Powerplus or Bust, Eh?

[Tom Lovejoy]

Hey Kevin, I am mocking up a Powerplus engined boardtrack single speed racer and I hope to build the engine also - well be my first. I started reading your thread again from the start - fantastic stuff !! I just made the mounting plates for my engine, really appreciate your very detailed post, as I well need all the help I can git - thanks again and keep it up.

[Shaky Jake]

Hey Kevin, I am mocking up a Powerplus engined boardtrack single speed racer and I hope to build the engine also - well be my first. I started reading your thread again from the start - fantastic stuff !! I just made the mounting plates for my engine, really appreciate your very detailed post, as I well need all the help I can git - thanks again and keep it up.

That's cool Tom; I am also building a PowerPlus motored single speed Indian. Mine will be a road model though, not a speedway bike. This one isn't going to be for the Cannonball, it's just going to be a rider. Will you be doing a build thread?


Kevin


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[Tom Lovejoy]

Yes, I well try to do a thread - but I well hold off until, I git enough to be of interest. I am calling it a boardtracker, because I well have those Indian racing handlebars and seat, single speed with peddles . But mine well be for riding also, putting a brake and clutch on it. Probably just short rides though, think my body won't be able to handle to long a ride on the thing :-) a custom Gas tank is being made for it right now, a couple other pieces also. When I git those together, I well start a thread, I am sure progress well be slow though. Would also like to see and hear about your single speed.

[Shaky Jake]

Yes, I well try to do a thread - but I well hold off until, I git enough to be of interest. I am calling it a boardtracker, because I well have those Indian racing handlebars and seat, single speed with peddles . But mine well be for riding also, putting a brake and clutch on it. Probably just short rides though, think my body won't be able to handle to long a ride on the thing :-) a custom Gas tank is being made for it right now, a couple other pieces also. When I git those together, I well start a thread, I am sure progress well be slow though. Would also like to see and hear about your single speed.

Tom, Are you using a rigid frame with the eccentric for pedal adjustment? Mine is a cradle frame, so it has the pedal hanger that bolts on like a transmission. Basically it will be like a 1914 or 1915 single speed, which as called the 225 Regular model without lights, or the 260 Standard model with lights. The difference is that I plan to use a 1916 PowerPlus motor, so it won't be correct, but I think it will be a great bike to ride. The part I haven't figured out yet is the clutch. The Hedstrom single speed clutches don't seem to come up very often. I've never gotten the chance to look at one. I'd like to figure out if I can make a custom hub to adapt a PowerPlus clutch to a single speed. I don't know if it can be done, if you know anyone that's got good pictures of a disassembled single speed clutch I'd like to see them.




Kevin

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[Shaky Jake]

Valve Action

Throughout the entire 2016 Cannonball, I felt like my engine was not making the power that it should. It did fine on level ground, but always struggled with hills, and always ran hot. The other odd thing; the last 1/4 turn of throttle opening made no difference. There was no difference between 3/4 open and full open on the throttle. It was not a function of linkage geometry. I could reach down to the carburetor while riding, hold the throttle at 3/4 open, then turn it to full open. There was no change in speed and no change in the sound from the engine. I suspected that there was shortage of valve lift, causing the flow to be choked either at the intake valve or at the exhaust valve.

I must admit, that, as time was short in the end before the start of the event, I did not mount a degree wheel and indicator and verify valve timing and lift when I assembled the engine, which I normally would have done. I did dimensionally compare three different cams, which all had the same amount of lift, duration, and all had their lobes oriented the same with respect to the timing marks. I figured I didn't have time to do anything about it anyway, so I assembled the timing gears per the marks on and called it good. It ran, and it sounded right, so I never looked back.

Now I have degrees the cam and measured the valve lifts, and I believe I have identified the problem.

Anyone care to offer a guess as to the apparent cause of the trouble?









Kevin


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[indian301]

Wrong length pusrod?

[indian301]

Sorry, meant push rod!

[Shaky Jake]

Sorry, meant push rod!

Sorry 301, not that simple. But thanks for having the courage to guess.




Kevin


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[Tom Lovejoy]

totally guessing - cams from a Hendstrom ? they had a shorter stroke, maybe not as much lift on the cams too ?

[Shaky Jake]

totally guessing - cams from a Hendstrom ? they had a shorter stroke, maybe not as much lift on the cams too ?

Great guess, but sorry, that's not it.




Kevin


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[T. Cotten]

Even if you found something other than the manifold, Kevin,...

I'd bubble-test it anyway.

PP manifolds are evil.

....Cotten

[Shaky Jake]

OK, I'll give you some more information. Here are the valve timing design specs as published in Construction and Maintenance of Indian Motocycles 1916 & 1917 Military Models, ppg. 20-22, paragraph 18-21 and pg. 18

Inlet Opens 0 DEGREES (TDC)
Inlet Closes 52 DEGREES AFTER BDC
Exhaust Opens 58.5 DEGREES BEFORE BDC
Exhaust Closes 29.5 DEGREES AFTER TDC
I have not found any published design values for total lift on PowerPlus engines.



Here are my actual results, at the valves:

#1 cylinder:
Inlet Opens 31 DEGREES ATDC (31 degrees later than design)
Inlet Closes 21 DEGREES AFTER BDC (31 degrees early)
Inlet Total Lift .111 inches
Exhaust Opens 47 DEGREES BEFORE BDC (11.5 degrees late)
Exhaust Closes 35 DEGREES AFTER TDC (5.5 degrees late)
Exhaust Total Lift .264 inches


#2 cylinder:
Inlet Opens 25 DEGREES AFTER TDC (25 degrees late)
Inlet Closes 17 DEGREES AFTER BDC (35 degrees early)
Inlet Total Lift .128 inches
Exhaust Opens 44 DEGREES BEFORE BDC (14.5 degrees late)
Exhaust Closes 28 DEGREES AFTER TDC (1.5 degrees early)
Exhaust Total Lift .250 inches




In summary, at the exhaust valves there is some shortage of duration ranging from 6 degrees on #1 to 16 degrees on #2. The exhaust action is also shifted a bit in the late direction by about 8 degrees. Note that the timing mark on the cam was correctly oriented.

The biggest problems though, are at the Intake valves, which are short 60 to 62 degrees of total duration. That's a little over a quarter of the design duration. In other words, the Intake valves are only open 3/4 as long as they should be. On top of that, the Intake valves are only opening half as far as the exhaust valves. I don't know what the design values are for valve lift, but if I had to guess, I'd say they may have used 1/4 inch for both Intake and exhaust. If that's the case, they are only opening half as far as they should.

It's pretty clear that the Intake valves are my choke point, causing the symptoms that I described. I have a pretty good idea what is causing this, and I've already started working on the solution. Any guesses? I love it when you guys participate in the discussion...




Kevin


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[Shaky Jake]

Even if you found something other than the manifold, Kevin,...

I'd bubble-test it anyway.

PP manifolds are evil.

....Cotten

Yes they are. That is not the problem in this case, but I do have a story about that. On the second or third day of the Cannonball, my #2 spark plug looked good, my #1 spark plug was all sooted up. At the time I was still focused on getting my automatic oiler adjusted correctly, and the engine was still over oiling and smoking a lot. I assumed the fouled plug was due to excessive oil consumption, but I couldn't understand why it only affected one spark plug. I was discussing this with Iron Dinosaur Dave in the motel parking lot and he asked me if I've been adjusting my carb on the fly. I said yes. He said something like "I think you have a vacuum leak on one cylinder. You've richened your carb to the point that the cylinder with the leak is running right, which means the cylinder without the leak is way rich." Sure enough, I walked over to the bike, put my hand on the manifold nuts, and the one on the #2 cylinder was loose enough to turn by hand. After I tightened it I no longer had spark plug problems. I didn't have equipment for a bubble test with me, but I tested it with starting fluid. I checked the manifold nuts every day after that.




Kevin


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[TechNoir]

Ha, i was going to guess duration but then thought that was too obvious so didn't bother.

As for a solution. What i would do is go back to basics. You have published data for timing so i would get it as close to thst as i could first. Then see how it rides. Then see if any published tuning data makes a difference, testing small timing changes one at a time. (All assuming that you are 100% happy with ignition timing). Then, if you think lift might be an issue i would use a spare set of cams and make small changes and test incrementally. Being a side valve at least you dont need to worry about valve/piston clashes.

John

[T. Cotten]

Yes they are. That is not the problem in this case, but I do have a story about that. On the second or third day of the Cannonball, my #2 spark plug looked good, my #1 spark plug was all sooted up. At the time I was still focused on getting my automatic oiler adjusted correctly, and the engine was still over oiling and smoking a lot. I assumed the fouled plug was due to excessive oil consumption, but I couldn't understand why it only affected one spark plug. I was discussing this with Iron Dinosaur Dave in the motel parking lot and he asked me if I've been adjusting my carb on the fly. I said yes. He said something like "I think you have a vacuum leak on one cylinder. You've richened your carb to the point that the cylinder with the leak is running right, which means the cylinder without the leak is way rich." Sure enough, I walked over to the bike, put my hand on the manifold nuts, and the one on the #2 cylinder was loose enough to turn by hand. After I tightened it I no longer had spark plug problems. I didn't have equipment for a bubble test with me, but I tested it with starting fluid. I checked the manifold nuts every day after that.

Kevin.

As you surely know, Kevin,...

Tight nuts mean nothing to a vacuum leak.
Especially with the evil pinch slots at the bottom of the manifold.

And spraying stuff while running only shows big leaks, not the little leaks waiting to bite you, or rob you of performance.
Bubbles don't let anything get by..

Never does only one thing go wrong at a time.

....Cotten