OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa 160cc drift trike build

Hi everyone,

For the last week or two I have started in the sport of drift triking, I suggest you youtube it if you don't know what I'm on about they are pretty cool at 90kmh plus with vpc over go kart tyres for rear wheels.

Anyway I live in Hervey Bay with a population of around 100k and the trend hasn't really caught on up here yet, meaning that I get a 30 second ride down a hill then a 10 min walk back up (most people do it in groups and have someone driving a car with a rope behind it to tow them back up).

So I have done some research a decided the best bang for buck motorized setup will be a victa 2 stroke 160cc which I picked up today from the local dump for a big fat 10 bucks

Okay so far I have pulled the engine out of the mower and stripped the engine right down to just a block with a piston, rod and crank ohh and that fan lookin thing on the back. I plan on pushing as much power out of this thing a possible by doing a full rebuild (if I can) and what ever modifications aren't going to cost an arm and a leg as my car has already cost me this and I'm pretty sure it's after my nuts too lol.

So I'm open to any suggestions and links to good threads, so far I'm thinking
1: new carby (suggestions on make and model would be good)
2: I was going to up the compression by filling the top of the piston with liquid metal but it has a dome top piston on it already. Can I get a better head maybe?
3: doing some backyard porting with a dremel ( I have done my car manifold before but have no experience with small engines so a how to on this would be
4: an exhaust as the mower didn't come with one I chose it over the others as the compression felt great.
5: any other cheap go fast parts would be great

In conclusion,
How many hp can this thing push out? I'm planning on making this a all in one build thread to help others in the future, the thread will be aimed at the motor with the occasional photo of the trike, so have I posted this in the correct place? And where can I find the exact details of the motor as all I have to go by is the fact it said victa and a google of the engine number and head number didn't turn up to much but I do believe it's 160cc?

Btw on the engine it says 22 dec 94 I'm assuming the build date and the engine number is 72916z and the head number is 72515a

Hello Chev,
You say you have a domed top on your piston.
Is it like the one on the left in the image below, if so you have a 125cc engine.


Plenty of threads here to help you with your rebuild. (see victa engines under the forum list.)

Oh wow no mine is the one on the right, and after some more research and measurements I'm sure it's a 160. Thanks for the pics though that's interesting to know

I'm planning on shaving the head today, I'm just gonna get the belt sander out I think. I know it bodgy but I have heaps of 1.8 mm gasket paper and I'm not paying for thinner stuff when I've got over a square metre of the 1.8, besides I figure if the head is a bit out of square the 1.8mm paper will squash down a bit and keep it sealed anyway.

Does anyone know how much I should be taking of, I was think of filling the decompressor port with weld and taking 3-3.5mm off the head. the 1.8 gasket paper should add about 1.2mm anyway, if guess is correct.

Does anyone know the standard compression of these engines and how much each mm changes it.

Also I've pulled the piston out and I'm thinking of getting new rings but there's a few things I'm unsure of.
1: does the block need to be honed
2: do I need a piston or just rings
3: how do I know how far oversize the rings should be, it looks as if it's had a fair bit of use and one side of the piston was black from what I assume to be combustion slipping past the rings
3: also the entire engine block is covered in a mix of rust, dirt and general filth what the best way to clean this. Plan on having the head shiny and the block painted red, yellow or blue

Most regulars on here are far more experienced than I, but before you take to the head with a belt sander I think you should do some research. I know these 2 strokes have forgiving tolerances but still need to be treated with some integrity.

Maybe you can look up go-cart sites for hotting up the donk, they were popular for that some time ago. Have stumbled across some sites with some impressive rebuilds.

But please read some other threads on here and other sites on doing it up or you will be wasting your time and resources.

No offense is intended. Wish you luck.

Here's a beauty on a cart.

Chev as far as performance goes, I am happy to have a stock, well running engine.

To answer some of your questions: (without actually seeing the condition of the parts)
1. I normally give the bore a light hone. (hope yours has no scoring)

2. If your piston is in good shape, reuse it.
I remove all the carbon out of the ring grooves, being careful not to take any metal off. (use a broken piece of ring, sharpened up as a scraper).
Look at your piston crown to see if is stamped as an oversize piston. ie. +20
This will let you know if it has been bored out oversize.

3. I am low tech, and clean parts by scraping with an old knife, wire brush, degrease.

Put some images up of your engine, others will chime in and help.

Thanks for the replies people, I think I have a plan now though after many hours of browsing this forum and some go kart ones.

1: I've shaved roughly 2.5-3mm of the head using a belt sander and then a glass table with some sandpaper on it. I'm planning on putting a bolt in the decompressor hole and filling the void with liquid metal.

2: giving the bore a quick hone as I had my neighbour over to have a look after i realised he's a 2 stroke model boat and plane expert, and he thinks it's pretty good.

3: replacing piston rings if I can get them alone but if not I might just buy one of $35 rebuild kits from ebay

4: porting the intake and exhaust, wider but not longer so my timing doesn't change.

5: 22-26mm carby from ebay

6: a 2 stroke exhaust from a pit bike or something similar. As long as it's the same width I figure it should be okay

6: other than that just a very nice clean and paint. I'm thinking painted block with a polished head

I,ll get some photos up tonight

Ok I've just given the motor a quick once of with the brass brush on a drill. I think after I finish the disassembly I'll soak it in laundry detergent over night,then do the porting before a good degrease and paint.

Not sure if I'm uploading these right?

Thanks for the image.
People here know what you have now.
Its a 160cc power torque engine, I thought you had a full crank 160cc engine.

You will need orings for the rebuild.(where manifold meets block, where carby seals onto the inlet manifold, large starter oring, small starer oring). I have reused them in the past if they look ok.

Make sure your bearings are alright.

I was thinking of buying the piston,rings and hedge on pin for $35 off ebay and then the large starter oring separately for $6 as I don't see the point of buying the full kit for $65 as I won't be using a lot of the parts. I was thinking of just getting a carby and then drilling and tapping straight into the block. Would this be okay? And also the same for the exhaust.

Btw where is the small starter oring I don't recall seeing one?

Thanks for your help

I have never modified from original. So the carb and muffler questions are out my area.

I watched this youtube video, he has fitted a different carby with a throttle.


Yes, it is better to have new orings with the aim of sealing the engine up, to prevent over-revving and starting problems. Which can be frustrating.

The small oring is inside the starter, see image below.(71)

Chev, your engine is looking good. Head came up well.

To insert an image is a 4 step process.

Thanks for that mark.

I've ported the intake to about 22mm and the exhaust, I'm not sure on the measurements of the exhaust port but I've basically rounded it as much as possible right through to the bore. I also angled out the channels running from the crankcase that deliver fuel an air to the combustion chamber, probably 4mm on either side of each port. I think I should go a lot further with those but I'm not to sure ATM (will upload photos Tommorow).

Other than that I'm waiting till next pay day and I will order a cylinder hone, piston rings, o rings and a carby. I'm not sure if I will need to buy a new piston but according to the micrometer the bore is currently 4-6 thou bigger than the piston. after much consideration I think a fair bit might need to be taken off the bore as there are some marks from dirt, and I don't see the point of chasing more power if I'm losing power from a poor cylinder bore.

Another thing I'm still somewhat unsure about is the carby. The standard carb is roughly 16mm into the block. And a lot of people put a 26mm on, however the inlet port can't really go bigger than 22mm and a bigger carby would only result in a loss of low to midrange power. I found a calculator online that estimates a 20mm carby will be the best fit to peak power at 6000 to 8000 rpm.

I honestly don't think the engine will hold up to more the 8 grand,and I've found a 19mm high performance replacement carb for the stand 19mm ones found on 50-80cc pocket bike. I know these carbs are designed for a much smaller engine but a lot of those 49cc mini bike rev well past 12000rpm.

Thoughts on my theory anyone? The carby I found is $28 including postage and pod filter I would copy a link but I'm on an iPad and well......

An exhaust will be the last thing I buy, I'm thinking of just getting any 2 stroke exhaust that has baffles and the same diameter as the exhaust port. Would this be the best way to go as making one up is a bit beyond my interests ATM?

I have considered a trumpet but my commodore with a full blown speedway engine pisses the neighbourhood off enough as it is (before I need a flame suit I would like to state no I don't hoon around local streets)

I'm open to any thoughts and constructive criticism on anything I've mentioned, after all that's why I'm here.

Hi 350chev94, and a much belated warm welcome to the OutdoorKing forum. It's nice to welcome a new member aboard with an interest I personally have not heard of...drift triking! As we all like to learn new things and tinker here, I am most interested in your progress in this project as I am sure other members are, as well.

Once again, 350chev94, to OutdoorKing.