Cannot stop throttle shaft seal leaks

[Robert Dell Aquila]

My bad I didn't read your siggy. Kinda have a 2 OP thread going here, good to know the advance is working well. Since the pamco is on the cam you will see some timing movement from cam chain slack and harmonics. There is no way to avoid that with a cam based ignition trigger. pamco or points.

All good, no worries. The guy who started this tread has a similar problem as me, so I'm sure he can benefit from your insight as well. I'm going to assume my advance is ok and focus on the throttle shaft leak. Maybe I'll take em apart and use some grease to seal them better. Out of ideas for now. Thank for the help though! You guys are epic.

 

[authenticnovelty]

Hi Guys, sorry i’ve abandoned this thread for a bit. Got tied up with some work stuff and then finally decided to just pull the engine yesterday (the lean-over method on this site was perfect for a single person tear down).

Sump filter was surprisingly clean, oil screen on the side was pretty much a fine aluminum paste (never seen in any previous oil changes).

I’ve got the top end off and the cam chain guide is wrecked (as everyone predicted) with a pile of 3” plastic chunks from the guide resting in the bottom of the engine case.

I appreciate that robert is continuing to follow up as the posts ive seen on timing subtlies with cams will be very helpful going forward. Sorry I can’t contribute any new findings to that topic for a week or two.

Just wanted to give you guys a heads up, i’m going to continue posting on a previous thread I opened regarding the engine noise. I have a feeling my specific issues may relate to timing more than carb leaks (although my carbs do leak intermittently, similarly to robert’s). If I come across anything relating to a cause for the carb leaks, i’ll post here, but now while inside the engine, i feel it’s better focused in the other thread, beginning at post #26.

http://www.xs650.com/threads/1978-xs650e-standard-consistent-whining-engine-sound.54000/

As Robert said, thank you all for your patience and insights so far. The owners manuals and service books are pretty straight forward, but there are so many unpublished subtleties on these bikes only known through years of personal experience, that this site and its members have become a major lifeline to those starting out with them.

 

[5twins]

Boy, looks like you've been running without the rubber on the front guide for a while, it's pretty cut into. That's what's all over that side filter, ground up front guide, lol. Don't throw the old one out, Jim can fix it, lol.

 

[authenticnovelty]

Haha. Definitely planning to keep it in my growing museum of 40 year old removed parts from the bike. On a related note, i’ve seen your post about modifying a used guide with rubber from a smaller bike. I’m not sure if i should make one as you did or if I should just buy one, so i can keep the project moving. what is the xs650 cam chain guide and tensioner replacement supplier you guys trust at the moment? From reading and personal experience i have my hesitations about getting the guide from mike’s, due to the rubber reputation, but don’t know if its actually an issue with this part.

 

[5twins]

You have no choice really, the MikesXS replacement is all there is at the moment. The guy I mentioned, Jim, did adapt an SR500 guide for the 650. I have rounded up all the parts I need to do it too but haven't done it yet. Here's Jim's thread about modding the front guide .....

http://www.xs650.com/threads/cam-chain-guide-mod.51730/

 

[authenticnovelty]

Ah sorry, my memory lead me to believe you had done it (sorry Jim). Either way, thats the thread I was referring too. Thanks for sharing. I dont think i have access to the equipment to do the guide merge as precisely, and opening this engine was surprisingly easy enough, assuming i can make a couple years out of a mike’s guide. I’m going to replace the cam chain, but do you guys think the tensioner looks reusable, or just make guide, chain, trnsioner, all fresh? I typically try to just do it right/new once, but i have a feeling this rebuild may start adding up quickly. Plus, ive replaced a couple things on the bike previously with lemons (barbed carb boots specifically) i’d hate to have to pull the engine again just because the old tensioner broke down or worse, because a new tensioner was poor quality.

 

[5twins]

The rear guide holds up fine and doesn't fall apart like the front one. The grooves in yours are pretty typical. I wouldn't bother replacing it, or worrying about it. The front guide and the chain are the two things you pretty much always replace if they're originals. While in there also check the rings (end gaps) and replace if need be. Cylinders should be checked too. If worn too much, you could need more than just rings, you could need an over-bore. Valve guide seals should be replaced. They're rubber and 30+ years old. Some of the valves may need to be re-sealed if they're leaking (hand lapped back in).

 

[kshansen]

I believe I have guides and adjuster with the sprocket from a 1972 if that would be of any help. I could dig them out and post some pictures in the next couple of days if anyone is interested,

 

[Robert Dell Aquila]

Ah sorry, my memory lead me to believe you had done it (sorry Jim). Either way, thats the thread I was referring too. Thanks for sharing. I dont think i have access to the equipment to do the guide merge as precisely, and opening this engine was surprisingly easy enough, assuming i can make a couple years out of a mike’s guide. I’m going to replace the cam chain, but do you guys think the tensioner looks reusable, or just make guide, chain, trnsioner, all fresh? I typically try to just do it right/new once, but i have a feeling this rebuild may start adding up quickly. Plus, ive replaced a couple things on the bike previously with lemons (barbed carb boots specifically) i’d hate to have to pull the engine again just because the old tensioner broke down or worse, because a new tensioner was poor quality.

Hey man, so I actually did a method to my carbs with some success thanks to @5twins. He told one of my buddies to put some red rubber grease on the throttle shaft seals to help seal. He also mentioned an idea about using an O-ring to place inside the throttle shaft seal lip to help seal even more. I put the grease in the carb seal passge. All shafts were sealing properly when I sprayed carb cleaner into the area except for the right outer seal. So i used the o-ring idea and it stopped the leak. However, I used a an o-ring that was too big, so when I throttle the right shaft comes down slow. As a result I have a hanging idle now. Im pretty positive that if you use an o-ring with the correct thickness and diameters you would have some success. This is just for future reference. Thanks 5's youre a legend.