Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - GMC

Pages: [1] 2 3 ... 236
1
General Discussion / Re: Another new friggin tax
« on: December 22, 2017, 03:24:35 PM »
I remember the old days of doing 'bottle drives' for the Scouts
We used to collect long necks to sell them back to the breweries, a line of us would be throwing bottles to each other from the bottle stack to the trailer, then from the trailer to a stack at the Scout hall for the Brewery to pick up.
It helped to fund camping equipment.

I doubt kids would be allowed to throw glass bottles to each other nowadays, OH&S would be all over everyone.
Christ, I was refused to be allowed to put a bottle or Argon in my ute last week as it seems OH&S now demand that bottles be carried upright. Like the gas knows which way is up or down :o
Couldn't carry the bottle upright without a special rack to hold it so had to wait for them to deliver it instead. Lost a days welding waiting for it to turn up >:(

2
General Discussion / Re: Better than Tattslotto
« on: December 22, 2017, 03:15:16 PM »
No their not taking the piss.
A slow reply, because I have been in therapy for selling you the winning ticket that I nearly kept for myself :o

Congrats, look forward to hearing some stories when you get back.

3
Vintage Track / Re: KX125 hagon track master
« on: December 22, 2017, 03:09:38 PM »
Kerry may have moved it on?
I built a chamber for just such a beast early last year for a guy in SA
It was also a KX motor with some KE bits

4
Yamaha / Re: dt1 question
« on: December 22, 2017, 03:06:05 PM »

Maybe they've heard about me!

Would you really want to belong to a club that would have the likes of you as a member?
 ;D

5
General Discussion / Re: Better than Tattslotto
« on: October 23, 2017, 09:09:23 PM »
Ticket sales have finished and I have taken the order form down from my website now.

On behalf of the Whitsunday Motorcycle club I thank you for your support.

Not long now till the draw
Good luck to all who entered

Cheers
Geoff

6
Yamaha / Re: YZ125K Rebuild
« on: October 22, 2017, 03:22:18 PM »
My 2c worth;

Oil Brand
Seems you are running TTS, you will get many recommendations about oil brands but I doubt there is anything fundamentally wrong with TTS otherwise bikes would be dropping like flies all over the place.
I have swapped oil brands a few times over the years and I currently run TTS without drama and I also used it in the eighties without drama as well.
I doubt that the oil brand is the problem

Oil ratio
You will also get many recommendations about what oil ratio to use but if you’re running anything between 20 and 40 to one then you should be fine.
People run ratios inside this window all the time without drama. Changing the ratio will cause more jetting issues due to changing the viscosity of the fuel so if you’re running inside this ratio I would also leave well enough alone.
There may be decent argument for decreasing wear with more oil but I doubt it would straight up cause a seizure otherwise bikes would be dropping like flies all over the place.
I assume you run your other bikes on the same oil and ratio without problems!

Fuel flow
This one is often overlooked, if the gauze filter in the fuel tap is blocked or if you’re running a fuel filter you may be restricting fuel flow which will throw your jetting specs out the window.
You should take the fuel hose from the carby and hold it in the same shape as if it was on the carby and turn the tap on to see if you have decent fuel flow.

Piston marks
Pistons are made oval and tapered, the theory is due to more material around the crown and gudgeon is that they will expand to become round when at operating temperature, this same theory says that if they become hotter than intended then they will expand more to become out of round thus crating seize marks at certain points on the piston.
I doubt that Eric Gorr stuffed up the machining however some brands have misjudged the expansion rates for their pistons and rubbing the high spots is an old school trick to get them to spec.
Most modern pistons I thought were pretty much on the mark though.

Exhaust
People use all manner of brands without drama and I can’t see this as causing any problems unless the stinger/muffler core is the wrong size. A 125 should be approx. 23mm ID plus/minus 1mm
I have seen guys fit 125 mufflers on a 250 and wonder why it doesn’t run properly.
Even had a guy fit a 4T muffler to his 2T and wonder why it didn’t rev properly!

Carby size
Increasing the carby size will mean more air enters the motor at full throttle so you will need a bigger main jet than normal to compensate to the correct fuel/air ratio. What main jet people are running on smaller carbies will be irrelevant
You may have miscalculated this one!

Timing
Being an aftermarket ignition it will be a bit more complicated to set compared to stock.
It may even have an odd advance curve so checking this out thoroughly would be my first thing to check.

Multiple issues
Often problems can be caused by more than one issue, jetting alone may not cause it to seize and timing alone may not cause it to seize but both being a little bit out may push your specs over the edge.

Good luck, when you feel it’s doing your head in then sometimes it can be best to sleep on it

PS. Yes beware the European dial gauge!


7
General Discussion / Re: Better than Tattslotto
« on: October 20, 2017, 03:04:52 PM »
Only a few days left, ticket sales close next Monday and the draw will be a bit over a week after that.
I still have a few tickets left to sell before I send them all back next week.

Don't miss out on the trip of a life time.

8
Yamaha / Re: YZ125G Build
« on: October 11, 2017, 10:44:27 PM »
You've done well.
Its also good to listen to lots of advice, absorb it all and then go your own way.

The only thing I would add is that you should weld the gusset pieces on the inside as well so when you sand the outside down you will have material in behind it for strength.

I think the only thing you did wrong was to use the galvanized tube, it will play havoc with the welds and your old man is going to hate you, the gal will bubble up in the weld and cause a lot of porosity and keep contaminating the tungsten.
Looks like it is too late to get the tube back out, if you can then just sand the area where the patch is going to be otherwise hit inside that trap door area with a die grinder and remove as much of the gal as you can, allthough I think the gal that's inbetween the tubes will still give you grief.

9
Wanted / Re: Suzuki PE250 T or X exhaust
« on: October 11, 2017, 11:03:29 AM »
Yes  I was going to suggest you might be chasing a stock pipe.
Sorry for the hijack

10
Vinduro / Re: Vintage Class A4DE
« on: October 11, 2017, 11:00:37 AM »
Vintage class fully subscribed which is awesome to see. Obviously old bikes & blokes are still keen.
K

That's great, now I can stop procrastinating

11
Yamaha / Re: YZ125G Build
« on: October 11, 2017, 07:23:40 AM »
In a nut shell, Cro-Mo is basically mild steel with the addition of Chromium and Molybdenum (and some other elements) so yes it can be welded fine to mild steel with either Mig, Tig or Oxy.
Tig will give you the most control over the amount of weld filler and penetration although some others may argue the same for Oxy.

It can be welded with filler rod grades ER70, ER80 or ER90
ER70 is your normal Mig wire and you can use mig wire as a tig filler when you need a small diameter filler
ER 80, also known as Cro-Mo 2
ER 90 also known as Cro -Mo 1 and this is what I mostly use for my frames.

The up side of Cro-Mo is it is much stronger than ordinary mild steel
The down side of Cro-Mo is it becomes brittle in the heat affected zone of the weld which is not the weld itself but the part right next to the weld and it requires heat treating to bring it back to its normalized condition where it is at its strongest.
You will here also sorts of ways to do this heat treatment but I prefer to send it off to the experts that can do it in a controlled oven.

However I don't consider any of the manufacturers frames have used aircraft grade 4130 Cro-Mo
If you want to go down the 4130 path I have an assortment of offcuts in 2mm plate and various tube diameters and thickness, let me know what you need.

I think you should be fine using mild steel for this repair as you will be adding more material to carry the load. As Cro-Mo is stronger less thickness of tubes can be used which is where the weight saving comes from so by the same token you can use more mild steel to create more strength.

Give your exhaust place a miss and check out your industrial suburbs for steel suppliers, you should find some one that will sell you a few metres and they can also get in tubes that have a 2mm wall which would be better for your inner reinforcement, I have some here but can't recall what diameter.
Your industrial suburbs will be a better place to find industrial supplies rather than the likes of Bunnings etc.

The reinforcement tube you slide up inside you wont get a perfect fit as any welds on the original tube will suck in the wall so it won't be perfectly round, the important thing though is to get some plug welds either side of the join in the downtube to reduce the load on the join.
As the join in the down tube is covered by the gusset so you should be able to leave the head of the weld on for strength as it won't be seen.

12.5 tube with 1.5 wall sounds too thin for engine mounts

A 8 or 10 mill rod that will fit into your drill should help to clean out the down tube, cut a slot in the end that you can slip some emery cloth (around 100-150 long) into that will wrap around the rod

12
Yamaha / Re: YZ125G Build
« on: October 11, 2017, 06:50:46 AM »
GMC can do fix anything. Ask him for photos of my Pomeroy pipe!! J

Yes I fixed it, but it is now suffering a severe case of 'grandfathers axe' syndrome

13
General Discussion / Better than Tattslotto
« on: October 09, 2017, 11:59:15 PM »
The Whitsundays raffle for a trip to Diamond Dons is once again happening and raffle No 8 is underway and will finish soon.
I still have some tickets to unload.
Tickets sales will cease in a few weeks
Only $25.00 per ticket this year

Get your tickets here;
http://www.geoffmorrisconcepts.com/31/diamond-don-s-no-8-raffle-tickets






14
Wanted / Re: Suzuki PE250 T or X exhaust
« on: October 09, 2017, 11:01:05 PM »
Thanks for that info Leith
Is the muffler the same on the RS model too?


15
Yamaha / Re: YZ125G Build
« on: October 09, 2017, 10:48:09 PM »
Sounds like your onto it okay, these jobs are always fiddly and I have done this same sort of repair before but all brands have some sort of uniqueness just to keep you on your toes.
Patience is the key
Also when you finish it off only use a grinding wheel to take the bulk of the head of the weld off, leave taking the last bit of weld with a sanding disc.
Not a fan of flap discs myself and much prefer sanding discs, I like the 75mm quicklock style discs, you can get the fitting that holds them to fit onto a 4" grinder and when your done sanding slip on a medium scotchbrite disc and no one will know its been done.


Pages: [1] 2 3 ... 236