charliechitlins

Looking at the intake spigot is no good...you have to test it. You can spray water on it while the bike is running to see if the idle changes. You can also point a propane torch at it (don't light it!!) and the idle will change if it's sucking propane. It's probably electrical, though. Points and condenser are cheap and easy to replace. Often the first sign of a coil going belly up is it works for a few minutes, then starts to miss.

Bright white spark is no good. Fat and blue is good.

Plain old silicone. Don't you need "high temp"? Won't it burn out? That won't work! Blah, blah... I've been using it for over 25 years and had a repair shop for several of those years. I've used it on hundreds of exhaust pipes and manifolds. Bought it right from the hardware store in the big ol' tube and put it in the caulking gun.

There are cracks and holes.

What's the way to go with this? I have a crappy, dented delaminated tank. I don't need beauty....just keep the fuel where it belongs.

Thanks, Shaun! So...how are we fixing these tanks these days? This ones cracked, delaminated, etc. Don't need beautiful, just so it doesn't leak.

Looks almost right. Mine has plastic fenders. I couldn't say if they're correct for the bike, but they are Montesa fenders.

A little lube on the seal and a piece of PVC pipe the same size as the seal. Tap it in evenly with a hammer. You can also use the old seals to drive in the new. They're always exactly the same size

21M25425 Has some different stuff from my '74 which is also a 21M. Clutch arm on top, different engine covers, Amal carb... The guy I got it from tied it down to bring it home and when he took the straps off, the forks stayed collapsed. Any Ideas. The seat/tank is a WRECK. What are we doing with these things these days? I still figure I did OK. Buying bikes from rednecks is interesting. He took $375 and a 30-pack of Busch.

Hardware stores and auto parts stores are chock-a-block with great trials gloves at bargain prices these days! I even saw some (American) football gloves on sale at Walmart that looked great. Reinforced fingers with grippy stuff on index and middle fingers and palms...

I can't imagine how to get an accurate measurement of a cylinder without a bore gauge. There may be a way, but I doubt it involves inserting the piston and using feeler gauges. Feeler gauges are not meant to be used in curved surfaces. And a piston is "cam ground"..... oval. If you were REAL handy with geometry and math, I suppose you could insert a ring, measure the end gap, pull it out and measure the end gap again. I suppose the right person with a calculator and knowledge of the relationship between circumference and diameter could get close. If you can rock the piston like you say, your little end bearing might be shot. Don't forget to check the big end for up-and-down. If your new wristpin clips are wire (round cross section) they go in any old way. If they're flat snaprings, they have a thrust side (it's flatter with sharp edges) and it has to face out.

Measuring the height of the oil is always most accurate. Aftermarket fork seals are seldom found for trials bikes. All the ones I've dealt with are OEM only...and they're damned expensive!

Flywheel should have a TINY bit of side-to-side movement. No up and down. The connecting rod can move side-to-side on the crank pin (an inch seems like a LOT though) but should have NO up-and-down movement. The piston can have some scuffs on the thrust faces (front and rear), and the barrel can have some scuffs, too. Knowing what your looking at is the only way to know if this is excessive. If any material in the piston appears to be pulled or folded, it's definitely shot. The wristpin clips may just be circular and you can easily pry them out if there's a notch in the piston. Look closely for a place to get a small pick or screwdriver in. They may also be snaprings, and you'll need snapring pliers. WHATEVER YOU DO, STUFF A RAG IN THE LOWER END when working with a piston. You'll hate your life if anything drops down into your engine.

If the float was fine, it would have closed the needle valve and there wouldn't be fuel everywhere. If your piston was a little down, the lower end of the engine could be full of gas, too. Make sure the float is working properly AND the float needle is working properly. Also...shake the floats to see if one is full of fuel.

As always...check the last thing you messed with. Take the float bowl off and see if everything is right. But you didn't need me to tell you that.

Yeah...whenever something on my bike gets like that, I start thinking, "I have to do something about this!"

Yup...put pressure on them with an allen wrench, then tap them with a hammer where the washer-looking part sticks out over the fingers. I don't know why this works, but it does.

These tools were in wider use way back when. I have several of different sizes and they're all very old. Antique motorcycle wheel bearing retainers and intake manifold packing nuts come to mind. Here in the the colonies we just call them spanners as we don't use that term for "wrenches".

Also... Maybe the kicker was off and put back on in the wrong place. If it was rotated counter (anti) clockwise, the weight of the kicker could be pulling it past center in the wrong direction (toward the rear of the bike. You could try taking it off and clockwising (!) it a couple splines.

I made a mistake by stepping my son up to the full-sized GG 70 before he was ready. Too small is always better than too big. I think kids should be able to throw a bike around and be confident.

Maybe try pulling in the clutch, give it some stick and drop the clutch. I, too, have gone form a Sherco 290 to a GG 200. It's different on the big stuff.

On some bikes, the bearings protrude a bit into the neck, so you can knock them out from the inside with a long punch. If you are really lucky, the factory thought to include a notch or 2 so you can get a good purchase with the punch. Lacking those things, you may have to destroy the bearing and leave the outer race in the neck. If you run a bead of weld around the race, it will literally drop out when the weld cools.

In the absence of stop-squeak goo, I've used plain ol' silicone and it's worked fine. Anything to stop the pads from oscillating.

Believe it or not....this might not be the best method. The "timing-by-ear" method that many of us learned way back when, for cars (advance it until it pops, then back off a hair), doesn't necessarily work for less forgiving air-cooled engines. I've never timed one without a light, but I'd be reluctant to say that what feels best actually is best. What makes the most horsepower, for instance, just might cause the engine to run too hot.

Maybe check your flywheel key just in case. It seems that when the flywheel slips, the motor invariably starts running hotter.