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About Tillerman6

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    Advanced Member

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  • Bike
    Yamaha TY 250 A

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  • Location
    North Idaho (Sagle to be exact)

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  1. Tillerman6

    Still can't find the missing needle bearing - advice?

    I like the kerosine idea better than water. And I had some terrible results from WD 40 with making things rust, so that one is out as well. I will have to remove the engine from the frame in order to shake the cases well enough. I have some magnetic tape that might fit between the crank case weights and the inside of the cases. I am not trying to use the old needle bearing again. I am sorry my sad story sounded that way. I have a new needle bearing set and a new pin and piston and pin clips, new rings of course. I might get real energetic and clean out the shop floor 100% into the driveway and see if anything shows up on the floor. that would be the easiest route if it works. Just now I rotated the crank with a bunch of 2 stroke oil in the cases and I could not feel any dragging or friction. There is enough oil in the cases to coat the crank shaft weights as they dip into the oil, but they are not showing any signs of skuffing or disturbing the oil coating as the weights rotate thru the oil. So now I'm wondering what is the down side of splitting the cases? Are there any parts that would be hard to find/replace such as special gaskeIts or anything that would be risky to do? And the other question is : Assuming that all the above sloshing and dumping does NOT turn up anything - then what? I did not see anything fall into the engine, and there is still the possibility that the bike was put back together without the roller at some earlier point in time. So would you just put it back together and fire it up? I could put all the old parts back on it too. I still have the old piston, cylinder and rings etc. That way if it goes ka-pow it will only be the old piston and cylinder at risk. I would use a new upper roller cage with this scenario of course, but having a few minutes or hours on the engine without a failure would probably rule out the chance that there was still a gremlin lurking inside without exposing the new piston and bore to the risk of FOD damage.
  2. Due to the home projects I had going (new boat shed) plus some upcoming winter weather and the extended time it took to get a cylinder re-bored and plated, new piston, etc, I have not actually started putting the engine back together. That is because of one other nagging problem that is bothering me. That is the missing needle out of the upper needle bearing cage that was part of the engine when I tore it down. I noticed that it was missing from the cage when I took the piston off the con rod. There was a rag under the piston, but with my luck it could have found it's way down into the cases under the flywheel. I have looked everywhere for it, and I even got a fiber optic light cable down under the con rod between the flywheel weights to look for it, but I can't see anything out of the ordinary. I looked on the shop floor of course and tried a magnet as well. but got nothing. So the next step is to split the cases and look for it inside. This step is beyond my expertise and tool selection so it would probably cost around 150.00 to do the inspection (I am guessing) but at least I would have the peace of mind knowing that there is no foreign object lurking in the cases waiting for the worst possible moment to come loose and ruin the new piston and bore that I have already spent 450.00 to get to this point. If anyone has any advice or expertise in this area, I would be very glad to hear it!
  3. Tillerman6

    Securing studs into rebuilt cylinder -advice?

    Will do. And looks like there is a slight difference in the threads on the studs so that the longer end is down in the aluminum. Thanks for the info!
  4. Maybe someone knows this one? I got the rebuilt cylinder back from Millenium with a chrome bore and new piston,(ended up being a Wiseco piston) but the 6 studs that hold the head on were not installed. The threaded holes are in fine condition and very clean, but can someone tell me what sort of chemical(s) should be used to keep the studs from backing off? I am thinking some sort of Locktite, but I am not sure. Also, the studs have more thread on one end than the other. Which end should go down?.
  5. Tillerman6

    Piston to cylinder wall clearance

    You could call Millenium Technologies and they would know for sure. They do hundreds of cylinder overhauls a month. I have no connection myself. Or email them on the web. Sales/Customer Service Millennium Technologies/ Revolution Performance 1404 Pilgrim Rd. Plymouth, WI. 53073 1-888-779-6885 EXT.351 www.mt-llc.com
  6. Tillerman6

    Next item to modify (for me) Rear Brake Lever

    I apologize for my ignorance, but you must be saying that the rear brake can be used to help balance the bike? Can you elaborate a bit? And are you saying that the kits will move the pegs even further back than the rear most position of the TY 250 A model?
  7. If anyone would care to post a picture of a trials gear shift lever for the TY 250 A and / or just tell me what the length is supposed to be? I think mine is non- standard as the original owner had the bike set up for trail riding and I want to switch it back to trials mode for the time being.
  8. Tillerman6

    Next item to modify (for me) Rear Brake Lever

    Could you please please post some pictures of your TY? I am starting to understand, but without pictures it's a lot harder. Also I was thinking of getting a TY 175 as a second bike, but I don't know much about them, and they only come up for sale rarely around here, so I was hoping to see what your bike is like and boost my knowledge. I am especially interested in mods for better control and rider comfort if that is what you are doing.
  9. Tillerman6

    To Nikasil or Not to Nikasil - That is the question.

    Metisse, Well, that's good information. Hope mine turns out as well. Millenium called today and could not get a piston from Wossener, but he could get a Wiseco, so my Nikasil'd cylinder will now eventually get back to me with a new piston and be the original size.
  10. Tillerman6

    Advice/thoughts on top end and clutch. 74 TY250A

    Johnnyjazz, A little more researching and looking at clutch replacement kits and I discovered that the brown tips of the plates you showed in your picture are actually made from friction material which is naturally brown already. So that is not rust you are seeing in the photo, just normal friction plates! Makes sense to me. Every other plate is steel, and every other plate is friction material, So I would leave it alone until you know you have a problem. But since you drained the oil you might want to try some Belray 75 weight gear oil. That stuff is great and the clutch pulls in like butter. Does not seem to need as much clutch lever force as before to get it to release either, so I think I will stay with it. If you are still thinking about replacing the main seal under the magneto (mine was leaking 2 stroke mix) I put in a photo of the seal that was removed with sheet metal screws and some very carefull shallow drilling of the metal ring which is built into the seal itself.
  11. Tillerman6

    To Nikasil or Not to Nikasil - That is the question.

    metisse, That would be great! The more detail we can get on this subject the better. And if there are any other mods to the piston or cylinder such as a ceramic coating on the crown of the piston, or porting mods, or changes to the flywheel weight, or the head itself that has been done? Depending on how long this takes, I might be able to still have it done to my cylinder while it is being overhauled. Way back when I started riding, there was a story in one of the Dirt Bike magazine issues that ran an article on two stroke mods that one shop was doing to some of the engines. It had mostly to do with balancing the piston to the crank shaft so that the vibration was minimized. This was around 1972 and I have long since lost track of the information, but this was also about the time that everyone started using reed valves and adding or changing the shape of the ports in the side of the piston. This had a real postive effect on the low RPM torque of my motocrosser and was not that difficult to do. It made a drastic difference in the way the bike would pull and made the power band much wider than it was before the mods.
  12. Tillerman6

    To Nikasil or Not to Nikasil - That is the question.

    So you didn't buy the bike from him right? In my case I developed a bad habit of closing the throttle and coasting down hill letting the engine do the braking. That might be OK for a couple of feet, but is not a good idea for much more distance than that. All my fault. Could not find more brake shoes to replace the worn out ones I had, plus the brake pedal was pretty hard to catch with my foot. It was the longer version and the pegs were already moved back to the trials position. I was never in competition with the bike, so it did not seem to matter much.. At that time the rattle was bearable, but later on the bike developed a "detonation" sound that I could not figure out, so I took the cylinder off looking for clues. I don't think I would have done that if it was not for the detonation banging on down hills with the throttle closed. Anyway, I still am hoping for a much quieter bike after the exhaust is cleaned out and the new piston and bore is put back together. Also hoping I can rule out the possibility of a lost pin from the upper end needle bearing that might be floating around somewhere inside the cases. I discovered the missing pin when I pulled the piston out.
  13. Tillerman6

    To Nikasil or Not to Nikasil - That is the question.

    jon v8, I wish I had 3 other "donor" engines to take parts from like you do. Then I could have quickly determined that my cylinder was junk from the get go. I had nothing to compare it with, so I sent it off for inspection. Glad I did that because the machine shop said it had too much damage to be economic to repair. So I found another cylinder on Ebay and had it sent to me first. This all took some time, but that delay caused me to start looking for other problems that might have caused the hard starting and kickbacks that were happening if the engine was cold. As soon as I got the next cylinder it was obvious that it was different than the original in that area around the intake port. All the edges were equal distances from the top, so the old cylinder was definitely bad after all. So I sent in the next cylinder for Millenium to work on. It has some wear, but should be useable. And this waiting time that was created from having to swap cylinders actually worked to my advantage because I started working on the expansion chamber and spark arrestor. I think I found enough caked on carbon to say that it was causing a restriction for the gasses and most likely contributed to the hard starting while cold. Feetupfun clued me in on the Yamaha "swirling" gas spark arrester, and I found that these are built with an aluminum bullet shaped cone that is supported in the spark arrester by a "web" which causes the gasses to spin as they are exiting the restricted area. However, the clearances for the escaping gas are very small, and the carbon can easily clog the area in question. (especially in 44 years) It is sort of a man made "bottle neck" situation. I cleaned out the silencer with solvent and de-greaser only because the aluminum bullet would be destroyed by a "burn out" of the carbon, but I did a slow burn out of the main expansion chamber itself in an effort to rid myself of any restrictions. I think some of that "rattles like a bag of spanners" might be from the restrictions in the silencer you have or possibly from missing rubber vibration dampers that were put there by the factory to dampen out some of that rattling. The cleanout is very straight forward and just re-pack the spark arrestor, but the rubber dampers themselves my be hard to come by.? Maybe some high temperature silicone sealer would work as well. Nikasil- I have a feeling that Millenium will not do a Nikasil plating on this "new" cylinder after all. I don't have enough positive "votes" for it from the guys here to make me want to order that process. There are some new variables that tend to make it a more risky proposition than just plain cast iron for the bore, and so I am not so keen on having it done.
  14. Tillerman6

    To Nikasil or Not to Nikasil - That is the question.

    metisse, You must be the guy that mentioned it first on here? I could never find your post about Nikasil again. Thanks for the input. Wish I knew more. The hard part about it seems to be getting the rings to seat without any seizing in the process. Some of the other guys mentioned that you might need special rings to keep them from sticking since a high percentage of the ring material is nickle to begin with. Another guy who was running 2 stroke 750 cc four cylinder sidecar engines said it worked well after a cylinder has seized once as a repair, but the pistons would wear out sooner with the Nikasil and have to be replaced again. (see other comments in this thread) So it looks like the idea has not caught on well here in the states except as a repair when no oversized pistons are available. Sort of a "plan B" ? And finally the Nikasil is the only way to go if there is no cast iron liner in the cylinder and you are on bare aluminum. This would be the case if you are running a non sleeved 320cc cylinder in a bike that uses the same outside cylinder with a cast iron sleeve for a 250cc displacement. All that being said, however, I would still like to hear more about your friend's Nikasil improvements. We all would if that is still possible? How has it been doing lately and how many hours are on it now? What piston was used as a replacement and has there been any problems or changes made?