Chevy ignition modification to GL1100

[SJBikesaws]

*********EDIT******* This mod can only be done on models with OKI MPS-200 ignitors and mechanical spark advance!!!!!!






I have been running these instead of the OKI MPS-200 igniters on my GL1100. This mod will work for the GL1200 as well. You also don't need to run ballast resistors since the HEI modules are designed to handle a huge amount of voltage, and since the load is split, it will never have to work at its full potential. I did have to advance my ignition timing around 8 or 10 degrees by twisting the vacuum pod (which might have been a problem I already had), but I have been running them for over a year and they have worked great. I used the stock honda coils for a while and they worked good with the setup, I have been using coil packs from a DIS system now (plugs gapped at .050), and they work good too. I can burn one up on a Sunday and pick one up from Autozone for under 15 bucks (still haven't burned one up yet though). Same deal with the coils for price and availability. Wings only break on Weekends you know.

Here is a quicky diagram I drew up on how to wire in the chevy 4 pin modules, you need 2 of them. You also need to mount them too a good sized piece of aluminum to dissipate heat with some dielectric grease, this is also how they get their ground so ground the plate to the frame or negative battery cable. as for wiring in the Chevy Caviler coils, they wire in just like the stock ones, only it does not matter which side you run the hot and the ground too. EASY CHEESY!



Here is a video of it running

Chevy HEI module part number -- DR100 or DR300, 2-7000, CBE4P, CBE4, GM08, GM09, GM21, M143, D1906, TP45, TP45SB. Or to make it easy to remember, it fits a 74 to 88 Chevy 350 HEI in anything they put a 350 in. The coils I used are from a Chevy DIS ignition system in most Chevy cars from the late 80's up to 2005.

[ericheath]

You're my freaking hero!!! Nice mod. I have all those parts in the bank already. I wonder if this would work with a Dyna system?? The gm spark units just need a pulse. Have you ridden all day with these coils yet?. I thought they would get too hot.

[sunnbobb]

nice nice nice nice That sounds soooo smooth

[jimmyz3286]

Yes very nice. Clean work there. W is the tach lead if I am correct so if one wanted to run an electric tach.

[JBz]

Are those the short wide round coils that plug right into the top of the module. Would you have a pinout on the module. Thanks JB

[82aspy]

coil part # ?

[SJBikesaws]

The coils are the ones that plug into the modules, I just fabbed my own mount (rubber) with 1/4" flat blade connecters. As for heat, this is New Mexico, and I have blazed it through some hot desert with no problems (also with the stock coils, no problems). Here is all of the GM part numbers: 80110-38300, 81046-83910, 81047-24010, 10472401, 10467067, 10468391, 10472401, 10477602, 10495121, 1049777, 11103646, 1103662, 1103663, 1103744, 1103745, 1103746, 8011038300, 8104683910, 8104724010

I really never needed to change the coils out, the honda ones worked great, and threw a huge amount of spark with the ballast resistors removed from the circuit, I just did it because I liked the thought of being able to get them anywhere in the event of failure. Now the OKI igniters were another story, those were crap right out of the gate from Honda, and I dealt with them on a few other CB's I had in the past, they build immense heat and eventually just burn themselves out, and they are just too expensive for a simple transistor trigger circuit burried in goo IMO.

I think the W is a tach lead but who knows what the heck you would read, the module was designed to fire 4 times per revolution on the chevy, it fires once per revolution on the wing. At least I know you could never reach the limiter, but I suppose you would be turning 5000 rpm and showing 1250 rpm on the tach.

I don't have a pinout, just my scribble I put up. I know that the B pin is the 12v lead from the switch, G is the magnetic sensor from the pickup, and C is the lead that lifts ground from the coil to make it fire. Both of the white wires from the magnetic pickups at the rear of the motor just run to ground to make it all work. I never worried about where to wire it in directly to the factory wing harness since mine was a burnt mess when I got it, I am sure it could be done though.

When I first researched it, I came up with tying the pickup grounds to the W lead. That did not work right, it would fire but acted strange and I almost scrapped the idea over it.

[JBz]

Thanks A Lot Sean..........JB

[SJBikesaws]

I suppose if you wanted to get fancy and go for a cool yellow factor,
http://www.summitracing.com/parts/acc-35361/overview/
http://www.summitracing.com/parts/acc-140017/overview/

And its still allot cheaper than the stock stuff. For plug wires I has a set of Napa wires I was going to put on my 97 Chevy Vortec, I found 4 wires in the box with just the right amount of length.

I wasn't going to put this info out on this forum until I thoroughly tested the setup. I didn't want anybody to hunk out cash and cut up their harness only to find out it was crap. Every trip to town for me is 100 miles round, and as for testing I have over 10k on the chevy parts conversion now with no problems. Coupled with the VW 28 PICT carb, it is the simplest and most reliable bike I have ever ran and even running mountain I seem to average about 52 mpg. I know the 28 Solex is a little small for an 1100 wing, but I live at over 9000 foot in elevation and drop down to 4000 foot when I hit town, under carburating the bike alleviated allot of problems associated with running a bike at both high and lower elevations and making it run good through the spectrum. I will admit that when I was running a 32/36 weber, it felt allot faster.

As for the jetting on my carb, bone stock VW jets, It feels a little fat at my elevation, and runs just about perfect at 4000. If I were running 4k ft to sea level I would go two jet sizes fatter on the main, and I keep a jet that size in my tool bag "just in case". To change the main jet on this carb, a 5/8" wrench, a flat screw driver, and 1 minute is all it takes.

[salukispeed]

Nice write up thanks. I wanted to do this conversion on a 1966 305 Honda dream but the points signal is reversed. I may be mistaken but the setup may not work properly for the 1200's because the advance function is completely controled by the ignition module. The trigger/pickup coils are in the rear cover of the 84 and in the timing belt cover on the rest. It will likely run but without the ability to advance and retard the timing. If I am wrong please say so as I dont want to mislead anyone.

[JBz]

http://www.ebay.com/itm/LX345-Ignition- ... 87&vxp=mtr

I believe this is the module Sean was reffering to. I found new coils and the module brand new a few weeks ago for less than 30.00 shipped from 2 different sellers as it was something I thought doing myself. For some reason I thought there might be a pair of ignitors built into the module. Good to see it can ne done. I still would like to find the weatherpack plugins for the module............jb. Whereabouts in NM at 9000 feet AngelFire??

[SJBikesaws]

As for the 1200, I wasn't sure. I always thought they were the same but I haven't messed with one. But yes, It does need to have a mechanical advance to work. I do know that all Hondas from the 80's with the OKI MPS-200 igniters are mechanical advance, this goes for CB's too. I went back and edited the header, I don't want to mislead anyone.

As for where in NM, I live in Sunspot in the Sacramentos, when I refer to "town", I am talking about Alamogordo.

[El_Taco]

I just moved to Odessa from Alamo because the money is better, but I built my 77 down there. Nice country there.

[Wolfie666]

Actually the other pin is for bias and also goes to the pickup on GM vehicles.
You just don't use it when running it for motorcycles.
... and the 84 still has the advance unit.

[socrace]

This guy did this same conversion a few years back, and documented it with a whole bunch of detailed electrical info.
He wound up with a circuit similar to yours!
http://home.comcast.net/~loudgpz/GPZweb ... vCoil.html