Recent Posts

61

Tech Talk / Re: PVL Timing

« Last post by 2T on April 17, 2025, 03:11:06 pm »

Was very careful with the pressure, pokey. Took it slowly to 5 psi and it dropped fairly quickly. With a soapy water mix sprayed over the seal the leak was very evident around about 50% of the surface.

I now see that assembly lube or grease should have gone on the crank surface before the seal was fitted and I didn't do that. It went on dry. Could that be the problem?

Re: seal fitting. That was on the clutch side. This side was a much firmer fit when I installed it. I also used a wipe of threebond.


Am about to remove the spring off the seal and see if I can inject some oil or assembly grease under the lip.
Update: Still leaking.

62

Tech Talk / Re: PVL Timing

« Last post by pokey on April 17, 2025, 02:36:19 pm »

What pressure did you use to test? I ask as over pressuring can damage a new seal. You can get lucky and reposition the seal lips if not ton on assembly. I recall your previous issue with the seal not fitting thus not sealing.

63

Tech Talk / Re: PVL Timing

« Last post by 2T on April 17, 2025, 01:36:38 pm »

I have just reassembled my motor and a leak down test has air coming out the stator side crank seal on the inside where it wraps around the crank shaft.

When I disassembled the motor, I inspected the area around the stator and there was no sign that oil/fuel had been leaking from the seal. Makes me think I've got something wrong during reassembly. The seal is new and genuine Yamaha.

Can anyone suggest what's gone wrong?

64

General Discussion / Re: MX Spectator

« Last post by vmxrider on April 16, 2025, 01:03:02 pm »

Were there many "mature" spectators watching? and how was the track?

Peter

There were a few. Track was "mint" according to one of the junior riders being interviewed.

65

General Discussion / Re: MX Spectator

« Last post by PeterC on April 16, 2025, 07:11:56 am »

Were there many "mature" spectators watching? and how was the track?

Peter

66

General Discussion / MX Spectator

« Last post by vmxrider on April 15, 2025, 10:57:40 am »

Haven't been on here for a long long time.

Went down to Appin on the weekend to watch round 2 of the Pro MX series.

Sitting amongst the large crowd of spectators it occurred to me that it's been 50 years since I first went to Amaroo Park to watch the MR Motocross series.

Thats a long time and I still reckon it's the best sport in the world.

67

Tech Talk / Re: Wiseco Ring End Gap

« Last post by 2T on April 10, 2025, 06:20:59 pm »

As Wasp mentioned, 'minimum' looks like the key word, which I overlooked when reading the destructions.

The workshop manual lists standard gap as .35 - .50mm, with .8mm as the limit and, although Wiseco may have different specs, it wouldn't have hurt me to read that a little earlier than just now.

68

Tech Talk / Re: Wiseco Ring End Gap

« Last post by pokey on April 10, 2025, 05:31:46 pm »

 Wasp is correct  and the gap should be fine.  My calcs are not too far off your actuals and bearing in mind a higher compression means more heat thus more expansion.
 

69

Tech Talk / Re: Wiseco Ring End Gap

« Last post by 2T on April 10, 2025, 10:24:57 am »

I would say the gap should be MINIMUM  .35  . Yours is only .13 more than minimum =4 hairs..... I wouldn't worry, especially on a big piston that expands a lot. Better too much than not enough.

Thanks for your help.

70

Tech Talk / Re: Wiseco Ring End Gap

« Last post by Wasp on April 09, 2025, 12:49:01 pm »

I would say the gap should be MINIMUM  .35  . Yours is only .13 more than minimum =4 hairs..... I wouldn't worry, especially on a big piston that expands a lot. Better too much than not enough.