blown motorized bike carnage!

[Fabian]

Please refer me to a scientific, controlled study using multiple identical engines with and without Jaguar CDI's.

I have over 50,000 kilometers (30,000 miles) of "controlled study" with these engines. using multiple combinations of parts and aftermarket items.
The reliability i have gained from careful study of the Chinese 2-stroke bicycle engine hasn't been pulled out of thin air.

The quality control on these china girls is so poor that there is little consistency between any.

My experience has shown them to be surprisingly consistent, regardless of their external appearance.

There are too many variables confounding the results

It sounds like your ideas are confounded by lack of long term knowledge of these engines.

I would love to believe that a CDI can significantly improve engine life, however I have yet to see any repeatable evidence of this.

If you want to "believe", then join a religious organisation, otherwise you will have to accept my long term use of these engines (under arduous conditions) as confirmation of their reliability.

Again, 1800 miles is very good for a HT 2-stroke top end.

I completely disagree, and by your comments, it is obvious that you've not operated these engines over an extended time frame.

 

[Deleted member 12676]

Thunder, I am starting to make another version of my CDI that allows a greater range of adjustment and it will be available in 3-4 weeks. But with greater adjustment range there will be novices that will adjust it for maximum power (maximum advance) and then wind up seizing the engine. Design engineers on low quality engines never design them for maximum power. They design for the best power that allows for normal reliability. There will be a warning concerning this new version that it is not for novices but for racers and people who are experienced at two stroke engine tuning.

 

[flashstar]

Again Fabian, we really need more than your experience with one, two, or even three engines to conclude that "the Chinese 2-stroke bicycle engine"..."can be surprisingly reliable with nothing more than an ignition upgrade".

I do not think that the OP's CDI caused his cracked jug. It's probable that the metal in the jug was weak.

I ran a thatsdax HT 70cc engine for almost 2 years without a single engine issue. I put 400+ hard miles on that bike before selling it. My average speed was around 26mph the whole time.

I agree that these Chinese engines can be surprisingly reliable, however it's a crap shoot more than anything.

I studied the AX100 engine recently. The AX100 was a 2-stroke bike which was built in the 1980's and 1990's by Suzuki. This engine too had a low compression ratio at ~6.5:1 even with a much higher quality CDI. The CDI was not pivotal there and is probably not the reason HT's are typically kept to low compression ratios either.

Many 2-stroke dirt bike racers rebuild their top ends once or twice each race season just to be safe. Do you want to risk getting hot metal in your legs? It's up to you.

 

[Fabian]

Again Fabian, we really need more than your experience with one, two, or even three engines to conclude that "the Chinese 2-stroke bicycle engine"..."can be surprisingly reliable with nothing more than an ignition upgrade".

What about 8 engines?

I do not think that the OP's CDI caused his cracked jug. It's probable that the metal in the jug was weak.

I agree. Under normal circumstances, ignition timing will not crack the jug.

Many 2-stroke dirt bike racers rebuild their top ends once or twice each race season

If they derated those engines by 50%, they would last forever, because they're at the opposite end of the performance envelope compared to a Chinese 2-stroke bicycle engine.

Do you want to risk getting hot metal in your legs?

Oh hush now. You're starting to sound more theatrical than i am.
Keep that up and you'll be hauled into the office under a demarcation dispute.

 

[Fabian]

I am starting to make another version of my CDI that allows a greater range of adjustment and it will be available in 3-4 weeks.

I was really hoping that the Huffy Davidson CDI would take the Jaguar CDI to the next level, but sadly they missed the mark by a long margin; manufacturing a product with less functionality than the Jaguar CDI; having only a fixed ignition curve on the Huffy Davidson product.

Hopefully the new and improved Jaguar CDI will add a lot more ignition curve adjustability to the current jumper switch design

Design engineers on low quality engines never design them for maximum power. They design for the best power that allows for normal reliability.

I agree. the manufacturer must give a warranty, so their product must be designed (at least reliable enough) to get the product through the warranty period, though a 3 month warranty reflects the quality of the item.

 

[flashstar]

What about 8 engines?

Were these engines built by the same factory and entirely identical, aside from the CDI? How do you KNOW that the CDI is the only thing dramatically improving engine life in every case? Let's discuss some factors that affect the life of these engines:

-quality of casting (the OP described a cracked jug!)
-quality of moving components like wrist pins, etc. The OP mentioned that his engine had a bad wrist-pin from the factory.
-temperature
-richness of air/fuel mixture
-oil/fuel ratio
-the engine operator (how hard were you on each engine?)
-Many other things

Unless you have isolated all of these factors, there is no way you can conclude beyond the shadow of a doubt that the CDI affects engine life to the degree you assert.

Oh hush now. You're starting to sound more theatrical than i am.
Keep that up and you'll be hauled into the office under a demarcation dispute.

Do you think these HT's are a joke? These machines are engines with pistons moving as fast as 7000-8000 rpm. They also have very poor quality control. If anything, they should be serviced more often than high quality Japanese-sourced dirt bike engines.

Tell this HT motorbiker that I am being "theatrical":

"my motor made a loud bang, and since i was in a full tuck, i was looking at it. a small fireball came out of the head, it blew my exhaust pipe off, and grenaded inside." -bairdco

My experience has shown them to be surprisingly consistent, regardless of their external appearance.

I would beg to differ. You imply completely the opposite in post #35:

You will find that (at least with a standard exhaust and standard intake) there is no meaningful power difference between a poorly cast cylinder and a well made cylinder.

Numerous other forum members mention differences in internal engine quality, including the OP. Clearly, you understand that these HT's are inconsistently produced.

 

[Fabian]

I would beg to differ. You imply completely the opposite in post #35:

I am entirely consistent between posts 35 and this post - prove it to be otherwise.

Numerous other forum members mention differences in internal engine quality, including the OP. Clearly, you understand that these HT's are inconsistently produced.

I am forced to agree with you, from the experience of the other forum members, however, all of the engines i have purchased have been mechanically reliable except for the big end connecting rod needle bearing assembly.
Since the factories have changed to the crowded needle roller connecting rod big end bearing method, this weakness has effectively been eliminated, though i can't say that it was actually a problem because my current engine has been previously rebuilt with the older style caged needle roller big end assembly and it's still running perfectly well, with over 1,200 kilometers on the engine.
This is the first engine (of the caged needle roller big end design) that i have run from the start with the Jaguar CDI plugged into the system.
So far it's still running smoothly which is a little frustrating because i'm waiting for the big end to fail so i can install the new engine design that uses a chainsaw style ignition system.
Having said that, i'm going to need to let a few more road trips pass under the wheels of the bike because the last engine that was partially damaged at the 300 kilometer mark (using the standard CDI) went for a total of 3,000 kilometers when the Jaguar CDI was installed.

 

[Fabian]

Tell this HT motorbiker that I am being "theatrical":

"my motor made a loud bang, and since i was in a full tuck, i was looking at it. a small fireball came out of the head, it blew my exhaust pipe off, and grenaded inside." -bairdco

That sounds terribly theatrical, considering that when you are going flat out in a full tuck, you're looking ahead at the road and certainly not at the engine. The "fireball" as you so (theatrically) describe it, may have caught your attention as would have the other parts disintegrating off your bike; leaving a catastrophic trail of mechanical carnage in your wake; expressing themselves in the Vietnamese language; whilst bouncing down the road - thuc, diem, took, minh, tung , nam, bon, tin, bing.

 

[Fabian]

How do you KNOW that the CDI is the only thing dramatically improving engine life in every case?

I am not in any way saying that i am an oracle when it comes to these Chinese 2-stroke bicycle engines, but i do know (through extensive experience) what kind of components improve engine reliability and the components that do not.

I most definitely do KNOW (using your expressive use of capitalisation) that the Jaguar CDI gives a significant improvement in engine longevity, which also translates into engine reliability.
If it didn't, it wouldn't be on my bike.

 

[Fabian]

.
.
.

Let's discuss some factors that affect the life of these engines: - oh yes, please lets discuss!

-quality of casting (the OP described a cracked jug!) - i have never experienced such a failure when the engine is in operation.
-quality of moving components like wrist pins, etc. The OP mentioned that his engine had a bad wrist-pin from the factory - all of my engines have been mechanically sound.
-temperature - my engines have all operated close to and at times 100% duty cycle; working their guts out; running reasonably warm.
-richness of air/fuel mixture - my engines have always been tuned to perfection.
-oil/fuel ratio - 25:1 day in and day out.
-the engine operator (how hard were you on each engine?) - all of my engines have spent their time working their guts out, but never excessively over revved.
-Many other things - oh yes, there are many other things...

Unless you have isolated all of these factors, there is no way you can conclude beyond the shadow of a doubt that the CDI affects engine life to the degree you assert - i have isolated all of these things and quite possibly much more.

My reply is answered in bold type; incorporated in the quote above.