Speedo is WAY OFF!

[CHADAWAY]

That 47 rear sprocket is the biggest reason it’s off. Probably to turn that heavy tire combo u got back there lol

If it has a jackshaft, those sprockets are probably the same size and don’t factor. The front sprocket behind the clutch slave master is the one u want to check.

Speedo healer is all u need.

I've run 190 and 200 on my Gen2 and that seems to just about correct the stock speedo which reads high with the smaller stock tire. ...so maybe there is more to it than the 300 tire. If anything, a larger tire should make the speedo read slower. +25 mph at an actual 80 does seem like a lot even with a stock tire. A Speedohealer will take care of it but I'd want to find out what's causing such a large discrepancy. If the rear sprocket is stock size, I'd almost bet the front isn't.


You have a clutch slave cylinder and a sprocket cover to remove. Proceed with caution, the clutch slave might need some extra preocedures to prevent it from popping out while removed from the pushrod. ...also, torquing the clutch slave bolts, lots of sprocket covers have cracked so be careful. I believe it's just one bolt that's the culprit. I wish I had a tutorial thread I could point you to. I started a sprocket cover tutorial years back but never got around to finishing and posting it yet. I found plenty of info on sprocket cover removal on here though so take your time and ask questions. OH--aligning the sprocket cover to the dowel pins is another thing I remember requiring extra care. I wouldn't expect this to be a one day job if you've never done it. LOL if you search, you'll probably come across threads I asked questions on.

It’s a SPR520-47T sprocket on the rear. The sprockets between the transmission and rear sprocket are both 18 tooth. No clue what the sprocket is on the transmission. The tire is a 300/35R18, not sure what factory is supposed to be.

The front tire is a 120/60ZR17 55W. Haven’t had a chance to look at what the front sprocket is yet, spent the last 2 days riding and crashed when I got home.

 

[sixpack577]

The front tire is a 120/60ZR17 55W. Haven’t had a chance to look at what the front sprocket is yet, spent the last 2 days riding and crashed when I got home.

Front tire size doesn't matter on a Gen1 or a Gen2(but 120/70/17 is stock), as the speedometer pickup is at the front sprocket.
17/40 is factory Gen1 gearing

 

[CHADAWAY]

Front tire size doesn't matter on a Gen1 or a Gen2(but 120/70/17 is stock), as the speedometer pickup is at the front sprocket.
17/40 is factory Gen1 gearing

Right, I was just throwing that out there. I’ve got to access the front sprocket then sit down and try to use the gear calculator. If I find the gearing to be wrong I’m assuming I’m in for a bit of work to change it?
Hoping to fix the issue I had with feeling like the bike was screaming for me to shift out of 6th when on the highway running 80 with a bunch of Harleys.

 

[Dnyce]

It’s an easy fix.

How bad did u crash it?

 

[CHADAWAY]

It’s an easy fix.

How bad did u crash it?

Crash? I didn’t, it’s still mint. Just working out the kinks I’m finding after I bought it.

 

[Dnyce]

Oh hahahau meant u crashed like knocked out

Misread that one this morning lol

 

[sixpack577]

Oh hahahau meant u crashed like knocked out

Misread that one this morning lol

...me too
lol

 

[Mythos]

Oh hahahau meant u crashed like knocked out

Misread that one this morning lol

...me too
lol

@CHADWAY don't scare us like that!

 

[CHADAWAY]

So I was finally able to count the front. It’s 17 tooth front, 47 rear and 80 chain links between both chains and 18 tooth on the middle sprockets. This is what I got when I put it in the calculator, not sure how to interpret it.
Aside from the speed being off I’m wondering if this is suitable for the power of the bike. From first to third it likes to spin a lot when I’m on the throttle pretty hard.

 

[Dnyce]

If u know cars, this may help visualize: let’s say stock is a 3.23 rear end, what u have is like going from that to 4.11 or 4.56.

probably the easiest thing to do is buy a 18t front sprocket. I think that will change it enough to still be fun, shouldn’t need to cut off any links off chain, it won’t spin as bad, and the Speedo will be off by less.

You could also buy a smaller rear sprocket but then u definitely need to cut the chain, along with making sure you can find a chrome sprocket for that wheel as I doubt it takes oem sprockets.

 

[GIXERHP]

Isn’t that just a bandaid? There has to be a reason the Speedo is off to that degree.

Size of the rear tire but it should be low

 

[GIXERHP]

The front sprockets are 1 to 1

Stock gearing is 17 40 for a gen 1 for reference

 

[turtlezx]

your off about 25% look at the front sprocket.The nut has 4 pie shaped posts on it . Cut 1 off thats will change your speedo by 25% .Should be real close to correct speed with the gearing you have cost you nothing

 

[LC4CARL]

Tire Size Calculator

Free calculator to find the dimensions of a tire based on its code. It also helps in choosing alternative tire sizes based on rim size or comparing two tires.

www.calculator.net

 

[CHADAWAY]

your off about 25% look at the front sprocket.The nut has 4 pie shaped posts on it . Cut 1 off thats will change your speedo by 25% .Should be real close to correct speed with the gearing you have cost you nothing

I bought the speedohealer yesterday lol. Looking into finding a new rear sprocket considering mines a little worn. Trying to figure out if I should go up or down in teeth count

 

[sixpack577]

Down 3 on the rear or up one on the front will bring the rpms down around 600+ at the same speeds you're at now.

 

[Dnyce]

Yup, if u wana change the rear I’d say 3 or 4 teeth less is all u need.