blown motorized bike carnage!

[OCCStingray]

ran darn good right up until its final wheelie. was actually still running on that junk..


there I do believe I have explained myself.

Nuf said. Well done haha.

 

[Fabian]

I have looked at your product before but not found as much comprehensive info as id of liked.

No real need to redo the homework because it's already been done; many times over.
The Jaguar product (at least in my case) has proven to dramatically increase engine life without any negative effect on power.

It's a simple case of pulling the credit card out to order a Jaguar CDI.

 

[Fabian]

I actually like the stock cdi advance for power sake now that I have gotten to see it, though I wish it had a stronger spark charge which I believe to be its main downfall.

The standard CDI doesn't provide any positive benefit.

 

[Fabian]

to jag: do you make a kit with heightened spark with more aggressive timing curves?

The timing curves just work.

With a low to medium compression cylinder head, you can successfully get away with setting the jumper pins on Jaguar CDI to the maximum ignition advance curve.
I use the highest octane pump grade fuel (listed as ethanol free) to guard against it being blended with ethanol.

 

[Fabian]

as im redoing the top end I cam across this which is really interesting. these new style cylinder jugs can be very questionable - here is the video comparison (motorized bike jug good vs bad)
https://www.youtube.com/watch?v=55BbALTGlzM

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.
The most powerful engine i've had, used a cylinder with casting flash in the ports from top to bottom, and a cylinder that i cleaned up (spending much time removing all of the casting flash from the ports) made less power.

Now i don't bother getting overly excited about the quality of the cylinders, because i have found little difference in their performance or longevity.
Just bolt the thing in place and be done with it.

Of more importance is the design of the cylinder head; because that "does" make a noticeable difference.

 

[flashstar]

Ignition timing isn't that big of a deal. The "Jaguar CDI" is unfortunately not typically a cost-effective proposition with these 2-stroke HT engines. Before spending $70 for a CDI on an engine which uses a $70 top-end, I would reduce the plug gap and jet up a bit. 1800 miles is excellent for a 2-stroke engine top-end, especially one as poorly manufactured as a HT. Now if you are going for a "high performance" HT, the Jag CDI might make sense if it does what it says it does.

If you are going for a "HP HT", you are probably going with the following though:

-Jag CDI?
-balanced crank
-high comp head
-quality bearings and blue-printed internals
-Shift kit?

With all of these modifications, you are easily looking at $700-$800. I bought an Honda XR80 dirt bike engine with 5hp, 5 gears, a real clutch, and a red-line of over 10,000 rpm for $315. And no top-end rebuilding either.

When I was running my CAG engine with its cheapo stock CDI unit, I increased compression to around 11:1. Overheating was a problem until I went up to a size 80 jet. Measuring the head with an IR thermometer, temperatures decreased from 450 to 350 degrees.

The nature of 2-strokes is that the top-end should be rebuilt more frequently. If I were running a 2-stroke, I would rebuild the top-end every 1000 miles just to be on the safe side regardless of CDI. Who wants to risk metal slag flying at their legs?

Honestly, it all depends on what you'd like to get from your engine. The Jag CDI is not a panacea for poor quality internals. In fact, it's only one ingredient in the metaphorical icing of a high quality engine. And an expensive ingredient at that!

 

[butre]

on an otherwise stock engine with a low compression head you won't see any performance or reliability gains with an aftermarket CDI.

 

[Fabian]

on an otherwise stock engine with a low compression head you won't see any performance or reliability gains with an aftermarket CDI.

You are both right and completely wrong.

I will agree that on a standard engine, you will see little performance gain with a Jaguar CDI (just like you see virtually no performance gain by changing carburettors) but you will see a significant improvement in engine life by installing a Jaguar CDI.

 

[flashstar]

You are both right and completely wrong.

I will agree that on a standard engine, you will see little performance gain with a Jaguar CDI (just like you see virtually no performance gain by changing carburettors) but you will see a significant improvement in engine life by installing a Jaguar CDI.

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

The quality control on these china girls is so poor that there is little consistency between any. There are too many variables confounding the results without a controlled study.

Unless you or Jaguar can produce a controlled experiment, your assertion is incorrect. The most we can say is that we don't know.

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

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

 

[Fabian]

Ignition timing isn't that big of a deal.

You obviously are completely uninformed on this subject, for ignition timing plays a significant deal in engine operation; more so to the point - reliable engine operation.

The "Jaguar CDI" is unfortunately not typically a cost-effective proposition with these 2-stroke HT engines.

It is glaringly apparent that you have not spent a long period of time around these 2-stroke Chinese bicycle engines, because if you had, you wouldn't be making such a foolish comment.
Considering that when i was using engines fitted the caged big end needle roller connecting rod bearing, i was only getting 700 kilometers before big end bearing failure; using the standard CDI. With the change to the Jaguar CDI, came a dramatic improvement in engine life to 3,000 kilometers (on a partially damaged engine); meaning that the Jaguar CDI payed for itself (more than once over) in engine replacement costs.

My last engine ran for 10,000 kilometers on the bottom end and typically had cylinder life of 4,000 kilometers, using the Jaguar CDI ignition.

1800 miles is excellent for a 2-stroke engine top-end, especially one as poorly manufactured as a HT.

That mileage is around 70% of what i normally get, and the engine in my bike works it's guts out whenever it's operating.

I would rebuild the top-end every 1000 miles just to be on the safe side regardless of CDI.

That advise is nothing more than a load of rubbish.

The Jag CDI is not a panacea for poor quality internals.

I will agree with you 100% on the comment that the Chinese 2-stroke bicycle engine is a low quality unit, but for the money it can be surprisingly reliable with nothing more than an ignition upgrade.

The Jag CDI [is...] an expensive ingredient at that!

In the greater scheme of things (looking at the overall cost of replacement engines using a standard CDI) the $70 - $80 cost of the Jaguar CDI is the most cost effective investment you can buy; giving you not only much greater engine reliability, but having the option to change cylinder head compression ratio and altering the ignition curve to suit.