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Gazz81
07-20-2014, 12:57 PM
Ive come across a 2nd hand big bore kit that I think is reasonably priced, it would appear to be a genuine reason for selling, however I was a little concerned when the seller said there was 10 base gaskets to get the barrel to the correct height. Is this normal??!!!!

Zav
07-20-2014, 01:18 PM
I've seen that and not brought it for one reason it's a race kit needs new rings every 500 miles new piston every 1000 mile and a redone every 1500 miles

Gazz81
07-20-2014, 01:23 PM
Are we both talking about this?

http://www.ebay.co.uk/itm/191255055165?ru=http%3A%2F%2Fwww.ebay.co.uk%2Fsch% 2Fi.html%3F_sacat%3D0%26_from%3DR40%26_nkw%3D19125 5055165%26_rdc%3D1

I'm not worried about the lifespan, I probably wouldnt do 500 miles in a year!

Zav
07-20-2014, 01:30 PM
Yep that's the kit but if get squish wrong your fucked

Gazz81
07-20-2014, 01:34 PM
I'm pretty used to rebuilding my motocross bikes so I reckon I'll be ok. Whats the worse that can happen? A few quid down the drain and the need for a 2nd hand motor!!

Zav
07-20-2014, 01:38 PM
The piston will hit the head what will destroy the piston head and barrel then eather the crank will snap or the crank will stay intack and crack the cases

Gazz81
07-20-2014, 01:41 PM
Yep, so new engine. That's fine I can live with that.

Zav
07-20-2014, 01:46 PM
Buy it then

Gazz81
07-20-2014, 02:33 PM
I have! Hopefully my next post won't be a wanted for a new engine!

Zav
07-20-2014, 02:36 PM
I have! Hopefully my next post won't be a wanted for a new engine!

Well that kit should kill a stock crank within 20 hours of use

Gazz81
07-20-2014, 02:37 PM
Ok, so crank shopping next then.

Gazz81
07-20-2014, 03:13 PM
Has anyone ever had any success with shot peening a standard crank?

Gazz81
07-20-2014, 05:18 PM
This one looks quite good?

http://www.pedparts.co.uk/product/2282/stage6-hpc-crankshaft-12mm--minarelli-am6

Zav
07-21-2014, 01:59 AM
It's also more money

the Doppler endurance is the best standard stroke crank out there and it's only £100

Gazz81
07-21-2014, 02:48 AM
Cheers Zav, I'll check it out.

Gazz81
07-21-2014, 02:56 AM
Right, I take it this is the one? http://www.adrenalin-pedstop.co.uk/p/Doppler_ER1_Endurance_crankshaft_for_Minarelli_AM3 456_engines-2016.aspx

Looks like my plan of get it on the road quick has gone out of the window! Might as well do the whole lot ready for next summer!

apriliamandan
07-21-2014, 10:58 AM
Yep that's the kit but if get squish wrong your fucked

Come on......

Brilliant high end cylinder kit, will rev to the sky and back! Will need a good pipe and carb to get it running correctly. Should last many thousands of miles if treated in a reasonable manner.

Gazz81
07-21-2014, 11:08 AM
So the kit gets a thumbs up then! I will order the doppler crank and mains next and I reckon Ive got a spare 38mm Mikuni from my mx bike in the workshop!

apriliamandan
07-21-2014, 12:19 PM
So the kit gets a thumbs up then! I will order the doppler crank and mains next and I reckon Ive got a spare 38mm Mikuni from my mx bike in the workshop!

Big thumbs up for the Crank too!

Gazz81
07-21-2014, 12:22 PM
Cool. I couldn't find my spare mikuni, but I did find a 28mm keihin from a Kawasaki kx 80, should be ok?

apriliamandan
07-21-2014, 05:08 PM
Cool. I couldn't find my spare mikuni, but I did find a 28mm keihin from a Kawasaki kx 80, should be ok?

Should be mental!

Zav
07-21-2014, 05:15 PM
Should be mental!

Till it goes pop

not really just make sure you get the squish right or it will go pop or be really underpowered

Gazz81
07-21-2014, 05:27 PM
Till it goes pop

not really just make sure you get the squish right or it will go pop or be really underpowered

What should I be aiming for?

Pranja
07-21-2014, 05:33 PM
I think that 28 mm is too big for RS 50-even with BBK. 21 mm should be sweet spot.

Zav
07-21-2014, 05:33 PM
Non one knows till you get the kit and hope to go it still has all the paper work as it can range from 0.7 to 1.5 get it too close it will go pop get it too far off it won't rev right and would prob not start or. Run at full power

Zav
07-21-2014, 05:35 PM
I think that 28 mm is too big for RS 50-even with BBK. 21 mm should be sweet spot.

My road 70cc kit had a 24 mm

af1s 50cc race bike has a 28mm and that kit he has brought is classed as a full on track race kit so 28mm in my eyes is too small 32mm would be better but 28 should be okay

Gazz81
07-21-2014, 05:36 PM
from their website

KIT HEBO MANSTON RACING 70cc PATA NEGRA LEVEL OF PREPARATION: HIGH OR RACE ONLY AVAILABLE SPARE PARTS FOR THIS KITS.


MADE BY : ALUMINIUM
Nş TRANSFERS: 6 , LEAK TRANSFER WITH CENTER SEPARATOR
HEAD: 2 PC, HEAD MADE BY COPPER
PISTON: GRAPHITE RACING WITH 1 RING ONLY D. 47,60mm
CARBURETOR RECOMM.: 28/30mm OKO-KEIHIN
EXHAUST RECOMM.: YASUNI R3, SCR RACING LINE 70 O METRAKIT PRO RACE 70cc
CRANKSHAFT RECOMM.: METRAKIT PRO RACE, BARIKIT RACING, BRK O AIRSAL X-TREM
IGNITION RECOMM. SELETTRA DIGITAL O PVL DIGITAL

Pranja
07-21-2014, 05:46 PM
Ok, I didn't knew that. But how some 80 cc and 90 cc recommend 21 mm carb?

Zav
07-21-2014, 05:58 PM
Ok, I didn't knew that. But how some 80 cc and 90 cc recommend 21 mm carb?

Because there low quality kits with rubbish ports for example the top performance kit I have now says run a 24mm but i prefer the 19.5 as I get good low end power so it don't rev as high and saves a lot of fuel but if wanted more power and revs but loose reliability I could run a 24 mm to 30mm and it would still run perfectly but it woudl be very sensitive toweather changes where as with my 19.5 mm I can run a pod filter and not have to worry at all starts all weathers hot or cold and will run all day happily in rain and sun as I said in another thread I've been in rain this weekend what flooded the road up to my feet and the bike still ran fine even with my pod filter

I've ran a standard derbi engine with very minor port changes and ran a 21mm and arrow exhaust and it ran amazingly good lots of power and very good high rpm I even saw 70mph once or twice with just them mods

apriliamandan
07-22-2014, 04:34 PM
Tuning is all trial and error...and a lot of fun!

Gazz81
07-22-2014, 04:54 PM
Exactly, I spent a very long time tuning my 125cc MX bike and its so much fun to ride, I would like to think its around the 40bhp mark, that would be very nice, but its all trial and error.