alan_nc

I ride a '59 D7 in Trials. Had very similar problems. 1st I put a spacer between the carb and the cylinder. A Norton 650 carb mounting flange is perfect (about 1 and 1/2" long). Use gaskets on both ends to avoid leaks. 2nd Condenser: A condenser is a condenser. You don't want the standard BSA unit. Check the mf (micro farad range), of the unit. I found that old Chrysler units had a much higher rating (check hot rod web sites for ratings). Couple of things to check: When it doesn't start can you drain petrol from the crankcase? What color is the spark plug?, Probably need to go to a hotter (deeper tipped) plug. What kind of petrol are you using? They were designed to run on leaded gas (which runs cooler). I am able to buy leaded gas at a specialty store, most Air Ports have it. What oil/petrol mix are you using? I use a good synthetic oil and mix at 20/1. It is possible that the seals begin to leak after 1/2 hour of riding or the piston expands enough to stop the motor. Try this: After about 20 minutes of riding get into an open area, put the bike in third gear and ride at about 20 mph for 5 minutes. If you can then ride for another 20 minutes you definitely have a heating problem. They sure do seem to run hot - so do whatever you can to keep it cool. Alan - good luck, they sure are a fun Trials bike.

Guys, Well, I rode AHRMA (in the U.S.), took 2nd Nationally with the bike and never got a single complaint about the forks. I truly don't know if they are more lax over here or not. Alan

I went with early Yamaha forks on my '59 Bantam. You will find that the D1 forks are almost a "bolt on" conversion. A spacer is needed for the threaded stem. They are easy to rebuild, have the dampening you are looking for, and parts are available. It would seem they meet the "spirit" of the Pre-65 rules. I kept the Yamaha hub/brakes which are also an improvement. Some extensive grinding on the fork stops is also a big hellp.

Tony, Thanks for the info. Guess I won't bid on that one - really don't want to mess with changing all of that. Alan

Group, I have a 74 TY250A. Swingarm has some welding on it. There is a 77 TY250D swingarm on Ebay. When I looked up the part numbers the 74 and 77 show a different number. Can someone tell me what the difference is? Thanks in advance. Alan

Requesting an opinion here: Rode a Trial today. Several creek/river sections with the water probably 12 to 14" deep, also raining cats and dogs. Not in a sections but on the trail between, the bike started to run rough and finally quit (it has never done this before). Had to restart/ride a bit, restart/ride a bit then it cleared up. Ran fine for the rest of the Trial. Did I suck water into the air cleaner/carb or did I get the point wet? Well or any other suggestion you might have. Would like to solve this prior to the next Trial. Alan

I have had a bad set of shocks on one of the TY250's (leaking). Had a set of 14" shocks with great dampening but fairly heavy springs (don't know weight rating). I put these on this morning and then went out and rode several sections. When you went over an 18" log the front wheel cleared great....then the back wheel hit.... it was like dragging a brick over the log. It really showed me how much difference the spring rate of a shock effects the ride quality. We are so used to making minor changes that something like this really proves a point. Just thought I would share. Alan

As to tube position in clamp: Don't you really want the bike to sit level (front to back)? If you end up using slightly longer rear shocks and drop the clamp down on the fork tube wouldn't you end up with the front end much lower than the rear? I ended up going with a 6" rise bars as I found at the end of a Trial my arms were really tired from having so much weight on them. I also have the clamp even with the top of the fork tube. Rear shocks are 14" eye to eye, with standard foot peg position. With my size and weight (160#, 5'10"), I don't seem to have the problem with the forks bottoming out (no spacers -other than stock) and dampening seems fine. Guess you just have to play with it and find what works for you. Alan

Here is the guy from U.S. Ebay: I was slightly off on the price. Patrick Lytle info@lytleracinggroup.com Qty Item ID Description Unit Price Amount 1 JTF1263.12T JTF1263.12T 8.99 8.99 Subtotal: $8.99 Shipping: 5.98 Currency is in U.S. Dollars (USD) Total: $14.97 USD Alan

There is a fellow on U.S. ebay that stocks a whole line of JT or Sunstar sprockets. Just bought a 428 x 12 for about $12.00 including shipping. You need to check the different inside diameters (there will be at least 2) and tell the guy what they are. Usually Honda/Suzuki/Yamaha/Kaw sprockets are all the same. The one I bought is listed for a Suzuki. Look at the sprockets and just email the guy. I have two '74 TY250's, one has 520 chain and the other 428. I really don't notice any difference. No matter which size you go with replace the chain with the correct one when you do it. Chain is going to run about $15.00 (from any local motorcycle dealer). Alan

So is anyone else running NGK B5ES ? Alan - by the way the book does call for the 7

What did you use for oil when you re-assembled the bike? I usually use ATF in my bikes but my TY250 didn't like it at all. Had all kinds of problem shifting. Went back to straight 30 weight and haven't had any problems since. Just a thought. Alan

I bought six TY80's a few months ago (little rough, but mostly there) for $300.00. Built 2 very pretty ones from them and had no trouble selling them for $600 each. Sold another running but not pretty for $350. Once you get over 70 or 80 pounds you are to heavy for the bike. Alan (this is in the U.S.)

Mark, The multi-purpose tires are fine if you want to ride the roads some but you are going to be at a real disadvantage in a Trial. Don't know your local laws but a IRC- TR11, the Dunlap 803 or the Mich.... all will wear very quickly and be useless as Trials tires after just a few road trips, even if they are legal. Mainly because of the tires, Trials bikes don't lend themselves to multi-purpose use. Alan

What kind of bull is this. Every event they have planned this year has been cancelled. We had a group of us all packed and ready for the trip. I don't know about the rest of you but it's an effort for me to get a weekend away from everything for a Trial. Usually means juggling other plans (and owing my S.O.). I don't know what your problems are but lets get them straightened out prior to posting a notice that you are going to hold a Trial. Would you mind telling us now if you are NOT going to do Monroe................. Alan - a real unhappy camper.

Jon, Let me measure my ring and see if it is any different. Can't help on the cable - I have a local fellow who makes up cables, which seem to work fine. OK, question for everybody: If I'm jerky at slow (I'm talking very slow) speeds which way should the timing go to possible correct the problem? Thanks Alan

Well you gave me hope for a minute or two. Went to the garage and checked - both are standard "A" barrels. The one that is jerky at low speeds I know to be stock bore, the other I haven't had the head off. Both have the stock "T" (whatever) carb. My assumption would be that you advance the timing by a smaller points gap and vice versa. Thanks for the information. Alan

Group, Well I actually have 2 ,TY250A's. They run/ride quite different. I have not taken the time to pull the carbs apart and check jetting to see if they are the same. The one bike has a full width weight ring. It will run down to almost no RPM, I have actually never stalled it. I have a fairly fast-pull throttle on it and I think it responds fine. The other bike gets jerky when it gets that slow. It has a 1/2 width weight ring. Maybe my problem is jetting or timing rather than flywheel weight. Other than changing the point setting - is there a way to adjust the timing on a TY250A. My backing plate is a direct bolt on with no slots in the screw holes for adjustments. Any other suggestions would be appreciated. Alan

Didn't want to twist the other flywheel topic. Does anyone know where I can get the weight (ring) for a 74/76 TY250 flywheel? I'm looking for the full width one with as much weight as I can get. I have a 1/2 width ring and it just doesn't let the engine lug down the way I would like. I have emailed Trails and Trials, UK and Speed and Sport, Inc., U.S. neither have responded to my email. Alan

Looking at this from the other side: I have 5 Sherpa flywheels (both points and electronic ignition) and it doesn't look like any of them. Also have several 74/76 Yamaha flywheels and it doesn't look like them. But I guess you already knew that. Alan

Tony, Congrats on completing the PRE-65 After looking at the photos of what you guys went through and realizing how tired I was after just riding a standard U.S. Trial I know I'll never even try it. Alan

Dave, Bike ran great.... Thad still beat me on the old montesa. Alan

Have to put in a note about the '74, TY250. Rode a 32 section Trial this weekend. Both modern and vintage bikes. The TY never missed a beat. Started 1st kick every time. Used all 5 gears as it was quite a distance between a couple of sections, no shifting issues. Had plenty of power for all the climbs, brakes worked well on the downhills. In the hands of a good rider I can see where this could be a very competitive machine. Alan

Andy, Interesting thought. I'll richen up the mixture on that bike and see what happens. Thanks Alan

Dt piston does fit in a TY (ports should be the same but do check). You will need to grind the corner (if thats the right word) of the skirt to clear the crank. On your shim discussion: Doesn't the book say "if needed" by the shim? Lord knows how you know if it's needed. Alan