Strat divider removal, bigger carb?

[Hoolio]

Hey guys. I've been reading AS for a few years now.
It made me buy a 550xp n MM mod it, for my 1st saw.
I did a lot of research then decided on a 372xp with the intention of modifying it.
I tore down and ported my wipper snipper as a practice.
I put 2 litres through the 372 then decided that was enough for the stock saw.
I tore down the 372 then realised it was very different to the pics I'd seen...
Now I know what a stratto 372 is!
Anyway... More research, on porting the 372xp XTORQ this time.
I measured and did a base gasket delete, muffler mod widened the exaust port a little (I got scared) slightly shaped the inlet, blended the transfers to the base gasket.
Tuned it and ran another couple of litres through it, really happy!
So I decided to port it more.
Cut the transfers down to the base and blended them then I removed all the dividers in the intake side.
My question is do I need a bigger carb or will I get away with the stocky?
Thanks.

 

[bikemike]

The stock carb will feed your saw just fine. Is it a work saw or a hobby saw?

 

[Hoolio]

The stock carb will feed your saw just fine. Is it a work saw or a hobby saw?

Thanks. It's not for commercial work if that's what you mean, it's for my personal firewood, a fair bit, family etc. so it needs to be usable.
Just finding it hard to tune. It idles but wants to die when I try to rev it, like I pull the choke on?
I am new to tuning so it might just take me longer playing around with it.

I know in stumpys thread where he ported 2 372 xtorqs (one johnsered) side by side the one he guts the strat on he put a tilly 385 carb on?
And from my experience with old v8s upping the power is very limited with the stock carb?

 

[bikemike]

Thanks. It's not for commercial work if that's what you mean, it's for my personal firewood, a fair bit, family etc. so it needs to be usable.
Just finding it hard to tune. It idles but wants to die when I try to rev it, like I pull the choke on?
I am new to tuning so it might just take me longer playing around with it.

I know in stumpys thread where he ported 2 372 xtorqs (one johnsered) side by side the one he guts the strat on he put a tilly 385 carb on?
And from my experience with old v8s upping the power is very limited with the stock carb?

I se where the v8 thing makes you wonder about bigger carbs. I think just having it ported nice and exhaust ported too that when you find the sweet spot with tuning youl be happy with the stock carb

 

[Hoolio]

Yeh thanks. I guess being a strat saw that's now feeding fuel to all the ports. Theoreticaly a stock strat needs %20 less fuel, just de strating alone ups the fuel needs.

 

[bikemike]

Yeh thanks. I guess being a strat saw that's now feeding fuel to all the ports. Theoreticaly a stock strat needs %20 less fuel, just de strating alone ups the fuel needs.

The reason they run the fuel to the lower section is for lubrication of the bearings

 

[bikemike]

Thing i dont like about the strato is if ur only running about 3rd throttle they flood the engine out id be curious about seing how twin carbs would do on those motors i bet they would sreem

 

[Chris-PA]

So what was the motivation to removing the strato divider?

 

[Hoolio]

Thing i dont like about the strato is if ur only running about 3rd throttle they flood the engine out id be curious about seing how twin carbs would do on those motors i bet they would sreem

There's 3 ports so I might have to look into a triple weber carb setup!

So what was the motivation to removing the strato divider?

Haven't read anything of full stratos making more power than without dividers but I have read of them making more with the dividers gone, (obviously at the cost of fuel consumption)
So I decided to try it.
In the thread 'project stumpbroke 71cc Swedish stratos' one saw has the dividers intact, it's timed cut is close to 6secs the one with the same mods but diferent carb and dividers removed it's almost 4!
Only one way to find out!

 

[bikemike]

Do it up but we need a before and after vid

 

[Hoolio]

Do it up but we need a before and after vid

Video!?! This is my 1st post and I'm a bit of a technophobe, still trying to figure out where the fuel goes in this ipad.

 

[Hoolio]

The carby boot wasn't on properly!?!? Tuned it up now n seems to run really good, except, the idle speeds up after 5-10secs a little, then a blip on the throttle and it goes back down for another 5-10? It's not a terrible real big change in revs, but noticeable. Do you think there's an air leak? Maybe I was a bit light on the base gasket goo. (Threebond) or could it just be how a ported, de stratted saw runs?

 

[Hoolio]

Also it's a little smoky at idle even when it's hot. Would this be because of feeding fuel into the strat ports now? It seems pretty clean at WOT.

 

[Chris-PA]

This thread got me to look at the 372 strato design, and I find it is much more Zenoah-like that the other Husqvarna stratos. It appears to have quad transfers on the sides as opposed to long dual transfers with an entrance under the exhaust port. If the 372XT were AutoTune it would really be a fantastic design.

I'd love to see some pictures of the XT port configuration - the only one I could find was from an eBay AM P&C ad, and that didn't show much. Looked like the strato ports on the cylinder were small?

 

[Hoolio]

This thread got me to look at the 372 strato design, and I find it is much more Zenoah-like that the other Husqvarna stratos. It appears to have quad transfers on the sides as opposed to long dual transfers with an entrance under the exhaust port. If the 372XT were AutoTune it would really be a fantastic design.

I'd love to see some pictures of the XT port configuration - the only one I could find was from an eBay AM P&C ad, and that didn't show much. Looked like the strato ports on the cylinder were small?

Sorry that's the best photo I have of inside the cylinder.
I actually don't know what an xt is? If it's an xp XTorq than yeh there's only the two transfers.
I would say the strat ports are small but I haven't opened up any other strat saws to compare.

 

[Chris-PA]

Sorry that's the best photo I have of inside the cylinder.
I actually don't know what an xt is? If it's an xp XTorq than yeh there's only the two transfers.
I would say the strat ports are small but I haven't opened up any other strat saws to compare.

Thanks! That's quite different from the picture I saw on eBay, which is what I get for looking there - it looked like it had a divider in the transfer runner and a smaller strato port.

And I should have typed XP, not XT.