Can’t top out past 43ph

[BergyPatty37]

@dmonkey I think it depends on if the speeds he was listing were GPS or speedo readings. If they were GPS then I would lean towards re-geared. If its Speedometer than it would have to have a speedo doctor also, otherwise 43MPH on the speedometer would be 3rd gear without speedometer fix pretty much regardless of gearing.

@Mntnmike Does your ABS light flash rapidly?

 

[dmonkey]

Good point. As for testing, you can run the bike on its center stand (at your own risk) to put it through the gears, but personally I wouldn't attempt WOT like that without rolling resistance. At the least it would enable you to verify it's shifting from 3rd to 4th.

 

[BaldRider]

The JA65 cover is a pain to take off but you get used to it

 

[DeadguyAle]

I would just note what the max speed is in each gear then post here. If all gears show lower than expected then it's an external sprocket change. If only forth gear is impacted then probably not actually going into forth gear.

 

[BergyPatty37]

@Mntnmike Any updates?

 

[Mntnmike]

I was having a similar issue recently. I just replaced my fuel filter and it helped.

What altitude are you at? Currently running around just over 5000’ and losing that whole HP feels pretty noticeable compared to when I’m riding at sea level. Definitely seeing a reduction in top speed.

I live at 4000’ and ride up to 6000’. Are you saying you get a significant drop in RPM at higher elevations, after the fuel filter change?

 

[Mntnmike]

@dmonkey I think it depends on if the speeds he was listing were GPS or speedo readings. If they were GPS then I would lean towards re-geared. If its Speedometer than it would have to have a speedo doctor also, otherwise 43MPH on the speedometer would be 3rd gear without speedometer fix pretty much regardless of gearing.

@Mntnmike Does your ABS light flash rapidly?

Sorry for the delayed response as I didn’t get back home to the bike until today.

Yes, Speedo reads 43 and GPS reads 42.

 

[Mntnmike]

I would just note what the max speed is in each gear then post here. If all gears show lower than expected then it's an external sprocket change. If only forth gear is impacted then probably not actually going into forth gear.

Yes, so this is close approximation for max speed:

1st: ~18mph
2nd: ~ 26
3rd: ~35
4th: ~43

It definitely is going into a four gear. After 3rd and going to 4th, rpms drop and I can easily accelerate up to 43. But then the engine is screaming.

 

[Mntnmike]

@dmonkey I think it depends on if the speeds he was listing were GPS or speedo readings. If they were GPS then I would lean towards re-geared. If its Speedometer than it would have to have a speedo doctor also, otherwise 43MPH on the speedometer would be 3rd gear without speedometer fix pretty much regardless of gearing.

@Mntnmike Does your ABS light flash rapidly?

Forgot, no, the ABS light does not flash. On until I hit 5mph.

 

[Mntnmike]

The JA65 cover is a pain to take off but you get used to it

I want to switch the chain anyways so maybe I’ll have a project day and do chain, tires and tubes. Not looking forward to it at all!

 

[BergyPatty37]

Its really not as bad as you are working yourself up. Just have an extra set of hands to line up rear wheel and brake bracket and youll be fine. Tires are super easy to do on these too, since they are usually only 4-ply.

 

[Mntnmike]

Its really not as bad as you are working yourself up. Just have an extra set of hands to line up rear wheel and brake bracket and youll be fine. Tires are super easy to do on these too, since they are usually only 4-ply.

Thanks! I know I’m definitely working myself up. I’ve rebuilt car engines but for some reason I’m hesitant here.

And I flooded replies to your queries the past several days! I got back late to the bike so just now addressing it.

On Sunday I’ll work on getting sprocket counts. But I’m thinking you’re right that there might be something wrong with 4th, considering the first owner did something that necessitated replacing the shifter. (Oddly, they gave me the old one that has the slight bend.)

 

[DeadguyAle]

Yes, so this is close approximation for max speed:

1st: ~18mph
2nd: ~ 26
3rd: ~35
4th: ~43

It definitely is going into a four gear. After 3rd and going to 4th, rpms drop and I can easily accelerate up to 43. But then the engine is screaming.

I haven't noted what each gear winds out at but 35-40 mph in third gear is not really pressing the RPM limits. In fourth 48 to 52 mph on flat ground via the slightly optimistic speedo. Even at 52 mph you are not really winding the thing out RPM wise.
If you're still on stock tires then it would appear that your bike has had the sprockets changed.

 

[Mntnmike]

I haven't noted what each gear winds out at but 35-40 mph in third gear is not really pressing the RPM limits. In fourth 48 to 52 mph on flat ground via the slightly optimistic speedo. Even at 52 mph you are not really winding the thing out RPM wise.
If you're still on stock tires then it would appear that your bike has had the sprockets changed.

Can the sprockets be changed and the ABS light still acts normal, on until 5mph? My ABS light doesn’t flash. I am still on stock tires. Yeah, even on a 8% downhill grade in 4th, the best I get is the 43mph.

 

[BergyPatty37]

Can the sprockets be changed and the ABS light still acts normal, on until 5mph? My ABS light doesn’t flash. I am still on stock tires. Yeah, even on a 8% downhill grade in 4th, the best I get is the 43mph.

Yes: 2 options:
1.) Gearing was changed and Speedo DRD was installed, which allows you to re-adjust the speedometer to be accurate.
2.) The gearing change was minor (1 tooth on front or 1-3 on rear) and didn't offset speedometer enough to cause ABS flashing. This is a hit or miss, some people have a 13T front sprocket (stock is 14) and have ABS flash, other's don't. That wouldn't offset your RPM that much to be screaming at 43 though

Is the 43MPH speedometer reading or GPS?

 

[DeadguyAle]

Can the sprockets be changed and the ABS light still acts normal, on until 5mph? My ABS light doesn’t flash. I am still on stock tires. Yeah, even on a 8% downhill grade in 4th, the best I get is the 43mph.

I'm still running with stock gearing so can't really comment on the ABS or speedo impact.
On long downhill grades I have seen the speedo read 65 mph while the GPS shows 57 mph. Even at that speed there is little engine vibration and the limiting factor seems to be wind resistance and hp not running up against the rev limiter.
On level ground with minimal headwind my bike will run 47/48 mph. Get rid of the headwind and I get 52 mph. At those speeds you are out of hp not RPM.
I weigh in at 210 fully geared up, run my tires at full pressure (33/35 psi I believe) and have a very low profile top box on the rack.

To drop the top speed down to 43 mph down hill and run up against the rev limiter is going to take more than a drop of one tooth on the counter shaft.
Time to start counting sprocket teeth, and verify the speed with a GPS as @BergyPatty37 recommends.

 

[BergyPatty37]

@DeadguyAle Im running 13/42 and I can hit baout 59-60MPH actual down hill before it redlines in 4th. 70 on speedo. It would really need steep gearing, im thinking like 13/52 or something like that to get redline in 4th at only 43mph.

 

[Mntnmike]

@DeadguyAle Im running 13/42 and I can hit baout 59-60MPH actual down hill before it redlines in 4th. 70 on speedo. It would really need steep gearing, im thinking like 13/52 or something like that to get redline in 4th at only 43mph.

Yeah, when the Speedo says 43, the gps says 41. Yesterday I did get it to 45(!) and I was WOT, no wind, slight downhill, elevation 5,000’.

I am starting to think you might be right that it might be damage from previous owner, since the first owner did have to replace the shifter as it was bent.

I took a video to show the play I have in my shifter, both up down, and in and out; realized I can’t post videos here. Not a lot but there is play. I purchased a stabilizer bracket that I plan to install. If the shaft is damaged in any way, the bracket won’t fit, so that will possibly point to internal damage.

 

[Mntnmike]

I should also add as far as accessories that could limit speed: I have a very small windshield I made to attach to the front basket. It’s 8”x10” and its sole purpose is somewhere to put a resident parking sticker on it. (I saw no change in speed after I installed it.) Otherwise, typical milk crate in the back.

 

[Mntnmike]

Yes: 2 options:
1.) Gearing was changed and Speedo DRD was installed, which allows you to re-adjust the speedometer to be accurate.

2.) The gearing change was minor (1 tooth on front or 1-3 on rear) and didn't offset speedometer enough to cause ABS flashing. This is a hit or miss, some people have a 13T front sprocket (stock is 14) and have ABS flash, other's don't. That wouldn't offset your RPM that much to be screaming at 43 though

Is the 43MPH speedometer reading or GPS?

Both of the previous owners were older gentleman in their 70s who each realized they couldn’t ride it. First one damaged the shifter, sold to second owner, he struggled to ride it and put it up for sale. That’s when I got it. Had 245 miles on it. 2023 model year and I bought it Aug 2025. Didn’t think there was a problem until I saw others posting about their top speed.

Based on the age of the two previous owners, I seriously doubt either one did a sprocket change.