pmk

Appears the two rear bash plate guard bolts are 08x20mm. These are different than the o8x16mm they show for earlier years. The difference being the bash guard itself. Do you have the smooth bottom bash guard with no curled edges, or is yours the curled edge style? If you do have one for a 2007, it is supposedly the non curled edge type, and takes the 20mm long rear bolts. The fronts I am not sure of. The part number does not code in the diameter and length. All four bolts use nylon locknuts. Fuel tank bolts are 05x40mm, however the proper bolts are washer heads built into the button head bolt style, and are possibly stainless, like the subframe bolts.

Wanted to add, if anyone has a SY250F or SR280; the measurement of the spring wire diameter on those may work also.

My SY has the white progressive spring. Wondering if anyone has the later year bike with the yellow spring. Need an accurate wire thickness and number of coil wraps if possible. Wanting to find a straight rate spring for mine to try.

No doubt downloading manuals and parts catalogs is worthwhile. Besides the one you linked, I also downloaded pretty much all the years they offered the SY250R. As for the carb being assembled wrong, the illustration may have helped the previous person that assembled it, then again, maybe not.

I revived this old topic on account of its releavance. First off, the info from peterb is incorrect since the SY250R stock TK carb is not the style cable retainer he described. The info straycollie got from Birketts is accurate and correct. There should be a small washer with both a tang and dimple. The tang is inserted into the applicable hole in the slide. The dimple serves to engage the opening in the needle clip, preventing the needle from rotating during engine operation, provided the clip is snug in the needle groove. Here is my main reason to bring this forward. My 2005 SY250R was purchased several months ago. I removed the engine and suspension, rebuilding the bike as I assembled it. I did disassemble the carb, cleaned, and reassembled it. Upon riding the bike, the jetting was always a bit rich. Obtaining pilot jets and a nozzle is diffiucult in the USA, though I tried to order them, planning to rejet the carb to get smoother running. Without all the jets I desired, my choice became to adjust the needle clip position. I had not removed the needle during the major teardown. Upon removing the carb slide needle retainer, I noticed someone previously installed the tanged clip under the needles clip, thereby raising the needle, causing the rich jetting. In an effort to see a change to less rich engine running, I installed the clip in needle slot 2, and correctly assembled the tang washer position. With just some test riding around the yard, the engine runs very clean, and no longer rich. Next I plan to raise the needle one clip groove to the middle, as it was when assembled incorrectly, to verify that setting. In simple terms, if the tang washer is installed incorrectly, and positioned under the needle clip, vs correctly which is on top of the needle clip, the needle is raised the thickness of the tang washer (and dimple), or raised about slightly more than a clip position. Assembly sequence, needle with clip into slide, tang washer on top of needle, needle retainer / cable holder with spring holder for needle next, secured with screws. Then slowly rotate needle and clip until you feel the gap in the clip engage the dimple.

Or leaking electricity and magnetism from the flywheel side...

Ironically, this exact process was suggested yesterday to me by a long time rider. I have called him a couple times to get advice simply because he is a good rider and experienced. Also, he is the one I purchased the SY from, not that he rode it, but rather knew the entire history of it, and swapped it as a partial payment on another bike he was selling. So far, I like the SY, just a few items to sort out. The clutch grabbiness being one. Being in the USA, finding a clutch cover gasket is not simply a run out and get it sale. Been inquiring with a UK Yamaha dealer for that gasket and several other parts. Plan to email Birketts in a moment.

Yes, originally, the original setup was with the nut on the opposite side of the arm. This mod is pretty much to ensure the clutch slave cylinder does not bottom out at clutch disengagement, causing damage to the slave cylinder. Overall, the clutch arm position is a based on the clutch itself, as in wear of the friction plates, pressure plate and inner basket. Those items justify where the clutch pushrod sets with the clutch engaged and slack removed. Moving the nut to the opposite side of the arm stuffs the slave piston slightly further into the bore, preventing bottoming at when the lever is drawn to the grip. Since most of the clutch arm and slave movement remains very similar regardless of where the nut positions, I doubt there is any gains there, other than I previously mentioned. As for the oil, I used Shell Rotella T4 15w40. Based on what Yamaha recommended (10w30), and the good results Rekluse seems to have in the auto clutches, plus on the advice of other riders suggesting avoiding synthetics. http://rotella.shell.com/products/rotella-triple-protection.html

No worries, the photo is of my SY and how I set it up just recently. Clutch is bled properly, and adjusted properly. The clutch releases absolutely fine. The clutch engagement is grabby, going from smooth to right now with little lever movement. As far as the clutch mechanism, mechanically it works well releasing and engaging, just is grabby as it finds that point.

Nut is installed on the adjuster pin, so nut is closest to the hydraulic slave cylinder not on the outside of the clutch arm.

I did a search and read what has been written, seems it is not uncommon for riders, even well experienced riders, to find the SY clutch kind of grabby or on. / off. Without condemning the bike, engine or fact they adapted a hydraulic clutch setup onto a cable design setup, has anyone found a means to smooth the engagement of the clutch, especially as the lever just begins engagement. FWIW, my own bike, the clutch is properly bled, and does have the required freeplay. It is just a bit more grabby than smooth. Open to ideas, no doubt will hear about buying a new bike, but ideas on making modifications would be better.

Not exactly the beauty queen of protection, but certainly should beat that beauty queen up when the going gets tough.

Bondy, any luck finding the carbon or other protectors for the cases? Photos if you did would be nice.

I recently went through the details of my own SY250r. This was my answer to carb hoses and routing.

The short hoses could explain debris inside the float bowl, but not dirt inside the airbox.

I tend to agree, and not to steal your thunder, I suspected that, the moment I opened the new filter, but wrote it off as a production mistake when cutting the foam.

I was fine with you replying to and almost debating your own post, although, I did kind of offer up a head scratch seeing both posts were from the same person. Initially, after seeing both were from you, I suspected your account had been hacked.

I see several of the recent posts recommend the Jitsie air filter. I recently installed the same in my Scorpa. Did anyone else notice, the filter has the coarse foam on the clean side of the airbox, while the fine foam is the first filter media. Seems Jitsie has it backwards.

Interesting, debating the merits of the front mudflap with yourself...

When you remove the upper rear shock bolt, be certain there is blocks under the rear wheel, or that it can not drop. These bikes will snap the rear brake hose at the master cylinder if the wheel drops and the hose goes tight.

One more item to inspect, the rubber airboot, between the carb and airbox. I suspect it is not torn. Look close at this detail. If the airboot aft clamp, that secures the airboot to the airbox is overtightened, or has been previously, the airbox spigot may crush and no longer be round. This will create a gap, unsealed. I had read where another owner had this issue, and utilized a slice of metal tubing to support the airbox spigot. This allowed full tightening of the clamp.

I have a SY250r also. I want to ask, is the air filter assembly complete? When I say this, does your bike have the rectangular plastic frame, that supports the foam filter flanged edge, forcing a tight seal around the foam perimeter to the airbox? The rectangular plastic cage, is then retained by two sort of swing type bent spring steel wire clips. These two clips, one front and one rear, apply pressure to the plastic cage, forcing it to tightly clamp, and sandwhich the foam flange, sealing the filters edge. With those parts securing the filter, and properly installed, myself I do not even grease the filter edge, it seals that well. It is possible to have the filter fail at glue joints, or become torn where the plastic cage touches the foam if the filter is forced into the airbox. As for the mudflap, oem did have a rubber flap with a circular hole the shocked passed through. The flap mainly keeps dirt away from the exhaust midbox, it may protect the shock shaft somewhat, but the shock shaft is on the upper end and pretty well protected by the airbox. Other areas to inspect for dirt entry, the several holes that secure the mudflap as stock, must be plugged. They are open holes into the airbox. Also, there was an upper dust guard, under the fender, it too was secured with screws. Those too may be possible leaks. Also consider the mount points for the subframe and exhaust, while sealed as oem, if the brass inserts have failed, and a home remedy was employed to save the airbox, those too are possible leaks.

Thank you for both dimensions

Can I ask a quick favor, would you measure the spigot diameters on both ends of the carb. Just purchased an aftermarket carb for my SY250R and currently too lazy to remove the original carb.

Wanted to add some details about this countershaft sprocket change. Initially when built and during my rebuild, the 73 OSSA MAR came with stock gearing of 12/46. After some use, rides, I made a change to 11/46. This was a very noticable change. The downside being tight sections or some climbing required use of the clutch. Most recently, I installed a 10 tooth countershaft sprocket. Initially, I rode the 10/46 setup in my yard, prior to yesterdays event. The change from 11 to 10 was also very noticable. With the 10 tooth, the low speed control is improved. The need for using the clutch is almost never. The good of the 10 tooth was low speed control. Steep climbs were not a problem, and my riding buddy commented there was no tire spin at all. A secondary benefit it how improved the rear braking has become. The downside of the 10 is how quickly the engine revs out. Riding between sections, this is a non issue. The main drawback so far has been when using the throttle to lift the front wheel. With the 11 or 12 tooth, the engine had a longer pull and could keep the front wheel lofted longer. Understanding the lower gearing not being able to hold the front end up as long, timing becomes a bit more important. At the event yesterday it was a learning curve, for various reasons and my mistakes were my own. The bike certainly did not struggle. For now, I plan to run the 10 but if I deem needed, will go back to the 11.