Husqvarna 350 build thread

[farminkarman]

@farminkarman how much do you think full machine work and port work would gain over the mild porting you plan to do on this one?

Probably another 20% if using a 44.3mm top end.

 

[Shane¹]

Probably another 20% if using a 44.3mm top end.

What about doing machine work on the 350 cylinder? Do you think it is worth the extra work or not?

 

[old guy]

I do not have a mill, but I can get what ever squish I want with those bearing blocks by using 80 grit wet r dry on a flat surface & sanding the top of the block on this.
It is very easy to get a good flat surface this way, measure each corner with a caliper first & know where you want to end up at, I make a large black mark on the visible side to keep track of where I'm at, then with firm pressure give it a push-pull on the sandpaper, turn it 90°, push-pull again. Do this till you are back to the starting side, then measure to see where you are, if there is a high corner use a little more pressure on that corner.
Do this till it gets to the thickness you need, i'ts actually very easy to control

 

[farminkarman]

What about doing machine work on the 350 cylinder? Do you think it is worth the extra work or not?

I have tried it and there are small gains, but not worth it in my opinion. It is hard to raise the transfers enough and still aim them the right way when you cut the squish and base.

 

[farminkarman]

I do not have a mill, but I can get what ever squish I want with those bearing blocks by using 80 grit wet r dry on a flat surface & sanding the top of the block on this.
It is very easy to get a good flat surface this way, measure each corner with a caliper first & know where you want to end up at, I make a large black mark on the visible side to keep track of where I'm at, then with firm pressure give it a push-pull on the sandpaper, turn it 90°, push-pull again. Do this till you are back to the starting side, then measure to see where you are, if there is a high corner use a little more pressure on that corner.
Do this till it gets to the thickness you need, i'ts actually very easy to control

On the 350’s, doing a gasket delete almost always yields perfect squish clearance, so I’m not sure why you would do this.

 

[old guy]

On the 350’s, doing a gasket delete almost always yields perfect squish clearance, so I’m not sure why you would do this.

On the last one I did you are right, .017 with base gasket delete.

 

[Jusgunn3]

I have had the same results with a prefect squish with a gasket delete.

 

[Outback]

Compression is power. Machining always helps within the confines of the design.

 

[old guy]

On the 350’s, doing a gasket delete almost always yields perfect squish clearance, so I’m not sure why you would do this.

This was probably 5 years ago, I don't remember the details, maybe one I put a 346 on.
I have at least 3 of those blocks in parts bin, when it warms up (-19°f this morn.), I will go out & see how much difference the thickness is.

 

[Sloughfoot]

On the 350’s, doing a gasket delete almost always yields perfect squish clearance, so I’m not sure why you would do this.

To decrease squish and keep the gasket, maybe. I believe Randy has said he prefers to keep the base gasket.

 

[cuinrearview]

Randy

Never heard of her

 

[EFSM]

Base gaskets are on average easier to work with than sealant and a little more forgiving with dirty or oily surfaces.

 

[Sloughfoot]

Base gaskets are on average easier to work with than sealant and a little more forgiving with dirty or oily surfaces.

It's amazing the sealant works at all considering how thin it is, but it does.

 

[old guy]

It's amazing the sealant works at all considering how thin it is, but it does.

I have had sealant fail once, it was the old permatex hard dry stuff I had put together a husky 550 with.
I recognized the high revs instantly & shut er down so no damage
I like the permatex red rtv gasket maker.

 

[farminkarman]

To decrease squish and keep the gasket, maybe. I believe Randy has said he prefers to keep the base gasket.

If the gasket were that important I could see it, but it isn’t. I only use base gaskets on some builds where the cylinder base can afford the extra 0.020” of material removal.

 

[Sloughfoot]

If the gasket were that important I could see it, but it isn’t. I only use base gaskets on some builds where the cylinder base can afford the extra 0.020” of material removal.

I've done the same with the few I've ported. Deleted the gasket on one that a Tree monkey recipe called for 90k off the base. Kept it on another that MM's recipe only called for 30k off.

 

[Sloughfoot]

I have had sealant fail once, it was the old permatex hard dry stuff I had put together a husky 550 with.
I recognized the high revs instantly & shut er down so no damage
I like the permatex red rtv gasket maker.

Been using Reinzosil lately. It's really easy to work with, gives you a few minutes before it starts hardening and it cleans up easily. A vintage Brit bike restoration guy sold me on it. Says it's the only thing he's found that will keep exhaust pipes sealed to the cylinder.

 

[singinwoodwackr]

It's amazing the sealant works at all considering how thin it is, but it does.

Most of the time…

 

[Sloughfoot]

Most of the time…

or till it doesn't.....

 

[farminkarman]

Most of the time…

or till it doesn't.....

The only sealant I’ve had fail was Hylomar blue. I’ve never had Dirko fail, and I know others have had the same good results with Permatex Moto Seal.