YTD725 Information needed
 

I just picked up a trimmer from HF, it's the YTD 725 clutched trimmer. I plan to put this in either a KMP Hurri (I have) or the new KMP Spitfire (coming this week). I assume this is a long shaft motor, it does have the new cast front case that I will have to grind off. My questions:

A) Are there any disadvantages to the long shaft other than the clutch removal ?

B) I want to push the engine as far back as possible due to the hurri's short nose, I plan to get the wackerengines conversion parts and flat plate mount and have Peter custom turn an output hub to the length I need. Will the longshaft cause any problems with this ? or would the short shaft be better ?

C) Is this the twin ringed version ?

This seems like a fun thing to do and has really blown some new life into me to get some of my planes done and flying for the new year.

Appreciate any assistance,

Mike

RE: YTD725 Information needed
 

A long shaft engine offers one the opportunity to make a much shorter engine than using a short shaft engine.

Sounds funny?

You make a shorter hub with a clearance hole all the way through. You thread the end of the long shaft at the correct length for your prop nut. The prop nut holds it all together. The hub itself can be Locktited to the shaft.

With a short shaft engine, your hub must have enough threads to grip the crankshaft and in addition, have enough threads to hold the prop shaft. This makes for a longer hub.

Enjoy,

Jim

RE: YTD725 Information needed
 

Jim,

Which motor version would allow me to position the prop the furthest distance from the flywheel ? This is what I need to get the head and plug as far back as possible.

Thanks for the help,

Mike

RE: YTD725 Information needed
 

In the extreme situation the short shaft would.

Don't forget, the longer the hub, the greater the vibration. This problem increases more rapidly than your increase in length. Just a little change in length makes a considerable difference.

You can make your long shaft engine as long as what the crankshaft will aloow you to use it as a prop shaft.

You can cut the long shaft off and thread it and make a hub as long as you could on a short shft engine by threading the hub onto the shaft.

Another point of view is that the long shaft engines are usually close to 3/8" whereas the short shaft engines are 5/16" or 8mm in diameter.

Enjoy,

Jim