Topics

31

Tech Talk / Air cooled twostroke, best head gasket material?

« on: January 22, 2023, 08:10:20 pm »

If the above style of bike comes with a fibre headgasket, is changing to aluminium or copper a better idea? Is it better to have good heat transfer between head & cylinder? I guess the best for heat transfer would be copper, as long as it is annealed sealing should be ok.

32

Tech Talk / Thoughts on 125 twostroke powerband?

« on: January 19, 2023, 07:04:49 pm »

I've got a bit of a mental-block, so,'77 TS125 suzuki, ported to RM100 (50mm stroke) specs, RM100 pipe, VM32, the bike has an awesome midrange, revs out nicely but no top-end power.

I'm running stock ign timing with a high compression head, maybe I need to retard the ign timing? I'll have a bit of a play with jetting, might need a bit more fuel, ideas welcome, thanks :-)

33

Suzuki / Who's is this !!!!!!

« on: January 16, 2023, 10:44:06 am »

Wild !

https://burnsandco.hibid.com/lot/81445-277351-69779/1977-suzuki-250cc-twin-cylinder-motocross-vmx/

34

General Discussion / TODAY'S TIP :-)

« on: January 16, 2023, 10:23:45 am »

This could be good, each day if someone could post a helpful, motorcycle related tip, one per day, if you come with a tip and someone beats you to it, save it for the next day, I'll start .......

An old throttle grip works a treat as a sleeve/seal where the muffler slips onto the expansion-chamber, I just fitted one to a 125 but could stretch for a 250? Your welcome, have a nice day :-)

35

Suzuki / When is CCI not CCI.

« on: December 11, 2022, 01:50:47 pm »

This '77 TS125 that I am building, the frame sidecover has a CCI decal but the oilpump only has one oil feed, going to the inlet manifold, the left case has a feed channel running down to the left main from the bottom of the transfer. Not needed on a 125?

36

Tech Talk / Aircooled cylinder head temps?

« on: December 10, 2022, 11:28:24 am »

Anyone know what temps a 125cc aircooled cylinder-head should run at? I just ordered a go-kart sparkplug sender & gauge, so I will soon find out :-) It would be good to have an idea before my first run with it :-)

Thanks, John.

37

Wanted / WTD, complete front-end, or forks, Pre 78, non leading axle.

« on: November 25, 2022, 11:03:37 am »

I have bad rusted forks on a '77 TS125 that I am building, anyone have a set of 30mm fork-legs or a complete front end with a non leading axle they want to sell?

38

Wanted / WANTED, Chasing a rear sprocket for early RM/TM/TS125, 428 over 55t

« on: November 20, 2022, 04:26:02 pm »

Can anyone help me with a Suzuki rear sprocket, the style with the 64mm ID to suit 428 chain size, anything larger that 55 teeth, steel or alloy, new or good used, thanks.

39

Tech Talk / Thoughts on different transfer port bottom edge heights?

« on: November 02, 2022, 10:45:41 pm »

I have noticed in a couple of cylinders (RM125M & DT1MX) that some of the transfer port outlets, being both the middle port of a 5 or 6 transfer design, has the bottom of the port open below that of the piston crown at BDC.

Does anyone know the technical reason for this, or your own suspicion? At first, I consider a little extra cooling for the piston, but why only that part? Then I consider; as the piston approaches BDC, the flow out of that centre transfer would abruptly change, or be different in relation to the other transfer openings possible creating a 'vertical wall' at the window, or directing the flow from that port in an upwards direction? Possibly creating a better wall of mixture (when combined with the transfers) to push out the exhaust gases?

I like to keep you Guy's entertained, and me learning (just to take it to the grave).

40

Tech Talk / Piston skirt cut v inlet port drop?

« on: October 31, 2022, 08:45:39 pm »

Sorry for all my posts, I love the experience on here :-)

So ...... Rather than cut 6mm of the inlet skirt of my TS125 piston, surely dropping the inlet port the 6mm should give the same effect on performance, while still keeping the strength & stability in the piston in the bore .... no?

I've gone to a VM32 so the inlet port needs to be opened substantially, it's a '77 model with the reed into the crankcase, although the reed cage has been opened-up with a carbon petal.

My thoughts also consider keeping the piston-port smaller to help keep up flow inertia.

Maybe I'm a bit crazy trying to re-invent the 1977 wheel ;-)

41

Tech Talk / Has anyone ever welded a piston, and used it?

« on: October 31, 2022, 08:29:32 pm »

What are your thoughts on welding-up a couple of exhaust bridge lubricating holes in a piston? I imagine there wouldn't be enough heat to distort the piston?

42

Wanted / WANTED, STD piston to suit RM125M or TM125.

« on: October 29, 2022, 10:03:27 am »

Would anyone have a new, or very little use, standard bore (56mm) piston for sale to suit an RM125M or TM125, I have looked at the TS125 pistons but once I shorten the inlet skirt, most of the strengthening rib along the bottom of the skirt is cut away, I want to reduce the chance of cracks appearing.

Needing a piston WITHOUT the exhaust bridge lubricating holes.

Maybe aftermarket (forged?) piston might be different, if are they better in that area I will try one, thanks.

Regards, John.

43

Suzuki / They are still out there.

« on: October 14, 2022, 11:54:30 pm »

So about 5 years ago my Missus brings home a TS185A ('76) engine complete (with carbs, pipe & electrics) in a bare frame from the tip where she use to work, I spray a bit of Start Ya Bastard in the carb; runs for a couple of seconds, heaps of comp through the kick lever. So I tuck it away down the back corner of the shed, I thinks to myself "that might come in handy one day".

So I just tore it down, it's never been apart before, std bore still with cross-hatch in the bore, no blow-by past the rings, it needs NOTHING, everything is like brand-new inside, I am truly amazed !

I have a TS125B rolling chassis, might see if it will fit (even if it doesn't, it will ;-) ) ........ Now where's that porting tool ;-)

44

Tech Talk / Toolbox tricks, what's yours?

« on: August 27, 2022, 08:09:47 pm »

Because sometimes the Missus helps me in the garage, plus my eyecrometer is starting to fail, I decided to colour match my spanners, I wrap a band of coloured electrical tape around the spanners..... 12mm = red, 13mm = blue, 14mm = yellow and 17mm = black, when I go to the drawer of the toolbox, in an instant I can spot what I need in the sea of spanners. To avoid any confusion in the future, please adhere to the above colours ;-) ha ha.

Also, my favourite tool in the workshop is masking tape, I wrap all my socket extensions with it, they are slippery little buggers with oily hands.

45

Wanted / WANTED, Suzuki dirtbike steel tank.

« on: July 07, 2022, 08:25:25 pm »

I'm needing a fuel tank, the '76 TS185A has a flip-cap that is rooted, I guess any TS (or TM) 125,185,250,400 will work, anyone want to sell something that I can make work?