R65 below 4200 RPM and raiseing 5th gear

[mrclubike]

How does the R65 engine vibration compare to other air heads below 4200rpm.
Do any other  air heads have a similar  problem with vibration
Does  the R45 have the same issue as the R65.
After finding out it is normal for this bike I have learned to live with it.
Not a big problem when riding the back roads but  would be a problem if I road on the interstate highways a lot.
Just curious. Is their a way to just change 5th gear without affecting the other 4. I think changing the rear end gearing would make it to sluggish off the start.
4th and 5th are so close together it would be nice if it were a little taller.
Thanks Mark    

[Barry]

Using a special gear wheel it is possible to change just 5th gear to give a 5% increase. Most of the well know Airhead shops would be able to do it for you or the part is available if you want to do it yourself. Motobins have them if you want to see one.

For me vibration is not something I think about in every day use. Sure it's smoother at some revs than others. There is a slight roughness around 3000 rpm but it could hardly be called vibration. At 4500 RPM it's turbine smooth and the the usual buzz doesn't arrive until 5000 RPM and then goes away again at higher revs. I think all airheads have these characteristics to a greater or lesser extent with some variation in the rev bands.  

Rubber engine mounts are reckoned to help or you could even experiment with engine mount torque settings which I found will move the hi rev buzz period up the rev scale.

Obviously carb balance has an impact and not just vacuum balance as I've found getting float levels and mixture settings as close to the same as possible can help. I've often thought that any slight increase in roughness at 3000 RPM is down to carb balance as the carbs will be just coming up on the tapered section of the needle at those revs.

The high rev buzz is probably more a resonant frequency effect. By that I mean it might not be that the engine vibrates more in a certain rev band but the engine and the frame as a unit together hit a natural resonant frequency. That would explain why changes in the way the engine and frame couple has an impact. Fitting rubber mounts doesn't fully isolate the engine as there is still metal to metal contact but it does change the coupling effect. As does changing engine mount torque settings to a much lesser extent.

[John M]

I have a 1986 r65 monoshock with the 3.36 rear end , I had the 5 % taller 5th gear fitted and am very happy with it. when i shift into 5th my final drive is around 3.2 instead of 3.36.  The bike pulls the taller 5th with no problems and 4th is always available for more kick when passing.I initially was unsure about the bikes ability to pull the taller gear but 25,000 km of riding with it have been a pleasure

[mrclubike]

The higher 5th gear would be nice.
After installing my new crossover pipes this weekend
I had to re tighten the motor mounts
I have noticed the vibes did get a little worse but the bike is so fun to run the back roads with that  I am not sure I care about running over 60 mph anyway.
If I ever have to take the tranny apart it will get the higher 5th gear.
Thanks Mark

[Barry]

As the speedo drive is taken from the gearbox output shaft does the 5% taller gear impact on speed accuracy. I'm thinking it doesn't.

[Bob_W]

Barry

No more so than running in fourth gear. Or any other gear for that matter.
Bob

[Matt Chapter]

I have a 1986 r65 monoshock

John what fairing is that and how is it mounted??  I'm looking into changing from a Pichler to something different.

[John M]

Hi Matt, Its a Hannigan. It has a metal support bracket which mounts below the steering head on the front down tubes.  Mine sits about 1" lower than standard because I modified the bracket . Great to ride behind and the bike is more efficient on the highway with it. I can comfortably cruise at 130KPH for extended time with no fatigue

[Matt Chapter]

It has a metal support bracket which mounts below the steering head on the front down tubes.

Are there any side supports? Do you know if it is the RT fairing bracket or something else?

At 170$ for an RT bracket I really want to make sure I get the right pieces.

[John M]

Hannigan had their own bracket

[NC Steve]

I recently installed a taller final drive, changing to a 32/10 ratio, and the difference across the entire range is dramatic. As mentioned earlier, the stock gearing had 4th & 5th very close together, so much so that it was often hard to tell which gear the bike was in. It also began losing steam and vibration became very unpleasant much above 60mph or so.

Now, with the taller gearing, I usually find myself running around town in 3rd, up to maybe 40-45mph, and will shift into 4th at speeds much above that. I also catch myself riding at 50+ in 4th gear without any undue strain or vibration being felt. 5th has become a "semi-overdrive", and is used basically at speeds above 55 or so. Highway speeds, while still not the R65s forte', are very smooth & vibration free up to the 75mph or so that I normally ride. I've pushed the bike up to 85+ before I start to become uncomfortable, but that might have just been me; getting too old to enjoy going that fast! And, I've noticed very little if any difficulty in starting from the line in 1st. Changing the rear end has really transformed the bike! [smiley=thumbsup.gif]

[John M]

Hi Steve , your final drive ratio in 5th ends up being identical to my taller 5th gear. I was interested to hear that your bike pulls the taller final drive in the lower gears well also. When I changed to the taller 5th the conventional wisdom seemed to be that the R65 didn't have the power to pull the taller gearing. Glad to hear that your experience is similar to mine, one of the best alterations I have made to the bike.

[wilcom]

I recently installed a taller final drive, changing to a 32/10 ratio

Sure glad to hear that. I bought a 10/32 a couple of years back to make that swap. Before I got around to swapping it I loaned it to a fellow a couple of states away to make a ride when his had gone bad days before he was to leave. It came back with a stud bent and I haven't got around to replacing the stud.

Your feed back may get me to make a move. I always run out of gears. I'm always towing the lever for one more gear to find I'm already in 5th! I was worried about off the line acceleration , but you have made me comfy that it isn't an issue

Thanks for the report!!