Schwinn feather chain guard and the Schwinn and Excelsior decals to come in so I can finish. I've put quite a few hours in riding and breaking in, really with only a couple of minor problems noted and hopefully corrected. I'll be fabricating an "oil tank" of steel and copper to mount in front of the rear wheel that will act as a lower forward fender brace and fill in the air gap between the seat tube and rear wheel. Getting very close to completion and it's turned out to be a very pleasant bike to ride though to those who require an upright riding stance it looks uncomfortable. It suits me just fine and is quite sporty to ride.  Rick C.