What I have is a 99 Lowrider, TC88, bored 10 over with SE pistons, Comp ratio 10.25, adjustable pushrods, stock heads, Andrews 26's cam drive in her. 33 tooth on the tranny. Mikuni 42 Carb. 2 up 95% of the time. Bike runs good and strong, but am always looking for another gear. Am thinking of going to a 95 kit with the 9.4 ratio. Possibly going with a 34 tooth on the tranny, just to get the r's down at freeway speeds. Most of my riding is hiway and freeway. So here is where your 2 cents comes in....much appreciated.

gammy

 

Have the heads done to work with your cams and pistons, will be your best investment right now. As far as high rpm on the highway, what do you consider high RPM? Every tooth you add to that front sprocket will decrease rpm by 200-250 in 5th gear at a given speed. I run my 99 t/c ultra classic at 80 mph constantly and that is around 3500 rpm, and that is usually only when I am in the Texas Arizona regions and it is usually pretty hot outside. So far, so good with Andrews 26's, 2/1 pipe and ness big sucker, all else is stock.

 

Thanx for your thoughts...I was considering getting the heads reworked, now I might put that idea on the front side of the oven...At 70 she is taching about 3 grand and thru Idaho and Montana 3200-3300 for the 75+ there....would like to see and maybe aquire better mileage than what I get when I am 70 and above, it's like opening the spicket right up.....44-48 at 65 below, 28-38 above.... On yours, did you do your heads to match up with the 26's?....If so, what did you have done to them?...I also run the V&H 2 into 1.....nice pipe and sound....also with a hypercharger......

 

Most head porters have a "street port" or Stage I head packages that would be just what you need. Hillside and VeeTwin Performance both offer similar packages I believe. You will need chambers measured and volume set (heads milled) to set compression in the sweet spot for those 26 cams; I would go for about 9.8 but that's between you and the head porter. They will install new guides and seals, port the heads and do a Serdi valve job. That's about all you need.

Consider swapping the OEM rocker arms for the higher ratio rockers; some with SE204 cams and the 26 are reporting good results for a fairly inexpensive modification.

If you add another tooth to the trans pulley, I am not sure even the larger displacement engine is going to like it, particularly two up. Additionally, another tooth could mean a belt change.

I have been looking at various options to reduce my highway cruise speed recently but I don't want to lose the torque multiplier by going to a 34T trans sprocket and not addressing the loss of acceleration in the frist four gears. The obvious solution is a 24/37 primary and a Baker DD6 but that's about $3000 for parts. If I was a long distance tourer, I would do it but most of my riding is in the Texas hill country where there are lots of changes in elevation and twisties; 4th and 5th gear and 50-70mph; sometimes 3d gear at slower speeds. So, the cost/benefit of the Baker upgrade just isn't there. Howeve, I have run across the Johnson Twist Gear which lower the ratios in the first four gears by 10% and pulls them closer together; a close ratio four speed with a 10% torque multiplier in the first four gears while retaining the 3.15 1:1 final drive. Or, use a 34T pulley on the trans and drop the final drive to 2.96 reducing highway cruise speeds by 200rpm; the Twist gear kit cost $500. Just thought I would throw that out.

Actually, passing on the 95" upgrade, having the heads worked, installing the high ratio rockers and the Twist Gear wouldn't put up the same numbers as the bigger bore motor would but might be just the ticket for your situation.

Sorry for the long winded post but too many times we overlook the impact gearing has on performance and immediately go for heads, cams, etc. when a thought out approach to gearing would be a better solution; just no the obvious one.

BTW, my gear calculator shows a 100rpm reduction to maintain the same speed for each tooth you go up on the trans pulley.

32T trans pulley with 25/36 primary = 3.15 final drive@3000rpms = 72.84mph
33T trans pulley with 25/36 primary = 3.05 final drive@2900rpms = 72.62mph
34T trans pulley with 25/36 primary = 2.96 final drive@2800rpms = 72.24mph

 

Hey thanx for all that valuable information. Alot of different ideas and possibilities....Like the idea of the twist gear...gonna have to check that out....From what I read, your in the same type of riding that we do up here, just not in the damn snow.....Thanx again for the info, and we'll report back when it be done......

 

I've been riding since the 60s and have had bikes with 3, 4, 5 and 6 speed trans. I've looked for another gear with all of'em. It's natural, don't spoil your bike by gearing it up too much. If we had ten gears we would still look for another one!

By raising your gearing by one tooth you have reduced torque in top gear by around 3% and if you go to a 34T you reduce it by a total of 6%. You will find yourself struggling on slight grades, especially with a headwind, then you'll have to change down a gear. And you also waste that money you spent in tuning it, to improve performance!

I have stock gearing on my 107" and with over 100TQ fifth/top gear is just fine.

 

Just as an FYI, the EFI touring bikes from '99-'00 came geared with 3.37 final drive; yours is carbed and they came with 3.15 final drive.