Help me figure out my Frankenbike GasGas build
 

To make a long story medium length, my first GG was a 99EC300. In fact it was S/N 0001, first one off the boat. It was supposed to have the torque monster "true EC" ignition and a counter balancer. Well, as anyone who has owned a Gasser might guess, it had a small 2k-whatever ignition and no CB, and the main bearings with plastic ball retainers that eventually locked up. But it was a great bike, got a tag for it, rode it for along time and finally sold it quite some time ago. But I never got over the desire for a counter balanced 300 with a plate. Plus I miss the awesomeness that was Smackover and Jim Cook; good to see Jim is still on here, getting it done.
I have been drinking the orange Kool Aid for some time, so I am a little rusty with my GG knowledge, but I remember some quad shop was doing a good job finish machining the cases and installing the CB. Maybe LTR too? I think 2004 was the last year with engine cases with the space for the CB. Will a pre-2005 motor fit into a more modern frame? Are there any particular model years 2005-on that were big steps in handling/suspension that I should shoot for? Will the old "true EC" ignition plug into a modern wiring loom? Or should I not worry about that, as I chanced across the thread about the 23oz flywheel weight! Counter-balancer plus 23oz FWW = dualsport from hell!
Naturally, I am trying to do this on the cheap as I have one in college and one headed that way before too long. if anyone has a line on a plated bike or any of the "parts" mentioned, I'd love it if you would PM me. I'm finally going to build the 300 I thought I ordered!
TIA

This is a great idea and I've thought about doing the same thing. A counterbalanced motor would be awesome. The early ones were fitted with the external lighting rotor and this performed like a flywheel weight. It made for a setup with good traction and would be an easy to ride bike for those of us who don't like a hard hitting powerband.

Now that I have a 2011 GG, I still think about a counterbalanced motor. Mine has moderate vibration and is OK offroad. If I did some dual sport riding then the CB motor would be a benefit; however this highlights the major issue.

The real problem as always is the gearbox ratios. They are just not wide enough to have a truely versatile bike. So the CB motor that is most useful at higher RPM is hindered by a not tall enough sixth gear. If you run sprockets that favor road use, then first is not low enough for real nasty trail situations.

While your project is a great idea, I concluded it wasn't worth the effort for me. If you proceed, I'm sure a few of would be interested in the results. You might also consider looking for a quad engine. They are counterbalanced, but I don't know if they are identical to the bike motors. I believe the reverse is just an electric motor that was added, so a quad engine might be the best place to start.

I think that quad shop your refering to was MotoWest down in So.Cal......They also made MotoWest pipes for the bikes as well!

David,
Reading this, I was prompted to reply as Neil and Rick did, with a quad engine recommendation.

The counterbalanced engines were velvet smooth. I stayed on bikes with those engines until 2004.

side note:
Those quad engines with the reverse had an ignition which allowed the engine to start backwards, reverse rotation, and then run backwards at low rpms; which gave it the "reverse". (Which is why the 4-stroke quads had no reverse.)
It had two sets of pickup coils. You had to crank it up, back it up, kill the engine, and then start it with the ignition switch in the "normal" position to go forward.

The same people who told me the things I repeated in my private message to you, also told me that a change in the engine castings kept the 2000 (or 2001?) and later engines from being candidates for the "line sight bore" job to install the counterbalancer.
I don't know personally; I'm just repeating what a better mechanic and engine builder than I told to me.

Both the '96-'98 250cc and later 300cc quad counterbalanced engines used the small ignition, with the 35 watt lighting coil. The counterbalancer takes up the space in the "hump" that is the location of the pick-up coil for the large igniton. They all used the magnesium ignition cover with the lighting windings bolted inside. There was also thick add-on flywheel weight bolted to the outside of the flywheel, which functioned as the magnet carrier for the external lighting.
This external wiring had a 100w output. I was told that "there was actually two sets of windings together in the external lighting set-up. If you used both of them, you could get 200w from that, making a total of 235w total output."

If you use the quad engine, it is all done for you. If you use the older 250 '96-'98 250cc engine, you will have to trim the metal of the cases to accept the '99 or later 300cc cylinder's skirt.
The project we did was to put a '98 250 c/b engine into a 2005 DE200 chassis.

Regarding gearing:
I ran my first '97 EC250 for a long time, in both low sandy woods and mountain singletrack rocks, with the stock final 13/47 gearing. I did fine with it. It put first gear more nearly where first is on a stock '99 KX250 and made 6th really tall.
On my Moose P3, it showed the bike topping out at '97 mph (running the Messico pipe and the old large cdi). The bike was not over revving at that speed, but was running out of the power needed to go faster.
We got '93 miles an hour out of a '99 4-speed MC250 with 13/52 gearing, and an identical '93 mph out of a '99 Prototype ('98 c/b engine) 6-speed XC250. Gabriel and Josh were racing each other on a one mile straight stretch along the hay field fence at the Red River Enduro. Both bikes were running the Messico pipe and the older large cdi. While topping out at the same speed, the rpms of the two bikes at that speed were different.
(Josh's 6-speed pulled Gabe's 4-speed 1/2 a bike length at the end of the mile. Gabe's front wheel was even with Josh's rear wheel.)


Good Riding and Wrenching!

I'm curious, what is the deal with the 4 speed bikes? Was that just the MC's or was it intermingled? Which trans had wider ratios?

I'd like to make a counter balanced GG 2T dual sport but the gearing is the hangup. At CO altitudes you'd be burning the clutch pretty hard with 13/47 to get up some of the hills here.

The 4 speed transmission was for the early MC models, and was a wide ratio 4 speed. The 4 speed transmission had a first gear ratio that was between the 6 speed's 1st and 2nd gear and the 4th gear was just a hair lower ratio than the 6 speed's 6th gear.

That is why Gabe was using the 13/52 final drive to race in the rugged terrain BJEC and Arkansas Hare Scrambles series.
I raced the bike at the CrossTimbers Enduro at Oklahoma city about 12 years ago.
I preferred the 6 speed transmission.

I have one or two used 4 speed transmission clusters in my stock.

Jim