Derbi GP1 for Track Use

It's show and tell for your custom scoot! Post photos of your project scooters, etc.

Moderators: SLOWRIDER, Areomyst, scootertrog, mikal

User avatar
Areomyst
Site Admin
Posts: 5275
Joined: Tue Jul 10, 2007 11:39 pm
Location: Haw River, NC United States of America!
Contact:

Re: Derbi GP1 for Track Use

Postby Areomyst » Mon Nov 28, 2016 5:01 pm

dan v wrote:Thanks for the heads up on the jet size. I have a 90 in there now - what the PO was using with an Airsal. Guess I'll keep it in there for now. Interesting how the airbox to your doppler setup changed the jet size so much.

You're quite welcome! The stock airbox is pretty restrictive. On the PHVA carburetors, if I'm switching filters or modifying an air box I'll usually start out with a 125 main jet or so. Sometimes, depending on the build, that's WAY too slobbering rich. It's better safe than sorry though.


After working on the above mentioned Aprilia for almost 2 years now, I finally got to fire up the new engine this afternoon. So apparently no problem running that 12 mm piston in the Polini kit, just as you said. A few other minor things to work out before trying it on the road, probably won't happen till spring. Thanks again for all your help on that project.

I'm glad to hear that you were able to fire it up finally. It's nice to get some feedback, and I hope your scoot does really well for you!
Nice work on the porting. I wish I had that skill. I was going to give it a go on the Polini, but only found info on porting for the Piaggio model, and no confirm that porting info was the same for Mina. So left it stock.

Please pardon the minor threadjack. Looking forward to see how you make out at the track!

Thank you for the compliments! Damn, I saw your thread about that project and meant to reply... I'll go hunt it down. :)

Cheers!

~Josh
"The more a man learns, the more he realizes how little he knows."

User avatar
Areomyst
Site Admin
Posts: 5275
Joined: Tue Jul 10, 2007 11:39 pm
Location: Haw River, NC United States of America!
Contact:

Re: Derbi GP1 for Track Use

Postby Areomyst » Tue Nov 29, 2016 9:04 pm

Hrm... How hard can it be?

...
Attachments
IMG_2621.JPG
IMG_2621.JPG (594.37 KiB) Viewed 2415 times
"The more a man learns, the more he realizes how little he knows."

User avatar
Areomyst
Site Admin
Posts: 5275
Joined: Tue Jul 10, 2007 11:39 pm
Location: Haw River, NC United States of America!
Contact:

Re: Derbi GP1 for Track Use

Postby Areomyst » Mon Dec 05, 2016 10:13 pm

In the photos you'll see Daniel O, teaching me the fabrication ropes! We joined forces to build the expansion chamber. After I made the patterns and cut them out of sheet metal, I went to Daniel's and he showed me how to use the slip roll to roll cones, along with some other techniques in shaping the metal. It wasn't long before he had the TIG welder fired up and was joining pieces together! This is most certainly one of the most exciting projects that I have been involved with in a while, and I am outrageously grateful for Daniel taking the time to teach me. Sheet metal fab isn't something that I had any real experience with before now. I've learned a fair amount about welding as well!

I can't wait to test it on the scooter. We still have to finish a bunch of welding, and I need to sort out the header section. I believe I'll use the header off of the Tecnigas. I'll be sure to update the thread again when there's more progress.


~Josh
Attachments
IMG_2658.JPG
IMG_2658.JPG (420.59 KiB) Viewed 2373 times
IMG_2656.JPG
IMG_2656.JPG (418.84 KiB) Viewed 2373 times
IMG_2681.JPG
IMG_2681.JPG (510.86 KiB) Viewed 2373 times
IMG_2675.JPG
IMG_2675.JPG (499.97 KiB) Viewed 2373 times
IMG_2674.JPG
IMG_2674.JPG (477.91 KiB) Viewed 2373 times
IMG_2673.JPG
IMG_2673.JPG (461.74 KiB) Viewed 2373 times
IMG_2667.JPG
IMG_2667.JPG (411.22 KiB) Viewed 2373 times
IMG_2661.JPG
IMG_2661.JPG (557.99 KiB) Viewed 2373 times
IMG_2659.JPG
IMG_2659.JPG (552.88 KiB) Viewed 2373 times
"The more a man learns, the more he realizes how little he knows."

dan v
Posts: 358
Joined: Thu Nov 05, 2009 5:45 am
Location: Grand Rapids, Michigan USA

Re: Derbi GP1 for Track Use

Postby dan v » Wed Dec 07, 2016 5:40 am

Nice!!! Kinda like Santa and his helper making toys for big kids.....
How many scoots is too many?

Dabby-D
Posts: 3
Joined: Sat Jul 01, 2017 6:03 pm
Location: Washington State

Re: Derbi GP1 for Track Use

Postby Dabby-D » Mon Jul 03, 2017 1:43 am

Thats so cool, I was staring at my exhaust asking the same question with the limited amount of racing exhausts there are for the S9 and some models. I saw you started preferring Arrow exhausts. many companies claim racing performance, but are more like plug and play sports stuff. I got annoyed wasting money on the "racing verb-age", learned whats for show and whats for go, But no matter what money i wasted i am entirely grateful for the lessons learned and the people to learn from. Glad you got some pics of the exhaust fabrication process. Pretty soon Im sure your going to be welding your own aluminum race frames :) I really appreciate the great detail you place on porting, and educating the importance of it with timing and HP, no doubt your fab polishing skills are obsessive compulsive and off the hook. I get excited seeing your updates and its good to see you pushing yourself to new limits.

User avatar
Areomyst
Site Admin
Posts: 5275
Joined: Tue Jul 10, 2007 11:39 pm
Location: Haw River, NC United States of America!
Contact:

Re: Derbi GP1 for Track Use

Postby Areomyst » Wed Feb 07, 2018 12:07 pm

Dabby-D wrote:Thats so cool, I was staring at my exhaust asking the same question with the limited amount of racing exhausts there are for the S9 and some models. I saw you started preferring Arrow exhausts. many companies claim racing performance, but are more like plug and play sports stuff. I got annoyed wasting money on the "racing verb-age", learned whats for show and whats for go, But no matter what money i wasted i am entirely grateful for the lessons learned and the people to learn from. Glad you got some pics of the exhaust fabrication process. Pretty soon Im sure your going to be welding your own aluminum race frames :) I really appreciate the great detail you place on porting, and educating the importance of it with timing and HP, no doubt your fab polishing skills are obsessive compulsive and off the hook. I get excited seeing your updates and its good to see you pushing yourself to new limits.


Thank you very much for the kind words! I know the feeling of being frustrated because you bought 'race parts' and received something that wasn't far removed from stock. I used the Arrow exhausts for a while - and I like the performance. Unfortunately, with the KYMCO ones anyway, I have had every single silencer have problems on those exhausts. Arrow replaced one of the exhausts, but after it happened a few times I stopped carrying them. \

Thanks for your input Dabby! Ciao!

~Josh
"The more a man learns, the more he realizes how little he knows."

User avatar
Areomyst
Site Admin
Posts: 5275
Joined: Tue Jul 10, 2007 11:39 pm
Location: Haw River, NC United States of America!
Contact:

Re: Derbi GP1 for Track Use

Postby Areomyst » Thu Mar 15, 2018 11:00 pm

Dear Everyone,

It is acceptable to me if you digitally yell at me for my actions. I sold the Derbi to a buddy in Greensboro. I did this because I got a really really sweet deal on a Vespa ET2 - which is what I was actually looking for when I bought the Derbi in the first place. I'm taking the Derbi money and getting the Vespa - and coming out with some cash leftover to boot. It's a total win-win for me. I did hate to part with this bike so soon, but it is in VERY loving hands... My buddy Dee has done more with it in the past 2 weeks that I have been able to do in a couple of years. Attached are some teaser pics that I am posting with his permission. You guys might (just maybe) get treated to more details on his build. I'm bending his arm a little to get him to start a build thread for it. ;)

Ciao!

~Josh
Attachments
20180314_232734.jpg
20180314_232734.jpg (4.51 MiB) Viewed 538 times
20180314_232108.jpg
20180314_232108.jpg (4.72 MiB) Viewed 538 times
20180314_210053.jpg
20180314_210053.jpg (4.15 MiB) Viewed 538 times
20180314_202547.jpg
20180314_202547.jpg (4.13 MiB) Viewed 538 times
"The more a man learns, the more he realizes how little he knows."

User avatar
Areomyst
Site Admin
Posts: 5275
Joined: Tue Jul 10, 2007 11:39 pm
Location: Haw River, NC United States of America!
Contact:

Re: Derbi GP1 for Track Use

Postby Areomyst » Thu Mar 15, 2018 11:18 pm

Oh, I almost forgot to mention!

I kept the exhaust that Daniel and I built for the Derbi. Shamefully it's not 100% complete, but a lot of the hard work is done. I can't wait to test that exhaust to see if it was a success or failure in making more power. Based on Daniel's experience testing and tuning expansion chambers built according to the FOS calculations, I am fairly certain our exhaust will do well. I'll try to get the Derbi back out here for some dyno pulls with our exhaust installed, as that's the best way to do a fair comparison of the exhausts tested for this build.

~Josh
"The more a man learns, the more he realizes how little he knows."


Return to “Scooter Showroom”

Who is online

Users browsing this forum: No registered users and 2 guests