jse Posted September 4, 2009 Report Share Posted September 4, 2009 Well, since the A/C Mono forum has gone a little silent, I thought I'd throw something in for us to chew on. This 85' TY350 has been in the family since we bought it new and I like to ride it at our Vintage events in Non-Comp, just-for-fun class. It has become a test mule for my wild-hair, "hmmm, what if we did that?" brainfart projects and has been modified so many times it starts to whimper when I walk in the shop door. Photos are of a couple of the latest changes: I revalved a Works Performance shock, added a steel-braided line and a adjustable remote reservoir. The intake is a one-piece reedcage/manifold I made several decades ago and uses early CR125 dual-stage reeds. The internally modified Mikuni flatslide 26mm has a machined sleeve to extend the spigot. Anybody else out there doing weird things to TY Monos? Jon Quote Link to comment Share on other sites More sharing options...
wherry Posted September 4, 2009 Report Share Posted September 4, 2009 OK let's keep it going! Looks good, Jon. Have the mods you've mentioned been generally positive and improved things? Or have they been interesting exercises but that's all? Oh and can we see some pics of the whole bike? Quote Link to comment Share on other sites More sharing options...
jse Posted September 5, 2009 Author Report Share Posted September 5, 2009 OK let's keep it going!Looks good, Jon. Have the mods you've mentioned been generally positive and improved things? Or have they been interesting exercises but that's all? Oh and can we see some pics of the whole bike? Actually, I can't think of any modification on the bike that didn't provide the improvement I was looking for. I do, however, spend a lot of mental time/visualization on the mods before fabricating them so the actual building is fairly easy. I just manipulate the material I'm using to fit the mental image, kinda weird I know, but I doubt I'm alone in this. I'll take some photos when I get it back together. It's not a Concours show piece, but is designed for hard riding. I guess that after riding it for 24 years, the changes now and then make it still fun to use. Jon Quote Link to comment Share on other sites More sharing options...
wherry Posted September 5, 2009 Report Share Posted September 5, 2009 Good answer! I totally agree with the visualisation thing - you've got to build it in your head before you can build it for real. True in many walks of life I reckon! I've always had a bit of a soft spot for the TY monos. They were THE bike to have round here when I was 18 or so, back in the day. I never rode one then but they seemed a world apart from my TY175 or Italjet twinshocks. I've ridden one recently though and I think I preferred the feel of it in some ways to my friend's GG250Pro. The only problem with it was we just couldn't get it to run right - rattling like mad on the over-run and not wanting to rev out at all. Had to be a carb issue I think but we tried changing just about everything, including a new OKO, crankcase seals, cleaning out and re-packing the whole exhaust, timing, coils, spark plugs and nothing we did seemed to have the slightest effect on it which makes you think there must be some other fundamental thing going on. I haven't seen friend or bike for a while now so I don't know if it's been resolved but I suspect not. Do I remember from an old thread that you've done a fair bit of head work to get the 350 going well? Or was that someone else? Quote Link to comment Share on other sites More sharing options...
jse Posted September 5, 2009 Author Report Share Posted September 5, 2009 Good answer! I totally agree with the visualisation thing - you've got to build it in your head before you can build it for real. True in many walks of life I reckon!I've always had a bit of a soft spot for the TY monos. They were THE bike to have round here when I was 18 or so, back in the day. I never rode one then but they seemed a world apart from my TY175 or Italjet twinshocks. I've ridden one recently though and I think I preferred the feel of it in some ways to my friend's GG250Pro. The only problem with it was we just couldn't get it to run right - rattling like mad on the over-run and not wanting to rev out at all. Had to be a carb issue I think but we tried changing just about everything, including a new OKO, crankcase seals, cleaning out and re-packing the whole exhaust, timing, coils, spark plugs and nothing we did seemed to have the slightest effect on it which makes you think there must be some other fundamental thing going on. I haven't seen friend or bike for a while now so I don't know if it's been resolved but I suspect not. Do I remember from an old thread that you've done a fair bit of head work to get the 350 going well? Or was that someone else? The key to good running on the 85/86 TY350's was a change in the combustion chamber design (very much like the early Honda CR500's-great engine, but poor execution of the head design). The trapezoidal combustion chamber was the rage at the time and, although workable, it was not as effecient as the later hemi, and when matched with an overly wide squish clearance in the 350's (usually measuring 2.5mm on up on the TY's I've checked- 1mm would be the design target) it produced a rattling, wheezing response-especially when the engine got hot. The TY 250's of the era were a better running engine (affected to a lesser degree by design parameters), but we got the 350 here in the U.S. almost exclusively. I'm guessing that the marketing department at Yamaha felt that the "small" engine wouldn't sell well here in the land of "too much is just right". It would seem that the theory still is in effect to a degree, with the larger 280/300 engines popular here and the 250's seem to be more popular in the rest of the world. The 250's are making a small comeback in the U.S. as newer riders have a chance to ride the bike and find that the power is more than adequate. Maybe we will get fewer "how can I soften my bike's response" questions... For the higher altitudes, the 280/300's still make good sense. I machined the TY head to a hemi configuration and use a .003" copper head gasket with the squish set to .039". Never a rattle or signs of overheating and the throttle response is like a newer type engine. Jon Quote Link to comment Share on other sites More sharing options...
jse Posted September 12, 2009 Author Report Share Posted September 12, 2009 Oh and can we see some pics of the whole bike? A couple of quick photos of it in it's present condition. As I say, it's a runner not a poser so it has it's share of scrapes and dings, and it sure is fun to ride. Jon Quote Link to comment Share on other sites More sharing options...
jse Posted September 12, 2009 Author Report Share Posted September 12, 2009 A couple of quick photos of it in it's present condition. As I say, it's a runner not a poser so it has it's share of scrapes and dings, and it sure is fun to ride. Another quick shot. Jon Quote Link to comment Share on other sites More sharing options...
pedronicman Posted September 16, 2009 Report Share Posted September 16, 2009 I see your TY350 looks like it has a TALON front disc brake conversion also.. Quote Link to comment Share on other sites More sharing options...
jse Posted September 16, 2009 Author Report Share Posted September 16, 2009 I see your TY350 looks like it has a TALON front disc brake conversion also.. It does and it works quite well. The Talon uses the early AJP pads and is quite simple in operation. Jon Quote Link to comment Share on other sites More sharing options...
wherry Posted September 29, 2009 Report Share Posted September 29, 2009 Caught up with this the other day. Nice looking bike, Jon, and just the way I like them. My bikes and cars are all runners as you say as I hate polishing for the sake of it - I don't mind in the least giving things a good clean if I'm fettling them but I always seem to have 1001 better and more interesting things to do with my time than polishing things. Quote Link to comment Share on other sites More sharing options...
kuelmuel Posted January 11, 2010 Report Share Posted January 11, 2010 Could you post some details of more of the mods you've done? I'm collecting information slowly for if I can ever find one in the UK or afford to import one. Quote Link to comment Share on other sites More sharing options...
jse Posted January 11, 2010 Author Report Share Posted January 11, 2010 Could you post some details of more of the mods you've done? I'm collecting information slowly for if I can ever find one in the UK or afford to import one. Here's a few modifications: Frame/suspension modifications: Footpeg mounts lowered and moved back 1 Quote Link to comment Share on other sites More sharing options...
marky g Posted January 11, 2010 Report Share Posted January 11, 2010 Nice work jon, I've just bought an 86 250 (a 59N I think?) nice original bike that will get some TLC, i've just cut the old foot rest mounts off and re-made some better ones. What do you think of the Sammy Miller seat/tank unit?........i see he still sells them and I might buy one for mine........I'll post some pics when it's done Quote Link to comment Share on other sites More sharing options...
jse Posted January 11, 2010 Author Report Share Posted January 11, 2010 Nice work jon, I've just bought an 86 250 (a 59N I think?) nice original bike that will get some TLC, i've just cut the old foot rest mounts off and re-made some better ones.What do you think of the Sammy Miller seat/tank unit?........i see he still sells them and I might buy one for mine........I'll post some pics when it's done I like the tank, it's well made and fits nicely. You will need to seal it before using (I used a product called "KREEM" here in the states) and I've never had any sign of leakage. The tank on my bike is quite a few years old and if you don't throw it on the rocks, is quite durable (when I fall over, I try to position myself between the tank and the rocks..... ). The air filter is easy to get to by taking out the rear fasteners, take off the fuel line and then the whole tank pivots up at the back. They are fairly pricey here, but so is trying to find a stock Mono tank in really good shape on this side of the pond. I still have my stock 85' tank which cracked all over the outside, but intererstingly, never leaked at all. Jon Quote Link to comment Share on other sites More sharing options...
jse Posted January 12, 2010 Author Report Share Posted January 12, 2010 Nice work jon, I've just bought an 86 250 (a 59N I think?) nice original bike that will get some TLC, i've just cut the old foot rest mounts off and re-made some better ones.What do you think of the Sammy Miller seat/tank unit?........i see he still sells them and I might buy one for mine........I'll post some pics when it's done A photo of the one-piece intake and the carb mod: Quote Link to comment Share on other sites More sharing options...
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