1oldbanjo

The TY80 is a low stressed motor, and as long as the carb is jetted correctly you are not going to see much difference in buying a high dollar spark plug instead of a basic one. Go with the stock plug and see how it works - if you are not having any problems there is no reason to buy anything else. Modern fuel injected engines in cars can benefit from plugs that are made from exotic metals because they can go for many, many miles before the tip of the plug wears out - you will not see that kind of miles on a TY80 and will probably replace a plug because it is dirty....not worn out. I just bought a standard Champion plug last week for a $ 1.50 at the local auto parts store....and the bike runs just fine with it.

Avgas 100LL runs richer than pump gas and you need to rejet if you want it to run well. Your eyes are burning because they have not re-jetted their bikes and they are running too rich. I used Avgas in my bikes and chainsaws for about a year - it ran OK but wasn't worth the 1.5 round trip that it takes me to go buy it. Avgas is not refined petroleum but is made from 70% Alkylate, 15% Isopentane, 15% Toluene and it keeps a long time and will not varnish anything up or cause corrosion. When it evaporates it leaves nothing behind but a little bit of blue dye. I have had problems with ethanol blended pump gas. It will dissolve fiberglass and some rubber parts, it rusted the inside of my Suzuki RL250 tank, and caused the fuel tank on my Sherco to swell and get very soft. It grew so much it started slide on the rear mount and there was a gap between the bottom of the tank and the frame and it was pushing the rear fender back. You can test any fuel for ethanol by taking a small clear bottle (soda bottles work fine), and fill it about 1/3rd with water. Carefully mark the level of the water and then fill the upper 2/3rds with the fuel you want to test. Put on the lid and shake for a about 10 seconds, then set the bottle down and see where the level of the water at the bottom of the bottle is. If the level of the water is right where you marked it - then the fuel does not have any ethanol in it. If the water level has risen it is because it has absorbed ethanol out of the fuel. I have found a source for gasoline that is delivered to farms for use in the bulk tanks that does not have any ethanol blended in. The ethanol blended fuel does not store well in the outside tanks farmers use, and it does not run well in their old equipment, and the distributor is not required to blend ethanol into fuel used for off-road farming. I have been using it for almost 2 years and my Sherco tank has not swelled and it runs fine.

I love Happy Endings! I do appreciate when the solution is posted so we can all learn something.....Thanks! Now go ride!

Something about the mixture adjustment seems backwards...or at least not matching the operation of a normal carb. I am not familiar with a Bing - but on a Mikuni and most other carbs if you start backing out the mixture screw the mixture will richen with each turn until you reach the maximum flow that the pilot jet of a given size will allow. Opening the screw allows more air to flow into the area around the pilot jet - which then picks up more fuel. My initial thoughts on any mixture screw/pilot jet adjustment is that if I have to open the mixture screw more than a couple of turns and you don't hear the engine idling mixture becoming too rich - then the pilot jet needs to be larger. If the idle mixture becomes too rich before you get a full turn then I suspect the pilot jet is too big. Do you think you have an air leak somewhere in the intake/carb connection?

This topic is also beat to death on a Chainsaw forum that I watch. People spend far too much time worrying about which exceptional product to use. Don't go cheap and start using oil made for boat motors or snowmobiles - use a good quality synthetic or synthetic blend made for motorcycles and you will never notice the difference. Most of the problems occur when you either use old fuel or something gets in the carb jets and make the bike run lean. If the bike is not running right find out why - don't just keep riding and hope that it will cure itself.

1 inch is 25.4 mm - So 360 mm would be equivalent to 14.17".

Does anyone have a contact at Betor Shocks? A little more than a year ago I bought a pair of Betor shocks for my TY80. When the shocks arrived I had the wheels apart and was getting the rims chromed and installing new spokes. The wheels were completed, new tires installed and shocks installed in August 2010 and the bike was ridden about 20 minutes. The seal in one shock started leaking and there is a green piece of rubber sticking out from inside the seal. I returned the shock to Matt at Speed and Sport where I bought the shocks and he has been trying since October of 2010 to have his distributor replace the shock. At the time they sold me the shocks Speed and Sport only had 2 pair in stock and those have been sold - and it has been more than 6 months since his distributor has sent him any Betor shocks for his inventory. His distributor has not followed through on helping him to get any replacement shocks and he has not provided him with any contact information for a contact at Betor. Even if they won't stand behind their product - it would be nice if I could buy a single replacement shock instead of a pair. Can anyone provide me a contact at Betor......or a place where I can buy a single replacement TY80 shock?

I hate stories without a happy ending.....so here are the results. I bought a new Suzuki Piston, rings and gaskets. The new piston had about 0.002' clearance when measured at the skirt with the piston upside down - and the ring end gap was about 0.016". It all went together well and it runs fine. It now makes less noise - but I guess with all those fins it will always make more noise than a water cooled bike. The original rubber spacers that go into the fins were hard and brittle and I have not replaced them as it just doesn't seem like $ 40 that would be well spent - maybe if I watch eBay long enough I can find an affordable set some day. Thanks to everyone that gave me advise - my initial measurements were just too big as I was measuring the top of the piston....and not the skirt.

I do want to caution everyone not to trust the "ethanal free fuel" stations without testing. The Pure-Gas.org site listed a local station as having ethanol free fuel - but my test showed that it is blended with 10% ethanol and my discussion with the delivery truck driver confirmed that it is blended. I sent an email to the site and informed them and they added my comment - but for some reason they didn't change the site to remove this station from their site. In an earlier post I described how to test for ethanol......and I beleive it is necessary to test any new fuel source to confirm that it is ethanol free. I also believe it is necessary to re-test frequently when getting a new batch of fuel - as the ethanol content can change with just one delivery of ethanol blended fuel.

First: Test your local pump gas for ethanol. If it doesn't have ethanol...use it. Second:If can find some local Racing Fuel - Try it and see if it works. It won't damage anything - it just may not run any better with it. Third: If you can get Avgas at a decent price and it is not too far away - Try a gallon and see if it works for you. You will not damage anything - but it may not run any better with it. Forth: Try local motorcycle shops to see if they carry VP, Klotz or other racing fuels - they can be pretty pricey and may not be necessary in a trials bike - but I know some people use them. The only reason to try the Second and Third items is to avoid ethanol - if you can't find a source for pump gasoline without ethanol.

Good Points: Stays fresh for years. Will not gum up or corrode anything. Good Octane rating. Bad Points: Runs rich and may require re-jetting for best performance (which means if you make the adjustments and happen to put a tank of pump gas in you may then be running lean). Contains lead - the Low Lead is misleading as it contains as much lead as the old High Test pump gas used to - but it is low compared to what other Aviation fuels use. It is made for low rpm (2,400 - 2,800 rpm engines) and may not run all that well in performance engines without timing and rejetting. I used Avgas 100LL in my chainsaws for a year and finally stopped. Even after mixture adjustments they didn't idle all that well, and the performance was not any better than pump gas. I think the Torco and other racing fuels that you can usually find at gas stations around drag strips runs better than Avgas and doesn't require mixture adjustments. I just found a source for Sunoco 96 Octane racing fuel and it works very well.

Buying higher octane does not gaurantee it to be ethanol free. A local motorcycle shop used to drive to the next county south to get fuel as they felt is was ethanol free - when I tested it they were wasting their time as it had ethanol in it. The fuel delivery truck was there when I arrived and I talked to the driver, and he told me that all grades of their fuel are blended 10% with ethanol....and every station receives the same blends in this area. (He did tell me their plant sells 87 Octane gasoline to farms that is not blended and I got the phone number for the plant and I now use that fuel). The only way to know for sure of the fuel has ethanol is to test the fuel. You can buy test kits - but any plastic soda bottle will work just fine. I use a 20 oz. soday bottle and I put a piece of tape about 2" up from the bottom. Fill the soda bottle with water to the top of the tape - you want the water level exactly level with the tape. Then fill the bottle with the fuel you want to test, put on the lid and shake for a few seconds. When you set the bottle down the fuel and water will be all frothy then the water will settle down to the bottom. If there is no ethanol in the fuel it will sink to the bottom and the water level will be right at the top of the tape line. If there is ethanol in the fuel the water level will have risen above the tape line - the water absorbs the ethanol out of the fuel and increases in volume.

Avgas 100LL is not made by refining petroleum - it is blended using generally about 70% Alkylate, 15% Isopentane, 15% Toluene - the additives of lead, Dyes, Scavnegers and Antioxidants. It is really cool for storage as it will not gum anything up and evaporates with no residue. It will keep a long, long time - which is important for aircraft that can remain in storage for long periods of time. It runs richer than pump gas and if you don't rejet your engine will run too rich - and this is especially noticeable in the 2 cycle engines. When I have used racing fuel I have not noticed the engine running too rich.

I am sure the Duraweld or similar product applied with a torch can only be accomplished with the case removed. There is no way to get the engine case hot enough with it assembled/attached to the engine. There may also be some epoxy repair methods worth trying - however epoxy generally softens with heat and may not be suitable for use on an engine. Heli Coil or TimeSerts may work - but if the holes are open on the back and not closed off (blind) then the drilling and tapping of the inserts will result in all the shavings going inside the engine. You do need some professional help on this one - it is probably necessary for you to find a competent shop or mechanic to help you.

I have been fighting with ethanol blended fuel in the Cincinnati area for years. The first problem we had was when my uncles muscle cars got stored for winter - and then every spring we had to replace the accelerator pump diaphragms as the rubber had somehow dissolved over the winter. Then the ethanol blended fuel started doing the same things to the fuel pump diaphragms in the Briggs and Stratton engines - the little check valve flaps would be shriveled up. My uncles antique cars started to have problems with the copper,brass and bronze fuel system parts corroding and getting a green gell lodged in the fuel system. Then the unlined steel fuel tanks in my motorcycles started rusting inside and the aluminum carbs started getting corroded in the float bowls. The latest problem I had was my 2009 Sherco fuel tank swelled and started pushing the rear fender back after only 4 months. I have found a source of 100LL Avgas at a local airport that is self serve - but after trying Avgas for about a year I found that it runs richer than normal fuel and it take me about 1.5 hours round trip to get the Avgas....it just wasn't worth the effort. Since then I have found a local Bulk Distributor that sells unblended 87 Octane gasoline to farmers to store in their above ground tanks that they use for their farm equipment - the only problem is I have to buy 100 gallons at a time! I have most recently bought 10 gallons of 96 Octane Shell racing fuel and I am going to try it in my Sherco. I believe the EPA cares little about our problems - they don't care if our older equipment is damaged as they would prefer we stop using the old equipment and buy newer engines that are more in compliance with their imposed regulations.

Be sure if you get a new plug - the threaded length is the same and the electrode sticks out the same amount. If you get a plug with a shorter lenght it will not reach the combustion chamber and your performance will probably be affected. I don't know if they make a plug with a shorter porcelan section on top - and if they do will the cap you have fit the shorter top?

Thanks for everyones input. I have a new piston that is standard size and the measurements for the new piston versus the old one are only about ).001" tighter with the new one. I don't have a factory manual and wanted to know at what point I was due for an oversize piston and rebore of the cylinder, and it sounds like I am there. I plan on sending the cylinder to B&J Racing for boring and they are very familiar with the RL250 and should be able to get it right. Here is a photo of a change I have made to the clutch. I bought a TM250 clutch cover and stripped the black paint and polished the case. I installed a TM250/400 clutch basket cover with the cogged release actuator and installed a TM250/400 clutch cable. I removed the center push rod and spiral clutch mechanism from the magneto side of the engine and plugged the oil seal. I have not ridden the bike yet at the cylinder is still off - but the clutch pull is far easier and much smoother now. I can't post pictures as I don't have any place to link the pictures to - but here is an eBay add with pictures and I am selling a second polished case that I had. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=320649337217&viewitem=&sspagename=STRK%3AMESELX%3AIT

The feeler gauge I used was as long as the piston, and the largest measurement I could get was with the piston pushed down about an inch from the top of the bore - the feeler guage was measuring along the cylinder wall just above the exhaust port.

My 74 RL250 was getting a bit noisy so I took the piston and cylinder off to see how things looked. The crank looks fine and I cannot feel any play in the crank or rod bearings. The piston had a crack on both sides that runs straight up from the piston pin - but the crack is tiny and doesn't go too far up the piston. I cleaned the piston and cylinder and a 0.009" feeler gauge slips in easily and a 0.010" is snug - I doubt if I could get a 0.011" gauge in without a good amount of force. The piston is the stock 70mm size. I ran a hone in the cyclinder and it is obvious there is some uneven wear as there were high and low spots as indicated by the uneven honing marks. I have a new piston and the clearance is very close to what the used one measures - it is about 0.009". What is the maximum clearance that is allowed and is 0.010" the probable cause of my noisy bike?

I rode motocross and hare scrambles in my youth in the early 70's. We knew a little bit about trials and a local club would have an event or two during the summer and I went to watch once. Most of the bikes were not dedicated trials bikes - but people just threw some large sprockets on their enduros. It was interesting......but I had a "Need for Speed" and kept riding my race bike. I stopped riding and racing when I went to college and sold my bike. After about 35 years had passed I ended up owning a large piece of hilly and wooded property. I thought it would be great to have a motorcycle again, and I bought a Suzuki RL250 as I wanted a bike that was good at riding around the hills without making a bunch of noise or going too fast, and an older trials bike with a seat would probably be just the ticket. After having the bike for a year or two I really started to enjoy riding it and the newer bikes became really appealing to me. I bought a used Sherco 290 and found it to be a huge improvement. Then a year later I sold it and bought a new Sherco 320.....and I love it. I have not yet competed - but probably will do so in the summer of 2011. I don't have a big need to be a competitor again like I was when I was young (I am 55 now). I just really enjoy riding my bike around my property, climbing hills, jumping logs, etc. I am in great shape for my age and hopefully this bike will help me stay that way for another 10 - 15 years. When I am no longer safe to ride a trials bike.....maybe I can switch over and get an older Dual Sport or Enduro bike that has a low seat height and keep riding for more years.

The wobble is not felt when riding - but when I am on a smooth area in 4th or 5th it bothers me to see the tread wobbling back and forth. I have not measure the run out - but the point on the front of the fender goes from the middle of the center row of knobs to the left edge of the knob as the wheel rotates. I will probably make a quick press and see if I can "coax" the rim into being a little straighter before spring gets here. Right now it is just above freezing and rainy - and the ground has about 5 mm of thawed soil on top of the frozen ground beneath. It is really not good riding around here right now.

I have a 2009 Sherco 3.2 that has a front wheel wobble. I have never had a hard fall on it and I am not a very aggressive rider - mostly slow trails, hill climbing and small log crossings. I have attempted to loosen and tighten spokes to straighten it without success. I loosened all the spokes a bit, then tightened the ones on the side opposite the wobble trying to pull the wobble back to center and then I snugged up the remaining spokes. The alignment is a little bit better - but it still has a noticeable wobble. I have laced up wheels before and can get them straight when I start from scratch using a straight rim - but it appears that the soft aluminum rims can get bent form side to side without too much effort. I feel that it is not just a straight rim that had the spokes tightened improperly and pulled the rim out of shape - I believe the rim has a sideways bend in a small section of the rim and the rim remains perfectly round. Is this a common issue? Has anyone had success getting any bends out of rims using a press or hammer? I feel I could support the rim on each side of the bend and apply pressure to help straigten out the kink.

If it runs fine for a little bit and then acts up - It sounds like you have a fuel flow problem. You may be running your float bowl dry when under full power. Check for a restriction in the lines running from the tank to the carb, a low flow filter, or a restriction in your fuel tank vent.

Is it related to throttle opening....or revs....or both? Does it miss under full throttle right from the very start - or does it only happen at the higher rpms? Generally when an engine misses under heavy loads and full throttle - it is and indication of weak ignition if it happens at all rpms when applying full throttle. The spark has more throuble jumping the plug gap when the cylinder is full of air and fuel (while it may be able to run OK at lighter loads when the thottle is only partially open). If the engine just misses and backfires out the exhaust it would lead me to believe it was spark - if it misses and backfires through the carb I would think the fuel mixture is lean. It might also be that your valve guides are too tight and the valves are not closing fast enough at higher rpms. I once had this problem with an engine that had new guides installed and the machine shop did not ream the exhaust guides with enough clearance.