Question about welding the engine

[thebottle]

I called around the dealers here and a complete set of rings is $65, head gasket $35.

I'm going to hone the jugs and ring the pistons... I'll have a shop grind the valves and be done with it. I'm not going to weld the jug I have now if it costs the same and requires the same amount of work to replace it. That would be foolish.

[ViperRon]

Hi I think the plan is great as it is what I would do. I do however want to ensure you go the correct direction with the head work. When people say shop is going to grind the valves it worries me some. First of all it should be done by a motorcycle shop familliar with japan motorcycle valves. The valves in these bikes are not nomally ground down they are lapped and fitted removing very little material. There is very little material that can be removed from them and the seats and still run properly. That also is a really nice price on the rings as when I got mine some several years back they were 28.00 a set. I am just mentioning these things because I knew a guy who got a great deal re-doing his bike at a shop that specialized in cars and Harleys and it was not done properly.

Also get new Orings or the gasket for the bottom of the cylinders. You can seal it with form a gasket but it could be terrible to get loose in the future.

[trbig]

Valve seals are cheap also and would definately change those if that far into it. Most places I've seen sell those rings for @ $45 a set now, so make sure that was for a set of 4, not just a set for one piston. Honestly, if you just check your old rings' gap in the new cylinders, you'll probably find that they are fine. A light hone where they'll seat in to their new home, and away you go. Plus, I've re-used many many head gaskets as long as they didn't delaminate on removal. If you do use new, make sure to re-torque the head nuts again after you run it to operating temps. The metal heats up and squishes it further, so when the motor cools, those nuts are fairly loose. A used head gasket is already pre-squished and won't need re-tighteneing.

First of all it should be done by a motorcycle shop familliar with japan motorcycle valves. The valves in these bikes are not nomally ground down they are lapped and fitted removing very little material.

I've had the head/valves done several times by a car guy. I don't understand what the difference is that you speak of? You have a valve seating against a seat, just like any other engine. A touched up seat and good 3-angle grind, and things were good to go... and still going.

People normally lap valves because it's cheaper than a grind, but it also lets there be variances to how the valves are seating against the seat and changing airflow. You may have a valve that is sealing against the very top of it's face, and the next one sealing at the very bottom of it's face. A good 3 angle grind gets rid of all of that. Before re-installing the head, turn it on it's side and pour gas into the 4 ports standing up and let it sit a while. After that, repeat on the other side and make certain there is no leaks or seepage getting past the valves. If so, then it was not done properly.

[ViperRon]

All good advice from TRbig but I still differ on grinding surface treated valves. I do agree with grinding on tempered hardened valves. Your choice thebottle and good luck with it.

[ddragon63]

Valve seals are cheap also and would definately change those if that far into it. Most places I've seen sell those rings for @ $45 a set now, so make sure that was for a set of 4, not just a set for one piston. Honestly, if you just check your old rings' gap in the new cylinders, you'll probably find that they are fine. A light hone where they'll seat in to their new home, and away you go. Plus, I've re-used many many head gaskets as long as they didn't delaminate on removal. If you do use new, make sure to re-torque the head nuts again after you run it to operating temps. The metal heats up and squishes it further, so when the motor cools, those nuts are fairly loose. A used head gasket is already pre-squished and won't need re-tighteneing.




I've had the head/valves done several times by a car guy. I don't understand what the difference is that you speak of? You have a valve seating against a seat, just like any other engine. A touched up seat and good 3-angle grind, and things were good to go... and still going.

People normally lap valves because it's cheaper than a grind, but it also lets there be variances to how the valves are seating against the seat and changing airflow. You may have a valve that is sealing against the very top of it's face, and the next one sealing at the very bottom of it's face. A good 3 angle grind gets rid of all of that. Before re-installing the head, turn it on it's side and pour gas into the 4 ports standing up and let it sit a while. After that, repeat on the other side and make certain there is no leaks or seepage getting past the valves. If so, then it was not done properly.

+1 On the port fill. We use to call it the poor man's pressure tester... But we used solvent so it wouldnt evaporate. Fill up the ports with mineral spirits and walk away for a few hours. If they are still full when you come back you still have a good seal between the valve and seat. If you are going to pull the valves number them to know where they came from. @ the point of installation it doesnt hurt to give them a good lap before you lock em back in.