Timing Advancement - Who dunnit? - Page 2

katoranger · 04-25-2008, 01:55 PM

I wouldn't be surprised if the CDIs have different curves. Also the pushrod engine probably responds differently than the OHC.

Allen

TeamCheap · 04-25-2008, 02:01 PM

I got one of each OHC and pushrod and after I get my wifes bike redone it will have almost the same mods as mine as far as air filter, carb and exhaust.So comparing a OHC to a pushrod will be possible.

If it helps a lot then I may buy one for her bike and one for the ChinaBlaster project of mine.

katoranger · 04-25-2008, 02:13 PM

Th performance CDI is probably going to one of the best mods available to us.

I don't expect big gains from one either.

Allen

VinceDrake · 04-26-2008, 12:50 AM

Hey There!

I did the "Knothead Mod" to a Loncin Engined 250cc ChinATV. I found anything over 1.5mm Advance was just too much for low rpm torquing. (Keep in mind, I'm running an Atv...) Other thing I found-- The gap between the pickup and the thingummy is *critical* Specifically .020" on my ATV. Any more, and it would start coughing and snorting at low rpms, and gag completely at higher rpms. Almost like a bad plug....

Although, I've drilled the muffler and Uprated to a 110 Mainjet, with a slightly modified airbox. I'm really surprised, at 4mm more advance, the ATV wouldn't turn over on the starter, and would barely push-start. I think mine would have run backwards at 10mm advance....

--Vince

red2003 · 04-26-2008, 07:46 AM

Quote:

Originally Posted by culcune

If I'm not mistaken, Roketa's enduro engines are manufactured by Zongshen.

That is correct.

truthfriend7 · 04-26-2008, 07:54 AM

Quote:

Originally Posted by VinceDrake

Hey There!

I did the "Knothead Mod" to a Loncin Engined 250cc ChinATV. I found anything over 1.5mm Advance was just too much for low rpm torquing. (Keep in mind, I'm running an Atv...) Other thing I found-- The gap between the pickup and the thingummy is *critical* Specifically .020" on my ATV. Any more, and it would start coughing and snorting at low rpms, and gag completely at higher rpms. Almost like a bad plug....

Although, I've drilled the muffler and Uprated to a 110 Mainjet, with a slightly modified airbox. I'm really surprised, at 4mm more advance, the ATV wouldn't turn over on the starter, and would barely push-start. I think mine would have run backwards at 10mm advance....

--Vince

Hmmm.... Well that's interesting. After I moved the pickup back closer to stock, it seems to be doing the very things you describe, Choking at mid to hight rpms and losing top-end power. I just assumed it was the carb, but maybe I need to check my gap between the magneto and the pickup. Thanks for the heads up.

Cal25 · 04-26-2008, 07:55 AM

I would really be interested in seeing an advance curve on one of these boxes and a stock box. If the stock has a flat line and the aftermarket has a curve to it, I could invision Retarding the pickup just a bit and improving the very bottom end while the box would eventually advance past stock and improve power at the top as well. Of course a "magic box" would do all that on it's own I suppose.

VinceDrake · 04-26-2008, 03:21 PM

Well, this is slightly off topic, but I just got a 200cc Gio "for the wife" It's got much better acceleration and top end speed than my 250cc bug-eyed monster. Granted, the 250 is much heavier, with a brutal suspension set up, but the p/n on the carby's and exhaust are the same, so I thought, unto myself, "Hmm, what if I swap out the CDI box between the two?"

So I did so

Now the 200cc is about a 125 and the 250 pings like a biz-otch at mid range. Good power, but lots, and lots of nasty engine yacking ping. Hmm. Sadly, neither CDI box has a mfg. name or a part number, but I am kind of thinking, maybe not all are created equal in stock form either. (Swapped back, needless to say...)

I am thinking I are going to order up one of the "PorterzCrustomz Magic Box" and try it out on the bug-eyed monster first-- Probably about 2 weeks from now, somewhere in that neighbourhood...

--Vince

truthfriend7 · 04-26-2008, 04:46 PM

Please let me know when you do and what the results are.

VinceDrake · 04-26-2008, 07:23 PM

Certainly, be happy to. Sadly shipping to Canada is going to be slow....

--Vince

truthfriend7 · 04-26-2008, 08:30 PM

Well I messed with the pickup one last time today. I put it back slightly advanced but close to stock and made sure that it was close to the magneto. It got me up to 65mph while sitting up which is about what it used it used to be. I think I'm done with this unless I hear some new information. I have two other china bikes and I'm tempted to try swapping out CDI boxes to see what kind of results I'd get. I'll let everyone know if I do.

As for the manual timing advancment, on my 200cc OHC engine roketa engine (after about 8 tries), the results were negative.

TeamCheap · 04-26-2008, 08:46 PM

Me and I think slimjim have the "magic box" coming so you will hear shortly the results.

I have 1 each of the pushrod and OHC so I can tell you if there is any difference between those if any at all.But you'll have to remember that both of our bikes will not be stock since we have done the air/fuel/exhuast mods already.

I still think the CDI box will help, I'm more concerned with doing damage than if it will work.

knothead · 04-26-2008, 08:50 PM

Vince is right about the gap being critical. It MUST stay within spec... I'm not sure what the spec is though! Since He's already been there/done that I'd be willing to go with what Vince has said, .020". I marked mine before I took anything loose and tried to change only the lateral positioning of the pickup.

As far as the CDI boxes go, I have seen adjustable units on E-bay for less than $30.

I'm just wondering if a Motocraft ignition module would work, the pickup works in a similar way (magnetic), they are cheaper and they have the advantage of a selectable retard (IIRC, +12v to the green lead retards overall timing by around 4 degrees). The plugs on the Lifan are just standard, off the shelf items and I have two good Motocraft units and coils to match.... I might try it once finals are over.

ambassador · 04-26-2008, 09:19 PM

TC,
You guys aren't the only ones, I ordered one Wed. should be here Mon or Tues, looking forward to trying it out but I'm in the same boat I hope it does more good than damage, we'll see... In the meantime I'm looking for another exhaust, I don't really think the CDI will do a whole lot without air/exhaust mods, which you already have, I've drilled my pipe and have a cone filter but the clamp on the filter is starting to turn white(erode)from the salt air in FL, that can't be good so I may try to put the box back on and mod it to fit the cone... What jets are you running in your bike? Gonna order some from Bruce but I want to get a few and experiment...

TeamCheap · 04-27-2008, 05:39 AM

ambassador glad to hear it, soon we'll have lots of input on the "CDI magic box".
With the "DREAM CRUISE" coming up I want my bike ready to blow away all the cool old muscle cars running woodward.

Well I purchased jets from around 105 to 125 in 2.5 intervals but I ended with a 115 but that is with what amounts to an open exhaust unless you think that tiny spark arrestor screen adds back pressure

.(I love the way my bike sounds/rumbles)

K&N filter (the filter alone did little and I got it retuned without HAVING to rejet-a slight rejet may have made tuning easier though)
xr200 after market exhaust (terrible fit but more of a pipe manufacturers miss fit than anything)
rejet main at 115
Soon to add a modded CDI box to top it off or blow it up

Those changes did make a noticable difference in my bike and we'll be putting an exhaust from a chinese 250cc dirt bike on my wifes bike soon that I suspect will work as good or maybe slightly (barely) better than my exhaust.

04-25-2008, 01:55 PM	#16
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	I wouldn't be surprised if the CDIs have different curves. Also the pushrod engine probably responds differently than the OHC. Allen __________________ You meet the nicest people on a Honda Clone.
	0

04-25-2008, 02:13 PM	#18
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Th performance CDI is probably going to one of the best mods available to us. I don't expect big gains from one either. Allen __________________ You meet the nicest people on a Honda Clone.
	0

04-26-2008, 12:50 AM	#19
VinceDrake Join Date: Nov 2007 Location: Southern Saskatchewan Posts: 491	Hey There! I did the "Knothead Mod" to a Loncin Engined 250cc ChinATV. I found anything over 1.5mm Advance was just too much for low rpm torquing. (Keep in mind, I'm running an Atv...) Other thing I found-- The gap between the pickup and the thingummy is critical Specifically .020" on my ATV. Any more, and it would start coughing and snorting at low rpms, and gag completely at higher rpms. Almost like a bad plug.... Although, I've drilled the muffler and Uprated to a 110 Mainjet, with a slightly modified airbox. I'm really surprised, at 4mm more advance, the ATV wouldn't turn over on the starter, and would barely push-start. I think mine would have run backwards at 10mm advance.... --Vince __________________ "Sometimes it is better to say nothing, and let people think you're an idiot, than to open your mouth and prove it."
	0

04-26-2008, 03:21 PM	#23
VinceDrake Join Date: Nov 2007 Location: Southern Saskatchewan Posts: 491	Well, this is slightly off topic, but I just got a 200cc Gio "for the wife" It's got much better acceleration and top end speed than my 250cc bug-eyed monster. Granted, the 250 is much heavier, with a brutal suspension set up, but the p/n on the carby's and exhaust are the same, so I thought, unto myself, "Hmm, what if I swap out the CDI box between the two?" So I did so Now the 200cc is about a 125 and the 250 pings like a biz-otch at mid range. Good power, but lots, and lots of nasty engine yacking ping. Hmm. Sadly, neither CDI box has a mfg. name or a part number, but I am kind of thinking, maybe not all are created equal in stock form either. (Swapped back, needless to say...) I am thinking I are going to order up one of the "PorterzCrustomz Magic Box" and try it out on the bug-eyed monster first-- Probably about 2 weeks from now, somewhere in that neighbourhood... --Vince __________________ "Sometimes it is better to say nothing, and let people think you're an idiot, than to open your mouth and prove it."
	0

04-26-2008, 07:23 PM	#25
VinceDrake Join Date: Nov 2007 Location: Southern Saskatchewan Posts: 491	Certainly, be happy to. Sadly shipping to Canada is going to be slow.... --Vince __________________ "Sometimes it is better to say nothing, and let people think you're an idiot, than to open your mouth and prove it."
	0

04-25-2008, 02:01 PM	#17
TeamCheap Join Date: Jun 2006 Location: directly under the earths sun............NOW Posts: 2,302	I got one of each OHC and pushrod and after I get my wifes bike redone it will have almost the same mods as mine as far as air filter, carb and exhaust.So comparing a OHC to a pushrod will be possible. If it helps a lot then I may buy one for her bike and one for the ChinaBlaster project of mine.
	0

04-26-2008, 07:55 AM	#22
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	I would really be interested in seeing an advance curve on one of these boxes and a stock box. If the stock has a flat line and the aftermarket has a curve to it, I could invision Retarding the pickup just a bit and improving the very bottom end while the box would eventually advance past stock and improve power at the top as well. Of course a "magic box" would do all that on it's own I suppose.
	0

04-26-2008, 04:46 PM	#24
truthfriend7 Join Date: Dec 2007 Location: Florida Posts: 92	Please let me know when you do and what the results are.
	0

04-26-2008, 08:30 PM	#26
truthfriend7 Join Date: Dec 2007 Location: Florida Posts: 92	Well I messed with the pickup one last time today. I put it back slightly advanced but close to stock and made sure that it was close to the magneto. It got me up to 65mph while sitting up which is about what it used it used to be. I think I'm done with this unless I hear some new information. I have two other china bikes and I'm tempted to try swapping out CDI boxes to see what kind of results I'd get. I'll let everyone know if I do. As for the manual timing advancment, on my 200cc OHC engine roketa engine (after about 8 tries), the results were negative.
	0

04-26-2008, 08:46 PM	#27
TeamCheap Join Date: Jun 2006 Location: directly under the earths sun............NOW Posts: 2,302	Me and I think slimjim have the "magic box" coming so you will hear shortly the results. I have 1 each of the pushrod and OHC so I can tell you if there is any difference between those if any at all.But you'll have to remember that both of our bikes will not be stock since we have done the air/fuel/exhuast mods already. I still think the CDI box will help, I'm more concerned with doing damage than if it will work.
	0

04-26-2008, 08:50 PM	#28
knothead Join Date: May 2007 Location: In the land of the busted up ricebowl Posts: 815	Vince is right about the gap being critical. It MUST stay within spec... I'm not sure what the spec is though! Since He's already been there/done that I'd be willing to go with what Vince has said, .020". I marked mine before I took anything loose and tried to change only the lateral positioning of the pickup. As far as the CDI boxes go, I have seen adjustable units on E-bay for less than $30. I'm just wondering if a Motocraft ignition module would work, the pickup works in a similar way (magnetic), they are cheaper and they have the advantage of a selectable retard (IIRC, +12v to the green lead retards overall timing by around 4 degrees). The plugs on the Lifan are just standard, off the shelf items and I have two good Motocraft units and coils to match.... I might try it once finals are over.
	0

04-26-2008, 09:19 PM	#29
ambassador Join Date: Jan 2007 Location: Bradenton, Florida Posts: 1,200	TC, You guys aren't the only ones, I ordered one Wed. should be here Mon or Tues, looking forward to trying it out but I'm in the same boat I hope it does more good than damage, we'll see... In the meantime I'm looking for another exhaust, I don't really think the CDI will do a whole lot without air/exhaust mods, which you already have, I've drilled my pipe and have a cone filter but the clamp on the filter is starting to turn white(erode)from the salt air in FL, that can't be good so I may try to put the box back on and mod it to fit the cone... What jets are you running in your bike? Gonna order some from Bruce but I want to get a few and experiment... __________________ 06 Lifan 200 GY-5
	0

04-27-2008, 05:39 AM	#30
TeamCheap Join Date: Jun 2006 Location: directly under the earths sun............NOW Posts: 2,302	ambassador glad to hear it, soon we'll have lots of input on the "CDI magic box". With the "DREAM CRUISE" coming up I want my bike ready to blow away all the cool old muscle cars running woodward. Well I purchased jets from around 105 to 125 in 2.5 intervals but I ended with a 115 but that is with what amounts to an open exhaust unless you think that tiny spark arrestor screen adds back pressure .(I love the way my bike sounds/rumbles) K&N filter (the filter alone did little and I got it retuned without HAVING to rejet-a slight rejet may have made tuning easier though) xr200 after market exhaust (terrible fit but more of a pipe manufacturers miss fit than anything) rejet main at 115 Soon to add a modded CDI box to top it off or blow it up Those changes did make a noticable difference in my bike and we'll be putting an exhaust from a chinese 250cc dirt bike on my wifes bike soon that I suspect will work as good or maybe slightly (barely) better than my exhaust.
	0