1989 tour glide....swapping out the 80" for a s s 111"...looking to up the gearing so I can still get around town, but id like to ride at 80mph without the engine revving to the moon like the 80" does going 70....


I was hoping to make the change with the front pulley.... its all stock now...
what size front pulley should I go to and how do u figure out what belt size u need also?


thanks

 

You will be making the same hp/tq at a lower rpm with a bigger motor.

 

Just some generally info: normally you should get away with a 2 tooth change and keep your stock belt - I went from a stock 32T to a 30T(six speed as opposed to your 5 speed) and had no problem adjusting the belt. More than 2T then probably going to need a new belt.

The amount of change you get can be determined by dividing the number of teeth you are changing by the original pulley tooth count. So in my case 2/32 = .0625, then X 100 = a 6.25 percent change in your rpms for a given speed.

 

I'm running an S&S 107" which gives similar numbers to yours and it's fine on stock gearing! Seems a waste of good money to reduce performance by raising gearing, mine will rev to around to 6,500rpm IIRC, so you should be fine at any cruising speed you choose! If you think it sounds buzzy then wear ear plugs - we should all do so anyway, for all but short trips. Much easier and cheaper.....

 

yeah but quicker acceleration is not what im after at all.....i want the bigger engine to pull a taller gearing to reduce the rpms at higher speeds....


that's my goal! lol

 

You don't need it because a bigger engine will make the same amount of power at a lower rpm than the smaller engine.

 

Your S&S engine is a 'built' engine, being closer to a custom build than ever our ole Evos were, so it will be very smooth and free running. Mine is 7 years old now and as smooth as silk, as I expect yours will be once it is run in. So IMHO the riding experience with your 111" will be significantly different to your 80". The simplest thing to do is leave gearing as stock for now, you can always revisit that later.

To change gearing there are 6-speed transmissions available, from SE or Baker plus others, which will let you keep the lower five ratios the same and add a taller sixth. I've already considered doing that, my own preference would be to use a Baker DD6 with a reduced overall ratio, to give a slightly lower bottom gear and only slightly higher sixth.

When raising overall gearing all the ratios are geared up, which is fine until it comes to tackling those tight hairpin mountain passes!

 

I would like to have the 6 spd...but I was hoping to spend 200 on a belt and pulley rather than 2000+ on transmission gears! Lol.
What's the difference between the 89 and 90 transmission. I noticed a lot of builder kits start at 1990-up.

Also is the oem primary strong enough for the 111"? I have a brace on the engine.

 

Let me see if I can explain this a different way...

I have motorcycle that is 675cc. To reach 50 mph, the RPMs are at 3000.

Today I rode a 125cc motorcycle. To reach 50 mph, the RPMs were at 9500.

Small motor = high rpm at 50 mph.
Big motor = low rpm at 50 mph.

Using the same principles , we get the following:

80" = high rpm at 70 mph.
111" = low rpm at 70 mph.

Conclusion - no need for taller gearing to lower rpm at 70 mph with a bigger motor.

 

Ok. I get it. Never thought about it like that.



And if the primary and clutch can handle the 111"?