Yamaha TRX850 Enthusiasts Forum

Hi guys

I'm rebuilding a TRX to keep company to my first TRX and I have a coupe of questions...

1. Coils - maybe daft question but do they earth via their mounting points? (I've swapped frames and the "new" frame's be delugged so was going to use so plastic fasteners to fix the standard coils on the frame)

2. Blue spots - One of the pistons is seized and fully inside the caliper, any tricks on how to un seized it?

3. H3 buld - I'd like to replace the standard headlight unit with a small round unit I have which is fitted with a H3 buld (just one wire coming out of the bulb). How is a H3 buld supposed to be wired up to a conventional headlight buld? Web search results have left me puzzled!

Thanks guys!
Adrien

Can confirm one answer, the coils do earth through their mounts to the frame so keep them electrically conductive

Can confirm another .

Remove caliper from it's mounting restrain the free pistons from moving. Cable ties are a good solution.

Pump out the sticky piston and clean and polish it
.
Remove caliper half joint bolts and separate the 2 halves. Do not lose the 2 square section half joint seals.

Carefully pick out the dust seal and then the piston seal. The dust seal is often damaged and useless.

The chances are that there is aluminium corrosion behind the piston seal that needs a good clean out.
This corrosion grows and is what "jacks" out the seal onto the piston.

Rebuld with new seals. (I have always found the piston seals fine and reused them. I have always found the corrosion in the seal groove to be the culprit) Likewise I also reuse the half joint seals.

bagmaker wrote:Can confirm one answer, the coils do earth through their mounts to the frame so keep them electrically conductive

Thanks!

sanddune51 wrote:Can confirm another .

Remove caliper from it's mounting restrain the free pistons from moving. Cable ties are a good solution.

Pump out the sticky piston and clean and polish it
.
Remove caliper half joint bolts and separate the 2 halves. Do not lose the 2 square section half joint seals.

Carefully pick out the dust seal and then the piston seal. The dust seal is often damaged and useless.

The chances are that there is aluminium corrosion behind the piston seal that needs a good clean out.
This corrosion grows and is what "jacks" out the seal onto the piston.

Rebuld with new seals. (I have always found the piston seals fine and reused them. I have always found the corrosion in the seal groove to be the culprit) Likewise I also reuse the half joint seals.

Thanks, I'll try to pump it out by better blocking the others but my fear was on refitting them back in being tricky/not possible (think that's what a previous mech had told me)!
As far I can tell, can't separate my caliper (I think only Thundercat ones are in two parts, R6/R1 blue/gold/silver are all one part)

drix wrote:

bagmaker wrote:Can confirm one answer, the coils do earth through their mounts to the frame so keep them electrically conductive

Thanks!

sanddune51 wrote:Can confirm another .

Remove caliper from it's mounting restrain the free pistons from moving. Cable ties are a good solution.

Pump out the sticky piston and clean and polish it
.
Remove caliper half joint bolts and separate the 2 halves. Do not lose the 2 square section half joint seals.

Carefully pick out the dust seal and then the piston seal. The dust seal is often damaged and useless.

The chances are that there is aluminium corrosion behind the piston seal that needs a good clean out.
This corrosion grows and is what "jacks" out the seal onto the piston.

Rebuld with new seals. (I have always found the piston seals fine and reused them. I have always found the corrosion in the seal groove to be the culprit) Likewise I also reuse the half joint seals.

Thanks, I'll try to pump it out by better blocking the others but my fear was on refitting them back in being tricky/not possible (think that's what a previous mech had told me)!
As far I can tell, can't separate my caliper (I think only Thundercat ones are in two parts, R6/R1 blue/gold/silver are all one part)

If you use compressed air to get the pistons out - beware of your fingers!
That little piston-bugger hurts like hell when your finger gets jammed in the caliper

sanddune51 wrote:Remove caliper half joint bolts and separate the 2 halves. Do not lose the 2 square section half joint seals.

Unfortunately, I did lose one of the half seals and then found it impossible to buy new ones. In case it helps anyone else in the same position, my solution was:

• Internet research to identify a suitable material (EPDM rubber).
• Scrounge sample sheets from a manufacturer.
• Get someone to machine a couple of simple hollow punches (couldn't source commercial ones of the correct internal and external diameters).
• Punch new seals using the hollow punches in a press.

It took a few attempts to get the punching concentric, but now they are in and work a treat. Of course, it's easier not to lose the originals, although I'm not sure that reusing 20-year old seals is a great idea.

Barry

And to the final question: H3 bulbs earth trough their base. Just like the coils, actually!

pushing the pistons out, if still attached to the hydraulic system -
block of wood between the ones that move, so they don't,
G clamp holding the other one opposite to the ceased one then pump the hydraulics until it starts to move,
when it does start to move stop it half way out and clean piston, put a bit of oil on it and slide it back in slightly so the seal is oiled then push it out again slowly.

If on 1 piece blue spots the "blue" bit removes with a special tool and then it is relatively easy to remove a ceased piston with a "rawl bolt" type pulling arrangement