will my MK3 pull a 24t front sprocket?

George Hirvela

George Hirvela

Joined
Mar 4, 2014
Messages
59
Country flag
I am going to use my street bike (mk3) to do my rookie run at El Mirage. Given the higher elevation of 2,840 ft. and the loss of power that presents, do you guys think it will pull a 24t front sprocket? I'm running an 18 in. rear wheel and the course is 1.3 miles.
 
I ran a 24t with my wife on back for a couple of years. Not at high altitude tho, <1000', and not trying to go for high speed. When she stopped riding, I dropped back to a 20t for the thrill.
I don't believe you'll have to worry about the redline with that 24.
 
George Hirvela said:
I am going to use my street bike (mk3) to do my rookie run at El Mirage. Given the higher elevation of 2,840 ft. and the loss of power that presents, do you guys think it will pull a 24t front sprocket? I'm running an 18 in. rear wheel and the course is 1.3 miles.
Click to expand...
My stone stock 850 runs out of power before the redline, just about 115 mph, using the 22T.

JFWIW

How much additional hp have you added?
 
That doesn't seem right. Although I've never been 115 I've been 110 with my MK3 and a 23t sprocket and it was still pulling pretty good. I guess the 18 rear makes a lot more difference than I thought. Sticking it next to the 19 it was nearly the same height so I didn't think much of it.
 
George Hirvela said:
That doesn't seem right. Although I've never been 115 I've been 110 with my MK3 and a 23t sprocket and it was still pulling pretty good. I guess the 18 rear makes a lot more difference than I thought. Sticking it next to the 19 it was nearly the same height so I didn't think much of it.
Click to expand...
I'm not right in many ways.

I have nothing further.

Let us know how you do. 😎🏆
 
George Hirvela said:
That doesn't seem right. Although I've never been 115 I've been 110 with my MK3 and a 23t sprocket and it was still pulling pretty good. I guess the 18 rear makes a lot more difference than I thought. Sticking it next to the 19 it was nearly the same height so I didn't think much of it.
Click to expand...
jaydee75 said:
I ran a 24t with my wife on back for a couple of years. Not at high altitude tho, <1000', and not trying to go for high speed. When she stopped riding, I dropped back to a 20t for the thrill.
I don't believe you'll have to worry about the redline with that 24.
Click to expand...
I wasn't worried about redline just if it had the balls to not run out of power at the top end.
 
Where I ride and how I ride then the stock sprocket works great for me, I don't ride on long highways and always riding up in the ranger/mountains where the roads are tight and twisty, with a bigger front sprocket won't mean you will get more top end be just a bit harder to get up there, I like quick response to my throttle, more fun that way, but with stock gearing my hotrod Norton will sit all day from 65 to 90 MPH if I need to, on the highways to many cops and speed cameras all back roads for me, more fun as well, up in the hills/ranges the lower gearing is a lot better for pulling up them big climbs.

Ashley
 
trident sam said:
I ruined my T160 years ago by fitting a 21 front and 47 rear, never got into top gear.
Click to expand...
I did similar, I fitted one of John Andersons smaller rear sprocket kits to my T160 and proceeded to spend much more time in a lower gear, at higher revs, than I did before.

However, after I fitted the 850 kit (along with some other work to boost oomph) it really benefitted from the raised gearing.
 
Last edited:
There are more things involved than just gearing. With higher gearing, you lose vacuum in the inlet tract, because you tend to use more throttle, For high alitiude, you use leaner jetting because there is less air, but the air at high altitude is often colder, so then you need richer jetting. You should be able to tell if your motor is running too lean - it will run like a bag of shit. With the heavy crank, lowering the gearing often does not help the bike to accelerate faster. A lot depends on the revs and the spread of the internal gears. Raising the overall gearing should only slow the bike if the taper on the carb needles is too rapid. If the mixture richens too quickly, the bike will have slower acceleration. With stuff such as this, I usually suck it and see. I would carry a couple of slower taper needles, and use practice sessions to optimise the jetting.
 
concours said:
True story.
Over gearing will lug the engine, destructive to an engine, just in different ways than over revving. 💡
Click to expand...
There is definitely a balance/trade off all right.....Better fuel economy/top speed at the expensive/compromise of reduced mid range throttle/acceleration response...final theoretical top speed is one thing...running out of road before you finally there is another...🤣
 
Fast Eddie said:
Unless you’ve done engine work and significantly increased power output, 24t is too tall IMO.

It will be counter productive, making you actually spend more time in lower gears, using higher revs, as a result.
Click to expand...
What you say might be true, but if the needles in the carbs are further onto the tapers because of the gearing, the mixture becomes richer, quicker so the bike won't accelerate as well as it might. If it leans-off more, the rate of acceleration should not change much.
I suggest just changing the gearing without changing anything else would be counter productive.
 

Similar threads

nopdog
Changing front sprocket 961
Replies
3
Views
283
TonyA
TonyA
olympus
  • Locked
Front Sprocket deliberation
Replies
19
Views
3,384
acotrel
acotrel
K
  • Locked
Changing front sprocket, what other work should I do?
2
Replies
38
Views
2,914
kwoody51
K
D
  • Locked
Front Sprocket
Replies
8
Views
1,977
VA Rebel
V
Back
Top