TOPIC:

Glad u like it. Yes it is the same exact frame as the 250. But this one breathes fire!

do you have it road legal nelson?

leon

yes! That's why I bought it.

nice,
it has to be a riot .


leon

I'm actually working on it again! You guys probably thought I gave up on it... nope. Just real life and stuff. Anyway I've installed the wiseco 1070 pistons without rings and using old gaskets. gotta check the clearance ya know... You can see my clay placement here. Look good? What else should I be checking?

I found a stripped hole in the ebay cylinder block.. darn! The chain guide bolt hole. Well not a big deal I guess.


I spent a lot of time cleaning blast media out of the head today. How can I be sure there isn't any left in the oil passages? I squirted in contact cleaner, immediately followed by air and some nasty stuff came out.

My plan is to assemble the head with just the light valve springs then rotate to indent the clay. Before that (with the head upside down on the bench) I'll put thin oil in the combustion chambers to see if any leaks past the valves.

Seats, valves and guides are all pretty good, so I'm not gonna spend money on that. Just new stem seals. Feels great to be working on it again

If you have any mechanic buddies who have a kit, I'd recommend a timesert over a heli-coil. Stronger, seats better, less chance of it ever coming out and causing more damage.

Also, that 380 is one hell of a bike!!

everything looks good. u can mathematically measure the deck hight if u want. just measure how far down the hole the piston edge is (over the wrist pin). i use an old base gasket and spacers on studs, then torque it. then do the math. aim for .040" to .050".
heli coils work fine for me. i order them long at Fastenal. some of the ones u buy r pretty short.
u can even use solder to measure valve clearance. i put it through the spark plug hole and hold it under the valve while turning the motor over..

thanks for the idea of torquing it down with spacers. I measured the deck height with it just sitting there on an old gasket, but I knew that wasn't going to be super accurate.

This is how I measured deck height. This is correct, yes? I'm getting about .024" on all 4.

The caliper looks crooked in the picture, but I held it square for the measurement.

My new base gasket measures .020" thick. Does this mean I should run 2 base gaskets?

hey we talked about this before... I think you mean the piston to head clearance or "squish." I don't think it's the same as deck height. So I need to take my deck height of .024" and add the thickness of a compressed head gasket, correct? That number should be .040 to .050" correct???


I found your old post Mark:

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Nelson wrote:
so you're saying .040" is the minimum safe piston to head clearance?

Yes ,u can go lower on the track , but this is fine for the street. but remember to use compressed gasket #s in your equation.
if u mill the head the chamber will get smaller , and closer to the outer edge of the piston dome. i have no data on this, but it is something u need to measure. a set of 1075 pistons would be better all around than milling the head.
larger pistons give u a larger squish area, and give u the compression u want without complications. If u mill the head u cannot use it later with 10.25:1 pistons.

I just measured the new, big bore cometic gasket. It's .053 uncompressed. It's labeled .043 so I imagine that is a compressed number. So if I add my current deck height of .024 and .043 I end up with .067" total.

This assumes that the used base gasket is the same thickness as the new one.

Actually I imagine none of this really matters much right now - what really matters is the clay measurements I get with everything assembled.