[2 stroke] Twin 350cc development ?

Salut Lozza :)
Now i have a desktop computer and not the iphone , i can develop a bit :)


First , and in the order , to get the maximum power , i would run a square stroke/bore then , you have 400Rd low end or a banshee stroker crank

I have studied the problem during hours and hours :)
The 61 stroke +7 banshee crank with 15 rods machined billet are VERY VERY relaible , my +10mm ( 64 stroke ) has about 8 hours and is still 0.00 wear ( 12 k rpm with 73mm pistons ! )

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then a 7mm stroked cheetah , 72 bore and a liner pressed in at 61 bore ( 356 cc )
Cheeaths use Cr250 reed cages that allow big carbs etc etc ( Cr250 are not that big in fact but compared to stock banshee ones , they look huge :) )


About the gearbox , you can acheive a nice racing gearbox using mixes between banshee and street Rz/rdlc bikes

Main problem is to get the rod / piston combo to get easily both to rebuild .....

Hi Gordon

I know it's a bit off your topic, but I thought you might be interested to see a direct back-to-back dyno comparrison between an HPI and Ignitech ignition installed on one our Honda CR250 Superkart engines. The HPI is a 2-curve digital programmable CDI unit, just replacing the stock Honda unit and plugging into the Honda generator and taking the trigger off a raised segment on the rotor periphery. We powered the Ignitech with Lipo battery, rectified and regulated 13V supply off the Honda generator and both (which is actually illegal for us. The regs only allow 1 power source). We also triggerd this in the same manner. As well as the lack opf power with the Ignitech you also see a big rise in the EGT's, which under normal circumstances I would say was due to a retarded ignition. The only other thing I could think was that a low spark energy was taking longer to actually fire the plug.

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The curves programmed in are identical and were verified on our ignition rig prior to installation on the motor. After the big difference we also verified the curves on the motor (by strobe).

I did speak with Ignitech and they couldn't shed any light on the difference and we did check everything at least 3 or 4 times. We did also try both coil outputs feeding into the single coil as suggested in Frits' comments, but it made no difference. Shame as it's a well priced and featured box. Perhaps they have sorted it now. Our boxes are about 18 months old.

We have had exceptional results with the RTD (Racetech Developments) EMX-04 (for singles and tandem twins) and the EMX-05 for a 2 trigger system.

Best Regards

Ian

Ian was the Ignitech timing strobed against a flat line advance curve on the running engine? The rotor need not move far to get +/- 2deg. Were you using the Honda coil? Ignitechs like RGV coils best.
Where are a few PVP,BRC,FPE and DEA dyno graphs?

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Thanks for all the feedback guys
I had just spent the last hour answering some of the points - went away to do something else - and lost the lot - so here's the second attempt.
To Frits - I'd forgotten the RD400 - might be worth looking at - although they are tending to be a bit rare these days - I seem to remember the width dimensions are same as 250/350 - but I think the flywheels diameter was bigger....long time since I worked with them...

Lozza - your comment

Citation :

"The banshee option is a good one as the components can still be purchased new in the US"

is probably the most important consideration - I know about the CPI cylinders - and have heard of seen pictures etc of the Athena Banshee kit - what are the differences - & who makes the Athena stuff ?

Citation :

Now about those RGV cylinders ..........

If you are serious - send me an email - we can start talking - although my preference would be to sell a complete engine rather than just the cylinders...

Seb - thanks for the link - nice looking crank - is it rebuildable ? - and is the centre "keyed" - I would prefer any crank to be rebuildable at that price...there are so many cranks on the market - difficult to know which are any good - the cheap ones would be worth using if we could get a season out of them - it costs probably more to rebuild the TZ crank...
AS for the cylinder - so many options - need to find out if Calvin can cast a small enough bore - and work out the porting to suit - getting suitable pistons might be a problem too - not too many listed anywhere at 61 / 61.5
I still have to study the gearbox ratios - I have probably all the options listed - when I have time to look at them - the easy (and costly) way out is a Nova close ratio box.

Ian - thanks for the information - I am in no hurry with the Ignition - so hopefully they solve any issues by the time I need it - I wasn't aware of the RTD - although - it looks expensive - did I mention we are a "low to no budget" operation ?
The dyno must be an essential part of your operation - we have no easy access to one in our area - other than rolling road about 50 miles away.
I would be interested to hear if the Mota simulations are of any value in pointing in the right direction - or a waste of time ? - the simulation of TZ350 with bore / stroke changed to 61 x 61.5 was quite surprising - extra 10hp - just from that....

Just another thought on the Ignitech - I know a guy that has been running one for a few years now (probably 2 - 3 years) - he's had no problems - that is on a classic 2 stroke 250 kawasaki - so just wondering if the problem could be showing only on a later design / more advanced type of engine ??

Citation :

Were you using the Honda coil?

No swearing here please...

Hi Guys

Lozza,

I can post a BRC dynograph tomorrow from work, but I am conscious of pulling Gordon's thread "off beam".

Of course dyno's work differently upside-down!! but we would never see anything close to 100 on a 250 twin on our Dyna-Pro T62LCC.
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I believe our UK Horses are much stronger than Aussie (or Canadian) ones, but it's only a comparisson. As long as you always use the same ruler your OK.

The strongest 250 tandem twin motor I ever had on the dyno was Aussy, Scott Ellis' SAFE motor that I built/tuned/prepped the last couple of years.

We were using the standard Honda CR250 coils with all ignitions. To be honest they never missed a beat. Is there any year of RGV coil to get and/or do you have a part No.
We are pretty solid on the HPI box. I would like to try an MSD 4217 at some stage which I also believe is also good.

Gordon,

From memory the RTD box is about £350.00, but I'll check that out.

Heres an image of some of the ignitions we run or have tried on the Honda.
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From the left: PVL, HPI, RTD, Ignitech

Yes, the dyno is the most used tool in our toolbox, but it does eat time like you wouldn't believe.

Our current single exhaust was basically developed by copying what has gone before and then by very tedious trial-and-error on the dyno. If I input our engine data into the MOTA exhaust design programme, I get something quite different. We have a "thinny" and a "fatty". Here is the "fatty":
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I'm guessing that you (and others) had problems with the Honda coil?

Best Regards

Ian

The ignitech does not give it's best with 13v lipo , i've spent a few hours on the dyno to find out that you need 4000-6000 mah 4S lipo unit ( 16.4v when full ) to give it's best

Test were done on a 125 Rs hrc with Hrc kit barrel ( not JHA ) , after 4 hours to set up the ignitech ( honda stock coil , 1225trs plug cap and r7282 plugs ( important ) i got the same thing , with 30 more minutes job i was 1 to 2 hp higher on all the curve .....

You should try again

Ian don't believe everything in the Dynapro hymn book, as I have seen wildly inaccurate Dynapro readouts , namely a TZR250 that read 75hp and then subseuently went 65hp on a Dynojet.
Try one of these before a MSD.
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All RGV coils are the same, as Seb said use race plug and cap.

Gordie I thought you were going to give me those cylinders Who makes the Athena kit.....Athena of course.

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I haven't seen a 64mm bore one in a while but they do make them. Mota is a rough guide EngMod 2T is far more accurate, and as Frits is fond of saying it's as accurate as the info going in. Garbage in=Garbage out.
The cranks are rebuildable and everyone just welds them(yeesh) or buys a new one at seasons end.
Usinga RD400 bottom end is a good idea but you will to over come the problem I found when I had the bright idea to stick LC cylinders on one, they fit OK but the spacer needs to go on top of the cylinder not underneath, otherwise you get something like exhaust open 70deg ATDC.
You could weld plates on to the top of the cylinder and sleeve after you could do that easy with a old set of stock LC cylinders............. Banshee/CPI/Athena/RZ have 1 stud off set compared to the RD/LC. TZ dry clutch fits though.
You can easy add sub exhaust ports to a LC cylinder.

Hi Lozza

I might well give that Zeeltronic a try, but as I say we are extremely happy with our HPI, but you keep trying!!

We've had the Dynapro around 6 years now and it is extremely consistent and reliable. We read about 10% lower than our nearest dynapro so our 90 is their 99. I don't know who's is the nearest to accurate and I don't really care, as long as our 90 is 90 today, tomorrow and next year!! But, customers do of course like a big number!!

What I know is that the BRC printout below is of an engine that won European races (in straightforward conditions), and still holds a few UK lap records after 2 years. This isn't it's best run, but it is a typical one that I have on the office machine.
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Gordon, my memory was correct on the price for the RTD box.

SEB4LO, only 4 hours, I feel like I spent a lifetime already. However, if you'd like to buy 6 Ignitech boxes!!

For now at least. . . .I'm out of here!!

Best Regards

Ian

That dispells a myth that kart engines are 'peaky'. Think a dyno's accuracy is a lot to do with where the weather station sensor is. Thanks for that Ian. 40ftlbs of torque is mighty impressive Shape of the curve and area under it important to , more area under the curve the easier it is to go faster* A 45 deg line upwards seems to be predictable.


* Untill you start to get better riders/drivers who can handle peakier delivery.

Zeeltronic ordered
Ian

Let us know your results. Did you get the USB or hand control?

The USB for now, but if it works I'll put 10 units into stock along with both programmer options.

It's despatched today, so I guess I'll have it by mid next week. But I have a bit of a queue of jobs waiting for the dyno, so it may be either just before or just after Christmas when I run it.

The HPI is an AC CDI which just plugs straight into the '01 generator (Trouble is I have to buy new '01 generators and they're not cheap!!.

Zeeltronic say their CDI will run fine using the Honda 2002/2007 rec/reg and condensor. But those units are only really designed to povide DC for the pv stepper motor. The Honda 02/07 CDI is actually a high voltage AC unit (for which nobody makes a direct plug-in programmable CDI). When we ran the Ignitech off the Honda rec/reg it got very hot, so we wired it with a 100Watt universal rec/reg which ran nice and cool.

Anyway, we'll try it both ways. I'd just like to find something that works well with the '02/07 Honda Ignition System as I have 50 brand new sets that we have taken off new engines over the past few years.

I'll let you know how it works.

Best Regards

Ian

Gordon Jones a écrit:

A little introduction first - we use a TZ 350 engine in a racing sidecar class in the UK - for many years the TZ350 was the main engine used in the F2 sidecar class - but in the early 1990's - 4 cyl 600cc "diesel" engines were allowed into the class - & when they became too fast - we retired - I had no wish to ride one of the "heavy" machines - I enjoy riding a 2 stroke - and also enjoy working on the engine - not so with a diesel...

The 350cc 2 strokes are now only used in a small series of races in the UK - we started racing again - about 5 years ago - and we enjoy riding the TZ - but always looking to improve performance - and maybe try some of the more modern ideas - after all - the TZ 350 is a very old design....

The class we race in allows up to 350 twin cylinder - the only other restriction is maximum carb size of 39mm.

Most people are using the TZ350 - there are a couple of people using the YPVS based engines - one using Banshee cylinders - and one using the CPI cylinders - the Banshee cylinder bike has been very fast - although a little unreliable - so I am looking at whether I should think about building a Banshee based engine - or whether the TZ is / has more potential for development.

During the 2011 season - we ran an engine with a 90 deg firing order - (not quite 90 deg - as the TZ centre splines will not allow it) - we were quite quick enough - but it did have a horrible vibration - it was easy to ride - and did not actually feel very fast - but the lap times were as good as a normal engine - I did worry though - that the engine was more stressed than normal - due to the vibration.

We have a few options to explore:

1. Carry on with the TZ "normal" engine - with possible improvements of Ignition / pipes / carburation

2. Spend time in developing the 90 deg engine. (with possible improvements of Ignition / pipes / carburation)

3. Build a Banshee / YPVS based engine - with better porting & the possibility of using the CPI cylinder.

4. Look into the possibility of building a "long stroke" engine - using a +7mm crank - and finding a smaller piston / cylinder.

5. We have an Aprilia v twin engine with 66mm cylinders - which was reputed to be very fast but fragile (in the previous owners hands) - but I'm thinking the fact that it is so over square will present some problems...
Sorry for the lengthy post - we would appreciate some comments - hopefully none telling us to get a "diesel" - that is not an option - there's no pleasure going down that road...

Thanks for reading this far

Hi new here.... I actually joined because I am looking at what people are doing with the little 250cc Aprilia/Suzuki V Twin. I am currently looking at one option being done in Italy and although it is early in the development it looks promising. It has only had 2 sessions on the dyno and already they have found another 5 BPH from its initial run and they know it needs more work with jetting and the exhausts. It is already over 80bhp and looking at the power curve it has potential for more with a little more work. It is running a longer stroke so it has gone from 50.6mm to the more traditional 54mm stroke.

If you want to keep up to date with what I find out please visit my facebook page....
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But please do not post the dyno sheet I am posting up here. This is being kept off facebook for now as I do not want to show too many possible customers what is still a very raw and undeveloped product at this stage. But I do find your possible project interesting and currently I am keeping my options open as there is also a 500cc V4 project I am closely linked to....

Here is the very early dyno sheet.
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Please remember this will be having a lot more work done over winter. I am planning to run one for my project at some point in the new year.

Can you actually contribute to the discussion?

Institute of TwoStrokes a écrit:

Can you actually contribute to the discussion?

I thought I had in a small way... The BRC motor is not an Aprilia motor it is a Rotax inline twin motor and the OP has a V twin Aprila/Suzuki based motor. There is a possible 350cc option coming but it is still early in its developement to say too much but it will be an option in the next few months. Playing with big bore RS motors is not really doing much for most as the bigger bore shrinks the ports and the power gains are not that impressive. But the guy doing this has cast his own cylinders and heads so it is going to be something that will give the OP an option for his RS motor.

Sorry for delay in getting back to this - a few other things to do - and I've had a stinking cold all week

Ian Harrison a écrit:

I am conscious of pulling Gordon's thread "off beam".
I'm guessing that you (and others) had problems with the Honda coil?
Best Regards
Ian

Off beam is not a problem - as long as we are talking 2 strokes - the Ho*da comment is just my view on some of the things they have done to harm the 2 stroke cause...
Looking at the Kart pipe - interesting to see the second connection on the end of the header...do you have alternative headers - or alternative "the rest of the pipe" ?
Looking at the Ignitions - all appear to have a "flywheel" - the Pro-digital we use has very little weight - consists of a 50mm dia disc with a single magnet - so very little weight compared to any of the other ignitions we have used.
The comments about the 13v on the Ignitech are interesting - the Pro-digital is supposed to run ok down to 8v (from memory) - but we have found it starts to be very borderline anywhere under the full 12v - although we are only using a 2400 nimh battery - which according to the Ignition maker - is a better battery to run than the usual L/A battery most people use - although - I will be looking at a much bigger capacity Lipo at some point - especially if we get the Ignitech.
There is a new Pro-digital under development at the moment - and if it has better software - I will be looking very closely at that - although you say "However, if you'd like to buy 6 Ignitech boxes!!" - does that mean you have a "clearance sale" on those ?

Sorry Lozza - can't afford to give you the new cylinders - I think I did say earlier that you could have a pair of the "in need of repair" though.
The "new" set I think will have to go on one of the bottom ends I have - probably stick it on Eb*y to see if there's any interest.
I was just curious where the Athena cylinders are made - was looking for an importer in the UK - but haven't found one that keeps the Banshee cylinder...

I've not had one of the after market cranks to look at - the standard Yam crank has the crankpins as part of the centre wheels - the ideal would be separate pins & the centre keyed like the Hoeckle crank - would make it so much easier for rebuilding - the other thing is - all the cranks I have looked at have "welded pins" as a Sales feature - and you know my opinion of those....

I do need to find some time to do a bit of swapping & changing to see what parts will fit either TZ or YPVS - I have seen pictures of a TZ box fitted in the YPVS cases - but not sure how much work is involved - I did have a quick look - & the most obvious problems are the YPVS crank is longer - and there are only 3 shift forks...

It will be interesting to see the developments with the Aprilia / Suzuki - I will try to keep an eye on that - I think I saw some of your posts on another forum about a billet crank for those engines some time ago.

The new TZ cylinder is the other possibility - but will have to wait until that is available - in the meantime spend a bit more time looking at the other options

I did look at making billet cranks... My background was making Cranks but they were for diesels like the WCM Moto GP Bike and F1 Cosworthless ect.... So pressed cranks were not something we made. But making a crank regardless of one, two or twenty pieces is the same it is just engineering. I got a price for the flyweels but had to order 10 sets at £500 per set. Then it needed the 2 piece center bearing and for a longer stroke engine a longer rod to ease side loading on the piston and cylinder walls.

But with Veronesi making them and being tried and now tested (up to a point) Using his is for a one or two off build a cheaper option for now. His cylinders may have a little port matching needed but it is not far off and after talking to a couple of others who know about this project we think 90BHP is possible and still have a ability to rev to 12,500 where the banshee doesnt like to go much above 10,500. TZ350G's dont produce much after 10,500 either and as you have to run 350cc the TZ350G is about as far as you can get with an LC based motor.

Hi Gordon

Off beam is not a problem - as long as we are talking 2 strokes - the Ho*da comment is just my view on some of the things they have done to harm the 2 stroke cause...OK, yes I understand. In fact Honda were dragged kicking and screaming into the 2-stroke arena, in the first place, so not surprising that they try and destroy the 2-stroke.

Looking at the Kart pipe - interesting to see the second connection on the end of the header...do you have alternative headers - or alternative "the rest of the pipe" ? For each pipe (fat and thin), we have 2 different headers to suit the '01 and '02 Hondas and one to suit the '05-'07 Hondas. They are just different lengths to compensate for the different internal cylinder dimensions (piston face to exhaust flage). The real reason for the spring-loaded articulated joint is to prevent cracking due to vibration and allow an adjustment angle for variations in installation.

Looking at the Ignitions - all appear to have a "flywheel" - the Pro-digital we use has very little weight - consists of a 50mm dia disc with a single magnet - so very little weight compared to any of the other ignitions we have used. We are only allowed one power source generator or battery. I prefer generator, but we also try the DC CDI's with batteries.

The comments about the 13v on the Ignitech are interesting - the Pro-digital is supposed to run ok down to 8v (from memory) - but we have found it starts to be very borderline anywhere under the full 12v - although we are only using a 2400 nimh battery - which according to the Ignition maker - is a better battery to run than the usual L/A battery most people use - although - I will be looking at a much bigger capacity Lipo at some point - especially if we get the Ignitech. Yes, LiPo is best, but just be careful when charging and once they have had a bit of use. You must always use a proper LiPo charger. We have found all these DC ignitions perform best from 13 to 14.8 Volts. Just type "LiPo explosion" or similar into you tube and you'll see what I mean, if you are not already aware.

There is a new Pro-digital under development at the moment - and if it has better software - I will be looking very closely at that - although you say "However, if you'd like to buy 6 Ignitech boxes!!" - does that mean you have a "clearance sale" on those ? Yes it does. All come with plug and harnesses which are wired for single pickup (single or twin coil output). So you would have to put an extra wire in the plug for the second pickup on a V-Twin, etc and for any functions required. £100.00 per CDI plus VAT including shipping or £550.00 + VAT for all 6

Best Regards

Ian

Here is a quick video of the 350cc motor on the dyno...

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Hi Gordon

Forgot to ask, where do I find deatails of the Pro-Digital ignition that you mention?

Well I received the Zeeltronic today, great service and delivery time.

Physically the box is quite large and very HEAVY. A bit like a house brick compared to the HPI and over half a kilo!
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This compares to the HPI at 175 grames
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Of course we will also have to run the Honda Rec/Reg which itself weighs nearly as much as the HPI box.
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I'm not sure that I like the programming plug on the box (which you can just about pick out in the first image). It looks a bit delicate, and it didn't connect first time. It looks like something you would find on a computer motherboard. I had to wiggle it about a bit to eastablish a connection.

Anyway, the interface worked fine, first time and the programme is absolute childs play. It may lack a bit of sophistication of others, but it does the job admirably. I programmed in a couple of our CR250 curves did a quick temporary wiring job and we put it on the ignition rig, just to make sure everything worked OK.
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The spark looks nice and healthy from bottom to top and the actual timing in crankshaft degrees was pretty close to what was actually programmed in. Just made one minor adjustment to the offset in the programming and we are ready to rock-and-roll.

This is the ignition programming screen and the other screens for programming Powrvalve and Powerjet are of the same style
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I'll report back as soon as I have chance to get on the dyno with it and do a comparative run.

Best Regards

Ian

morepower a écrit:

Here is a quick video of the 350cc motor on the dyno...

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Thanks for that - doesn't actually tell me a lot - unless there is a soundtrack to tell me what's happening ? - I don't normally have audio turned on - I'm quite deaf - so don't get a lot out of any audio content....

Veronesi makes a lot of internet bashing but this engine is only the first one he builds and i can say that he still looks how to make it work decently

power delivery is crap and torque curve is far from even a 250

As I said... it is only the second run so far.. It will need pipes making and some more time. But it has improved 6bhp in the past month and the curve is a by product of the pipes and I think trying to use 39mm Dellorto carbs. I have not posted that dyno sheet anywhere else as it is still very early in development so this is the first time it has been posted up anywhere... I have not even posted up the details on my own site or farcebook pages...

Give it a couple of months and I think the motor will be a good one...

I do think that the guy who paid a large ammount of cash nearly one year ago have some reasons to complaint but he does not....

I do have the dyno of this engine whatever you say , the porting choosen doesn't match to the bike programm , with such high diagramms and stock cdi there is no way it becomes a ridable bike
The maintenance of a 13000 reving rpm engine with large pistons is just insane ... And same for the crank life ...

I think there have been a few changes to the porting in the past 12 months. I saw a dyno sheet from 9th November 2012 with about 75BHP and then this one with 81BHP. It has been limited to 12,500 from what I have seen and to be honest I know Fahron run the 300cc kits with 61mm pistons to well over 13,000rpm in their air cooled Suzuki T6 race bikes.

Running 64mm pistons with a 54.6mm stroke is better than trying to run 66mm pistons and Hummel cylinders at 50.6mm stoke as both get the same 350cc capacity. For guys looking for trackday and road use the 54.6mm stroke option is the best one. 90+ BHP is possible from 350cc in that configuration and off the shelf pistons are available too.

I know nothing of the past with Veronesi as I dont see anything on the english speaking forums and although some of his parts are expensive items like Crankshafts are not a problem for me.. My back ground was making billet cranks for F1 and other world championship series like Moto GP and World Superbikes.