Re: Derbi Start V (Fiiiiiiiive)

Bump!

Re: Derbi Start V (Fiiiiiiiive)

I've been collecting parts but sadly this project is on the opposite coast of canada from myself.

It will happen though.

Re: Derbi Start V (Fiiiiiiiive)

Hi.

I use Fowler's... in the UK They even have micro fish...IYou can look at on the website. I know well old Tech! but it lists PART NO's....

It works for what I have.

Re: Derbi Start V (Fiiiiiiiive)

What're you thinking for belt with the overrange? Treats says stock dayco 7188 is 596mm long. I found this one for honda aero 50 that's like 634mm, and there's some other ones in a similar range. Pedal derbi motor belt is like 628, that'd probably be a good start too.

https://www.partsforscooters.com/106-134-Bando-CVT-Belt-634-15.5-29

It'd just be finding that balance of taking advantage of bigger rear while still getting the variator to close fully. I was looking around and on the motomatic bikes it looks like they're rocking the scooter vario that fits, but I also saw a few pics where it looks like they are running the big malossi variotop from french bikes. I haven't had my hands on much french stuff, but i think ya'd needa get that spline in there for derbi crank, maybe cut that out from old fixed cheek and weld it in to the french one to make it fit? Idk

Re: Derbi Start V (Fiiiiiiiive)

Looking for some tuning advice.

I have a Start V with 65 cc metrakit, TM24 (15 idle jet, 165 main jet, middle needle position, 5n13 needle) 6 gram weights, 16/33 gearing, removed starter clutch, stock contra and variator. Rk replica huge moped pipe w/ black baffle. Malossi reeds. Timing 1.8mm. No air leaks with leak down test.

The bike is 4 stroking - a lot at 1/2 to WOT and less frequently at WOT. The bike accelerates decently until 1/2 throttle then there is a lot of hesitation and losing of power and spitting gas.

I have tried leaning the main down to 115 and needle position but this makes the bike run worst and there is still a lot of 4 stroking in the mid range. The plug looks to be on the richer side but not bad. The head temps hang around high 200s. Leaning up the main jet did improve the spitting of gas.

I was looking on the tuning spreadsheet. There is another guy with a metrakit, start 5, with a tm28 with a 185 main jet.

I feel like I need to down jet but I do not have any reference and the lowest jet I have is 115. Or am I totally out of the ballpark and need a leaner needle?

Re: Derbi Start V (Fiiiiiiiive)

todd amundson /

> jordan * Wrote:

> -------------------------------------------------------

> What're you thinking for belt with the overrange? Treats says stock

> dayco 7188 is 596mm long. I found this one for honda aero 50 that's like

> 634mm, and there's some other ones in a similar range. Pedal derbi motor

> belt is like 628, that'd probably be a good start too.

>

> https://www.partsforscooters.com/106-134-Bando-CVT-Belt-634-15.5-29

>

> It'd just be finding that balance of taking advantage of bigger rear

> while still getting the variator to close fully. I was looking around

> and on the motomatic bikes it looks like they're rocking the scooter

> vario that fits, but I also saw a few pics where it looks like they are

> running the big malossi variotop from french bikes. I haven't had my

> hands on much french stuff, but i think ya'd needa get that spline in

> there for derbi crank, maybe cut that out from old fixed cheek and weld

> it in to the french one to make it fit? Idk

I believe you’re talking about welding the splined shaft off one crank and onto another crank web to fit?

Or rear output to fit larger pulley?

Re: Derbi Start V (Fiiiiiiiive)

Very cool.

I've been doing the same but to a Start3. I have two of them, so I'm going to keep one mild with a old school 70cc MetraKit for the short stroke start 3 and I have another that I filled in the cylinder studs and moved for the Stage6 kit.

IMG_0100.JPG
IMG_9959.JPG

Re: Derbi Start V (Fiiiiiiiive)

> todd amundson Wrote:

> -------------------------------------------------------

>

>

> I believe you’re talking about welding the splined shaft off one crank

> and onto another crank web to fit?

>

> Or rear output to fit larger pulley?

I've got a piaggio rear pulley on the way, that should just be boring rear pulley bearing pocket to fit derbi size pulley bearing like earlier in the thread.

Not tryna cut & weld crank arms, was more thinking cutting the spline from derbi fixed pulley and ramp plate and attaching those to the variotop pulley and plate so that you can have that giant 115mm diameter vario.

After looking at a buddy's variotop tho, it seems like the boss is much thicker than the scooter style derbi one. so in my head it seems like the amount of variation range gained at top end would be similar to the amount lost at least variation with the bigger boss. Latest pic I was able to find of barry's race revo he has scooter style vario again so idk if it broke or didn't perform or what

Another mockup on mine, needa mod the crank a little to get ramp plate to sit in further to get lined up with rear pulley and make an adapter for the stator

IMG_20201224_190532.jpg

Re: Derbi Start V (Fiiiiiiiive)

todd amundson /

Yeah I don’t get it but that’s typical with my disk lexicon. It’s ok as long as you’re doing something very difficult and expensive.

Biggest concern is getting that mvt premium working and not stalling when it drops rpm at idle.

Re: Derbi Start V (Fiiiiiiiive)

If you wanna run a bigger scooter vario in the front the problem I saw was that the crank wasn't long enough for full travel. If you use a vario with small diameter rollers you can kinda get around that but your still limited.

If you jam in a different crank this may solve this problem.

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