690 SX - Extra Parts Tail Rotor Build

[DaleT]

Ok helping my son build his 690 SX, and we built the tail rotor last night. When finished there were two round washer like shims (10mm diameter) and two black round plastic sleeves left over. I looked over the manual again and again, and cannot find where these parts go. Anybody else have these left over? Totally frustrated!

[corrosionate]

The washer-like pieces sound like the shims for the tail rotor shaft. You might not need them. With the tail assembly all mounted up and tightened, does your tail shaft slide back and forth left to right at all? If not, throw those shims in your spare parts box. If it does, tear the tail down and put a shim between the flange bearing and shaft spacer on the side which has the bigger gap between the belt and the lip on the tail pulley. Still slop? Add another shim... Etc...

A pic would help, but if they're super thin and approx 10mm outside diameter, I'd bet the inside diameter is the same as the tail shaft diameter, and those are your shims. They might have been excluded from the manual as they're a "only use if needed" item. My 480 came with them but didn't need them. My 600 uses one on the left side.

As for the black round plastic sleeves, are they spacers for between the tail pulley and flange bearing? I think those would be metal, the plastic ones are usually for centering the tensioner (anti-static) pulley/bearing. Again, pics would help

Hope that helps


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[DaleT]

Originally Posted by corrosionate

The washer-like pieces sound like the shims for the tail rotor shaft. You might not need them. With the tail assembly all mounted up and tightened, does your tail shaft slide back and forth left to right at all? If not, throw those shims in your spare parts box. If it does, tear the tail down and put a shim between the flange bearing and shaft spacer on the side which has the bigger gap between the belt and the lip on the tail pulley. Still slop? Add another shim... Etc...

A pic would help, but if they're super thin and approx 10mm outside diameter, I'd bet the inside diameter is the same as the tail shaft diameter, and those are your shims. They might have been excluded from the manual as they're a "only use if needed" item. My 480 came with them but didn't need them. My 600 uses one on the left side.

As for the black round plastic sleeves, are they spacers for between the tail pulley and flange bearing? I think those would be metal, the plastic ones are usually for centering the tensioner (anti-static) pulley/bearing. Again, pics would help

Hope that helps


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Thought maybe that what the shims were for but wasn't sure. Here is a pic of the parts leftover.

https://www.helifreak.com/attachment...1&d=1409154888

[corrosionate]

Hhmmmmm.... Those other ones look like they would fit on the tail shaft as spacers... Between the flange bearings you shouldn't be able to see any of the tail shaft... If you can see the shaft, the spacers should fill in the space. If you've already filled in all that space then maybe these are extras or something...

I'm afraid that's all I can help, they may be a part that is exclusive to the 690sx, and I haven't built one of those. My 600 has similar spacers but they're aluminum.


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[RyanW]

The shims (metal) are for taking the play out of the tail shaft (side to side).

The black spacers (if they are the 5x8x3.7) are for the tail output shaft assembly. One goes on the side of the pulley that is flat. I appears they may have put extras in your kit?

[Andy from Sandy]

The pulley doesn't look to be a two part item. On other models the shims would go inside the pulley. Therefore I think the metal shims/washers go between the two belt idler bearings.

See page four of the manual.

I agree the plastic spacer does go on the short end of the output shaft between the pulley and bearing.

[DaleT]

Both the shims and plastic spacers inner diameters match the output shaft diameter. If the shims are for taking out play in the output tail shaft, then they are not needed because there is no play between the two flange bearings. As for the plastic spacers, there is no room for them on the shaft. Between the flange bearings there is the pulley and one metal spacer, with no room for anything else.

https://www.helifreak.com/attachment...1&d=1409165621

[corrosionate]

I see the 690 tail assembly is definitely different than from other models. I guess I don't know about the plastic ones...


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[chc35]

Dale it looks like you got the tail correct, I had those pieces left also, as long as you do not have any play side to side you should be fine. Chris

[DaleT]

Originally Posted by chc35

Dale it looks like you got the tail correct, I had those pieces left also, as long as you do not have any play side to side you should be fine. Chris

Thanks Chris! I was fixing to call you on this one.

[tjmarti]

I too am in the process of building this bird and had the same pieces left over, mine also came with three 3x5x0.5 washers that go between the belt guide bearings, thing is the manual calls for only 2.

[Chanq]

I also had those parts left over after the build. I actually had several other parts left as well. I figure because Mikado uses their parts on several models some extra hardware is included for when they are used on other models than the 690. It is confusing however.

[sgrim80]

Originally Posted by Chanq

I also had those parts left over after the build. I actually had several other parts left as well. I figure because Mikado uses their parts on several models some extra hardware is included for when they are used on other models than the 690. It is confusing however.

I think you hit the nail right on the head with this. Just my opinion though! :-)

[ToddM]

So I just got finished with the tail build as well. Also had these extra parts. My issues has to do with the tail slider lever, the one tha the tail rod connects too. It is really tight on the metal piece it screws too even with the tiny washer. Any of you guys also experience this ?

[taosgraveyard]

I didn't

[RyanW]

Hello Todd,
Make sure the bearings are fully seated in the bell crank. Next step is to barely tighten the bolt going through the assembly. If you crank down, you can crush the bearings and they will never be smooth again. Tighten just to the point there is no rocking action on the bellcrank and it still rotates smoothly. Then let the loctite do its thing.

[ToddM]

Thanks Ryan. I reattached the bellcrank, making sure the bearings were seated properly and the washer was inserted . Barely cranked down to fully tighten and all is like butter now.

Thanks