K model belt sizes BX25 and BX75?

[Scooter4]

Good afternoon,
I have been away from my K model project for a couple of years and finally getting back to it.  I need to know the belt sizes and lengths for the K model.  I did a search I lost track in the threads, but it looks like they might be BX25 and BX75?
Can anyone confirm that?
I have an M model if those are similar to compare to.
Please let me know.
Thank you,
Scooter

[Ricks]

Good afternoon,
I have been away from my K model project for a couple of years and finally getting back to it.  I need to know the belt sizes and lengths for the K model.  I did a search I lost track in the threads, but it looks like they might be BX25 and BX75?
Can anyone confirm that?
I have an M model if those are similar to compare to.
Please let me know.
Thank you,
Scooter

Those are automatic belt numbers. Sorry,  I don't know the foot shift numbers.

[pd]

Welcome back Scooter .

Would the rear belt be the same , Rick . I see the transmission pulley was changed to 6" starting that year .

Pete .

[Ricks]

Welcome back Scooter .

Would the rear belt be the same , Rick . I see the transmission pulley was changed to 6" starting that year .

Pete .

Never owned a shifter bike, so I don't know.  We need KartJockey to jump in with the correct answer.

[kartjockey]

Here are the measurements from my original belts.  Belts have Dayton molded into them and maybe a run or mold number but cannot see a part number.  If there ever was one maybe it was printed on.  Primary belt looks to be settling down in the crank pulley a bit.  Measures .612wide X 26" long around the outside. The width measurement would explain why it sits deeper in the vee pulley This was taken with the rocker clutch tipped back to keep the belt taught so string would wrap around nicely.  Secondary belt measures .661 wide X 76.5" long around the outside.  Some wear but not bad. Kind of thinking about putting it back on to save originality.  Both belts are cog belts.

The long and the short of it.  Front belt  5L270.   Rear one matched best for me Gates 'green strip' #344. I had both of these on my '48 but since have put the originals back on just because.  Can't tell any difference in operation. 

[Ricks]

A 5L270 belt is a lower duty version of a BX24.

So for future reference lets call the shifter belts:

Short BX24
Long BX74


I'm sure a BX74 would work well on an Automatic also, as I have pulled the wheel back pretty far on some of mine to get the correct idler pulley position.

I'll put this info in a sticky when I get a chance so it will be easily found for future reference.

[Scooter4]

Thank you all for the replies.
I will get a set of belts ordered and when I get a chance, I will finish the muffler.
Thank you,
Scooter

[Scooter4]

Belts are spoken for. Thank you.

Good evening,
I have 2 extra BX74 belts to give away to any of you folks who help others.  I bought a triple belt off ebay for the same price as a single shipped ( I think the seller just wanted it to go to someone) and I cut it into 3 singles.
I will give it to you free if you will pay shipping (least expensive way).  I will understand if it does not work out since the shipping could cost what buying one at parts store does.
If you want one and ever visit with someone else who wants one, I can ship the two together.

Let me know.
Scooter

[Scooter4]

Good evening,
after messing with belts trying to make BX74 and BX24 work on this K model bike, I gave up.   I finally used BX75 and BX26 because the shorter rear belt caused the pulley bracket to hit the fender and the left pulley to hit the carburetor and the shorter engine belt caused the right pulley to hit the stator plate before there was enough slack for neutral.
This bike has a 6" right pulley.  Attached are images of the high position and neutral position.
Thank you,
Scooter

[Ricks]

Scooter, post a picture of the rear wheel position in the rear dropouts. I’m just curious how far back it is.  It makes sense that the larger transmission pulley would take a longer belt. 

[pd]

By the pics , it looks like the wheel is forward in the dropouts about as far as it can go .

Pete .

[Scooter4]

Good morning,
Attached is an image showing the location with the nut removed.  It is not all the way forward, but is not in the middle.  I tapped the belt into the groove a little to make sure it was seated before I adjust the belts.  No telling what it will be set at if driven some.
Thank you,
Scooter

[Ricks]

That looks right where it should be. You have plenty of adjustment left if it settles into the groove.