mcman56

I have an old aluminium gas tank that looks like it was not used for many years. I poured out some stinky gas, filled with fresh gas and shook it periodical for a couple of weeks to clean it out. After draining and drying, I can see sort of a layer of solidified gas lining some of the bottom. The petcock must have had a slow leak because it is covered with what looks more like dried tree sap than dried gas. Are there any solvents that will remove this? A non hazardous one would be nice but not required. I can also see that there are a couple of pin holes close together. Has anyone had luck with using epoxy to spot treat pin holes?

A flywheel weight really helps slow down the engine response. I believe all UK bikes come with them but someone may have taken it off. Pull the cover and take a look. They look like the picture below and are mounted to the outside of the flywheel. Also take a look at how many teeth are on your front sprocket. It is counter intuitive but lower gearing (less teeth on the front) slows response by reducing the transition from clutch in to clutch out. The bike will go slower in first gear. Lower gearing also makes it harder for the bike to totally get away from you because it will run out of rpms before too long. Many Betas come with an 11 tooth front. I ended up with a 10 but a 9 is even better for the situation you describe. A 9 kills come of the response to get over an obstacle but that may be exactly what you want plus you can always use 2nd gear. Front sprockets are also cheap. I also agree on comparison with another bike.

Looking at self etching primers, none show as heat resistant to go with engine paints. On top of that, engine paints seem desirable due to resistance to fuel. Are there any specific recommendations?

This is an interesting comment. I also noticed some odd looking rust on the bottom frame rails that were probably under the skid plate. The rust is protruding up from the surface, sort of like crystals growing on the surface. There is not much but it does look odd. I was planning to remove rust and paint this area. Other areas of the frame just look a little rusted and similar to what is found on other bikes this age. Are you suggesting that the frame should be totally rust free? The skid plate is also steel and will get cleaned and painted.

This is an interesting comment. I also noticed some odd looking rust on the bottom frame rails that were probably under the skid plate. The rust is protruding up from the surface, sort of like crystals growing on the surface. There is not much but it does look odd. I was planning to remove rust and paint this area. Other areas of the frame just look a little rusted and similar to what is found on other bikes this age. Are you suggesting that the frame should be totally rust free? The skid plate is also steel and will get cleaned and painted.

I have a 76 TL250 with pretty severe pitting on the outside of both magnesium engine side covers. They are structurally sound and this is not a restoration so I'm not concerned with a cosmetic repair. However, I would like to prevent further corrosion. For better or worse, they are both now bead blasted clean. This is an air cooled bike but must have spent some time parked near water. I'm in a mostly dry climate so there should be no significant moisture exposure. Some on line sources say that Alodine or some other "conversion" prep is needed first to prevent corrosion. Other sources say that Alodine will actually promote corrosion in magnesium and make it so paint will not adhere well. These chemicals do not seem readily available or cost effective plus can be hazardous so are not desirable. I do think I saw some gold tint on a cover when blasting but if it was Alodine, it did not help the original finish. All sources seem to agree on a self etch primer but it looks like these are mostly lacquer based except maybe the Rustoleum brand. They also come in different colors like green and gray which must signify some difference. Is one better than another for this purpose? I plan to top coat with some enamel roughly matching the original Honda paint color. Does anyone have experience with something like this?

Does someone sell a flywheel weight for a 2016 Evo 125? I had this apart a while back and IIRC it was not the newer "reverse mount" type flywheel like the newer models but it was a little tiny thing unlike anything I had seen on other models. The rider is 79 so I think most advice against putting a weight on a 125 does not apply.

I did that on a 2008 Rev 3 and believe it will work on all years. There is a bush pressed into the small end of the rod that needs to be pushed out to accept the 250 needle bearing. You will need the piston kit, cylinder and head. After that, it is plug and play. Exhaust, carb and everything else fits. Although you will see some listed specifications saying otherwise, I understand that the Beta 200 has always been a small bore 250 not a big bore 125 like other brands. Earlier models actually had a steel sleeve pressed into the aluminium cylinder to reduce bore size. I have seen pictures. Later models like my 2008 had an all aluminium plated cylinder. They run a bronze bush in the small end bearing with no needle bearing. Have you looked at the bore of your cylinder yet? I ended up putting the 200 top end back on the 2008 before selling it and still have the 250 top end. I may be interested in a 200 top end depending on condition. You could PM if interested.

The ball plunger/ spring mechanism on my TY175 kick starter is not doing a great job of keeping the kick starter rotated in out of the way when riding. I tried a stronger spring but it is still not great. Is there a way to improve that function? I wonder about deepening the hole that the ball drops into when rotated in but don't know if that would help or make it worse. The fit of the kick-start lever to the shaft it rotates on is not like new but not bad for an old bike. I had a similar issue with a TLR200 but never came up with a good fix.

Can 1976 Honda valves be resurfaced? It sounds like some valves can not.

I'm trying to clean the valves on an old TL250 but am not getting much progress. I have been using oven cleaner and the intakes are getting pretty clean but not the exhausts. Is there a better way?

In the US most everyone wears knee/ shin guards mostly of the MX type. I don't find them confining. I once cracked the hard plastic on the outside of the knee guard so am certain it saved me from a nasty injury.

I have also gone to 100 psi many times with no issue. For safety, I use one of the clip on air valves so I don't have to hold it on the tire. I have a steel man door on the garage and put the wheel on the outside of the door with me on the inside. I can then turn up the pressure from the inside until I hear a pop or just give it time. I can then also turn down the pressure before I inspect. Even if something catastrophic happens, I should be OK. I use regular tire mounting lube from an auto parts store. I do think bad things can happen. I once bought a bike that came with new tire but I don't know how new. I took it to a shop for mounting and got a call that I was getting a brand new tire because something happened during install and the installer broke his wrist. The tire in question was being saved for the insurance company but I could never get full details.

It looks like I'll be rebuilding the top end of a TL250. I don't see any piston kits on line so does anyone sell them? Are there other sources for valves, cam chain, etc.

I'm not sure if it is the same gearing, but I went from an 11 tooth to a 10 on a 2016 300 4t. I think it made slow tight turns with clutch slipping easier. It was also less abrupt when letting out the clutch. The bike picks up less speed when going over a series of obstacles close together. I tried a 9 tooth and it made tight turns even easier but killed some of the snap used to get over obstacles.

The cam chain has an automatic tensioner.

I know someone who had the same kind of failure. He suspects that the sprocket bolts got loose and led to the failure so was extra careful with reassembly using good, bolts, washer, thread locker, etc. It sounds like lacing those rims is no easy task.

Timing issue could be flywheel that was not located properly when installed after rebuild. Kick back is generally advanced timing.

These guys have base gaskets and may have head gaskets. IIRC, the head gasket is o rings that you may be able to source locally. If gaskets are in good shape, it is possible to reuse but probably not recommended. https://trialssuperstore.com/products/beta-techno-base-gasket More techno parts https://trialstribulations.net/index.php?main_page=index&cPath=91&sort=20a&page=4&zenid=cfaa76cb7fc85861dcb71200c4442b65

I have a beta 4t and it does not tolerate bogging down like a 2t. (Too much load at too low an rpm). A pop and stall is the usual result but sometimes just a stall. If I try, I can even bog it down in 5th gear and get it to do it. I just have to avoid dropping the rpm too low when letting out the clutch

Do you get a "pop" and stall or just a quiet stall?

I have tested several trials bikes and have always gotten something around 155 psi, maybe +/- 5. It would be good if you had some way to check the accuracy of your gauge...or test another bike for comparison because the gauge could be off..

What year is the Rev 3? I had a 2008 that did not have designed in advance. If you put a timing light on it, you would see maybe 5 degrees but all no advance ignitions will show that. An aftermarket company sells a coil/ CDI combo for that bike and I have one as a spare even though I do not have the bike. I tried it on the bike and it ran the same. At one time I had a 1997 Techno and is showed about 21 degrees of advance. https://www.electrostator.com/en/trial/5680-cdi-beta-125-rev-3-200-rev-3-250-rev-3-270-rev-3.html FWIW, I now have a 2001 Rev 3. I purchased a flywheel weight that was said to come from a techno and it bolts right on. It says Ducati right on the weight but I don't remember what is says on the flywheel.

Not the same bike but an extra 1 mm base gasket added to a 270 Beta made it noticeably easier to kick. The side effect was a slightly softer response. It is inexpensive, easy to do and reversible.

Nice video. Where can you get the rebuild parts?