TOPIC:

cartal wrote:

Madrid, Spain. Are you in the US?
 

Yes.  A local hardware store may have an o-ring to serve the purpose...
I'd be happy to measure one for you.

www.yelp.com/search?find_desc=Hardware+Stores&find_loc=Madrid

Thank you so much for your help. I know a good shop here in Madrid, and will take the old one to find a replacement.

 

cartal wrote:

Thank you so much for your help. I know a good shop here in Madrid, and will take the old one to find a replacement.

 

The 670B1508 o-ring measures 7.5mm ID x 2mm thick +/- with my digital micrometer.  The fit is snug over the clutch push rod and yet it allows the rod movement through with little resistance.  The new o-ring fits through a 12mm mic setting with ease, so me thinks the pocket that holds it is that or slightly smaller.

This is brilliant. Thank you so much!

My initial goal, 2 years ago was to finish the bike in February 2024. By the way it goes, it´s probably going to take at least 1 more year! No time means the engine is moving on really slowly. I hope I´ll gather some momentum at some point in time. 

For the moment, I just mounted the cylinder block. It was way easier than I expected, and the results are amazing; smooth movement of all pistons. Very rewarding. 

I planned to reuse the old chain guides (new chain) but saw some tiny cracks, and decided to buy some new guides.

I am tempted on mounting the engine already on the frame, so it will be easier. 

Next will be to focus on the head. I did a wire brush clean of the valves, and all cleaned up nicely, except the ones corresponding to the "holed" piston (If you look at the initial pictures, you will see I had a piston hole). I am planning, of course, on lapping all valves, and I believe they will end up OK; but would like to share this with the group´s knowledge. I´m ready to order some ZPower parts, so a new set of valves for this piston, is easy to get (all other valves are perfect). 

Here are some pictures for illustration:

  

It's looking good Carlos, regards time scales I am also way over my original estimate  . Those valves could be "re-ground" and then lapped but depending how deep they sit may need "tipping". As it's only 2 you have an issue with it may be more cost effective to replace them.

Thank you @wookie58, I just got 2 new valves from Zpower.

Will start lapping the rest... it´ll be fun!

Bear with me… first time ever lapping valves. 

Do you guys see this is OK?

Did first coarse then fine. Funny how the grinding noise suddenly stops.

Feedback welcome!

One more pic

i guess the real question is if the patch I have (circular all the way) should be wider or if it is ok  like this?

That's ok.. 

Thank you! Will do the rest of the valves tonight 

So all valves are in place. It was easy to do with a special tool; it would have been a nightmare otherwise. I will post some pics later, but unfortunately, I have (very small) leaks in almost every valve. 

I am wondering if more lapping will solve the issue...