Coil replacement

[Geoff7yea]

Hey all!

Been reading through all the advice and so on on the forum, and i too have decided my skorpion need editing to become a little less..well, cheap feeling lol.
front end is gone, replaced with an item from the fzr 1000. Have a TZR250 but as its the reverse cylinder am reluctant to steal its back wheel just yet!
horrible blue is gone, now a rather violent ORANGE. due to losing enthusiasm for spraypainting the bike myself half the fairings aren't on it either, i actually think it looks deadly without the plastics though! very evil with those 2 eyes up front.

Anyway il nag about other bits and pieces later on but a friend of mine is breaking his Yamaha Raptor quad, he sold his carbs but i was wondering is the Raptors coil better than the skorpions? i read the skorpion and xt's in general have a poor coil's resulting in weak sparks but as i can't afford the Ignitech sparker Bill suggests is the Raptors a worthwhile replacement? Or does anyone know of a coil off another bike that i could just put straight on?

Cheers!

Geoff

[Bill Jurgenson]

one thing at a time.
Ignitech make ignition boxes and rectifiers. They neither make nor supply coils. The "Sparker" TCIP4 is a programmable ignition for inductive pickups. It is not a coil and it is not a CDI, either, altho they do also offer a true CDI which will not work in the Skorpion - nor will any other CDI box.
The Denso coil in the Skorpion is probably the most common ignition coil there is.
The Raptor has the self-same coil, as do probably virtually all singles, not just Yamahas, not even just Japanese.
Personally, I do opt for a different coil where sensible. I use a "Motocoil" from SilentHektik which has nearly three times (120mj instead of 45mj) the spark of the Denso. It also uses SAE connectors and thus allows the use of highest quality automotive leads like the BERU POWERCABLE I prefer. All major suppliers (e. g. AC, Champion) offer similar silicon leads. They do not have twisted copper cores and so cannot be simply screwed into an old-fashioned coil like the Denso. They also cannot be shortened.
There is not reason, no advantage in a stronger coil for a stock or mildly tuned engine. You need extremely high compression and wildly overlapping cam timing to warrant an "arc welder" like the "Motocoil" or their 160mj(!!) "Solocoil.". There are other after market coils available as well which I have not tried.
A real upgrade everyone should do as long as they have a coil like the Denso with screw connector installed is to get the
red "Racing cable" from NGK, type CR3. This is a top quality silicon with twisted copper core and molded-on resistor
connector to fit on the sparkplug screw, not on a SAE terminal.
Again, there are other brands of automotive silicon leads with copper core (including BERU, Champion) and molded-on plug. Any of them is a decided improvement in getting the energy to the sparkplug without losses. Where a modern resistor cable is used, it is not necessary to use a resistor sparkplug, i. e. use a NGK DP8AE or better a DP7EA instead of a DPR(=resistor)... It is necessary to use some sort of RFI suppression and this does not lessen the spark. Always use contact grease on all connectors including the porcellain of the plug.

Re plugs:
Use a good plug with a fitting heat range. The "books" state NGK 8 or even 9.
Unless you live in the Mojave Desert, these are too cold, even for racing.
Use a NGK DPR7EA or Champion RA6HC or BERU 12-5DU or Denso X22EPR-U and set the gap to .6mm which is the gap and plug Champion recommends. The NGK will probably be factory set to .9mm which is too wide and makes starting difficult and otherwise has no advantages.
It is never a good idea to install a plug out of the box without first checking the gap. Always use the hottest plug the engine can take without undue deterioration. Better to check and regap the plug at reasonbly frequent intervals and replace than to use a too cold plug that might outlive the bike.

Do not waste a cent on snake medicine junk like a NOLOGY lead. Such capacitive "spark amplifiers" are as old as spark iginition and have never improved anything that cannot be remedied by keeping things clean and in order.

Cost issues?
A new Denso coil costs €45 over here.
The Motocoil cost €77, the Solocoil €97.00.
The NGK C3 lead costs €17.00.
The BERU PowerCable (and similar) cost around € 10.00.
A Sparker TCIP4 costs €145.00.
all retail including VAT.
Where such meager investments are an issue, there is no need to even contemplate tuning.

BTW
I use the stock Denso coil with the NGK CR3 wire and BERU 12-5DU in my stock (as far as the engine is concerned) Yamaha SZR.
I use the Motocoil with the BERU cable and again the 12-5DU in my highly modified Skorpion.
In both I use a Sparker TCIP4 with the same basic curve. HAving sold over 80 Sparkers, I have both some experience with them and can vouch for their effectiveness. Head a shoulders above the OEM box.

In my racer I used a PVL magneto from the beginning (after ditching the starter and flywheel) and later a SilentHektik TripleSpark box with - again - the Motocoil and BERU Powercable, i.e. a constant loss battery ignition. This started much more easily than the magneto and was not so finicky. Perfprmance was not improved, tho, and the static weight was increased altho the rotating mass of the crank was slightly less. The battery ignition also allowed me to use an electronic tach instead of the mechanical one. It also allowed a quickshifter - which we later ditched as unnecessary.
Maximum spark advance of the magneto wa 27º, of the SH box 28 to 32 depending on how it was set. Usable RPM (to 9500) were highest with the magneto.
Thus I have the Sparker programmed to replicate the magneto's curve - more or less, apart from the beginning which must take the decompression unit into account.
The stock SZR revs to 9000. and is constantly used to 8500 to good advantage. On the track or while "big game hunting" on back roads, I am mostly in third, sometimes 4th, almost never in 5th despite short 15/43 gearing.
With the stock coil.

[Geoff7yea]

Excellent info as always cheers!

Ok seems the Racing cable and a plug is the way to go, im sure i can stretch to 20 euro lol xD.

Quick question concerning the carbs bill, ebay is full of carb spacers for the raptor>>

http://cgi.ebay.com/ebaymotors/YAMAHA-R ... ccessories

I saw in one of your write ups that one of your bikes had greatly lengthened inlet manifolds, is this spacer here a worthwhile investment or is there a better way of doing it?

I picked up the MZ's back wheel next to my TZR's and had to laugh at how ridiculously heavy it is btw, must sap about 47 of the hp right there!!

[cat]

Interesting! Thanks, Bill.

Maybe you can explain this:

are available for both removable terminal nut and solid terminal nut spark plug designs.

What is a "solid terminal nut"? I've never seen a spark plug where the nut is not removable. Or do they just mean that the spark plug caps like the CR3 are for use with the nuts?

[DAVID THOMPSON]

i have seen plugs with a fixed cap no threads in my area
but do not remember the brand
dave

[cat]

ok. My last sentence in my previous post has to be correct. (

Or do they just mean that the spark plug caps like the CR3 are for use with the nuts?

)
See that one of the spark plugs Bill suggests is NGK DPR7EA; that is an ordinary plug with a removable nut. The NGK Racing Wires are available with caps for use with the nut (CR3) and without (CR1). Maybe Bill just prefers the kind that fit on the nut.

[Bill Jurgenson]

yes, I prefer the SAE terminal some call a nut or cap. Plugs for motorcyles have threaded, removable terminals but there are a lot in the car sector that are solid, not removable. My favorite plug, the BERU 12-5DU is available in both types. OTOH, I have never seen a NGK, not even one specifically for a car, with a solid terminal.
In the case of the NGK Racing wire, it doesn't much matter since the screwed in other end is the point of contention. Altho the SAE type is listed, I have never seen one over here; the jobbers stock only the type for the screw.

carb spacers: they are usually about 20mm thick and are better than nothing. They are simple to install and can be stuffed in when one is still using the airbox. Real performance gains demand 2 or more inches, not 2 centimeters.
In that respect, Y-bridges like the Bikeworx really do bring a very measurable gain in torque.
What usually done is to gut the airbox, leaving the sides and bottom as is along with the battery tray part at the back. Almost carb setup with K&N racing filter is then hid in open trough that was the airbox.

All-out racing setups use some sort of long manifold mated to modified(=welded up and remilled to get 2 larger and same-sized ports) heads and 38 or 39 dual flatslides. Andy Driver's ESA championship winning Slipstream Skorpion has two downdraft FCR39s mounted inside a very large ram air supplied airbox where the Skorpion tank normally is. Tim Barker's very successful SZR was similar. But the camp is divided with decided airbox users and those (like me) dedicated to open ram stacks with no box of any kind.

[Geoff7yea]

Ok cool cool.

Ive no problem hacking my airbox to accommodate the carbs and spacer, no MOT's over here .

If i get the Raptor carbs, open up my airbox and plug in a K&N is that spacer the best idea up front, or should i go longer using something else? from your experience is there an ideal extra length for the inlet?

Highly Appreciate the advice!

G

[Bill Jurgenson]

you don't need to hack anything to fit one of those spacers.

A better exhaust system with larger headers is more important than bigger carbs. In cross-sectional area a TM34-B65 is smaller than the OEM Tekei, altho it yields a plus of about 5hp along with about 20% better mileage. Anything bigger than the TM34 (the single TM42 is even smaller) is nonsense without much larger headers. Sticking a loud can on the OEM L&W system does nothing for peak performance, altho it can improve midrange somewhat. On the dyno, the OEM was just 1hp down(58hp rearwheel) on a good open racing can (BOS)(59hp) when fitted to a larger system mounted on a tuned engine with TM42 an Bikeworx manifold, JE102Ø, Megacyccle 280-2, porting, lightened flyeheel/freewheel unit, NO balancer...
You get the idea...
BTW, this should give you somethingof a frame to judge wishful thinking hp ratings very often made even by what one should expect to be serious shops.
Hp can be given as (SAE) measured at the clutch; this is the official 48hp of the XTZ engine which as a rule delivers a real-life 50-52. The SAE 48 equates to about 42 rearwheel hp. Up-to-date PC controlled dynos give a quasi SAE rating by calculating the measured rearwheel output back to the clutch. This is supposed to make comparisons easier but is never accurate without exact (not averaged) data on the losses incurred after the clutch. As an example, a normal heavy-duty X or O- ring chain uses 2hp all by itself. A true racing chain is thus the cheapest tuning you can do even if the chain is expensive. An oldfashioned open chain (DID ERT2) is best of all and cheapest to boot for racing. Just change it often.
Anyhow, 60hp is realistic and can be made dependable. Beyond that, every single hp cost hours of work and lots of money. Beyond 75, you run into serious problems with the crankcase castings and from there on up, dependability is measured in hours - or less. Been there, done it.

gettin too long again
Fitting one of those spacers will help midrange. The Bikeworx kit does this much more effectively and the flatslide greatly improves drivabilty IF you learned to control that that right hand. As long as stock exhaust headers are involved, I would use a TM34-B65 on one of those spacers. Anything more than that is a waste of time and money as long as the headers are too small.

[basser23]

Bill,
I have to smile about the headers,cause they would all be custom made.Well maybe Off The Road XTZ headers may work...but generally
as you have stated no headers are readily available..unless every one over here pesters Tim
Bernd had a prototype a couple years ago, and JEMCO will custom fab some...duals only,,,good bye side stand...

As far as using the raptor carbs...wont fit under the tank..linkage interferes with the petcock apparently.....

[Bill Jurgenson]

raptor carbs? do you mean the dual 39mm Keihins that were mentioned a while back.
Of course they can be mde to fit just like the Mikunis but they don't fit out of the box, none of the dual carbs do.
It is not the petcock. The cable fittings are too high and have to be modified.
The petcock should go any, regardless of carb, cause it is too small. I always replace it with a Coldwater quickrelease fitting for 8mm hose attached directly to the tank. Makes taking the tank off much easier, too.

[basser23]

H>ey Bill,
Not the FCR 39's,Geoff7yea was refering to the BST33 CV carbs from the Raptor..apparently the throttle linkage is interfered with the petcock on the Skorp tank..
I am looking into the quick discon for mine as wee speak....I agree 100%
Chip

[Geoff7yea]

would headers off a TDM850 go onto it folks ?

I was thinking - raptor carbs with long inlet, spacer, K&N filter. new fuel tap as mentioned. Headers off a TDM or similar, straight thru exhaust and the racing NGK cable with a decent plug. This combination of goodies work together?

I dont want to go mad, or even open up the engine really, im happy to just bring it up to scratch with decent bolt on parts that MZ should have put on to begin with!

At the moment the Front end's sorted anyhow, decent handlebars are on<<<<these make such a massive difference to the feel of the bike !! bin that shit that came with it. mine are off a cbr 600, odd how its the small things that can help! rear shock off a VFR is on. rear wheel is next, TZR's are rare as hell but i think the FZR 250 appears to have the same one.

[DAVID THOMPSON]

remember the age of these bikes and if you have the forks off do service and grease the fork neck bearings
and make sure there not messed from hard landings from the fellows that like to fly the front wheel
or jump them off a lading dock
dave

[Bill Jurgenson]

TDM headers do work and are a common starting point for DIY systems. Best to make a 2-2 not only because it easier. the larger volume of two cans goes a long way reducing backpressure while still damping noise, much better than a 2-1 could possibly be. Forget the side stand; flex the nose off with an angle grinder. Use a paddock stand like ever good racer you can easily attach the prisms (bobbins?) to thr swing arm by using nuts inside the square tube. Or pop nut if have thst sort thing.
Raptor carbs? Why those? What do you hope to improve by putting 2 sluggish CV carbs on?
Ovrr here no one would even conder using them. Not that the Tekei is all that good, it ain't, but it can be optimized and works well enuf even for 70hp. leave well enuf alone until you can manage 34mm flatslides. There was a pair of 33mm Keihin CRs (roundslide smoothbore) available for the XT/SRX. these work very well indeed as I know from experience. Or two 34 Dellortos or two of those spanish AMALs with 34.
Or a 40-42mm Dellorto SSI set horizontally with separate float bowl. I run this stuff on my Mondial but here of course you could buy two or three Keihins for what a 40mm SSI and separate bowl cost.
Seriously, the round slides are worth looking into because they can be much better set up for midrange response. none of them are plug and play. You have do some adapting/ modifying to connect the cables. The same is true of all dual flatslides. The big single Mikunis present no problem here.
Round slides are cheaper, too, but you need more spares to find the setup: three or more different sliders, as well as needles, mains, venturis, and idles. And experience. There is good basic pamphlet from Dellorto.
There is also one from Mikuni for flatslides; the TM42 is a popular upgrade for Harleys, here called HSR42, so look for a pamplet for this one. The Bikeworx kit uses the K&N airfilter for a Harley.