2007 VFR Gearing Change and Speedometer Correction Questions

Just today, I went to my Honda dealer and ordered a 2007 Interceptor (RWB) to replace my '99 and to go alongside my '86 VFR750F. After reading all the tests on the 6th Gen bike, it seems that the reason that most people think the VTEC engine is slower than the 5th Gen engine is because Honda actually widened the gear ratios. Therefore, I'd like to gear the bike back down at least to where the '99 was and maybe a little more. I'm thinking of going up 2 teeth on the rear sprocket. I was wondering if anybody has altered their gearing on the 6th Gen bike and what their opinion is on this matter. Is going up 2 teeth on the rear too much, not enough or just right?

Also, I want to order the SpeedoHealer to correct the speedometer error. I imagine that changing the gearing will only make it worse. Is anybody currently using the SpeedoHealer, and if so, how do they like it? Also, any ideas of how far off the speedometer actually is? My understanding is that it is 10% off with the stock gearing. If I go up 2 teeth, any idea how much more it will be thrown off?

Thanks,
Jim

 

Most 6th Gen owners prefer to go one tooth down on the front rather than larger on the rear, because any more than +2 on the rear and you have to go with a longer chain. I've tried both...with a 45-tooth rear I liked the gear ratio and overall response, but I disliked the fact that I had to remove my Red Fox hugger because the larger rear sprocket required me to rotate the eccentric adjustment almost fully forward, which meant the front of the tire was pretty close to the front area of the swingarm. So if you go with a 45t or larger rear, I would seriously suggest a longer chain.

I also tried a 15t front and 43t rear, which tightened the ratio a little more than just with the 45t rear. The response was awesome, but I went back to stock gearing because my riding requires too much time on the freeway and I often ride fast (85 mph), and with this ratio and speed that means the engine is very close to when VTEC kicks in. I didn't feel comfortable cruising at this higher rpm and near VTEC engagement.

Also, I have an Excel spreadsheet that allows you to plug in the front/rear sprockets sizes and get the corresponding ratios. I didn't create it, but I will share it with whomever wants it.

Lastly, I have a Speedohealer and it works great! I used my GPS to verify how much speedo error I had, which ended up only being about 5%. But if you don't have a GPS, you can go to the Speedohealer website and they have an online calculator that allows you to first input the % of the known speedo error, and then input stock and modified sprocket sizes to get the amount the Speedohealer should compensate. Check it out and you'll see what I mean.

 

I did the 15 on the front on my 05..Find it is noticable. I really like it for the low speed drivability, nicer to go slow with.. seriously tho, it is noticable around town ....It also (obviously) has a bit more response in any gear, especially 6th.. The best part is the wheelie thing..used to have to be in vtech to get it up easily, now will start a nice climb at 5000. It picks up maybe 500 rpm at cruising speeds, so nothing outa 12 grand. I can go 9around 90 mph before vtech..after that , Im gonna be wide open anyway probly .
..I find i leave the 15 in for most of the time, but i will go up to the 16 on any longer trips. Its a 15 minute job to switch, so no big deal... For the price of a front sprocket, its worth fiddlin to see if you can tell yourself!

I found a radar board and just figured what rpm= what speed and thats all i care about anyway..I never look at that lcd thing much anyway..usually the tach, so to me its not a issue about the speedo being out.

good luck!

NN

 

I like the idea of easier wheelies and more acceleration, top speed is not a huge deal for me. Anyone have instructions on changing to a 15t up front? Where do I buy the gears?

THANKS!

 

i put the 15 tooth on my '05 and found a dramatic improvement around town but as was said, on the highway it seemed a little "high strung". next to my dads harley ultra alphabet soup bagger my speedo was off about 8 mph @ 50 and 10 @ 70mph. i changed it back to the 16 that night, the bike just feels more relaxed, i may try the 45 on the rear come spring. the front sprocket was from sprocket specialists bought through chapparrel.

 

I recently did some speed-o checks with my gps unit. 2004 with stock gearing.

The speed-o was
5 off at 50
6 off at 60
7 off at 70
8 off at 80
9 off at 90.

 

I just bought a 45T rear sprocket from www.sumofallparts.net

They also sell the countershaft sprockets as well. I found that not many manufacturers make after-market sprockets for this bike.

 

I'd be interested in that spreadsheet.

It sounds like a 15t front yields a ~%10 drop in mph reflected... as someone else posted these bikes read about 10% fast - so I'm interested to see how close it is with teh 15t I just ordered.