Victa mods???

[housey]

hi, im getting a victa 160 to use for my go kart and im wondering what mods people have done to thier victas or 2 strokes in general

housey

 

[anderkart]

I found a bit of good info for you in the first page of this search link:
http://www.google.com/search?source...US_enUS221US222&q=victa+160+performance+parts (theres prolly more further on)

 

[sideways]

Which kind of Victa do you have? The old full crank version(with removable cylinder and round cylinder head) or the "Power Torque" with half crank and square cylinder head? If unsure post some pictures.

If you have the Power Torque engine then the best modification you can do is get the full crank one, the Power Torque won't take much power due to its half crank design.

1st remove that awful carby and get some thing off a 125 2 stroke motorbike, maybe even a smaller one. Bore out the bit that the origial carby mounts on (if you don't know what I mean I'l post photos when I get back from my holiday, on Thursday, or maybe brendonv could if he has them).

You can also replace the coil (with one off a car or motorbike) on models with points to allow them to rev higher.

Lap the decompression valve(they often don't seal very well) or just remove it(a standard Victa spark plug will fit in its place)

I've been experimenting with porting and I'l be making my own power pipe for it(I'l post up the dimensions once I've made it)

I'm also going to see how much I can skim the head before something breaks.

I'l keep you posted on how it goes.

Its good to see another person messing with Victas!

Hayden

 

[housey]

its the full crank version. i think i will get another victa and use one for my kart, but see what i can do to the other first before it blows up

 

[sideways]

its the full crank version. i think i will get another victa and use one for my kart, but see what i can do to the other first before it blows up

Great minds think alike .

I've got a spare Victa that I experiment on lol.

Hayden

 

[oscaryu1]

If you have the Power Torque engine then the best modification you can do is get the full crank one, the Power Torque won't take much power due to its half crank design.

Wrong. Same idea as case stuffing. No real information on this subject, just a common belief that full circle crankshafts provide higher primary compression within the crankcase and more negative pressure for the carby.

However, half moon cranks are said to be lighter, and better off in high RPM applications. Being lawnmower, I say a full circle would be more of a need.

I've been experimenting with porting and I'l be making my own power pipe for it(I'l post up the dimensions once I've made it)

Uh yeah, about that, don't. Much more information and math than you can deal with. Ever read Jenning's book?

I'm also going to see how much I can skim the head before something breaks.

. You'll start introducing exhaust into the crankcase mix, that's what.

 

[sideways]

Wrong. Same idea as case stuffing. No real information on this subject, just a common belief that full circle crankshafts provide higher primary compression within the crankcase and more negative pressure for the carby.

I said the full crank version was better because its stronger(
the half cranks are said to make more power though), I've seen standard Power Torques demolished just from the blades hitting a rock. The side cover on the Power Torque is made of plastic and if you were to stuff the cases on a power torque then you would need at least a liter of epoxy, on the full crank there's probably less than 0.5cm of clearance between the crank and the crank cases.

However, half moon cranks are said to be lighter, and better off in high RPM applications. Being lawnmower, I say a full circle would be more of a need.

I'm not sure if you know what I mean by full crank and half crank? I'm sure you are thinking of balance weights?

Here's what I mean.

Uh yeah, about that, don't. Much more information and math than you can deal with. Ever read Jenning's book?

I haven't read Jenning's book but I have read this one. And yes I do know there is serious maths involved but I Have aquired a few computer programs that calculate the dimensions of a suitable expansion chamber (got to get my old computer going 1st though! ) for me.

You'll start introducing exhaust into the crankcase mix, that's what.

Probably, or the head will blow off, I read about that happening on a Victa with a skimmed head somewhere,nthe head bolts/rods have a pretty fine thread on them.


No offence oscaryu1 but you obviously have no experience with these engines, you can't really discount my opinions when I have been stipping these engines down and rebuilding them for years and you probably haven't even seen one, let alone actually know the basics of these engines.

Hayden

 

[housey]

so, im kinda confused here. do i skim the head? do i port it (exhaust, intake or both?) do i port it and have a go at making an exspansion chamber? also has anyone tried using carbon fiber reeds?( russ2251 suggested that in another thread ).

 

[sideways]

so, im kinda confused here. do i skim the head? do i port it (exhaust, intake or both?) do i port it and have a go at making an exspansion chamber? also has anyone tried using carbon fiber reeds?( russ2251 suggested that in another thread ).

Yes, if you have access to a milling machine then get the head skimmed (you could send it off to a machinists shop but it wouldn't be worth it), port out the intake, if you can make a good expansion chamber (or find a suitable one off a motorbike) then port the exhaust too. The reeds won't work on your engine as it is piston ported, not reed valve so forget about them. If your willing to spend a bit more money then get a 2mm oversize piston and get the cylinder bored out to the right size, your engine will then be 167cc if you do that. depending on what kind of ignition system you have then you can change the coil for more revs.

But most importantly, get a decent carby.

Hayden

 

[Russ2251]

so, im kinda confused here. do i skim the head?

Lapping will allow the elimination of gasket and increase CR. Can always be reversed. Check clearances first.

also has anyone tried using carbon fiber reeds?

Won't work. I realized that Victa's are piston ported...no reeds.

 

[oscaryu1]

I said the full crank version was better because its stronger(
the half cranks are said to make more power though), I've seen standard Power Torques demolished just from the blades hitting a rock. The side cover on the Power Torque is made of plastic and if you were to stuff the cases on a power torque then you would need at least a liter of epoxy, on the full crank there's probably less than 0.5cm of clearance between the crank and the crank cases.



I'm not sure if you know what I mean by full crank and half crank? I'm sure you are thinking of balance weights?

Here's what I mean.

I haven't read Jenning's book but I have read this one. And yes I do know there is serious maths involved but I Have aquired a few computer programs that calculate the dimensions of a suitable expansion chamber (got to get my old computer going 1st though! ) for me.



Probably, or the head will blow off, I read about that happening on a Victa with a skimmed head somewhere,nthe head bolts/rods have a pretty fine thread on them.


No offence oscaryu1 but you obviously have no experience with these engines, you can't really discount my opinions when I have been stipping these engines down and rebuilding them for years and you probably haven't even seen one, let alone actually know the basics of these engines.

Hayden

I know plenty about building 2 strokes, thank you. Victas are indeed different, my bad about that. One thing you have to understand, a "full circle" crankshaft is literally two circular crankshaft counterweights, whereas a "half moon" are... well, half a circle or any smaller.

Whereas whatever terms Victas are familiar with, I am not.

Go modify a reed and reed port it. 5th and 6th ports, Boyesen, you name it. Should provide plenty of power.

And yes... I have ported 2 strokes... everything I say has a reasoning behind it, let it be common sense or something I learned (Generally, in a painful/hard manner).

I may have been wrong on the crankshaft subject, but everything else I said was justified and backed up with information. Good day.

 

[jr dragster T]

Go modify a reed and reed port it. 5th and 6th ports, Boyesen, you name it. Should provide plenty of power.

Except Boyesen reeds suck....

 

[Russ2251]

Except Boyesen reeds suck....

Because?

 

[Kenny_McCormic]

Just read everything Gordon Jennings ever wrote, you will then be a decent two stroke tuner.

 

[Russ2251]

I would recommend A. Graham Bell's "Two-Stroke performance Tuning" which is available on line as a PDF.
Much of what I have posted in the last 3 years comes from his writings and has been proven out in my garage/basement/living room.
Yes...living room.
Perhaps that's the reason the slu...er...wife left me.
Now I can listen to Hendrix as loud as I want.
Sometimes, there are benefits to being a jerk.

 

[sideways]

I know plenty about building 2 strokes, thank you. Victas are indeed different, my bad about that. One thing you have to understand, a "full circle" crankshaft is literally two circular crankshaft counterweights, whereas a "half moon" are... well, half a circle or any smaller.

Yes, I have read your thread on the scooter engine you were modifying and I do know that you know about 2 strokes, however, I was meaning that you have no experience with victas, probably should of made that more clear....

I do know what "full circle" and "halfmoon" mean by the way, I have been in the engine building industry for years, I know alot more than just the basics, all Victas are half moon BTW .

Sorry for having a bit of a go at you, it was just kinda the final straw on a really rough day.

Anyways, back on topic.....

Hayden

 

[oscaryu1]

Well now, count both of us... *****ing neighbors.

 

[sideways]

Just read everything Gordon Jennings ever wrote, you will then be a decent two stroke tuner.

Well I found Jennings book here, should make for a couple of afternoons good reading

I would recommend A. Graham Bell's "Two-Stroke performance Tuning" which is available on line as a PDF.
Much of what I have posted in the last 3 years comes from his writings and has been proven out in my garage/basement/living room.

So would I! Great book, I too have proven much of his writing to be true over the years.

Hayden

 

[jr dragster T]

On the dyno there hasnt been much of a increase over Boyesen VS stock. V Force 3 reeds are a awesome product and prefered by many racers. This is coming from a guy with over 30 years sled engine building experience.

 

[Russ2251]

My experience disagrees.
What's your experience?