Low Power Trouble

[dillondonnelly1]

Maybe you were not actually going 40 mph, unless it was gravity and wind assisted top speed.

Will you please just stop? You really aren't helping.

 

[Fabian]

The engine power issue sounds like a problem that only money can fix.

Interestingly that method of problem solving works with equal efficiency through all aspects of life.

 

[velzie]

I think Fabian has a point: 40mph on a stock motor? What kind of motor is this. We dont even know its displacement. It may also help if you followed our suggestions and answered my previews questions about modifications.I think you need to read more, become familiar with your motors operation then do some more diagnostics. Maybe your question will be more specific than, 'why am i slower than before'. In this case we could better help you.

 

[Fabian]

To run 40 mph you need around 3hp,

Just because the product manual says a 66cc engine produces 3hp, don't believe a word of it, because 3hp should allow you to run faster than 40 mph.

My engine on a good day produces just 1.2 rear wheel horsepower and on a bad day, it produces 1 rear wheel horsepower.
Factor in 20% for drive train inefficiency and the engine shaft horsepower of my 66cc engine on a good day is only 1.44 horsepower at the crankshaft, and that's with it tuned to perfection with all of the common engine accessories such as a higher compression billet cylinder head, Jaguar CDI and coil and modified intake and a different carburettor.

I've spent time crunching the numbers and you need around 3hp to run 40 mph.

I have somewhere between 1.2 and crankshaft 1.44 horsepower (bad day vs good day) and my bike doesn't do 30 mph on flat ground, so it's a tall order to get 40 mph out of a standard engine, let alone a modified engine.

 

[ua2pants]

It doesn't move at all. The wheel stays locked.

Well just with that note, you've ruled out any and all compression/leaking issues. How about when you're riding? Do you feel any drag like its slowing you down a whole lot?
Could be your brakes are engaged. If that's not the problem, are you 4-stroking? What color is your plug? Oil/fuel ratio? It very well could be a weak spark. Not necessarily related to the CDI but it very well could be. Try changing out your spark plug and wire for a better one with a solid core inside without any kind of cracks in the line. Open up your mag cover and see if theres any kind of gunk or anything around the magnet or in there in general. If there is, I recommend a electronics cleaning solution. I'm also from PA, im from the Somerset/Cambria county area. Maybe if you're close enough I could help you diagnose and fix the problem you're having. I have a spare CDI and Carb that are both stock but were working perfectly fine prior to my old engine blowing up from use that I could give you. Or at least try them and see if thats the problem.

 

[ua2pants]

So everyone knows as well. My first bike was completely stock with the exception of a modified air filter (thicker to catch more debris) and it went around 30mph on flat ground with wind resistance and I weigh about 190 and carry a small tool bag around with me all the time. So based off of his weight and wind restrictions, its very possible to hit 40 on a stock kit. Just remember that each kit is different from the other in just about every way.

 

[keatonx]

To run 40 mph you need around 3hp,

Just because the product manual says a 66cc engine produces 3hp, don't believe a word of it, because 3hp should allow you to run faster than 40 mph.

My engine on a good day produces just 1.2 rear wheel horsepower and on a bad day, it produces 1 rear wheel horsepower.
Factor in 20% for drive train inefficiency and the engine shaft horsepower of my 66cc engine on a good day is only 1.44 horsepower at the crankshaft, and that's with it tuned to perfection with all of the common engine accessories such as a higher compression billet cylinder head, Jaguar CDI and coil and modified intake and a different carburettor.

I've spent time crunching the numbers and you need around 3hp to run 40 mph.

I have somewhere between 1.2 and crankshaft 1.44 horsepower (bad day vs good day) and my bike doesn't do 30 mph on flat ground, so it's a tall order to get 40 mph out of a standard engine, let alone a modified engine.

How did you find those HP numbers? dyno?

 

[Fabian]

Rock Solid Engines has a small engine dyno, but my figures are derived from max top speed and vehicle weight over distance.

The numbers end up surprisingly close.

You are correct to say that there are differences between engines because Rock Solid Engines has found significant power variance between boxed engines out of the same shipment, which is why they assemble their own engines in house.

 

[dillondonnelly1]

Well just with that note, you've ruled out any and all compression/leaking issues. How about when you're riding? Do you feel any drag like its slowing you down a whole lot?
Could be your brakes are engaged. If that's not the problem, are you 4-stroking? What color is your plug? Oil/fuel ratio? It very well could be a weak spark. Not necessarily related to the CDI but it very well could be. Try changing out your spark plug and wire for a better one with a solid core inside without any kind of cracks in the line. Open up your mag cover and see if theres any kind of gunk or anything around the magnet or in there in general. If there is, I recommend a electronics cleaning solution. I'm also from PA, im from the Somerset/Cambria county area. Maybe if you're close enough I could help you diagnose and fix the problem you're having. I have a spare CDI and Carb that are both stock but were working perfectly fine prior to my old engine blowing up from use that I could give you. Or at least try them and see if thats the problem.

I'm from the Altoona/Hollidaysburg area. I ended up trying a new CDI with no luck. I should have mentioned this before, but didn't even think to. I had to replace the old motor with a new one because its clutch had gone bad. Ever since I started using the new motor, it barely pulls me up hills. The reason I ruled it out is because I'm almost positive it's the same motor. I mean the size looks the same and the design looks the same. I'm starting to think that I got a motor from the crappy batch.

 

[dillondonnelly1]

Well just with that note, you've ruled out any and all compression/leaking issues. How about when you're riding? Do you feel any drag like its slowing you down a whole lot?
Could be your brakes are engaged. If that's not the problem, are you 4-stroking? What color is your plug? Oil/fuel ratio? It very well could be a weak spark. Not necessarily related to the CDI but it very well could be. Try changing out your spark plug and wire for a better one with a solid core inside without any kind of cracks in the line. Open up your mag cover and see if theres any kind of gunk or anything around the magnet or in there in general. If there is, I recommend a electronics cleaning solution. I'm also from PA, im from the Somerset/Cambria county area. Maybe if you're close enough I could help you diagnose and fix the problem you're having. I have a spare CDI and Carb that are both stock but were working perfectly fine prior to my old engine blowing up from use that I could give you. Or at least try them and see if thats the problem.

No, I don't feel any drag. If by 4 stroking you mean my motor, then no, I have a 2 stroke. I replaced the spark plug and my other bike is using the same fuel and it's running just fine. I replaced the wires and I checked the mag.