lack of power

[pat_in_the_hat]

So I have been noticing that my engine is slowly producing less power. It has stock gearing. But I have to be in 3rd gear around 25mph. Took it out on the highway last night and wasnt able to get above approx 60mph while full throttle in 5th gear. (I dont have a spedo). It seems to run just fine, but it just wont reach a high speed before a high rev.

Maybe Im just getting more comfortable with it and am expecting more. But I highly doubt it.

Compression is right at 140. Everything looks good. what else could cause it to not be a fast as it originally was?

 

[Fleksta]

When is the last time you cleaned the carbs? Jets might be gunking up.

But if you are getting high revs to an unusually low speed it may be that your clutch is slipping.

 

[pat_in_the_hat]

carbs were last cleaned at the beginning of the summer. Most likely not them.

wouldnt I notice if the clutch was slipping? like a jolt? It has smooth acceleration all the way thru its range.

 

[fredintoon]

carbs were last cleaned at the beginning of the summer. Most likely not them.

wouldnt I notice if the clutch was slipping? like a jolt? It has smooth acceleration all the way thru its range.

Hi pat,
so clean 'em again, they like that.
but no, I'm with Fleksta, most likely you got clutch slip. Slip don't jolt, that's clutch grab.
Slip pulls away nice and smooth but only transmits a limited amount of torque before it starts to slip and that slippage lets the engine rev without making the bike go faster.

 

[pat_in_the_hat]

Hi pat,
so clean 'em again, they like that.
but no, I'm with Fleksta, most likely you got clutch slip. Slip don't jolt, that's clutch grab.
Slip pulls away nice and smooth but only transmits a limited amount of torque before it starts to slip and that slippage lets the engine rev without making the bike go faster.

hmm that makes sense. I was planning on an oil change this week anyway. So ill take the right side cover off and see if it looks like that is happening

 

[fredintoon]

hmm that makes sense. I was planning on an oil change this week anyway. So ill take the right side cover off and see if it looks like that is happening

Hi pat,
unless the spring compression screws are partially undone you can't tell if a clutch is slipping just by looking at it and you can't run the bike with the right side cover off.
I'd suggest that before you get medieval on the clutch itself you check that the clutch operating cable and arm has free movement enough that the clutch isn't a little bit pulled all the time.