Lowering Crusing RPM
#1
Lowering Crusing RPM
I want to lower the RPM's, at crusing speed of around 75 mph.
Three reasons for it:
1) Vibration is less on handle bars at my cruising speed.
2) Sometimes I'm shifting, because I think/feels I'm on 5th.gear, when in fact I'm already in 6 gear.
2)When off the throttle, the bike nose dives as it was in 5th gear and slows down fairly quick (very little off throtle rolling distance).
I know solution is: Bigger front sprocket (adding 1 or 2 teeth) or smaller on the rear (1 or 2 teeth less) .
Which one is easier/better/cost less to do????
I know low end will suffer a little, but I don't care.
Thanks for any info.
Three reasons for it:
1) Vibration is less on handle bars at my cruising speed.
2) Sometimes I'm shifting, because I think/feels I'm on 5th.gear, when in fact I'm already in 6 gear.
2)When off the throttle, the bike nose dives as it was in 5th gear and slows down fairly quick (very little off throtle rolling distance).
I know solution is: Bigger front sprocket (adding 1 or 2 teeth) or smaller on the rear (1 or 2 teeth less) .
Which one is easier/better/cost less to do????
I know low end will suffer a little, but I don't care.
Thanks for any info.
#2
#3
#4
#5
RE: Lowering Crusing RPM
I did a search and found, that it would be better to do the front sprocket.
The reasons are:
1) Less stress and wear on the chain
2) Eliminates the need of a new chain, since the rear circumference by being bigger would most likely require a new chain
3) The rear sprocket has a factory damper, that might not fit or be compatible with the "new" none OEM. (This might not be true, since I checked the service manual and don't see why not)
Thanks for the input anyways
Great web site for chains and sprockets.
http://www.sprocketspecialists2.com/Products.aspx
The reasons are:
1) Less stress and wear on the chain
2) Eliminates the need of a new chain, since the rear circumference by being bigger would most likely require a new chain
3) The rear sprocket has a factory damper, that might not fit or be compatible with the "new" none OEM. (This might not be true, since I checked the service manual and don't see why not)
Thanks for the input anyways
Great web site for chains and sprockets.
http://www.sprocketspecialists2.com/Products.aspx
#6
RE: Lowering Crusing RPM
Well... I'm one down in the front, and three up in the rear. My chain is stock 114 links. I do however go through chains in a little under 15000 miles. I am very good at oiling and cleaning my chain. When I replace my chain and sprokets next I will go with the stock size in the front even if it means a extra link. I feel I should get at least 20000 out of a chain since I'm so **** about them.
#7
RE: Lowering Crusing RPM
You might want to consider the effect of lowering rpm at 75. You could drop far enough down on the torque curve to adversely affect your bike. Admittedly my only experience with this was on a CB650, but lowering the rpm by two teeth turned it into a dog. The CBR1000's have gobs more torque and it might not be a problem.
Too, you might check your sprockets and see if a previous owner has fiddled with sizes already. You might be running higher than normal RPM now. For comparison, my '91 CBR1000 turns about 4,700 rpm at 70, 5,000 rpm at 75. Vibration is minimal.
Actually, if you are finding objectionable vibration at any rpm with this bike I'd check the engine out. It should run nearly glass smooth at all rpm. After working my CCT over and replacing the cams mine would cause numb hands in just a few miles of riding. The vibration was finally traced to the balancer shaft. After adjusting that as directed by the Haynes and Honda Service Manuals nearly all vibration is gone. How it got out of adjustment is a total mystery, but may have something to do with accidentaly turning the engine backwards for a couple revolutions while adjusting the cams. Be sure you turn the engine counter-clockwise as you face the left side. That pulls the cam chain down the front of the engine, and may also be necessary to keep the balancer shaft properly aligned. I don't know that for sure, I'm just guessing.
Too, you might check your sprockets and see if a previous owner has fiddled with sizes already. You might be running higher than normal RPM now. For comparison, my '91 CBR1000 turns about 4,700 rpm at 70, 5,000 rpm at 75. Vibration is minimal.
Actually, if you are finding objectionable vibration at any rpm with this bike I'd check the engine out. It should run nearly glass smooth at all rpm. After working my CCT over and replacing the cams mine would cause numb hands in just a few miles of riding. The vibration was finally traced to the balancer shaft. After adjusting that as directed by the Haynes and Honda Service Manuals nearly all vibration is gone. How it got out of adjustment is a total mystery, but may have something to do with accidentaly turning the engine backwards for a couple revolutions while adjusting the cams. Be sure you turn the engine counter-clockwise as you face the left side. That pulls the cam chain down the front of the engine, and may also be necessary to keep the balancer shaft properly aligned. I don't know that for sure, I'm just guessing.
#8
RE: Lowering Crusing RPM
ORIGINAL: Logan
Well... I'm one down in the front, and three up in the rear. My chain is stock 114 links. I do however go through chains in a little under 15000 miles. I am very good at oiling and cleaning my chain. When I replace my chain and sprokets next I will go with the stock size in the front even if it means a extra link. I feel I should get at least 20000 out of a chain since I'm so **** about them.
Well... I'm one down in the front, and three up in the rear. My chain is stock 114 links. I do however go through chains in a little under 15000 miles. I am very good at oiling and cleaning my chain. When I replace my chain and sprokets next I will go with the stock size in the front even if it means a extra link. I feel I should get at least 20000 out of a chain since I'm so **** about them.
Think of a ten speed bike, the front sprocket being smaller and the rear being bigger, your legs will spin like crazy.
This would increase engine RPM's and vibration.
#9
#10
RE: Lowering Crusing RPM
Logan, you are correct.
Sorry I miss read your post.
I talked to "The Expert" from Sprocket Specialist today and he said:
Add 1 tooth on the front and RPM's should go down between 400-500 revolutions.
Go down 2-3 teeth on the rear sprocket and the RPM's will go down about 500-600 revolutions.
Front sprocket 18 teeth ordered today, I will report on results.
OEM sprocket specs 17F/43R, 530 chain with 114 links
Sorry I miss read your post.
I talked to "The Expert" from Sprocket Specialist today and he said:
Add 1 tooth on the front and RPM's should go down between 400-500 revolutions.
Go down 2-3 teeth on the rear sprocket and the RPM's will go down about 500-600 revolutions.
Front sprocket 18 teeth ordered today, I will report on results.
OEM sprocket specs 17F/43R, 530 chain with 114 links