Derbi flatreed engine un/restricted

Here is what I found when I open up a 1984 flatreed engine(restricted install).

Look at the picture and you can see that the euro flatreed engine intake/reedcage area opening is unrestricted.

Thought I would share this since so many derbis are being found. I plan to open the 84 cases.

(anyone else tig welding the primary gear and output shaft and installing a soft plug into the disengagement hole.

I will show my broken parts a bit later)

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Re: Derbi flatreed engine un/restricted

Man what were they thinkin...Casting a whole different motor when all they needed to do was add a restrictor plate in so people could easily take it out later if they wanted more power. Something tells me the EPA had something to do with this

Re: Derbi flatreed engine un/restricted

Never seen that before. All the euro flat reeeds I've got had intakes that have had tamper proof bolts but that never stopped a drill and backout bit

This is a Start 5 i just got from overseas

Re: Derbi flatreed engine un/restricted

why would they do that shit...you're reeds break...well I guess you're fucked...who engineered that shit?

Re: Derbi flatreed engine un/restricted

I was trying to remove those damn things and snapped one off and broke a back out off in the other

Re: Derbi flatreed engine un/restricted

) Cupermcnewbster ( /

I've seen one or 2 flat reeds like that. Pretty silly.

Re: Derbi flatreed engine un/restricted

Wow that intake is huge.

Re: Derbi flatreed engine un/restricted

Tate in Madison /

Yeah, I have seen those but not on a Derbi.

Solution I used was to use a dremel to cut a nice clean notch all the way across the bolt then use an impact screw driver and hammer them out.

Why didn't they just keep the old Derbi way of restricting? Where they put a little plastic top hat down the intakes throat and put a washer up in the variator?

Damn the man. Or in this case, damn the Se

Re: Derbi flatreed engine un/restricted

ed what model did the restricted motor come off?

my 84/85 flat reed SLE is completely open into the crankcase like the picture on the right

Re: Derbi flatreed engine un/restricted

84 sl model

Re: Derbi flatreed engine un/restricted

derbeez ryderz /

my 86 sle is like the one to the left.

unless you have the 4 pedal and huge carb i doubt you would see gains from the huge open one. it might help case compression having that closed in area too, like the one on the left.

Re: Derbi flatreed engine un/restricted

agreed

Re: Derbi flatreed engine un/restricted

It uses a crankshaft that has a line cut into the wheels, so that the mix can get where it needs. I will post a picture of the wheels I had disassemble. (totally trashed)

Re: Derbi flatreed engine un/restricted

Most primary gears I seen are without holes in the gear. This engines has 3 huge holes in the primary (lighter then the newer style flatreed)

Re: Derbi flatreed engine un/restricted

I have seen this happen on .. 5 derbi engines now.

I plan to fix it by removing it and having the output shaft and primary gear tig welded/fused together, I hope I don't have push it any long distances ever.

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Re: Derbi flatreed engine un/restricted

gnarly!

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Re: Derbi flatreed engine un/restricted

I could wiggle the plate. So I remove it and the rivets.

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Re: Derbi flatreed engine un/restricted

Ϫ‡☄ಬ∞ ƀƖḬƝƊ ƤǂƿƎ ∞ಬ☄‡Ϫ /

my 86 has the one on the left side... restricted i guess? damn i have the lomat all ready to go was just going to wait for better reeds before i put it all together guess i'll rethink that plan....

Re: Derbi flatreed engine un/restricted

Here is the output shaft and primary gear fused/tig together.

Rebalance and refit/cut the bearing tolerances, installing ina bearings. I will show picture of the other parts that the weight is remove. No more weight mass spinning inside. Should help some.

next is the .. also the the sprocket front and back views.

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Re: Derbi flatreed engine un/restricted

Should much heat .. shrink the opening .0003's.

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Re: Derbi flatreed engine un/restricted

Ok, since the transmission was all broke up.

I plug the hole in the case where the disengagement lever/switch came through the cases.

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Re: Derbi flatreed engine un/restricted

So once I had the primary weld to the output shaft. I shrink the holes on the teeth/pedal side. So once it was honed with into tolances I press the new ina bearings into the output/primary gear. I deicded to remove all the spinning mass that was inside the derbi engine.

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Re: Derbi flatreed engine un/restricted

) Cupermcnewbster ( /

Very cool! That ought to help it spin up a bit faster!

Re: Derbi flatreed engine un/restricted

dude. word

Re: Derbi flatreed engine un/restricted

Thanks guys,

I have 3 more engines that I will need to do this do. Sad poor design.

Re: Derbi flatreed engine un/restricted

Hook me up with an engine Ed...I've got this BRN morini kit...

Re: Derbi flatreed engine un/restricted

Not many. even know that the morini kit works on the derbi and there .. much room to mod and make flowie.

Find a morini decomp head with you wanna sport this cylinder or .. pickup the moring racing head on 77

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Re: Derbi flatreed engine un/restricted

On the down stroke.

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Re: Derbi flatreed engine un/restricted

looks like there's room for modification ;)

I can make a decomp head...but I'd probably combo with something already in the market...but it would be nice to pair it with the cylinder so they dont look all stupid. The metra50 turned out nicely on the pp motor

I kinda wish I had the money for that choke derbi variant sport r that jeff was selling a while back. I love those red and white R versions. I gotta try and talk fred into selling me one with rad 3 star's on it.

Re: Derbi flatreed engine un/restricted

Never had to the chance to work on a pp engine yet. Red ones are nice for sure.

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