OzVMX Forum

Clubroom => General Discussion => Topic started by: Slakewell on March 25, 2013, 02:08:47 pm

Title: Pre 78 125's
Post by: Slakewell on March 25, 2013, 02:08:47 pm
What would be your pick and why?
I'm thinking that the little RM would be the best bang for buck in this class?
The KTM is to heavy and too rare the Monty whilst being beautiful is sadly uncompetitive ( Mostly because it is in pieces ) The Honda is expensive when you add aftermarket parts. Don't know much about the YZ D. Firko's little Pre 78 project looks interesting with Yam power. The Maico fits in with the KTM. What other choices are there?   
Title: Re: Pre 78 125's
Post by: Rookie#1 on March 25, 2013, 02:45:18 pm
You've pretty much already answered your question, YZ125D/E. although E us 78 all but swing arm are pretty much the same. Bits are plentiful and relatively low cost, you'll build a good 125d/e and keep it running for years for a hell of a lot less than maintaining and buying euro bits. Go for it, you'll love it. If you're heading to HBBB come say g'day and take mine for a spin.

Cheers, Brendan

(http://i1193.photobucket.com/albums/aa347/rookie110/IMG_2158.jpg)
(http://i1193.photobucket.com/albums/aa347/rookie110/IMG_2157.jpg)
(http://i1193.photobucket.com/albums/aa347/rookie110/IMG_2156.jpg)
(http://i1193.photobucket.com/albums/aa347/rookie110/IMG_2155.jpg)
Title: Re: Pre 78 125's
Post by: Big Scotty on March 25, 2013, 02:52:42 pm
only ridden yamaha d model 125 which seems just as competative as the rest,i find the 125 is the hardest bike i have to ride fast but is also the most fun when you get it right,riding my 400 makes you lazy,just ride the 125 like you stole it,seems though the rms are a fairly good bit of gear,except for a problem with the swingarm lol,
Title: Re: Pre 78 125's
Post by: albrid-3 on March 25, 2013, 03:15:10 pm
My choice would be a Honda cr 125 77 model. (TOP GUN)
Title: Re: Pre 78 125's
Post by: Slakewell on March 25, 2013, 03:22:54 pm
My choice would be a Honda cr 125 77 model. (TOP GUN)
Dave I was thinking this as my mate has one hiding in his unused stuff but when I went on ebay and saw kits going for 2.5k I stopped.
Title: Re: Pre 78 125's
Post by: albrid-3 on March 25, 2013, 03:32:33 pm
A standard 77 model Honda CR 125 would still eat a yz yamaha, These bikes would also eat up a 80 model bikes, you done need to put kits on them, they become to unreliable. stick to standard, the Jap`s did there homework on them.
Title: Re: Pre 78 125's
Post by: jimg1au on March 25, 2013, 03:33:43 pm
i like riding my yz125x its a fun bike to ride
jim
Title: Re: Pre 78 125's
Post by: Montynut on March 25, 2013, 04:13:57 pm
A standard 77 model Honda CR 125 would still eat a yz yamaha, These bikes would also eat up a 80 model bikes, you done need to put kits on them, they become to unreliable. stick to standard, the Jap`s did there homework on them.
Dave the RM125B & YZ125D are far better than the Honda for MX maybe in dirt track the Honda may have a faster engine but the chassis and suspension just is not in the same race as the YZ/RMs. Back in 77 the start lines where white and yellow not much red
Title: Re: Pre 78 125's
Post by: JohnnyO on March 25, 2013, 04:20:37 pm
The RM125b was the best stock 125 in '77 followed by the YZ but the Honda was popular in the US with the Pro's. Once you bolted all the aftermarket goodies to the CR and did a little cylinder grinding they were rocket ships.
The Husky is also a good bike but maybe a bit underpowered. They can all be made into decent bikes with the technology we have today.
Title: Re: Pre 78 125's
Post by: JohnnyO on March 25, 2013, 04:23:56 pm
A standard 77 model Honda CR 125 would still eat a yz yamaha, These bikes would also eat up a 80 model bikes, you done need to put kits on them, they become to unreliable. stick to standard, the Jap`s did there homework on them.
Dave the Honda was the least developed of all the 125's, it received minimal changes from '74-'78 and was left behind
Title: Re: Pre 78 125's
Post by: Montynut on March 25, 2013, 04:36:40 pm
The VB125 Montesa had no power, what was there was in a power band narrower than a bees dick and a hand grenade instead of bigend bearing don't even bother.
Title: Re: Pre 78 125's
Post by: motomaniac on March 25, 2013, 04:48:09 pm
A standard 77 model Honda CR 125 would still eat a yz yamaha, These bikes would also eat up a 80 model bikes, you done need to put kits on them, they become to unreliable. stick to standard, the Jap`s did there homework on them.
Dave the Honda was the least developed of all the 125's, it received minimal changes from '74-'78 and was left behind

true but more power was easy to get , 34mm mik alone made a big diff, head and porting and maybe a pipe and they flew .AB won the OZ title on one in 76  with close to stock suspenders. But for sure the RM was best off the floor in 77 .
Title: Re: Pre 78 125's
Post by: JohnnyO on March 25, 2013, 04:58:08 pm
true but more power was easy to get , 34mm mik alone made a big diff, head and porting and maybe a pipe and they flew .AB won the OZ title on one in 76  with close to stock suspenders. But for sure the RM was best off the floor in 77 .
AB was second in the '76 125 title to Steve Cramer but Darryl Willoughby did win the '77 Oz title on a CR.
Title: Re: Pre 78 125's
Post by: 09.0 on March 25, 2013, 05:04:45 pm
What would be your pick and why?
I'm thinking that the little RM would be the best bang for buck in this class?
The KTM is to heavy and too rare the Monty whilst being beautiful is sadly uncompetitive ( Mostly because it is in pieces ) The Honda is expensive when you add aftermarket parts. Don't know much about the YZ D. Firko's little Pre 78 project looks interesting with Yam power. The Maico fits in with the KTM. What other choices are there?   
Maico 125 is very competitive. With the tracks we run today most are competitive anyway. I would be just as happy with a cr125. The Smith brothers take turns at winning the pre78 nat's on a cr125.
Title: Re: Pre 78 125's
Post by: motomaniac on March 25, 2013, 05:18:20 pm
true but more power was easy to get , 34mm mik alone made a big diff, head and porting and maybe a pipe and they flew .AB won the OZ title on one in 76  with close to stock suspenders. But for sure the RM was best off the floor in 77 .
AB was second in the '76 125 title to Steve Cramer but Darryl Willoughby did win the '77 Oz title on a CR.

Jeez you're good . Anyway they were competitive in the day with some work and a good 125 pilot.At that level its all about max power , a reed valve  have less significance .
Title: Re: Pre 78 125's
Post by: mainline on March 25, 2013, 05:52:07 pm
i like riding my yz125x its a fun bike to ride
jim

I'm with you Jim, I love my 125c/x. Too many people think they have to ride a '77 model bike in pre 78, or an '84 in pre85 etc.
Title: Re: Pre 78 125's
Post by: albrid-3 on March 25, 2013, 05:53:19 pm
The cr may be behind in travel, they are still a rocket ship. today standard does it really matter. I have a 72 penton 125 mx I would ride in the pre75 125 class, it would be happy to ride it, to me its about having all different bikes on the starting grip.
Title: Re: Pre 78 125's
Post by: motomaniac on March 25, 2013, 06:02:41 pm
The cr may be behind in travel, they are still a rocket ship. today standard does it really matter.
I had a full 9" both ends on mine Dave with a fork kit and longer shocks .Handled to rough better than RMs and YZ's.
Title: Re: Pre 78 125's
Post by: JohnnyO on March 25, 2013, 06:35:51 pm
true but more power was easy to get , 34mm mik alone made a big diff, head and porting and maybe a pipe and they flew .AB won the OZ title on one in 76  with close to stock suspenders. But for sure the RM was best off the floor in 77 .
AB was second in the '76 125 title to Steve Cramer but Darryl Willoughby did win the '77 Oz title on a CR.

Jeez you're good . Anyway they were competitive in the day with some work and a good 125 pilot.At that level its all about max power , a reed valve  have less significance .
Yeah i like the CR even though i raced a RM125b in '77.
That's why i've got a Mugen kit sitting here and a '76 CR125 stripped down ready to build one day...
Title: Re: Pre 78 125's
Post by: Ted on March 25, 2013, 06:55:12 pm
Suzuki won every 125 World Championship from 1975 to 1984 inclusive ( the eras we all ride in )
10  titles in a row. They obviously knew something the others didn't
Title: Re: Pre 78 125's
Post by: TM BILL on March 25, 2013, 07:06:04 pm
For me its an RM 125A  :) the B was a better bike in most respects but the A motor really revs  ;)

I would probably run B forks dropped through the clamps to keep the ride height lower like a A and decent modern shocks .
Title: Re: Pre 78 125's
Post by: Slakewell on March 25, 2013, 07:23:53 pm
For me its an RM 125A  :) the B was a better bike in most respects but the A motor really revs  ;)

I would probably run B forks dropped through the clamps to keep the ride height lower like a A and decent modern shocks .

Bill wouldn't it be easier to fit a A barrel or porting to a B model?
Title: Re: Pre 78 125's
Post by: Davey Crocket on March 25, 2013, 07:26:26 pm
Different bore and stroke Slakey    54x54= B.....56x50=A.
Title: Re: Pre 78 125's
Post by: Slakewell on March 25, 2013, 07:29:46 pm
Different bore and stroke Slakey    54x54= B.....56x50=A.

Arhhh Ok so one needs to swap the engine, does the A corner better? And is that because of the frame or throttle response?
Title: Re: Pre 78 125's
Post by: TM BILL on March 25, 2013, 07:37:01 pm
Different bore and stroke Slakey    54x54= B.....56x50=A.

Arhhh Ok so one needs to swap the engine, does the A corner better? And is that because of the frame or throttle response?

When the track gets rough ( Old School rough) the B suspension will be an advantage  :) but on todays VMX tracks i think the A is a better option .

The A really revs out ( i compare it to an RM 125 S with an extra gear ) the B you have to short shift , if you try to rev it out it signs off real quick .

The RM 125B is a great bike i just prefer the slightly lower ride of the A and the A motor characteristics .

If you get a chance ride Joans 125 A /B hybrid its a really great ride  8)

Next favorites for this class would be

RM 125 B

RM 125 S

YZ 125 X

YZ 125 D

I have not cut a lot of laps on the 76/77 CRs but the ones i have were a good ride and very competitive .

I think a blinged up CR is the best looking bike for the era followed by the RM 125S and the RM 125 B
Title: Re: Pre 78 125's
Post by: Paul552 on March 25, 2013, 07:39:39 pm
Someone please say a stock yz125d with a far below average rider with above average weight is the go!!!
Please :)
Title: Re: Pre 78 125's
Post by: motomaniac on March 25, 2013, 07:45:27 pm
true but more power was easy to get , 34mm mik alone made a big diff, head and porting and maybe a pipe and they flew .AB won the OZ title on one in 76  with close to stock suspenders. But for sure the RM was best off the floor in 77 .
AB was second in the '76 125 title to Steve Cramer but Darryl Willoughby did win the '77 Oz title on a CR.

Jeez you're good . Anyway they were competitive in the day with some work and a good 125 pilot.At that level its all about max power , a reed valve  have less significance .
Yeah i like the CR even though i raced a RM125b in '77.
That's why i've got a Mugen kit sitting here and a '76 CR125 stripped down ready to build one day...
Is the kit complete ? What are you waiting for ?
Title: Re: Pre 78 125's
Post by: TM BILL on March 25, 2013, 07:47:13 pm
Someone please say a stock yz125d with a far below average rider with above average weight is the go!!!
Please :)

That combination is a shue in for the 1977 stock YZ 125 for the well fleshed Novice class  ;D ;D
Title: Re: Pre 78 125's
Post by: Big Scotty on March 25, 2013, 07:48:58 pm
Ok Paul,just for you my magic yz125d made an average oversize rider look good last year,well have to line up either side of scrivo this year,he'll think he's seeing double,see ya at glenbawn
Title: Re: Pre 78 125's
Post by: Paul552 on March 25, 2013, 08:09:43 pm
Ok Paul,just for you my magic yz125d made an average oversize rider look good last year,well have to line up either side of scrivo this year,he'll think he's seeing double,see ya at glenbawn

Can't wait

See you there.

I will drive in Saturday morning.

Title: Re: Pre 78 125's
Post by: oldfart on March 25, 2013, 08:13:29 pm
Bill,  Joan and I have had a few straight line drags over the years and the B motor seems to pull away in most cases..... Not by much
I agree the B motor drops off a little earlier, but it's all about the right hand and left foot combo  ;)
Title: Re: Pre 78 125's
Post by: JohnnyO on March 25, 2013, 08:25:27 pm
true but more power was easy to get , 34mm mik alone made a big diff, head and porting and maybe a pipe and they flew .AB won the OZ title on one in 76  with close to stock suspenders. But for sure the RM was best off the floor in 77 .
AB was second in the '76 125 title to Steve Cramer but Darryl Willoughby did win the '77 Oz title on a CR.

Jeez you're good . Anyway they were competitive in the day with some work and a good 125 pilot.At that level its all about max power , a reed valve  have less significance .
Yeah i like the CR even though i raced a RM125b in '77.
That's why i've got a Mugen kit sitting here and a '76 CR125 stripped down ready to build one day...
Is the kit complete ? What are you waiting for ?
Time is the biggest problem.. with so many projects already on the go and weekends where i'd rather go riding it takes forever to get them done.
Title: Re: Pre 78 125's
Post by: JohnnyO on March 25, 2013, 08:31:27 pm
For me its an RM 125A  :) the B was a better bike in most respects but the A motor really revs  ;)

I would probably run B forks dropped through the clamps to keep the ride height lower like a A and decent modern shocks .
When i got my brand new RM125B to replace the A i thought the B was better in every way, especially the engine with more bottom end.
Title: Re: Pre 78 125's
Post by: Nathan S on March 25, 2013, 08:38:38 pm
Someone please say a stock yz125d with a far below average rider with above average weight is the go!!!
Please :)

It is, actually. Mostly because of the motor that is relatively tolerant of being asked to do something when you're in a too tall gear.
They're also physically larger than the other pre-78 jap 125s.

If I were to set out to build the fastest possible bike for the class for me, I'd start with a YZ125D. DG swingarm, modern shock internals (and modified to get 9" of travel), 250D 38mm forks, plus all of the usual motor stuff.
I know the pro-Suzuki arguments, but I firmly believe the Yamaha is the better bike for the bigger and/or less talented rider.

I've got 95% of the bits to build such a bike but haven't, because I love riding my YZ-X - and I reckon that's the bit that really matters. ;)
Title: Re: Pre 78 125's
Post by: firko on March 26, 2013, 01:32:53 pm
I know that there's no way I'd have an RM125B or C with an alloy swingarm. Too many train spotters out there with their parts books in their back pocket. ::)

Being a biggish fella for most of my life I've rarely felt the need to dive into the 125 pool except for my Bully Sherpa S in 1969, Hodaka Combat Wombat in the 70's and MX125 Yammy in the early vintage days. Having said that, Jonesy and I have pooled our resources and we're building a pre 78 125 based on the Trackmaster motocross frame I got from Rob in Whyalla. It's a featherweight little Chro-mo creation already but AJ's fitted a Boyd and Stellings swingarm, we're using 36mm YZ250 X forks and front wheel, MX125 rear wheel, Ohlins shocks from a Maico, Yamaha MX125 5 speed engine with a Noguchi barrel (looking for a matching head), 34mm Mikuni, Vintage Iron pipe, YZ125X seat and tank. Neither of us have done a bike for this era before so it's all new ground. I realise that we're a bit restricted by the 5 speed MX125 motor but I was given a ute full of them so it would have been silly not to use one....plus the fact that the frame's made for that engine and all of the other parts were laying around both of our sheds. It'll be legal, trick, cheap and above all a fun little bike.
                                                                       (http://i1112.photobucket.com/albums/k495/firko2/trackmaster.jpg)
Title: Re: Pre 78 125's
Post by: Slakewell on March 28, 2013, 05:35:07 pm
IMO the best looking Pre 78 125. I did look at fitting a Honda crank or even complete bottom end to make one race ready but even I'm not that much in lust.

(http://www.vintagemx.us/images/photos/15492805-2524-large.jpg)

http://www.vintagemx.us/cgi-bin/largephoto.cgi?C=gqrMWvrxCHwT6qA4