OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Engines Victa 160cc Engine Specs

So im in the process of designing a tuned pipe to suit a 2 stroke 160cc engine, my questions are as follows:

1) What is the power output of this engine?

2) What is the rev limit of this engine?

3) Has this been done before? If so what were the results?

Thanks

1) What is the power output of this engine? Victa never gave specific figures, usualy guess is around 4-5hp, this can be made a lot higher though.

2) What is the rev limit of this engine? Technically around 3500rpm as they were governed to, I have seen them push 5500-6000 with no serious devistation but do so at your own risk.

3) Has this been done before? If so what were the results? Not by anyone on here that I have read, a good exhaust on any 2 stroke engine would benefit but there are several other things that could be done first, in a go kart situation I would personally junk the stock carby and get a 25mm mikuni to begin with alon with some port modifications.

thats interesting. I'll have to do some calculations to design a expansion chamber to suit a rev range around that. I'm pretty interested to see what i can pull from this engine. I was having a look on the mikuni website today at carbs and already had port work in mind. Since it hasnt been done or anything on it here, would you like me to make a build thread for the engine? Ive only just finished disassembling the engine this afternoon

Rather than a Mikuni you can get a AKO carb off ebay pretty cheap, its a copy of a Keihin i think.



Im also wondering if a reed block would help much.

Id probably go the mikuni because you can pick them up for around $50 on ebay australia which to me seems pretty rerasonable and they are a pretty good carb, ive used them in the past on trail bikes. As for the reeds valve, i dont know enough about them :S

A build thread would be great mate I for one am very curios as to how this turns out!

No problems! What part of the forum would it be best to post a build thread?

There is a place for a thread on modifying a lawnmower engine to make it a higher performance engine no longer suited to a lawnmower. That would be
Superforum: Restoring and Customising
Forum: Engines

On the other hand, you could have a thread on modifying a lawnmower engine and building it into a special, hand-made bike (which might be functional, or it might be a caricature of a bike). That would be
Superforum: Restoring and Customising
Forum: Unusual Cusomisation Projects.

I personally doubt there is a forum here that really fits modifying a lawnmower engine then going into detail about fitting it into an existing, or ordinary bike. In my opinion the part of the thread that was about an ordinary bike does not belong on Outdoorking, which is about outdoor "equipment". We are certainly about, for example, making racing ride-on mowers. I don't think we are about ordinary trail bikes, though.

Fortunately I don't make decisions about that anyway. If you want to write a trail bike thread, please say so - the moderators will discuss it with the site owner (Bruce) and come back to you.

i wasnt so much talking about building the bike, more so a thread on the engine build. Additionally its not a trail bike, rather a vintage australian mini bike, in specific a Deltek Grassgrub. Like this one here http://macbobaust.com/vintage_bike36.html however as you know i want to modify my engine to get the thing poking along a bit quicker.

It is all about the engine.
As a side line it is a little bit about the bike.
There was a whole era of little bikes that were lawn mower or stationary engine powered.
Sure they were mass produced on a small scale but they are very rudimentary and i would consider the ethos behind that to be very much what this forum is about. No different than the cart threads i have seen.
Very different if someone was wanting to get into the nuts and bolts of a honda monkey bike or one of the chinese offerings of recent years.

I for one would argue that hotting up a lawn mower engine is almost a pointless exercise, only something you would do for shits and giggles. For a lawn mower engine, victas went well enough. If it hasnt got enough go you are using the wrong tool for the job.

It seems like it clearly belongs in the Restoring and Customising Engine forum, it should be a very good fit there. Hopefully we'll get more threads on customising lawnmower engines.

i'll start a thread there. fair point on the power from the engine. the main idea behind the engine build was to apply a few of the different things that i have learnt in regard to building a performance 2 stroke engine. Ive got another deltek frame and i have a honda horizontal shaft motor to suit which i'll modify also (its a 5hp motor) for going quick. I'm not setting out to set a land speed record with the victa, more so just to improve on the base performance level of the engine and to put some theory into practice.

Hi Sanchezz, this could be a very interesting thread and I am looking forward to reading your posts....plenty of pics too please as you go along as this would be great for the archives.

I have been fiddling with this engine for my go-kart which you can see at http://www.victaproject.blogspot.com.au/. I tried an earlier victa Q3 slide type carby which works well and is like a simple Mikuni with just one jet. But that is the problem it runs a bit rich I feel and is set-up for a mower naturally so one jet is ok. I spoke to some 2 stroke dyno tuners about setting up a mikuni and the jetting of multiple jets to suit would be an epic process and buying something based on guesswork that is from another engine would be an untunable unknown. From speaking with vintage (victa) go-karters they use either the slide type amal, Q3 or a tillotson from an 80cc comer engine.
I have tried a tillotson with specially made adapters and tuning High / Low settings etc is possible but fiddly. In my opinion the G3 carby that the VC160 came with is the best of all that I have tried and if you replace the butterfly shaft with your own and get rid of the little plastic governer/gears it is awesome. The engine has no problem sitting at 6000rpm. I will post some new pics and video on the blog soon once I have the electronic ignition module working.
One more thing is the compression ratio. After taking 1.5 mm off the head and wondering how far I could go a friend gave me a Victa head that he got out of the Arc which has High C stamped on it and it has more metal cast into the head. I will cc them both soon but obviously Victa seem to think higher compression is OK.
Good compression and the G3 carby is where I would start. I suppose I will get the bug to try the exhaust one day and will blog it then.

Nice workmanship MrS....


"From speaking with vintage (victa) go-karters they use either the slide type amal, Q3 or a tillotson from an 80cc comer engine.
I have tried a tillotson with specially made adapters and tuning High / Low settings etc is possible but fiddly."

If you have the Tillotson stick with it, however your going to have to get that Victa "breathing" well other wise your only going to get a tuning response from the "L" needle as the carby wont have enough air velocity going through it for it to work properly. As for size I wouldn't go any bigger than 7/8th of an inch, or you will have very little torque, 3/4" would even do it for better bottom end, because I reckon thats where your gunna want it.....


I cannot speak with any authority on the Amal, however they were jet tuneable I gather.

Sanchezz..

another fellow "tuner" if your into making reverse cone expansion chambers, try to make a wide power band one, or as Rodeobob put it "shits and giggles" will happen when it "bucks" you off!

I hope Bruce supports these types of threads as the Humble Lawnmower engine has not only proved to be a great engine for its intended purpose but has the capcity for much more, i.e. applied, science/engineering and to stimulate and support the GREAT aussie spirit of ingenuity! Also from a purely business point of view, to quote K.G.DRAPER "The Two-Stroke Engine", chapter 6, "Tuning for Speed" states that "a greater rate of wear in all working parts must be expected." hence sell more stuff!


Oh and if you guys (the tuners here) get it right you could expect about 10-12HP, and be Bruce's best parts customers

Hey sanchezz, did you end up making a build thread? I had a look but couldnt find one. Oh and MrS, I was on your site the other day and the videos werent working. Might have been my end though.

My engine should be up and running this week for my kart, its a mk4 160. MrS, youve already seen it on Diygokarts ages back haha

Hi Guys, We're really starting to stray way 'Off Topic' here..
Please start a new thread in the appropriate forum.
I will now close this thread...if any member has something to add, please PM a moderator.