Messages

1

Yamaha / Re: Desperatly need clutch parts!!

« on: May 17, 2017, 10:01:09 am »

give pennas mcycles in Bendigo a call as they used to be Yamaha and have a bit of old stock laying about

Thanks Mate.  Tried them but no luck.

2

Yamaha / Desperately need clutch parts!!

« on: May 17, 2017, 09:06:22 am »

So as many of you know, I'm doing Finke Desert race this year on the YZ490.  The clutch started slipping so I ordered new parts from the local Dealer 2 weeks ago. They said they could get them but now are saying they can't.  It's too late to try and get parts from the USA now as I leave in less than two weeks, so I'm really up shit creek.

The main part I'm chasing is the outer pressure plate. #23X-16351-00-00

If anyone knows where I might get a new one, please let me know.

There are none listed here in Australia but someone may have one that's not on the database.

They also are the same part as these bikes.
 

 1985 TRI-Z - YTZ250N CLUTCH 

 1986 TRI-Z - YTZ250S CLUTCH 

 1983 IT250K CLUTCH 

 1983 IT490K CLUTCH 

 1983 YZ250K CLUTCH YZ250K L 

 1983 YZ490 - YZ490K CLUTCH 

 1984 IT490L CLUTCH 

 1984 MOTOCROSS - YZ490L CLUTCH 

 1985 MOTOCROSS - YZ490N CLUTCH 

 1985 YZ250N CLUTCH 

 1986 YZ250S CLUTCH 

 1986 YZ490S CLUTCH 

 1987 MOTOCROSS - YZ250T CLUTCH 

 1987 MOTOCROSS - YZ490T CLUTCH 

 1988 MOTOCROSS - YZ490U CLUTCH 

 1989 MOTOCROSS - YZ490W CLUTCH 

 1990 MOTOCROSS - YZ490A CLUTCH 

 1992 WR500ZD CLUTCH 

 1993 WR500ZE CLUTCH

It's part number 7 below.

3

Tech Talk / Re: Handlebar vibration big bore 2st

« on: March 22, 2017, 03:50:10 pm »

Cheers Mate.

4

Tech Talk / Re: Handlebar vibration big bore 2st

« on: March 22, 2017, 12:31:41 pm »

You can't just chuck in some rubber washer and leave the rear loose as it will tear the mounts to pieces in a very short time. If you where to rubber mount the motor you would need to bore out all the mounting holes in the cases and fit proper rubber mounts with inner and outer steel sleeves, especially needed would be an inner sleeve so the bolt can be done up tight. Even if the rear mount is left tight it wouldn't take long before it worked loose and the swingarm would be loose as it is the rear mount.
Your only practical quick fix would be some sort of rubber mounts for the bars. Other thing to think of would be a radical gearing change to get the motor RPM below the vibration at the speed you want to go at.

Thanks for the info.  The rubber mounting idea sounds a bit too involved to do.  I have changed the gearing from(14/48) to (16/46) and I'll still fill the handlebars with silcone.

5

Tech Talk / Re: Handlebar vibration big bore 2st

« on: March 21, 2017, 11:55:24 am »

The vertical component of the engine vibration is the one causing the problem  allowing the engine to pivot around the rear engine mount is how I have done it in the past. Harley handle bar mounts are a good source of isolation mounts (but for the imperial sizing)

Thanks. ill try and source some rubber washers or something.

Have you had the balance factor of the crank checked? It is quite possible to change the factor to a higher value which will move the vibration away from the RPM that is causing the problem.

No I haven't, but wish I did now while the crank was being rebuilt.

6

Tech Talk / Pre printed race number back grounds

« on: March 21, 2017, 10:34:00 am »

I need some graphics done for the 1990 YZ490 for finke this year.

Same as the ones in the picture with a number added.

Anyone got any recommendations on who could do a good job of this?

7

Tech Talk / Re: Handlebar vibration big bore 2st

« on: March 20, 2017, 11:50:39 am »

Hey Gibbit

A few of the big bore two strokes that I have brought from the states have had lead shot in the bars

I guess they used shot gun balls to fill the bars.
Thought it might be worth a test and cheap.

Thanks, I have also heard filling them with silicone works so I will try that.

Rubber mount the engine at the front and the head stay

What would you use? It would be hard to do the bottom mounts as it is a tight fit between the motor and frame, but would be possible to do the top mount.

are you still planning to run this at Finke ?

that is awesome.

Yeah mate, a bit over two months before we head out.

8

Tech Talk / Re: Handlebar vibration big bore 2st

« on: March 16, 2017, 12:36:17 pm »

Thanks for the replies guys.

The yz490 does have rubber bushes in the triple clamps so id hate to think what it would be like without them.

I will also put some sort of bar weights in as it will need bar ends anyway.

At $500+ for the Fasst Flexx bars, they are just a bit too exxccy.

9

Tech Talk / Re: Handlebar vibration big bore 2st

« on: March 15, 2017, 07:23:56 pm »

For general riding it's pretty good. It's when I'm sitting on 120-140km/hr, the vibrations go right up to my shoulders and I can't hang on for very long.

10

Tech Talk / Handlebar vibration big bore 2st

« on: March 15, 2017, 04:27:51 pm »

Looking to get a new set of bars for the YZ490A.

Just wondering if anyone knows which reduce vibration more, 1 1/8 or 7/8? I have the ability to use both.

I'm thinking between the renthal twinwall or renthal 7/8.

I will also pump silicone inside the bars to help reduce the vibration.

11

Yamaha / Re: Gibbits YZ490A

« on: February 23, 2017, 10:04:32 am »

johnny orchard started the thread i believe

Thanks mate,  Ill look it up.

12

Yamaha / Re: Gibbits YZ490A

« on: February 21, 2017, 10:45:23 am »

there is a trick to extend the pilot jet deeper into the bowl with some hose to prevent the vibrations allowing air into the pilot circuit. this stops the pinging apparently

Interesting.  Ill have to look into that. The vibration at constant high speeds is a problem. My hands go numb.

13

Yamaha / Re: Gibbits YZ490A

« on: February 21, 2017, 09:19:17 am »

Ok so she's basically ready for Finke this year. Nomination is in.

Just need some final testing for suspension, jetting, gearing and some race numbers.

I'm trying to find about any jetting and suspension spec's they used on them back in the day if anyone knows.

I hear a guy called Eddie Baldissera set them up for Gall and Curtis back in the day. Any idea of how to contact him? I think they used a completely different carby.

14

Yamaha / Re: Gibbits YZ490A

« on: December 12, 2015, 09:26:53 pm »

15

Yamaha / Re: Gibbits YZ490A

« on: November 28, 2015, 07:42:23 pm »

Retails for $1,300 so it would want to look good too. Thankfully I won't pay quite that much for it.