I just did a top end rebuild and when I pulled the cylinder off I noticed how the casting under the base gasket wasn't actually smooth all the way across. There was a slight lip between the two halves where the mold line was. It really should've been resurfaced at the factory.
I'm kicking myself for not taking a picture of it because it would've been a good one to post.
The solution besides replacing the base gasket is to use a little dab of gasket sealer across that small imperfection to fill in the gap under the gasket. That should prevent any future leakage.
common but in many TW's I've owned only one had a slight base leak and a re-torgue fixed it
In 2010 Yamaha came out with an updated base gasket which is the only base gasket they sell now regardless of year it has a little more silicone build up to seal the uneven case issue glowspud mentioned but I would also add a little sealant in that area if I removed the cylinder
I know of people who smoothed the "step" between cases by sanding and another who smoothed the low side with a tiny JB Weld build up
If you don't want to fix it simply tell the people it's an "Adventure" upgrade called the "self changing oil kit" lol
My base gasket leaked for so many years I lost count. When I did a valve job around 40,000 miles then I replaced the gasket with a non-oem gasket which had a silicone like sealer added to parts of the gasket and it never leaked again.
You can do it. I measured my bore at 40,000 miles and everything was still in spec so good that I didn't hone or replace rings. I am now over 47,000 miles
Of the 4 main head bolts, I removed two and lube the threads and washers with Hornady's One Shot Case Lube and torqued them to spec, then did the same for the next two head bolts. After that I did the same for the last four much shorter bolts that are on the side of the cylinder, again doing two at a time.
This cured the base gasket leak on both of my TW's.
I hate to sound like an FNG but I see only 2 bolts on the bottom of cylinder on the left side. And of course the 4 head bolts. I looked at parts look up at Riva and did not see them either. Was there 2 or 4 on your TW? Thanks
In addition to the 4 head bolts, 2 of the left side bolts secure the head/cam cover to the cylinder. 2 other bolts secure the cylinder to the case which is probably what you are questioning.
When I've had to re-torque the head bolts as elime has mentioned to stop my base gasket from leaking, I didn't re-torque those smaller allen head bolts on the left but I guess that depends on where your base gasket is leaking. Mine was leaking more in the front.
Im sorry I did not make myself clear. I have not tore it down yet. Just took out the head bolts. I could only see the 2 lower allen head screws at the bottom of cylinder. Im sure when I dismantle the top end Ill see the holes for the allen bolts in the top of cyl.
Thanks for the pics. Super nice. I bought the Service Manual for my Kindle. That should help too.
Finally got TW all tore down and repaired leaking base gasket.
Was not sure I could do it. I did it with lots of help from this site!!!! Thank you everone that responded to me. I let bowl fill with gas turned on key hit the start button and it could not start up fast enough and idle. No leaks or smoke or noise. Thanks again everyone
Finally got TW all tore down and repaired leaking base gasket.
Was not sure I could do it. I did it with lots of help from this site!!!! Thank you everone that responded to me. I let bowl fill with gas turned on key hit the start button and it could not start up fast enough and idle. No leaks or smoke or noise. Thanks again everyone
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