Author Topic: 2ma conversion  (Read 15964 times)

xracer

  • Full Member
  • ***
  • Location: Coleraine : N.Ireland
  • Posts: 139
    • biscuit46@sky.com
2ma conversion
« on: December 22, 2013, 09:20:30 PM »
Hi all
Since acquiring a multitude of various parts from around the globe and including forum members and am quickly coming to a stage where my 2ma will undergo a modern face lift . I am hoping to changed the front end to USD set from the 3ma4 model and the rear ( also from the 3ma4) . I sure others have achieved this feat in the past but even after trawling the old forum I was unable to get much info. If anyone out there can give any advice / help it will be much appreciated .As you can see from the attached photo I will have a shed load of issues / problems trying make all of these bits fit, Should certainly keep me very busy throughout the coming year

Bngt

  • Full Member
  • ***
  • Location: Sweden
  • Posts: 107
  • Bjärred, Sweden
Re: 2ma conversion
« Reply #1 on: January 23, 2014, 01:01:32 AM »
Any progress or are you still stumbling over Yamaha parts when taking a piss in the night? ;)
2x2MA+2xF2

xracer

  • Full Member
  • ***
  • Location: Coleraine : N.Ireland
  • Posts: 139
    • biscuit46@sky.com
Re: 2ma conversion
« Reply #2 on: January 23, 2014, 01:49:27 PM »
Hi
Nothing much to report on .like yourself trying to accumulate all the bits and pieces I think I might need , to make it easier when I start . I have been give some good advice from forum members , Martin 77 will hopefully be making the pipes when we get to that point although fitting will present another issue.( tyga end cans already bought ).Hoping to have front and rear ends out of frame this weekend and  off to an old friend who's son has an engineering company. He can compare the 2ma stuff with the 3ma stuff and hopefully make them fit. I was luckier than you in that I had bought complete front and rear ends , axles , discs , everything , certainly make life easier !!!, will keep you updated , good luck

Bngt

  • Full Member
  • ***
  • Location: Sweden
  • Posts: 107
  • Bjärred, Sweden
Re: 2ma conversion
« Reply #3 on: January 23, 2014, 01:54:22 PM »
Yes please, let me know what you find and post pictures. I'll do the same. I will also have to find out things like how to fix the brake torque arm to the frame since it seems to be done like that on a 3MA.
What wheels do you plan to use?
2x2MA+2xF2

xracer

  • Full Member
  • ***
  • Location: Coleraine : N.Ireland
  • Posts: 139
    • biscuit46@sky.com
Re: 2ma conversion
« Reply #4 on: January 23, 2014, 03:05:45 PM »
Hi
Because I have a complete front and rear , I'm going to use the 3ma wheels that came with it , however I'd love a 17" rear if I could find one and somehow smuggle it past the wife,

Bngt

  • Full Member
  • ***
  • Location: Sweden
  • Posts: 107
  • Bjärred, Sweden
Re: 2ma conversion
« Reply #5 on: January 23, 2014, 03:13:55 PM »
Ok, I have bought 3XV wheels so I hope it will fit the swingarm somehow. I also bought the 3MA rear just in case.  Maybe I could use it on my second F2 "the Mule" if I don't need it for the TZR.

With a bunch of parts you have many cool options!
2x2MA+2xF2

gammaguy21

  • Full Member
  • ***
  • Location: Canada
  • Posts: 137
  • Canada (Ontario)
Re: 2ma conversion
« Reply #6 on: January 23, 2014, 04:10:00 PM »
Interesting discussion guys. 
I like the way my 2ma handles now, but tires seem limited because of the rim size.
I'm guessing with these wheel upgrades, you'll have much more choice in tires. I've been thinking about doing a wheel swap but I think I'll watch and see how both your projects come along.

I have a complete early model R1 front end that I was going to use on a another project, but I have been thinking about trying it on the 2ma.  Can't do anything on the bike until spring though as it's burried in the shed.

xracer

  • Full Member
  • ***
  • Location: Coleraine : N.Ireland
  • Posts: 139
    • biscuit46@sky.com
Re: 2ma conversion
« Reply #7 on: January 23, 2014, 05:59:28 PM »
Hi Guys
I'm lead to believe that 3xv ( 4.5") rear wheel will not fit into a 3ma swing arm , previously tried by Keleytis on this forum . In fact Keleytis was the guy  who provided me with most of the parts I needed ( good guy ) . I'm currently sticking with the 3ma 18" rear hoping a FZR400rr rear will turn up and then modified it as per the Louis TZR-V4 guide lines , Every day's another adventure . When I send the front and rear away for machining ( I'll post all dimensions ) the next thing to tackle will be mounting the TZR 125rr tank and finding away round the fuel tap issue , all good fun !!!!

xracer

  • Full Member
  • ***
  • Location: Coleraine : N.Ireland
  • Posts: 139
    • biscuit46@sky.com
Re: 2ma conversion
« Reply #8 on: January 23, 2014, 11:30:44 PM »
Hi  BGNT
 Thank for reminding me about the rear brake torque arm , as you can see from the picture it is connected directly to the frame ,a common trait on any bikes in the 80's. This application eventually died a death when many of the more experienced riders complained of the rear end hopping under heavy braking . (when the rear is applied hard enough the torque bar prevents the rear shock from compressing in the manner intended by the manufacture ).  Think I will consider relocating it ,see how it goes, after all -  I no Rossi !!!!

Bngt

  • Full Member
  • ***
  • Location: Sweden
  • Posts: 107
  • Bjärred, Sweden
Re: 2ma conversion
« Reply #9 on: January 24, 2014, 12:23:09 PM »
Yes, should be fairly easy to fix the caliper if needed.

I haven't bought any shock or linkage yet. Maybe the stock 2MA parts could be used?
2x2MA+2xF2

Bngt

  • Full Member
  • ***
  • Location: Sweden
  • Posts: 107
  • Bjärred, Sweden
Re: 2ma conversion
« Reply #10 on: January 24, 2014, 12:26:44 PM »
3MA is 4" and 3XV is 4.5" it is like 6mm on each side. It seems feasible to make an adaptation but I don't know until I have the parts.

2x2MA+2xF2

xracer

  • Full Member
  • ***
  • Location: Coleraine : N.Ireland
  • Posts: 139
    • biscuit46@sky.com
Re: 2ma conversion
« Reply #11 on: January 24, 2014, 01:21:46 PM »
Hi
Some guys use the 3ma linkage with CBr600rr or R6 shock , I went for the Honda shock , loads of adjustability and reasonably cheap on Ebay .com ( Mine came from America ) as for the 3xv wheel see link    [uhttp://pure2strokespirit.net/forums/index.php?topic=968.msg10756#msg10756rl] .Believe it is possible but requires an adapter kit from japan
« Last Edit: January 24, 2014, 01:26:42 PM by xracer »

Bngt

  • Full Member
  • ***
  • Location: Sweden
  • Posts: 107
  • Bjärred, Sweden
Re: 2ma conversion
« Reply #12 on: January 24, 2014, 04:52:05 PM »
Yes the CBR has a good shock. I use the F4i on  my Firestorm with SP2 swingarm and home made linkage. Probably better with a newer shock than an old used 3MA. Should

I buy the 3XV linkage to use with the 3MA swing if they are the same?

Sounds strange that you would need an adapter to get the 3XV wheel in. I will know when the parts arrive I guess. I did buy the 3MA wheel too but would of course prefer not to use it. I have machining resources so I can fix quite a bit of adaptation.
2x2MA+2xF2

Jim Lyon

  • Sr. Member
  • ****
  • Location: Sheffield, UK
  • Posts: 253
Re: 2ma conversion
« Reply #13 on: February 19, 2014, 06:34:55 PM »
  Part 1  - UNSPRUNG WEIGHT

While I find this topic of doing chassis upgrades to the 2MA to have some potential ( & if we come up with anything definitive, shouldn't a summary of that be entered in the chassis & suspension sub forum? ), I have some doubts as to whether  it's being done with enough awareness? - To explain where I'm coming from, many years ago I had a 1980 LC 350, which I started upgrading. While the engine tuning went quite well, back then there just wasn't enough information available in the public domain on basic chassis upgrading ( this was before the internet existed ), or @ what point you were taking a good idea & taking it too far. So, with lighter exhaust pipes ( stock are double skinned ! & really heavy ), alloy tank & racing seat, Metmachex swinging arm, passenger foot pegs removed, etc. total weight removed was 27 lbs/ 12 & 1/4 kilos ( weighed on bathroom scales ), but that was all sprung weight. I then found that while it performed better in some respects, & seemed OK on local roads that I knew well where I had a smoother line, on longer trips where I didn't know the road so well, my lines were rougher because I wasn't avoiding so many bumps, & this affected me on longer trips, making riding more difficult & I was getting tired; not exhausted, but the kind of less obvious tiredness where, thinking back, I was starting to ride like an accident looking for somewhere to happen! - So, by removing weight that  was all "sprung", I'd made
the sprung : unsprung weight ratio significantly less favourable, causing the road holding to deteriorate.
  While this isn't a problem with cars , or even big four stroke bikes, with small 2 strokes of only one or two cylinders, there's less margin for error, when it comes to playing around with the (un)sprung weight ratio.
 I'm also well aware of the fact that, for many decades Yamaha sold the RD range on the basis they were "Race Developed". But what works on the race track doesn't necessarily work so well on the road e.g. racers are better riders, but most races are shorter, & on tracks that are better known etc. So, while e.g. bigger tyres may be able to transmit more power, it doesn't take too much to go beyond the optimum,  & obtaining the optimum requires balancing out various conflicting needs. The problem is not just bigger tyres, but if you go down that road too far, then you need wheels with wider rims, then because that results in more weight, & when @ speed more kinetic energy being stored in the wheels & tyres, you then need bigger heavier brakes to slow them down ( & I'd suggest that it's just too easy to end up banging your head against the "law of diminishing returns". And while racers favour double front discs in order to combat heat fade, I remain to be convinced they're necessary on lightweight 2 stroke ROAD bikes. A combination of heavier tyres, wheels & brakes results not only in increased unsprung weight & poorer roadholding, but increasing the weight of them @ the front & rear of the bike leads to increased POLAR MOMENTS OF INERTIA, which means that the bike doesn't steer so quickly - & surely that should be one of the strengths of a lightweight 2 stroke?
 Having touched upon the fashion of double discs on the front, I'm aware that some more mature riders who've used that set up on 3MAs & 3XVs think they've almost too much braking power. So, I'm inclined to back off from that level of braking on 2 grounds , in order to achieve an optimum - perhaps a single 320 m.m. disc with a monobloc 6 pot caliper( & while a lot of those off big 4 strokes are available sources, I suspect that those calipers are too heavy for OUR optimum, so perhaps an ISR caliper or similar might be more suitable? Either way, I'd recommend changing over to a radial master cylinder as it's better feel means getting more control, & power without control ( brakes or engine ) isn't much use.
  While a lot of people are impressed by the Suzuki RGV250 series, I think it's a classic example of what I'm complaining about i.e. tyres, wheels & brakes that are too big & too heavy. I've heard of quite a few production racers complain about it's poor road holding, which leads me to believe that the best upgrade I've seen done was to fit an RG500 engine into that 250 chassis - now that really sorted out the road holding problems by increasing the sprung weight, significantly.
  Quite a few years ago, the TZR Forum was originally the TZR List, run by Neil Ronketti who's a pretty clued up guy having raced TZ250s @ GP level, eventually "downsizing" to TZR 250 production racing on grounds of cost. His view was that running 120 front & 160 rear tyres made the steerig significantly less sharp.
  Having done a little research on this e.g. talking to a Bridgestone techie, etc, I've come to the conclusion that, for similar chassis to the 2MA, but sufficient for the typical power range of standard or tuned 250-400 c.c.twin cylinder engines the optimum tyre sizes are 110/70 x17" front & 150/60x17" ( by all reports the stock 2MA swinging arm will only accept a maximum tyre size of 140 m.m. on the stock wheel ). While Bridgestone recommend a  number of wheel rim widths
to accomodate these tyre sizes, because of the previously mentioned considerations of (un)sprung weight ratio & reducing polar moments of inertia & kinetic energy, rather than settling for the middle size, it seems to make good sense to go for the minimum widths of 2.75" front & 3.50" rear ( that's because stock alloy wheels are HEAVY. If we could get carbon fibre wheels, then I'd go for 3.00" front & 4.00" rear to give the tyre the optimum profile.
  If anybody remains unconvinced with my position, then be aware that Mark Boddy on this forum races a 2XT with narrower than stock wheels & tyres, & swears by the benefits that gives him in corners allowing him to out turn his opponents.
 ( Past 2 to follow shortly. )
« Last Edit: February 26, 2014, 08:37:39 PM by Jim Lyon »
YAMAHA RIDERS GO IN DEEPER AND COME OUT HARDER

xracer

  • Full Member
  • ***
  • Location: Coleraine : N.Ireland
  • Posts: 139
    • biscuit46@sky.com
Re: 2ma conversion
« Reply #14 on: February 19, 2014, 08:53:18 PM »
On purchase ,most biker look at their " used"  bike with some confusion as to whether to restore it to it former glory or choose the path of customising / personalisation, each to there own. Many change wheel sizes , brakes , suspension ,etc , assuming, often rightly, that these items will have had substantial  improvements in technology and should offer a better and safer ride . Most except that when modification's are made to one particular area of the bike,  it will upset / affect others and will require endless hours to achieve something that is suitable to their needs. Even the best can find the perfect set up difficult to find , ask Rossi !!!. Most of the changes are attempts to modernize the appearance of the bike , without going to the expense of  a 3xv ,which I could never afford to purchase or maintain ( 2ma parts are still reasonably cheap and readily available  ) As my name suggest I have in the past competed in many road and short circuit events ,including the NW200 and Manx GP , I am aware it will take time but that is all part of the challenge .
I will consider moving any further correspondence to the suspension section if that is what is required