COILS

SUBJECT: GT40T Coils

FROM: Rob Anderson
DATE: 7/8/01

My LM4 has had GT40T coils (mounted under the LH sidecover) with the motowitt ignition system for over 4 years now. I recently had a missfire problem, so I replaced the coils ... no change! it was the optical sender, the mounting had cracked giving an unstable output. *Not* a problem with the coils. It is pretty hard to get the GT40T coils now (reasons given include mass consumer stupidity) When I asked what had replaced the GT40T I was told it Bosch MEC717. Please confirm that with your Bosch agent but by *the book* they have the same primary and secondary specs, except they come in Black instead of Red.

Good huntin' Rob A

SUBJECT: GT40T Coils

FROM: Paul "Bart" Matterson
DATE: 7/801

> it has regular coils, and coils which have two plug holes in it. What's the difference?

2 plug holes for twin plugged heads ie 4 spark plugs 2 per cylinder

> I have decided to go with the Dyna ignition system so maybe GT40s are the go as with Barts MK IV.

Make sure you get the GT40T's (ie little rectangular transformer types u'll need to make up brakets to fit into orig coil spots as per digital photo's i sent u) don't get GT40S's cos thy're round & bigger than orig so won't fit measure then at the shop with a digital meter across the inputs to make sure that they're 3 ohms (should be as every set i've seen of GT40T's have been)

> Can you use any fuse box?

I got a 6 position blade fuse holder with waterproof lid from auto parts shop , about $30ish ,try Repco, use the 6th fuse for the NEW main fuse that U add

> Are distributors that have the cap & wires melted able to be fixed?

if you fitting Dyna then all u need is the lid to cover up pickup plate, try a Fiat car wreckers cos the lid has Magnette Marelli on it & that's wot they use, Dyna connects up to where orig points ran to,so has it's own set of wires from dizzy lid to main loom connectors, so if that main cable run from connectors down to coils isn't fried u'll be Ok

> I will get the frame powder coated what's the deal with plugging up swingarm holes and stuff like that?

I used a combination of LOTS of alfoil to protect smaller blind bolt holes U have to labourisly pick it out later on ), and for forks i made up sacrificial blanking plates outa plywood & siliconed then in, then off to sandblasters, then to powder coaters MOST important to protect your thread on your frame where the adjustable locater lugs thread in to fasten/adjust swingarm to frame V's, they're a real fine HARD to copy /fix thread use anything sacrificial to block/blank off holes or threads ie old bolts that are CORRECT thread that U don't want/need to replace (who cares if these are blasted/coated U can cut off excess powder coat with a razor then undo them to leave perfect threads for final fitup) i'l send U offlist a file for Dyna install that i found on the net

Bart

SUBJECT: Igniter (coils)

FROM: Doug Foskey
DATE: 7/8/01

> I have been told electricity will take the path of least resistance..
> would that not mean more spark to the plug in the carburised environment ???

The spark would be pretty much the same. Neither plug will fire until sufficient voltage has built up to ionise the gas in theplug gap. then both plugs will fire. 1 plug s/c will not change the other much, but o/c will result in neither firing (unless the coil or lead breaks down to earth, firing other plug.). 2 Coils in series would not have this problem, however, as the impedance to earth of the coil on the 12v side is still low relative to the HT side (Simplistic explanation), so even the upper (12v side) coil will still fire.

regards Doug.