Jeff B

Looked at the 23 GG. It is not a direct fit. If someone is very talented, they could come up with something. I just quit using mine. Still have the bike. The Contact is a great started bike, but, I was hoping I could use it for doing trail maintenance. The seat would be fine on pavement. Too weak for rough ground. If someone wanted to come up with something, it will need support in the middle. Too much flex in the middle.

At one time, GG made a bike called the Contact. Made it in the 90's and around 2017, 18. The latter ones came with a seat. Look at a 2017 Contact. Don't know if it will fit. I have a Contact. The seat is very weak. I modified my seat to give it some support at the rear where it is very weak. It flexes too much in the center putting stress at each attachment point. At best it is a touch above poor. One problem is that trials bike don't have a sub-frame to hold it up, I don't suggest much weight on it. It needs support in the center in addition to front and rear support. Interesting, the Contact came with a bigger tank. I thought it might be fun to be able to go on longer rides.

Had same problem. Newer, but same carb. Flip the choke on. Try that. Works on my bike. Stil, starts easier cold.

The CB 100N did not come to the US. But, it appears to be the same as the one from the early 70's. If it is the same, you will need proper piston to go larger. The US versions have a smaller opening in the cases. The 125 has the larger opening and thus there were big bore kits in the past. I don't know a 125 rod will help unless you plan on going BIG. You might research that model. E-bay can be VERY misleading as some adds will claim incorrect fitments. I have a 71 SL 100. I simply loaded a fresh 125 engine into the frame. What are you going to slip the engine into?

You can bore oversize, as long as you use a piston for a 100. The 125 piston uses a bigger wrist pin. Best thing is freshen it up. Not a lot to help it without spending a ton of money. A little porting. Might find a cam. But to make best use of a cam, slightly bigger carb and better flowing exhaust. The 125 could be punched out much more. The cases are different between the two. To put bigger sleeve in, you have to bore out the cases on the 100. A lot of work for little gain.

Well this sucks. Now this is another bike I need. I am 61. I'm not very good, but I have fun. Not kicking would be more fun. Jeff

If it has a lithium ion battery, make sure you understand the type of charger needed. Don't confuse ion and iron. My KTM has a lithium ion battery and I have a charger made for the ion battery. I don't understand why it requires a special charger, but I was advised to not use a standard charger. BTW...I am thinking about the TRS e start. Currently on a Gas Gas. I'm getting lazy with kick starting. I would like to hear a report after you get more seat time. Jeff

Runs for a few minutes? Is it running out of gas in the float bowl? The reason I ask, it looks like a Sammy Miller gas tank-seat. Fiberglass. Fiberglass and some fuels just don't get along. The fiberglass gets soft and mixes in the tank and can clog thinks up. Pull the fuel line off of the carb. It should pour out. if it drips, well you know. Also..if that is a fiberglass tank, it should be coated to prevent it from being ruined by the fuel. BTW good looking bike.

Adjust the idle so it is smooth and does not die. If it is too fast, it will pull you faster than you want to go. Too low idle, you will fight to keep it running. It needs to be very low to verify and adjust jetting, but after that you can set the idle where ever woks for you. If it is jetted properly, set the idle low and ride it. You will find a place it works best.

I also had pipe bang. By all means start with the air screw. It is free and you don't take the carb off. I had to richen my mixture. If you can't improve with the air screw, then take the carb off. You have not put fuel in it yet? I have found these bikes need a fairly high octane fuel. I am running 102 octane and 80 / 1 Oil mix. Adjust the carb after you buy the fuel you intend to use. Have fun.

I have a 2017 250 Contact. I have had zero problems. It needed jetting for my location. Still using the same 2 year old plug after it was jetted. Other than the seat being crap. It is a great seat as long as the trail is pavement smooth and you weigh as much as a 12 year old girl. Do not use it. It will break where it mounts in the back. I think it has the current 2017 engine as the TXT. So, parts can be found for a long time. Jeff

Is it coil binding?

We have trials events that offer a class called exhibition, no points, any line you wish. You just ride without a score. Look up ITSA Trials. Maybe your club could add that in.

Unless you have very good skills to balance the crank, I would let a pro do it. Your 125 spins a bunch more RPM compared to the BSA. I'm not saying you don't have the skills.

you should enjoy the Contact. I have a 2017 also. There was information all over the place, but that has kind of dried up a bit. I found that 102 octane runs the best with very minor jetting.