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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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Discussion Starter · #1 ·
Hi lads,

I got my hands on a TurboKit exhaust which looks like a Polini 6.2 kind of pipe. The seller could not tell exactly, but I was hoping it might fit my cag because here in the EU go-fast exhausts are all sold out. Also no luck on the China websites for faster cag pipes, so this is my best bet.
No usefull info on the website of this manufacturer, but the pipe looks like good quality.

So the idea is to try and fit it without cutting it up and to see if it will give me some gains. My setup now is a BB kit with 2-pc head, 2 shoe clutch, stock pipe with protruding bit removed and stock carb. It runs 28 mph on 6-68 gearing at 9700 rpm atm.
Did a mock up and it could fit if I remove two of the cooling fins on the cilinder head. Hopefully it will not give too much cooling problems. Hoping to get it fitted this weekend...

test fitting
Wheel Tire Crankset Bicycle frame Bicycle tire


Small issue clearing the cilinder
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Test fitting, here the pipe is too much outward. But it looks like it will fit.
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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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53 Posts
Discussion Starter · #4 ·
Looks great if that is a PBU head I would not modify it I would get a different head simply because of the rarity of the part.
Mmm, no it is not a PBU head kit. It is China made. However, all new head kits look different to this one indeed.
Will start grinding away tonight.
 

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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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53 Posts
Discussion Starter · #5 ·
I took the Dremel out and shaved off some cooling fins and made a new bracket for the pipe. It just sits clear of the cross bar on this L7 frame. Now to put on a new fuel line and see what this pipe does on this setup, weather permitting.

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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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53 Posts
Discussion Starter · #6 ·
So I also had a peek inside the cilinder with the exhasut off. I notice that there is about a millimeter of piston still showing at BDC. Now I don't have a clue about porting and timings, but would it need raising the cilinder to have it open completely? Or would that just mess up port timings and my squish?

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So I also had a peek inside the cilinder with the exhasut off. I notice that there is about a millimeter of piston still showing at BDC. Now I don't have a clue about porting and timings, but would it need raising the cilinder to have it open completely? Or would that just mess up port timings and my squish?

View attachment 161232
Don't care about this mm. Did you even measure you squish?
 

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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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53 Posts
Discussion Starter · #10 ·
Ok, thanks for the info guys. Indexing the piston sounds like marginal upgrade, only to do if other mods have been done.

I installed this head kit many moons ago. Like 2006:) and it was my first cilinder and piston swap. Pretty sure I measured the squish, but I can't remember what it was.
What I do know that it feels like a lot of compression when pulling the starter cord, especially compared to the stock cag.
It ran great all those outings on the karting track back than, so I will leave it for now.

Out of interest; how much should I widen the exhaust port? Also 1 mm? Should it be tapered or straight?
 

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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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Discussion Starter · #12 ·
Alright, I will do so when its time to take the cilinder off.
How many hours would you run these engines before you replace the piston or piston rings normally?

And what exactly are the feed ramps? Sorry for dumb questions..
 

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I run them until they start losing power or they get so clickyclacky it sounds like its going to blow it's always the same problem piston rings and cylinder wasted, wrist pin bearing, clutch side crank bearing.

These engines are so inexpensive sometimes it's not even worth rebuilding and you're better off getting a new one and starting with a blank canvas 60$
 

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What's your poison? Mine is 40:1
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Sorry didnt see this before. Well, I run full synthetic, with a little trans fluid, (detergent keeps them clean) and anywhere from 40:1-50:1. Depends what the individual motor likes. I have not kept a motor long enough yet to go through possibly three times. I've done one top end rebuild on a couple engines.
So maybe, I have never tried 60:1.
 

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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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Discussion Starter · #17 ·
Well, between wrenching on my C1 it was finally decent enough weather to try the cag with the new TurboKit exhaust. The pipe gives a good improvement in midrange. It really pulls stronger, so I am curious how it performs on our local track. Did not see much more rpm's showing on the tach, but the GPS on my cell phone indicated an increase to 32,3 mph. So thats pretty decent as far as I am concerned.

Throtlle response is good and it pulls nice with WOT. At top speed it felt like a little sputter/hick ups and it keeps running rather high in idle after full throttle before it returns to normal. I think it wants a slightly bigger jet..
 

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Lucky 7 with BB head kit, 2-shoe clutch w \zocchi springs, flywheel mod, lift-plates
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Discussion Starter · #19 ·
Finally had the chance to run this setup at the track with my son. He was slipping with his feet of the pegs exiting the pit, after having ridden the stocker before this one. So it pulls very good from low down, which is nice at this short and twisty track.
We'll keep it like this for this summer and just run it. As for the winter time I will dig up the 4 petal reed kit and look for a matching carb. Curious what gains that might give.
 

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Sorry didnt see this before. Well, I run full synthetic, with a little trans fluid, (detergent keeps them clean) and anywhere from 40:1-50:1. Depends what the individual motor likes. I have not kept a motor long enough yet to go through possibly three times. I've done one top end rebuild on a couple engines.
So maybe, I have never tried 60:1.
trans fluid eh? ive never heard of that one before. Does the detergent tend to ward of deposits in the exhaust port as well, or mainly just the fuel system?
 
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