New Jersey on the road

[69ST]

I'd be aiming toward ~6.5mph/1000rpm, that's the short end of the range, considering the 54mm crank you're running.

Dunno that I'd be too concerned about the generous speedo readings. Major props to you for your pursuit of perfection. Seems that you think as I do. Be afraid, be very afraid...

 

[Deoodles]

I’m going to see this to the end. But if it wasn’t for Pat I might have given up. Thanks, he is doing similar testing with me. Here is what I have and I didn’t know this stuff a week ago.

17/33 = 1.94 to 1
16/32 = 2.00 to 1
16/33 = 2.06 to 1
15/32 = 2.13 to 1
15/33 = 2.20 to 1

That can be looked up by anyone. The 17/33 @ 1.94 is tallest and the 15/33 @ 2.20 is the shortest.

Results so far

15/33 top speed 64 mph. Top rpm 11k. Temp post run 110c. @ 50mph 7.8k rpm
16/33 top speed 62 mph. Top rpm 9.5k Temp post run 110c. @ 50mph 7.0k rpm

These results eliminate the 16/32, and 17/33 combos as they will both be too tall. The 15/32 is next and may be the optimum for the build. But, the 16/33 while not the top speed winner does have an up side. It can pull 4th gear on a incline to 55+ mph and that’s all that is required. It is also a great choice to lower rpms while riding around. I will update when I have a chance to run 15/32.

 

[69ST]

By the numbers...

You're getting 6.58mph/1000rpm. 15/32 is close to 3% taller...6.8mph/1000rpm. Two possible outcomes...

The engine will pull it with nearly equal competence, in which case you'll drop cruising rpm by 250-300rpm...

...OR...

It falls on its face i.e. feels noticeably weak in 4th gear...in which case you'll know, firsthand, what that 3% threshold means, in real world terms.

That your top speed was higher with the shorter gearing tells me that you have a horsepower-biased tune. It may be possible to fatten-up the torque curve with a less aggressive cam profile. Guess what...as much as I prefer "stompers" (lots of usable power at the expense of absolute peak)...I wouldn't go this route. The hairier cam is easier on bottom end parts and reduces octane requirement.

IMHO 210F is ideal oil temp.


By the time you're done testing you'll enjoy the satisfaction of knowing that you've dialed-in your combo to perfection. Not many builders realize the full potential of their machinery.

 

[Deoodles]

temp correction in the post. 110c or 230F still a little warm. But this a wot run for 2 miles normal operating temps are 80 to 100c. I didn’t understand your tune comment. Am I better off leaving my cam?

 

[Deoodles]

I wanted to give the 32t a go. I had the 16 on so I decided to test 16/32 I am surprised by the results. 4th gear didn’t pull very well but it did match the 16/33 rpm’s it just took a bit longer so that made top speed faster it wasn’t that great for 4th but it did keep cruising rpm’s pretty low and for longer rides it would be nice. Next one will be 15/32.


15/33 top speed 64 mph. Top rpm 11k. Temp post run 110c. @ 50mph 7.8k rpm 2.20 to 1
15/32
16/33 top speed 62 mph. Top rpm 9.5k Temp post run 110c. @ 50mph 7.0k rpm 2.06 to 1
16/32 top speed 65 mph. Top rpm 9.5k Temp post run 110c. @ 50mph 6.5k rpm 2.00 to 1

 

[OLD CT]

Next up a shot of nitrous to get the tach up to 11k in 4th. Found this picture.

 

[69ST]

If you gonna buy a nitrous kit, get one that includes a pair of ballistic nylon shorts...just in case.

 

[OLD CT]

Ray's ride looks sharp! Right Bob? A ton of tuning, here today... Well it's 75 degrees here and 44% humidity. I went from the 150 main and stepped it up one size at a time till I found rich misfire with the 175 main! Just put the 170 back in and hit 67 mph with the GPS every time I tested each jet. max temp 86 Celsius. Good stuff! 16-33 gearing.

 

[69ST]

That's a nice photo, Pat. Both machines look good.

If your oil temps absolutely max-out at 86C in the peak of summer heat I'd almost be concerned about over-cooling.
Maxing out at that temp in 75F ambient air temp...IMHO...you're dead-on with the cooling & jetting.

 

[Deoodles]

I ran the last combo. By far the best option for this build and tune. I’m going to make a 17/36 my gear choice. It is 2.12 to 1. It’s really the 15/32 which is 2.13 to 1. But, the larger gears should give me some chain longevity. This combo just feels right for my riding conditions. 4th gear pulls from 30mph and I don’t have to shift a lot. Now I just have to lean on Pat to show me how to get it running cooler. The white pointer is top speed.

15/33 top speed 64 mph. Top rpm 11k. Temp post run 110c. @ 50mph 7.8k rpm 2.20 to 1
15/32 top speed 69 mph Top rpm 10.5k. Temp post run 110c. @ 50mph 7.3k rpm 2.13 to 1
16/33 top speed 62 mph. Top rpm 9.5k Temp post run 110c. @ 50mph 7.0k rpm 2.06 to 1
16/32 top speed 65 mph. Top rpm 9.5k Temp post run 110c. @ 50mph 6.5k rpm 2.00 to 1

 

[Deoodles]

After sleeping on it I think 16/32 is a better choice. I won’t go taller but can stick a 15 on if I head to the mountains. One chain can accommodate the choice. 17/36 would not allow a taller choice

 

[OLD CT]

16-34 is 2.13. I could probably run that and still be able to go back to the 33 or slap the 15 up front with no chain issues or in other words, run the same chain I have. What do you think Ray?

 

[Deoodles]

16/34 down to 15/33 is within the range of adjustment for the swingarm and chain. I know because I used all of those combinations with one chain

 

[Deoodles]

I looked at post 30 many times and did 4 or 5 50+ mile rides. All said and done the 15/32 is the best for my riding. I’m convinced it would be what the mfr would have used to balance out the bike. The problem I run into is adding the rpms here in the south = heat. I added a finned cam cover and changed the main jet on the vm20 to a 160. Those changes kept reasonable road riding motor temps around 105 Celsius. Temps here are about to drop and I expect to be closer to 95 celsius for the fall riding season. Gotta thank Pat for helping with the heat reduction. I didn’t get the jetting thing. Of course tire size changes gearing. This tune isn’t just gears,jets,build, it’s a complete package that makes it run cool, feel right, respond well, and hit road speeds on demand. Still looking at ways to knock off another 5 Celsius.

 

[OLD CT]

The cooler temps ahead and more miles logged will do it Ray. I figure by next summer it will all balance out with the extra miles on the build.

 

[69ST]

16/34 down to 15/33 is within the range of adjustment for the swingarm and chain. I know because I used all of those combinations with one chain

Easy way to figure this out is comparing the tooth count of various combos. 16 + 34 = 40; 15 + 33 = 38...only two links difference. There's enough adjustment range to compensate for 4 links difference, biggest-to-smallest combined tooth count, if the chain is optimal to begin with.

I looked at post 30 many times and did 4 or 5 50+ mile rides. All said and done the 15/32 is the best for my riding. I’m convinced it would be what the mfr would have used to balance out the bike. The problem I run into is adding the rpms here in the south = heat. I added a finned cam cover and changed the main jet on the vm20 to a 160. Those changes kept reasonable road riding motor temps around 105 Celsius. Temps here are about to drop and I expect to be closer to 95 celsius for the fall riding season. Gotta thank Pat for helping with the heat reduction. I didn’t get the jetting thing. Of course tire size changes gearing. This tune isn’t just gears,jets,build, it’s a complete package that makes it run cool, feel right, respond well, and hit road speeds on demand. Still looking at ways to knock off another 5 Celsius.

It's all of that. And ambient air temp can easily account for 20C difference in oil temp. That said, there is one thing that will not change...heat generation is linked to sustained horsepower output...no way around this, it's basic physics. Internal combustion engines are no better than 28-31% efficient, meaning that ~70% of the fuel used is turned into usable power. The rest ends up as waste heat. With everything optimized, a minimum amount of radiating (cooling) surface is needed to control oil temps and, unless a thermostat is used there's also a maximum amount of radiating surface, above which the oil can be over-cooled.

 

[airblazer]

I’ve been in New Jersey for work this week. Pat (OLD CT) & I met up at his favorite local pizza joint last night. We talked shop and had a good time, as good as one can have without riding bikes anyway! It was cold and rainy - no surprise there, right Bob (red69)?
Thanks Pat, see ya next time!

 

[OLD CT]

Thanks Ryan for letting me know you were in town. It's always nice to meet members from this site and hoping more folks plan on going to the Pennsylvania meet @ the Oley fairgrounds on May 8th & 9th this year! 26 Jefferson St Oley Pa.

 

[Deoodles]

I have the time off already! I plan on being there both days this year. Last year I was only there for Saturday and it wasn’t enough. For me it’s 9 or 10 hour drive. Hope others consider. It is worth going

 

[Deoodles]

Hate to say it but I won’t be at the swap meet this year. I guess no explanation needed. I was planning to go all out. Picked up a trailer and was going to camp. Next year I guess


The consolidation was I talked Pat into coming down for a ride. Got him to do my 75 mile loop at night. It was great but temps went low and we pretty much froze lol. Hope we can do it again