TM75...or....TMXR75....

[2fITy.J]

G'day all, somehow I have added another bike to my shed. One that is now the oldest in there, a 1975 TM75.

There is nothing special about them I hear you say, except Barry Sheene supposedly rode one around the pits at the time. That time being 1975. But it's a bike in need of fixin'...good enough excuse.

Initially it was gonna be a resto to as spec as I can within a small budget, gleaned from all avenues possible. At this stage I haven't seen too many indications this will be quick, so possibly a long standing search and rescue when out and about.



















I feel this resto will stretch to everything I have learnt and then some. I just know I will be learning a lot more doing this one, something I look forward to.


btw...The Massive Challenge is to get this baby complete!  

[2fITy.J]

Next bit....



I was given a surprise recently when a mate dropped off what he thought was a small Suzi like mine....I've since established that the cut up roller is an MX100, and is an H.....going by the frame numbers, likely an early '81 at 10,000 into the run.

Everything that was still bolted on come off easy after a 24hr soak with WD-40. Only one brake shoe lining came adrift...mind you it is only wafer thin (rear brakes) Hubs, axles and bearings are in good condition, rims are true but spokes are very rusty. And I now have a road legal rear tyre for the TC....It's an old Duallie type pattern.

Forks, although somewhat rusty have good movement and damping...seem in very good condition. The rear shocks at first had me thinking one was seizing, but it turned out to be mis-matched pre-load settings...one spring has curved slightly due to this.

Swingarm rubbers are cactus but the hardware is perfect....real pity the frame had been cut and the spine bent. I will offer the frame to anyone who wants a piece frame tubing for repair etc....









Steering head is good and in fact I have put the handlebars on my IT250, they are a nice bend with a bit more height...may help me more at snail speeds, where I most often come undone!

I will start stripping the TM soon and see if the swingarm and steering head can bolt up ok. A side by side prognosis looked good....

It may become a "TMX" for a while......

[2fITy.J]

Where it's at.....

Underway....during the strip it appears the bike was most likely run over by a car or truck. The motor may have been severely damaged and rendered useless.



Rear shocks have absolutely no dampening left, just very noisy pogo's at best.





The frame is actually quite straight....





Swingarm bolt is bent....




Swingarm is twisted....




Lower engine mounts seem to be the only effected part of the frame......





One of the most elaborate and over engineered ways to hold a 14" long front guard on......







Front wheel may have been on Mars when water was present.....





Rear axle proved stubborn....





Held up by a collection of horse hair and nylon twine...

[2fITy.J]

Rear wheel gets the good all over gong....





Swingarms are a pretty near match (MX on top)........





Doing some angle math....with the slightly longer arm and a slight slant forward for the shocks, it will lower the height very slightly and require the heaviest pre-load setting......





3mm will have to be shaved off the inside of each knuckle and the frame bushes diameter enlarged to take the thicker bolt.....





Guesstimating that the bend in the spine of the MX frame behind would have had them line up before....





It could possibly maybe straightened....perhaps.





The rest of it is within a centimetre or so.....






But now the little TM and MX surprise, have been put in little containers and shelved....






Hopefully to blend in with the rest and not be an ever present "project" on the floor, I would see it everyday and thought I should do something....I have come to the conclusion that patient waiting is the ideal approach...the strip and appraisal has sated my appetite to do anything on it for a while, hopefully!!


Mind you, those shelves were devoid of bikery a couple of years ago!

But the thought crossed my mind, I haven't been able to get another motor anywhere, but I am baby-sitting an old XR75 motor......


Cheers,
Chris.

[Hardex]

Hi 2fITy.J
Whats the story with the spin dryer I think that has "Domesticals mowing Lawns and femestics washing clothes " and a painted picture of an IT below it

[2fITy.J]

If I can't fit part A into part B, I often do something abstract to relax...then try fitting the parts again.

Living alone I tend to allocate chores into certain groups...my sons keep askin' me what I'm doing, it makes it easier when texting.

Making replica IT parts I would clean my brush on the spare spare drier...soon became a picture.


Tried drawing a TM75 motor but it's just not the same.....



Cheers,
Chris.

[2fITy.J]

Okay, well it's definitely gonna be a bona-fide 1975 TM75 now! 


http://www.ebay.com.au/itm/321038044273?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649#ht_500wt_975



  ....bargain! 



Cheers,
Chris.

[2fITy.J]

Okay, the above link is long dead...suffice to say it was a 98% complete TM75 in reasonable condition for $112.50, from near Newcastle. Forum members helped and the bike made it to my shed at the beginning of May.

Here's the update....

Was a bit gloomy weather-wise when I took the pics....















She's rough but runs....

The tank is toast, barnacle size clods of rust adorn the inside, condensation blisters on the inside of the cap. But it turned over and the motor all looks complete apart from the choke cable (and thumb-lever) I took he plug out and discovered the gap closed, I opened the gap and there was spark...amazing considering the lead is some 240v wire inside some clear fuel line and twitched around the plug end.

I replaced the plug and kicked it over...heard a clicking sound and then the kick-starter gave up the ghost. The bolt head snapped and the lever slipped on the spline.

Drllled a small hole into the other end of the bolt shank and drove in an "eazy-out", soon had the thread turning out. Replaced with a fresh bolt and put it on. It's still loose and I can see why the bolt was snapped. The pinch space is already closed and still loose on the spline, over tightening does nothing. It will need the inner surfaces of the pinch shaved a little and the entry hole opened up for more angle.

When I put the lever back on and tried kicking again, the clicking was still there...hmm, I took the plug out and sure enough....the electrode is flattened again. I replaced the plug with a short reach one and gave her another kick....for a missing click.

Sprayed some ether down the fuel line and gave it a kick...she fired and ran about 20 revs....sounded like a scooter. I sprayed WD-40 over everything that should move and eventually both brakes work, clutch and throttle both work and she selects all gears. The only thing that don't work is the choke which is stuck in the on position....I know this coz I pulled the rusty cable and it gave about half an inch and stayed there....

I bled some premix into the fuel line and gave it a tad of air pressure. Folded out the kick lever and gave it a prod...she burst into life and immediately hit about 3,000 revs and stayed there...although the throttle twisted and returned it had no effect on the carby.....3,00 revs braaaaaaaaaaaaaaaat absolutely filling the shed with smoke. This continued for 10....20.....30 seconds, and it doesn't have a kill switch. The 3000 revs didn't bother me but the pawls of smoke sure did....it was rancid. Shoved a screwdriver onto the plug lead to lever it of the plug as it's only twitched on....got a boot through the bars and the darn thing kept running as the lead was still about an inch away from the plug and it arced across. It eventally ran outa fuel and I was shocked.

I suspect the crankseals maybe shot judging by the smell of the smoke.

It's ALIVE!!.......  
...click on image!




Cheers,
Chris.


PS: Not bad for the bid price of $112.50.

[2fITy.J]

Okay...it may not be the crank seals...I discovered a plug is missing, there is a small hole to access the carby clamp which was loose, I blocked it off with a chair leg cap. Ran the bike again and it was on a high idle (choke is still on) but as soon as I wound the throttle...away she went again.





I checked the slide and discovered it was raised somewhat even with the throttle supposedly closed.....




If I hook my finger under the slide and lift it up then let it spring back, it closes.....





So the problem may lie within the throttle cable, trouble is the throttle is paired under the tank and one cable goes off to the oil pump. The oil tank is empty and so are the lines, I suspect the oil pump cable may be binding. I can just smell the Castor oil from the premix fuel and I think the rancid smoke smell is old gummy oil from within the crankcase....fueling up with just a fuel line is a bit spilly and heaps of fuel flooded the carby area.

It does start first kick and is a very very quiet motor....exhaust still sounds like a scooter though.



Cheers,
Chris.

[2fITy.J]

Oh boy oh boy oh boy....just went for a blat around the block 


I pulled the carby out and using the vice and 8" of cable, tugged the remaining stuck section of the choke out. Gave the plunger a rub with a scourer and did the same to the choke orifice....slides smoothly again. The sticking slide was due to the silly throttle stop adjuster.

This brought back so many memories, I had a 1973 TS50k for my first new bike...apart from one more gear and 25 less cc's than the TM, the TS50 motor is identical. I always had problems with the stupid throttle stop. It comprises a rod that runs through the slide and hits against the base of the venturi...adjustment is made by a screw in/out set up like a cable adjuster at the top. But the tiny pin that retains the rod against the adjuster falls out allowing the rod to drop down to the venturi. Because it is not secured at the top it can dangle at an angle....and not allow the slide to return home as it binds against the rod.

I turfed it and will use the throttle's cable adjusters as my idle speed....like I did all them years ago with the TS50.

The carby got a good soak in carby cleaner and some light air pressure to blow it all through. Put it back on and used a syringe to fill the carby bowl and the fuel line with premix and one kick start and went for a blast.

All gears and clutch work good, rear brakes are excellent, front definitely need attention. Forks are fine but the rear shock has no dampening evident...yet. Sometimes those old twin shocks need a bit of work before they wake up. It has burnt all the oil that was clouding the factory yesterday and now leaves a small blue R30 plume. Definitely a fun bike, was surpised how little revs to get off the line and there is a good powerband surge. Gears are spread just right for the power characteristics....if a fifth gear was in there it probably wouldn't pull it as she goes pretty quick in fourth but won't quite peak out...at least not with the iffy front brake.

Seat cover is one of the priorities as this one is hard and starting to show "cracks".

Tank clean out is my first little project though.


Condensation belies what's inside the TM's tank.....






Tank is toast, the other Rising Sun one I have will heave to be spruced up...on the inside.anyway.





Some rust remover, sand and a box of small electrical bolts inside...seal it up, wrap it in bubble wrap and roll it around the factory floor for a couple of weeks should do the trick....worked fine for my similar condition tank on the '76 TC125. I think I did the same to the XT600 when I got it too....



Pretty happy with the little TM.....



Cheers,
Chris.

[2fITy.J]

 

Uh-oh....I been spending.....


Some ridiculously cheap prices convinced me it was alright though....

I bought one of these for $40.14 delivered!




And on order are a choke cable for $1.81.....a Crankcase plug for $1.42...even got a short-reach sparkplug for $1.61, parts are bundled with a whole pile of parts for my DR and IT's so the shipping will be negligible.

Another forum friend bought from Babbit's (and has already sent on to me) a #22.5 and #17.5 pilot jet ($6.06 ea) and a needle and seat for the VM16SC carby ($32.83) Postage for these is $9.90.

Mate gave me some rubber bushes from some auto steering components, they make perfect front tank mount rubbers.

Swapped out the coil from the roller for the 240V flex one that was fitted, spark is the best I've seen on any bike! Mind you, it was a big fat spark with the dodgey lead one too but just plain dangerous...and dodgey!

Will dump the gearbox oil after a few more start up rides and give her some fresh oil again.

Then I can deal with the tank innards....

Lovin' this little baby....(maybe not so much the miniscule carby internals)




Cheers,
Chris.

[2fITy.J]

The Three Amigos....






...and the new seat cover......have three seats ready to be covered now.






Cheers,
Chris.

[firko]

Jeez, that poor little TM has sure been through the hoop. If it had been a dog its previous owner would have been prosecuted for cruelty. Nice to see it being used without one of those garage queen style over restorations. Cool little pitbike .

[2fITy.J]

It will be cleaned up but still show it's age....the patina on this is priceless....the surface rust not so.

My thoughts are the PO put a fresh piston/rings in two years ago but that didn't quieten the click sound on each full rev....and left it sit. I'm guessing the noise is the disc valve like my TS used to do.

There are a few fellas on various forums keen to have a "Tiddlers" class at some future vinduro events or ride days....there's a lot of old YZ80's and XR75's and the like, just dying to get a crack on the track. I have a ball riding my TC125 on or off the streets. The TM I can be more relaxed as there's less consequence.



Cheers,
Chris.

[2fITy.J]

Waiting for some carby parts to arrive from the states I decided to give the TM75 a decent scrub down with degreaser, brush and a scourer.


...it got pretty serious.....






You can just see a small dark patch under the end of the muffler....after a coffee and some forum time...that spot turned into a puddle of black splooge a few feet in diameter. Fresh 2t oil also exited the frame loop....along with several drowned spiders.

This bike just needs cleaning!


...and jets!



Cheers,
Chris.