Found the conversion specs on Andrews' site - 0.125" per tooth (1/8", or 1/4" per two teeth as stated above) for the front pulley. I'll have to validate that these numbers also apply to the rear, but if that is the case I should be in good shape.

Roger

 

Makes sense. Good luck bud. Keep this thread updated will ya.

 

Talked to a guy at Arlen Ness this morning, and he confirmed that they have a few styles that are 70t/20mm. He told me the diameter of one is 12.470. I also found an additional thread that indicated that the diameter delta should be approximately 1/2".

I had found a 70t/20mm Ness pulley on eBay for a great price (less than half) from a seller who coincidentally is very close by. I asked if they do will-call, which they don't, but they agreed since I was so close they'd overnight it. I should get it tomorrow and will get to see whether I can run it as is, or whether I'll need to do something else in addition... if I'm close but not quite there, I may also throw on the Andrews 31t trans pulley.

Best thing is that I will be able to break in the Direct-Lift table that I got yesterday!

Roger

 

I received the pulley just before noon yesterday. I was able to confirm that I have enough adjustment for the pulley to fit, and that I don't appear to have any clearance issues with the belt and the additional diameter. I didn't get to validate whether the belt guards were going to clear yet, but that isn't of huge concern at this point and I figure I can either mod the existing, find alternatives, or go without as some have done if necessary.

The pulley will require a spacer, however, as the original appears to be about 3/8" wider in the hub area. I've talked to one of the tech guys at Ness and he is talking with his engineer to see what they can do for me. I'm hoping they can come up with a solution that I can pick up this afternoon, so I can get it back together tonight.

Roger

 

Nice.... This is a good post.

If you need a 3/8" spacer I got mine thru Dennis Kirk for my DNA pulley. Needed the same.

Non chromed. Around 10 bucks I think.

 

Alot of progress tonight, but it will have to wait... have to get to bed as we're supposed to do a fairly long ride tomorrow, then I'll get a chance to update the thread... some good info and some interesting developments, but bottom line is that I have a 70t pulley on and will be getting some good saddle time in tomorrow to test it against my buddy's Heritage as a reference bike, which has been a pretty even measure so far.

Roger

 

would like to know how the 70T worked out

 

Short version - the end results were exactly as I had hoped and expected.

The pulley fit with my existing belt, I have plenty of adjustment front and rear on the axle, and it improved the torque without giving up much, if anything, on the top end. RPMs were shifted less than 200 to the right, so running along at 90 I was still only turning just over 3,000 rpms and had plenty left. As a side benefit, I can now run at lower r's in the higher gears without lugging, and it has plenty of torque to just roll on rather than downshifting, even on moderate grades.

It definitely gave me the added torque and pep I was looking for, without giving up anything related to usable performance.

I will have to figure out how to modify my belt guards, find replacements that fit, or run without. Not a big deal, and well worth the trade-off as far as I'm concerned, but as stated in another thread I don't want to be writing the next "something stuck in my ??? for $800" post!

So, here's what I ended up with:

Arlen Ness Sweeper pulley, part # 16-926, 70 tooth 20mm 2006 FXST (shown with original 66 tooth pulley):


Pulley spacer 16-896, purchased from Arlen Ness' technical specialist - I believe he said it was 0.375 (about 3/8"):


Chromed allen mount bolts and washers:


Here's an edge-wise photo of the two pulleys:


Here's how much adjustment I have with the new pulley and the original belt, which is almost 3/8" in the front now:


Here's what the pulley looked like before I had a chance to clean anything up:


It has been a very interesting quest, but it is good to know this one finally has a happy ending. For anyone else considering this mod, here are the major points to consider:

- You need to be sure to have sufficient forward axle adjustment if you intend to use your original belt; in order to go 4 teeth as I did, you will need nearly 3/4". If your adjustment room is towards the rear instead of the front, consider replacing the transmission pulley (Andrews 30t or 31t depending on how much you want to change - 1 tooth in front is equal to 2 1/2 teeth in the rear). Alternatively, if money isn't a major consideration you can change the front (1 tooth smaller) and rear (two teeth larger) to accomplish the same gear change without requiring any significant axle adjustment.

- You need to carefully consider whether to change the front pulley (likely cheapest solution, requires opening the outer and inner primary cases, should work with nearly all stock belts unless you have no additional rear adjustment), rear pulley (detailed above), or the clutch gear (46 - 49 tooth for similar fitments, same gear ratio adjustment, more only remove outer primary case, challenging install as you need to drill existing rivets and countersink replacement bolts, and is very expensive as offered from Evo Industries). There are quite a few factors to consider before arriving at your solution. Also, there are other combinations should you prefer different gear ratios... this was ideal for what I wanted to achieve, but if you want something extremely quick you will likely want to consider more drastic changes.

- Also, check your model's specific current gearing, as the MoCo made changes starting in '09 to address part of this shortcoming, and many of the earlier models had completely different gearing altogether.

Roger

 

Nice Tunaman.... tx for the update.

If I may ask... what were your prices on the pulley and the spacer?

 

thanks for the info,glad it worked. Cant wait to try this myself