Simplex 5 speed build

[ndian22]

I'd not checked the new offering but a replaceable battery would be great. The sealed ones I have do not cloud up with moisture big +.

The sender on these is a bit slow. I notice that when the engine speed is held constant the readout is constant but if I twist up to say and indicated 4,000 and immediately come off throttle when that 4 k is indicated, the tach might read 4,500 a second or so later. I'm thinking 4,500 rpm was actually reached (not 4 k) and the sender is just that slow. This is the reason I wouldn't trust shifting near red line as indicated by these little hour meters/tach. At 9k indicated you might be at an actual 11 k.

I'm thinking the tach is fairly accurate, but slow. Coming off throttle of course is way off indicated as well. I really just concentrate on the steady rpm indicated. 

It's a gadget that I find useful for comparison, just as I use the inexpensive laser heat units; if the stock head read 325 degress after a 30 minute ride, a heat reading of 250 degrees on a very similar test ride with a custom head would please me very much...though neither reading was exactly correct.   Rick C.

[pd]

For the few bucks involved , it's good enough for the 'light weight' work .

I found one at your back door : https://tinyurl.com/yc6gn9dw

It's suppose to have a 35,000 hour battery . That's a longgg time .

I guess , for 9 bucks we shouldn't ask for too much .

Pete .

[ndian22]

Pete that is the exact hr. meter/tach I have...seems the price has gone down though. How 'bout that battery life? A couple of mine are 3 plus years in use and still function well. No back light so using at night would require rigging a small LED. Visibility in strong sunlight can also be a problem, but quite a lot of utility for $9.

Bet you're glad to be out of Rockport, Tx. or the upper Tx. Gulf coast in general right now....

Rick C.

[pd]

Pete that is the exact hr. meter/tach I have...seems the price has gone down though. How 'bout that battery life? A couple of mine are 3 plus years in use and still function well. No back light so using at night would require rigging a small LED. Visibility in strong sunlight can also be a problem, but quite a lot of utility for $9.

Bet you're glad to be out of Rockport, Tx. or the upper Tx. Gulf coast in general right now....

Rick C.

Rick ,

That'd be a sure bet .
We've been watching that storm pretty closely , as we came to know a few folks down there .
We can't really imagine the level of devastation , but for pictures .

Yesterday , we visited with friends that were planning to spend the Winter in Rockport . I told them they may want to consider someplace else . I doubt they will have that area cleaned up and ready to host snowbirds , at least to a large extent . I'm sure some  camps were totaled .

Just wondering about the tach , have you tried attaching the pickup wire ( bared end ) directly to the plug connector under the cap ?
Maybe the 'slow' latency would be eliminated
Then again , I'm not sure the tach could handle direct contact with that much current .
That might just fry the tach as it is grounded and would likely ground the motor spark in the process .
Maybe it's a bad idea .

Pete .

[pd]

Rick ,
Maybe you already found this , but , I ran across this in an older thread and wondered if you still had interest in sidecar suspension .



From this thread : http://www.simplexservi-cycle.com/index.php?topic=788.0

Pete .

[ndian22]

Pete thanks for the photo and link. I had seen this rig on another forum but the angles weren't helpful. The photos in his posts here are pretty much what I was trying to verify. Thanks.

This is the leaning wheel design I have been planning to use for the Simplex rig, not an untested concept, it was fairly common in the 1930's up. Don't confuse this with the sidecar racing "steering wheel" design in which the car's "co-driver" actually steered the outside wheel as the bike rider controlled the conventional bars. The leaning wheel does not steer only articulates in and out as the bikes lean dictates & is transferred by the tie rod from bike frame to car wheel. Bike leans left or right and car wheel follows.  A mobile parallelogram is the geometric formed in the process.

Once I get off my current bike build and various motor's modifications I'll get on the side car starting with the Simplex frame mounts, all removable and then the side car connections. Probably my major Winter project. I hope I'm spared building another bike for awhile.  Rick C.

[ndian22]

Engine mods complete on the X-celsior Schwinn as well as installed on the bike and running. I'll run her pretty easy till rings seat and the reed valve gets a little flex in operation, but feels & sounds good. Rick C.

[ndian22]

Thought I'd share a problem with you guys. Runaway 2 stroke motors. Specifically single cylinder with carb. Caused by lean cylinder mixture, usually due to air leaks at a seal, intake or carb. Idling engine goes to full rpm under no load. Kill switch or pulling plug leads won't stop the motor, it's dieseling & doesn't require a source of ignition, just pressure & heat. Choking is in my experience the quickest and surest method of stopping the runaway. Shop rag if air cleaner is off. Stop the air and stop the engine.

I used to see this quite often in 2 stroke single cylinder outboards, but this one is the first I've experienced in many years & the only one I've ever had on a 2 cycle bike engine other than a Kawasaki.

Ever seen this on a Simplex?

I'll let you know where my engine leak is located after I fix it...still having fun. Rick C.

[Ricks]

I've never heard of this happening on a Simplex.  There must be a sizable air leak for this to occur.  Interesting topic!  What happens if you put a load on the motor? Without more fuel, I would think it would die.

[pd]

Agreed . Never on a Simplex .

I had a Suzuki 125 , that I rebuilt the motor , get broken in in a few seconds .

I had it on the hoist and doing last adjustments before firing . I was turning the motor over with the kick lever , by hand , when it lite up and off to the races it went . Kill switch ... no good . Choke lever ... no effect . I grabbed a shop rag and 'capped' the exhaust , which finally killed the runaway . I immediately heard comments from all the mechanics to the effect that I wouldn't have to worry about breaking in that motor , followed by laughter .

Cause :  a bad throttle cable that held the throttle part way open .

Replaced that cable and the bike ran like charm for years . It was the best performing small bike I've ever had . 

Pete ..

[ndian22]

Yes Rick it takes a pretty good size leak to cause the "diesel" runaway. Pete the throttle has nothing to do with this type runaway which can only be called a "diesel effect" if the throttle slide or butterfly are completely closed and yes placing a load immediately on the engine slows it down and gives one time to get the choke on which will kill it every time. On my motobike it would continue idling at about 30 mph & appeared to have no intention of dying, by adding throttle it actually accelerated pretty well. I know for a fact this particular bike normally has a difficult time getting to 30 mph... period, but I've noticed and had others mention that in racing 2 strokes they tend to noticeably pickup power just prior to running out of fuel and the charge begins to lean out.

This is sure not a topic that an owners book or shop manual will get into, but I saw it frequently working on 2 cycle outboard singles way back when...they sometimes detonated in the test tank before the engine could be choked out. 

I'm glad this hasn't been a common problem with the Simplex. This is the first time I've heard of it occurring with a China girl motor as well, but that's what happened.

Cylinder base gasket blew out, so I opted for the thicker black gasket & a smear of sealant. Idles normally now and is just as slow as it was before. It's a real putt putt, but fun. Rick C.

[pd]

 The throttle being partly open and who knows what the fuel ratio was at the time was the initiation of the runaway . As far as I know the throttle never opened more than that initial amount . There was nothing wrong with the kill switch , as it worked fine as long as I owned the bike . The only way I could stop that motor was by 'choking' the exhaust as the intake was a closed system and the choke lever did nothing , except maybe enhance the problem , as it was an enrichment type carb with no choke  butterfly . It was a matter of a second for it to reach screaming RPMs . I know the motor never reached that many RPMs again , at least not while I had it .

I probably never moved so fast before or after that event .

Anyway , maybe it wasn't the diesel effect , but it sure seemed like it with there being no spark once I hit the kill switch .

Pete .

[ndian22]

Even pulling the plug lead won't stop a traditional gasoline/oil fuel 2 cycle runaway "diesel"... that's why it's called diesel effect 'cause diesels don't utilize a spark plug and the runaway doesn't either ( once the motor is started by the ignition system); once the engine begins the "runaway" sequence all the ignition components are entirely useless including spark plug, CDI, Coil and the kill switch, they aren't needed & aren't a part of  running the motor at that point and can't be used in any way to kill it either... the motor in 2 cycle runaway will run until it's deprived of air, fuel or both, overloaded...or self destructs. Cutting the flow of air is the cheapest and unless the engine blows, quickest way to stop the motor...though a good wall or fairly solid object (or person) could be used to overload an engine mounted in a bike, cart or boat to create enough resistance to cause an engine stall. 

First time it's encountered there is a very great chance of trashing the motor. I had a small boat motor running and turned off the ignition, then pulled the spark lead & it was too late to try anything else...2 stroke toast! Rick C.

[carryall]

little off the particular engine discussed but an engine drivetrain swap I've wondered about would be using a Kawasaki mb5 or better yet the ar80.  GREAT little bike I have seen in good condition for $500

[ndian22]

Little off got my attention & now we're talking!

AR-50 or AR-80 Kawasaki, Morrini, or KTB 50 or 80 original or clone great choices all. I would love to see a Simplex built up with one...should fit the frame without a stretch.

That AR-80 at $500. would be mine if I could just hear it run, go through the gears and first be close enough to see & pickup. With the 6 speed and wet clutch & 12 + hp it would be my choice & I'd speculate 75 mph in a Simplex, dependent on final gearing selected. Total weight installed in the Simplex I'd think to be less than stock Servi-cycle. One design problem would be an expansion chamber that looked ok with the Simplex frame...might take some experimentation, but the factory pipe on the AR-80 was pretty straight, long & had a muffler, if recollection serves me. Might perform, look & sound pretty good as well with a stock type exhaust. I would think the hp rating to be with that stock exhaust installed.

I'd pretty much decided to use the KTBC-50 "auto" for my current bike build, I'm fond of the green machines; that's the 9 hp clone that's available new for $500. + shipping from Colorado, but decided to go with what I've been using & have had great luck with in bicycle frames. I sacrificed double the hp & 6 speeds/wet clutch, but since I ride with bicycle tires and brakes on my builds; it kinda made sense, especially to the cops?

Parts? That I don't know for sure on the AR's but KTB clone parts are available as are big bore kits to go to +- 80cc. though new 6 speed transmissions are not.

New versus used is always a factor in swaps...keeps it interesting. I'm hoping to see a performance 2 cycle build in this forum category soon!  Rick C