alan_nc

A weak spark would point at the condenser. Usual setup is to move it up on the frame near the coil getting it out from the heat/dirt/oil of the engine. Very often have a broken wire in that area also. Just something else you might want to check. Alan

I don't know that this addresses your post but I used the cub swingarm and the cub rear wheel and hub. The original Bantam wheel wouldn't fit a stock Trials tire which was my reason for going to a cub wheel in the first place. Alignment with this setup was one of the few problems I didn't have. Alan

Hum, I like the Gator idea. I've got Yamaha DT forks on my Bantam and that would hide them pretty well. ;0)

Couple of thoughts: If the plug is wet then there is enough suction to pull gas into the cylinder - so the seals aren't completely shot. You could try spraying WD-40 behind the flywheel (trying to get it onto the seal). That might seal a leak enough for you to see if that is the problem. The clutch side usually has oil splashed up onto it anyway. Definitely check the timing and for a sheared key. Make sure you DON'T have the air cleaner connected - that would slow gas pulled into the cylinder. Try a shot of ether (usually called starting fluid) directly into the cylinder. If the engine starts with either pure gas or ether shut it off right away - you aren't giving it any lubrication. Just some thoughts. Good luck with the problem. Alan

Welding (actually heliarcing) the cases is simple for a good welder. You will have to split the cases again and clean them very good. Oh, it will show, you can't grind or polish it out. Look a some of the work the welder has done on aluminum before you let him do your cases. Alan

This guy has always had the parts I need for my Bantams. I have re-done a D1, D3, D7 and am now doing a Bushman. chasbike650@ntlworld.com He is located in the U.K. HTH Alan

Don't know where or in which events you ride but "I Think" the flat slide carb is illegal in AHRMA events. Alan

I know you said you have been through it twice but it sure sounds like a clearance problem. It seems like a silly question but did you check the dims on both ends of the crank and the receiving points on the cases? Also, is the crank straight? Did you place it in V blocks, rotate it while running a dial indicator on different sections? Was this crank in this engine originally and did it run well? You may have a crank that wasn't heat treated properly and expands to much when hot. Just a couple of thoughts. Alan

Now you have to pull the side cover off and see if you have a lighting coil installed. If you do then you need to see if the wires are connected. Good luck. Alan

You have several options. How many wires are coming out of the gromet at the top of the left side case? Should be one going to the secondary coil (to provide spark), probably one going to the kill switch and if you have two more - one for the headlight and one for the taillight. Put a VOM (Volt/Om Meter) on the wires while the bike is running and see what the output is. If the bike isn't running yet remove the left side case and look inside the flywheel slots to see if it is fitted with a lighting coil. There will be two coils inside the flywheel - one to the front of the bike one toward the rear. The front one provides spark and the rear, if fitted, provides power for the lights. You may have to pull the flywheel to make sure the lighting coil is wired up correctly. It would have come from the factory with both coils but many riders remove the lighting coil to save weight and avoid complication. HTHs Alan

I picked one up about a year ago. I have ridden it in a couple of Vintage Trails, does fine. I never did take the time to sort it out properly but it had plenty of power and a very good turning radius. I normally ride a TY250 which I do like better - even though it is a bit heaver. I quit riding mine when I checked on the price of some spares. They cost 2 or 3 times what I can buy the same part for my TY250s. Probably should sell it as it's just sitting in the garage.

Bypass the carb and spray either a "small" bit of starting fluid directly into the carb with the slide up. Or use a squeeze bottle with the gas/oil mix. I would say that a good bit of your problem is not being able to get a good kick with the bike on a stool. Alan

While we are talking difficulty: I know I'm a bad rider but I have Fived the loop route more than once and had hill climbs harder than in a section. Don't forget the Novice Rider has to be able to get to the sections.

John, I think the comment on distance is a big factor. I would ride AHRMA and ITSA events but there is only one of each within a 5 hour drive of me (each year). To ride either series requires a big commitment and considerable expense. Nothing against Gated Trials but I really think they are just what we call a "Play Day". Peer scoring makes a Trial so much more fun as you have a group to ride with for the entire day. The new rider gets cheers and help/suggestions from the rest of the group. Also cuts down on planning and headache for whoever organizes the event. No simple answer, do think this forum helps.

In the Trials that I ride they have hills and large rocks that require quite a bit of power (or very low gearing if you have no power). Even with this engine overbored to 182cc's, electronic ignition and the 'special' head I did not have enough power climb some of the hills. I don't have anywhere to ride Vintage Trials so have to ride against Modern Bikes. I currently have the bike in the garage for a complete re-do. Have been riding a TY250 this year which, except for the weight, allows me to do just about any of the sections in a Modern Trials Course. Alan

Interesting point: When I was a kid the bike shop was a 'hang-out'. Not so today, in fact in my area the Honda shop (over 20 years in business)closed this year as did the Harley dealer. There are two multi-brand dealers: BMW, and other high end bikes, and Asian , who also sells jet skis and 4 wheelers. I don't think you can buy a Trials bike 'off the shelf' in NC.

Couple of thoughts: First if you ride on the street your Trials Tires won't last a month. If you put street tires on it the bike is useless for Trials. My personal choice for gas tank cleaning/coating is Caswells but I have also had good luck with POR15 - I would stay away from Kreem. I never powder coat. You can paint yourself for almost nothing and if you are going to actually ride Trials it is going to get scratched up no matter what you use. Sit on the bike as if you were riding on the street....and see where your butt is - I'm 5'9" and mine is on the back fender so putting a lot of money in a seat...... Just my personal choices. Alan

Here is another source for parts, just to get a comparison price. http://www.boats.net/parts/search/Yamaha/parts.html Alan

It has always been a problem with my Bantam (over heating). Here is what I did with the carb to try and help the problem. Also went to an electronic ignition - both helped but still was difficult to start at times when hot. Alan

If your not in a panic to put it back together check Ebay. I have purchased them for under $10.00 a set. If you want them "right now" this place has the best prices I've found: http://www.boats.net/ Good luck with the project. Alan

Bill, Should not be a 'press' fit. Check the O.D. of the crank journal and the I.D. of the bearing. It should be tight but not an interference fit. You may have to do some light tapping with a rubber hammer but not more than that. Lube the seal(s)prior to assembly. If you have further problems email "Feetupfun" directly with your questions. Alan

Nick, On the TY250's Most people don't actually remove the lighting coil - they just remove the lights. The lights command quite a price on Ebay most of the time but if you don't mind one with dents or scratches you can pick one up for a few dollars. I think even 20 miles on a TY250 would be pushing it. Mine are geared so that in 5th you are doing maybe 40 or 50 with the engine running a high RPM. Suzuki used to make a TC185 with a dual selector gear box. Had five speeds and a selector to change from low range to high range. Might be a thought. Alan

TY250 comes stock with a lighting coil (and lights). Most have been removed but it was there when bought. That said: Bit of a stretch to ride 50 miles on roads and then ride in the woods for several hours and ride 50 miles back on roads. The gearing you want for Trials would make your road speed either very slow or reving way more than you would want for a long distance. They do make things called "long ride" seats. Don't forget you are talking a 35 plus year/old/bike. Trailers are fairly cheap. Just some thoughts. Alan

Email "Black Cat" (check for his posts here), I think he has a listing for the years. Most people block off the autolub and use premix. Use any good synthetic 2 stroke oil - probably best with motorcycle specific oil. Mix the way it tells you on the can. For the gear/clutch oil. Most avoid synthetics (to slippery for the clutch). Some folks use automatic transmission oil. You really want the cheap 10/30 without the Moly in it. Don't have a heartattack over it - ride and enjoy, just make sure you do have oil in it. Alan

If you are in a really big hurry you can just go down to your Yamaha dealer and buy one. That carb is used on several bikes. Ebay will be cheaper. You can always get one from one of the vintage bike suppliers.