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I will take a small amount off each bolt with the new crush washers. Since the coolant is not leaking now I will procrastinate until I have a larger order for RYP.

The bolt length appears to be correct. I put a couple bolts in without the washers and did not have the bolts bottom out. I have a few parts that need ordered so I will get replacement copper washers with the order. I was at the TSC hardware today and saw a package of Nitrile "o" rings 1/16" thick x 5/32 ID x 9/32 OD. I put these under the old copper washers and carefully tightened the bolts, put the bike back together and went for a 15 minute ride. As of this evening no coolant has leaked. I will recheck the bolts tomorrow and report back.

That is what I will do. I removed the bolts and washers this evening. I will get some silicone grease also. Should I put Blue Loctite on the bolts?

I will look at the stock head. The cylinder top is flat with no recesses. I will take the top back off to confirm what I recall. Thanks again

Could I remove the copper washers, do the process correctly and then expect the washers to work properly or should I get new washers?

*Where did you find the head bolt torque figure, it sounds very low to me- Page 29 of the "Sherco Top End Maintenance Manual" and Cylinder Head[nuts or bolts] 7 lb/ft, 84 lb/in (10 n/m) from Copemech. *Did you change the o rings? - No. The new Head came with a new "o" ring that I did use, but I used the original larger outer "o"ring as I did not get a replacement "o" ring with the order. *short allen key- my head bolts are 8mm hex head bolts that screw down into the cylinder. I did use a small 8mm wrench and a 1/4" socket wrench to retighten the bolts after the first leaks. http://www.shercousa...t2.cfm?action=9 This Link has the listing of Sherco Manuals and Parts up through 2014 and at the bottom of the page is the Link to the "Sherco Top End Maintenance Manual". Page 17 of this Manual shows on Picture 24 small "o" rings for each of the six head bolt studs. My head bolts did not have these "o" rings. I tried calling RYP today but they are probably out for the weekend. I will send them an email to see if I should have these smaller "o"rings. I will probably retighten the bolts the next chance I have. That might be a few days from now though. I will post RYP,s response next week and /or give future updates as I work on the problem. Thanks, Chuck

I installed a Low Compression Head from S3 on my 2013 ST300. I am now having coolant leak from around the six copper washers under the six head bolts. At reassembly: I did NOT use Loctite on the bolts, I reused the six copper washers, I heated the copper washers with a torch (the washers were laid flat on my concrete garage floor) until red hot, I used a top quality torque wrench and tightened the bolts in multiple steps using the crisscross sequence until tight at 84 in/lbs. I ran the bike the first day for 20-30 minutes and all appeared okay. The next time I looked at the bike I saw coolant at a couple head bolts. I started the bike and then saw more coolant leaking from multiple head bolts. I shut off the bike and found the head bolts to be loose. I tightened each bolt as best I could without removing the air box, radiator and other parts. I then rode the bike for 30-40 minutes without any more coolant leakage that night. The next day I checked again and found the head bolts to be loose and coolant around multiple head bolts. I have tried to search the forums for a solution and found one result but I could not determine the fix by reading that search result. Thanks in advance for the advise, critique, help, etc. Happy New Year to all, Chuck

I did not have the line connected to the manifold properly. Thanks Steve for that diagram. Then, at the "T" connection, the fuel line had a small nick which was the source of a leak. Copemech, the bike now is running and idling okay after the proper hose installation. The next time I have the carb accessible I will check the float level. I was able to ride the bike for three evenings in a row after making the proper corrections. I did not notice any fuel leaking on the ground for those three evenings. Then on the forth ride I did notice that fuel was again dripping on the asphalt. I have not been able to check the bike out since that last practice session. Is it expected for gas to leak from the breather pipe hose when the front wheel is elevated for extended periods? This may be common sense, but still I need to ask. I am trying to learn to ride a wheelie and am only at the point of being able to balance the bike with both feet dragging. Thanks again for the help, Chuck

Thanks for this Diagram-perfect. I understand that the hose must be attached to the nipple on the manifold. Thanks for the help.

I too have a 2013 ST300. I am new to Trials so I have a bunch to learn. I did some winter maintenance on the bike that entailed removing the carb. The bike ran fine prior to my work. I put everything back together and when I got to re-attaching the fuel lines I became confused. I eventually got the job done and the bike started and ran fine. I am trying to learn the basics of controlling a wheelie. The technique I am using is to lift the front wheel while keeping both feet on the ground to learn clutch modulation and throttle control. Now (after my reassembly), with the front tire in the air, the bike wants (and does) stall out and fuel was leaking from somewhere. Today I went to work on the bike to troubleshoot this problem and found the gas leaking from the "T" in the fuel lines. This explanation would be simpler if I would include some pictures but unfortunately I do not know how to do that- I am humbly sorry! The "T" is located on the line that comes out the top of the Dellorto pumper. This would be my first question: 1. Is the Dellorto part the pumper? My carb is a PWK Keihin. 2. Is this combination of Dellorto and Keihin the stock setup? Assuming, for now, that the Dellorto part is a pumper, I just do not understand the workings of the pumper carb. The pumper has three ports. Looking at the assembly as it is mounted to the fuel tank while on the bike, the bottom left is marked with an arrow and the word "In". The hose to this port comes from the petcock. The top port goes to the "T" and is marked with an arrow and the word "Out". At the "T" one hose runs to the top of the fuel tank and the other hose is connected to an in-line filter that goes to the carb. The last port is also located on the left side just higher than the "In" port but this third port has no markings. The line from here is connected to the left side of the carb bowl. I had the carb apart but at this point I do not remember if this bowl connection was open or shut. So, 3. I am asking for help in an explanation of the function of each of the three ports and how the pumper system works. I am heading back out to the barn to see if there is an obvious reason why the fuel was leaking from the "T". I hope the write-up makes sense! All help will be appreciated,Thanks, Chuck