Topics

106

Tech Talk / Tapered bearings for steering stem

« on: January 01, 2009, 10:41:14 AM »

Gents,

If you need individual tapered bearings for steering head/stem (as opposed to sets/pairs from All-Balls) try Pyramid-Parts.com in UK. They have a reasonable selection & list sizes available on their site.

107

Foto Forum / Bermshot

« on: December 27, 2008, 10:09:33 AM »

Now that's a bermshot - Torleif Hansen heeled way over!

108

Bike Talk / Kaw KE250s in Oz?

« on: December 09, 2008, 08:58:18 AM »

Does anyone know if Kaw KE250s (77-79) came into Oz?

Anyone ever seen one or know the whereabouts of one?

TIA

109

Italian (Moto Villa, Beta, SWM etc) / Ancillotti

« on: December 05, 2008, 09:37:38 AM »

Gents,

Here's a shot of a nice  250MX to go w the ones posted in Gen Disc'n

110

Suzuki / TM-TS Flexy Flier Fix (?)

« on: December 03, 2008, 11:33:19 AM »

Gents,

I've been giving some tho't to some of the handling vagaries of  TS/TM250s since I picked up a 72/3 TS 250 frame & swingarm to go w my 76 motor w the tho't of a Vinduro mount. Seems to me the frame design, construction & geometry are half-decent, but the swingarm is lacking considerably.

At only 32mm OD & 18-19" long, its rather long & slender (to put it mildly) to be resisiting much flex. See 1st pic below. (Ignore the date)


Also, the cross-bracing near the pivot is minimal compared to any decent handling bike of the day, esp euro bikes. See 2nd pic (in subsequent post) along side Ossa Phantom swingarm (whose OD is 36mm). I could have put a Maico, Mon, Cooper or Bul swingarm there as the comparison is similar.

Suz improved things themselves on later TSs.  Compare 3rd pic alongside later TS250 swingarm (in 3rd post). Larger OD & better cross-bracing.

Add to that the poor quality of Japanese steel of the day & you have a recipe for a flexy-flier of sorts.

I'm lead to believe that the TS/TM400 swingarms are little/no larger in OD than the 250s 32mm (tho they are apx 1" shorter), which may also help explain some of their infamous handling traits.

As we all know, accessory Cro-Mo swingarms provided a fix back in the day, but where do you find them (at reasonable cost) these days? 

It seems to me that a gusset (apx 20x3mm) welded in the vertical plane along the underside of each arm would stiffen it considerably & reduce much of the flex. Bending stresses are highest at the cross-brace, so the gussets should be max height/depth there, then could be tapered down, which would also look better (less obtrusive). Obviously you’d need to check chain clearance too, esp at max suspension travel.

Thats what I plan to do on mine, but its a long way from being completed yet.

I'm not suggesting this would fix all the handling issues & its hardly original, but it is simple & cheap & might just help considerably.

The cross-brace could do w improving also, but thats a bit more involved.

111

General Discussion / New category suggested

« on: November 27, 2008, 11:03:57 AM »

Can I make a suggestion to Graeme/Admin pls - that we add a new forum category specifically for Vinduro, like we have for dirttrack & trials.

What you think Graeme?
(Nice of me to suggest another job for you!)

112

British (BSA, Greeves, Triumph etc) / PPM Rotax from UK

« on: November 20, 2008, 09:52:56 AM »

Does anybody know anything about the PPM Rotax (2-stroke)? And/or have any pics?

In the occasional pic I've seen it looks a bit like it may use an AJS Stormer frame - or a modified one.

Any info & pics will be greatly appreciated.

113

Twinshock Trials / TY250B bore x stroke

« on: November 19, 2008, 04:26:15 PM »

Can anyone tell me what the borexstroke is on the early TY250s?

I always tho't it was the usual 70x64mm, but was reading a DirtBike test last night which claimed it was 70.7x65.9mm. Seems wrong to me but I'm not that familiar w TYs.

114

Twinshock Trials / Classic Dirt Bike mag - Project TY

« on: November 19, 2008, 09:50:38 AM »

Does anybody know if the Project Ty article in the first few issues of Classic Dirt Bike mag is TY250 or TY175?

115

Kawasaki / Kaw USA contacts wanted

« on: November 06, 2008, 11:10:37 AM »

I know this is a long-shot but I can only ask.

Does anybody have emails or know how I may contact former Kaw riders Jim Cooke & John Desoto & mechanics Steve Johnson & Roy Turner?
(TIA)

116

Tech Talk / Sealed main bearings?

« on: October 14, 2008, 12:37:28 PM »

Gents,

I noticed in Doc's post on the 125KTM that it has a sealed main brg on the RHS of crank - which of course may not be OEM

Has anybody had experiencs running sealed bearings for main brgs?

117

Husqvarna / 73-75 360 WR-RT Husky pics/specs

« on: October 04, 2008, 05:32:15 PM »

Gents,

Anyone know much about the 5sp WR360RT (circa 73)?

How bad/heavy/slow were they?

Are they redeemable for VMX/Vinduro?

118

CZ / CZ125 (model 984) bottom end wanted

« on: September 16, 2008, 02:58:17 PM »

Gents,

Does anyone have a CZ125MX bottom end (mod 984) you'd be willing to part with?

Or have they all been disposed of as beyond hope?

119

Maico / Top end conversions for the humble 250

« on: September 09, 2008, 12:27:54 PM »

Gents,

Back in the day when my 73 250 radialfin was past its competitive day, I often tho't of putting a Yam 360 top end on it, but never had the resources.

Why? For me the 400 Maico was the quintessential MXer, even tho I was only a fly-weight at about 6-7 stone. I couldn't afford a new bike, but the Yam 360 had same 70mm stroke & centre-port exhaiust, so I tho't it could be the next best thing.

I still wonder.... but now I think of other options also.

The prerequisite is simply something w a stroke near 70mm & a centre-port exhaust. I'll post several options one at a time w a few tho'ts/observations I've made over the years.

You'll still have to check a lot of things yrself tho', eg piston deck heights, barrell hts etc to get the piston to line up with top of cylinder at TDC, & whether there's enough meat in the cases to relocate the studs etc etc.

Pls consider this thread as a floating of ideas/possibilities - alternatives to the 326 Maico topend route, altho that could be the easiest/best route.

Option 1 is 360 Yam top-end.

Forget the 74 DT360 & MX/MXA360 of 73/74. These barrels had 6 studs in a weird pattern, w weird location of transfer ports at the barrell base - shared only by the SC500 barrell. It would be a massive job to make them fit.

Consider using the RT1/2/3 or RT1/2M barrells. Stud spacing is of course diff to Maico & would have to be adjusted, but at least there's only 4 studs. Skirt dia is 89mm as opposed to 85mm in Maico 250 cases. I don't know if there's enough meat in the early (pre-440 Maico) 250 cases to allow milling out to 89mm & I susppect the liner/skirt on the barrel would be barely strong enough if turned down to 85mm. Perhaps need to meet somewhere in the middle - a bit off both.

440 Maicos must have had larger spigot in cases to suit 82mm bore, so later cases may have more meat there.

Even the trail-bike 360 Yam barrels have decent porting specs, if you raise the ex & perhaps lower the inlet - both easy enough to do. Most of these barrels also have a compression release facility that exits into the exhaust tract. Very neat & clean.

The RT2/3 barrels only have V4 reeds, but V6 reeds can be found or made to fit, if careful. From memory, YZ A/B reeds (if you can find them) or later IT175/200 reeds either fit or can be made to fit. (Early IT175s had V4 reads if my memory serves me correctly).

Transfers cutouts at the base of the cylinder are more angled towards the front (exh port) than on the maico cases but that should be fixable. Piston pin dia is same 18mm for both Yam & Maico.

Capacity would be 352cc w std Yam piston.

120

Introductions / JC = kawboy

« on: September 09, 2008, 11:38:27 AM »

Gents,

Just changing my pseudonym from kawboy to JC (cos its simpler). Will leave it as "JC (kawboy)" for a while.

Tho't I may as well do an intro as well, since I didn't do one when I first joined:

Bikes raced then: 71 Bul Sherpa S 125; 73 Kaw F11M, 73 Maico 250, 75 Maico 250 (borrowed), 76 Bul Mk9 Pursang 250, 77 YZ125D (borrowed) - in that order

Bikes owned now: same Sherpa S, same Pursang, KX250A, Mon V75, Ossa 350 SuperPioneer, CanAm 175 MX2/Qual, 80 KLX250 - not all complete, + a few 'bones' & projects/hybrids

Memorable moments: attending my 1st scramble meeting (as spectator in 1970)
                             my 1st powerslide on a race bike (Sherpa S) when 14. Oh what a feeling!!
                             riding a (friend's) CZ400 aged 15
                             seeing Gary Flood obliterate the oppositon in 74 on a track he'd never ridden
                             watching Trans-Tasman racing at Nerang in 74

Favourite marques then: Bultaco & Maico, then anything european

Favourite marques now: Bultaco & Kawasaki, then Ossa, Mon, Maico & anything VMX

Bikes I'd love to ride/own: RH, Phantom (esp GP2), 75/76 KX250SR, Rickman-Yoshimura 125

Most fun bike ever ridden: probably RM125B - pinball wizard!!

Pet dislikes: people who can't tell fact from opinion (esp their's)
                 people who abuse others on forums (or anywhere)
                 rip-off merchants

Biggest disappointments: Ake in 71, Willie in 73, Falta in 74

Best looking bike: Phantom GP2 or VB Mon

I wish:  I could find that F11M (or another) - anyone got any leads??
           I'd seen Joel Robert & Jim Pomeroy ride in their heyday
           I'd been able to afford a new Pomeroy Pursang in 74 instead of a 2nd hand Maico
           All my bikes/projects were complete
           I lived a lot closer to VMX action

Idosyncrasies: I collect porting specs & obscure chassis measurements of VMX bikes cos I'm keenly interested in the engineering side of VMX bikes. Always seem to be analyising something.