Author Topic: Winter project, BBK  (Read 1171 times)

gsx600racer

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Winter project, BBK
« on: October 20, 2014, 07:23:22 AM »
I purchased the Malossi sport 70cc kit(317200). The site claims this will work fine with stock carb and exhaust and should be able to retain oil injector pump(supplied with larger jet for carb).  Sorta disappointed that the kit does not come with a new wrist pin bearing.(seems to be the case with all kits) I want to replace with new.

Looking for some feedback. Tips, tricks, things to lookout for. Would like to do it once and right.

I am not looking to break any land speed records with this mod. I do expect to see some acceleration and hill climbing improvements.

My goal is to get kit installed and break in with stock carb and exhaust and then tune variator/clutch setup. 

I understand that a larger carb/intake, performance exhaust, and variator/clutch tweaks will enhance the bbk performance.(future project)

Thanks in advance.

 



zombie

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Re: Winter project, BBK
« Reply #1 on: October 20, 2014, 02:03:54 PM »
The first thing you have to do is soften all the sharp edges in the cylinder.


Next is to set the end gap on the rings. I set the top ring to .002", and the bottom to .0035 - .004

Third is to set the squish. .005 - .010".
Order a couple BR9HSA plugs from Jiangwayne.com They are one step colder, and really help.

A malossi red contra w/ the malossi torsion controller, and 5-6 gram malossi or polinni rollers.

The best pipe I have found is the Scorpion (small one). Scooter alley in Hawaii., 24mm Oko flatslide carb, and the Stage 6 MK II clutch, and vented bell.

Since you are taking it all down to do the work a new set of crank seals will be a bonus. Any tiny leak effects the jetting, and you will have a constant battle unless you have new seals.
 
Hope some of this helps ya.

Forgot... Drill a pair of oil holes in the wrist pin bosses (piston), shave the skirts lower edge to 60*. That forces oil up between the piston/Cylinder wall on the down stroke.
You can also sand/polish the piston dome to prevent carbon build up. Top quality oil helps here too.
I use Golden Spectro 32 platinum.
« Last Edit: October 20, 2014, 02:08:18 PM by zombie »
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

gsx600racer

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Re: Winter project, BBK
« Reply #2 on: October 31, 2014, 03:41:22 AM »
Hi Zombie,

Thanks for the feedback.

Was finally able to free up the bench to get my scooter on. Been busy resurrecting a late 70's Batavus Regency moped for a friend. They don't make'em like that any more. Forget getting parts for them, not much left out there for them. Fortunately just needed carb/tank cleaning, new chain, head light bulb, and a lot of tlc.

I got the engine removed from scooter, removed head/cyl & piston and was surprised how clean they were.

I need to get another shopping list together, need flywheel puller, crank seals, and wrist pin bearing.
Till then I have plenty to do.   

zombie

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Re: Winter project, BBK
« Reply #3 on: November 18, 2014, 11:34:47 PM »
I bought one of those 4 way flywheel pullers for scooter engines... Guess whaT? They don't fit the ZX.
Get yourself one of those universal pullers, and a pair of proper bolts to fit the flywheel.

"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

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