Some Q's re 70cc kits

Hey guys,

I wonder if i can pick some of your brains, I cant come up with some detailed info and reviews on these and i know there's a sea of 70cc threads, but im looking for specifics between 2 kits here.

Im looking at this Polini 70cc sport kit,
http://en.scooter-attack.com/index2...l.php?s=&artnr=M319541&modell=92&l=navigation

and this Malossi version,
http://en.scooter-attack.com/index2...l.php?s=&artnr=M319541&modell=92&l=navigation

I see they say the Malossi doesnt get going as quickly as the Polini but has its own pro's. Do both kits come with all the gaskets to rebuild the head?
Have any of you used either and could share your opinions and recommendations? would you go for a different kit altogether?

Also, is that site a reputable one or are their any better sources for a kit?

And finally, whats the typical run in period for these kits?

I know I'll benefit from a few other upgrades aswell as these kits but priority at the moment is to get the bike running again, as its blown the top end and needs a complete overhaul anyway.


thanks in advance lads.


EDIT:
the bike is a liquid cooled Katana-R from 2002 carb'd (not injected) standard zorst for now but deristricted, as is the variator.

 

PS, I just checked the links and they keep going back to the Malossi one for some reason, the Polini to the bottom left if ya scroll down.

 

Hey,

thanks for the reply, wasnt sure if id trust the shop but i'll go ahead now,

 

Hi there and welcome!

I have personally owned both polini and malossi cast iron kits on a piaggio zip AC.

Both kits came with new gaskets and everything needed to install, they come with some stickers too lol.

I fitted my kits myself, and they are very simple to fit and setup if you have half decent mechanical knowlage. The instruction manuals supplied wernt the greatest to read but easy enough to understand, you should know what your doing anyway before trying to install a 70kit.

The polini kit was lovely. Once setting up the transmission and carb the performance gains were big! Loads of torque, turned my zip into a wheelie machine! Got about 58-60mph out of it with a few other bolt on goodies. Keep on top of maintenance and your'll see upto 10,000kms out of the kit, I got around 8-9k out of mine and I gave it a good thrashing.

Malossi kit was very simular, I actually only sold the zip a few days ago and fitted the kit a couple months before.
Ever so slightly less torque than the polini but revs slightly higher so my topspeed was 1-2mph quicker.
And its still running today so id say its just as reliable as the polini.

Oh and to add to reliability, with both kits they were as reliable as 50s no breaking down at all.

 

Thats the kinda info i need, there's nothing like a personal opinion.

thanks man, I think i might settle on the Pollini kit then. I'm not too bothered with top end speed as I'm more interested in keeping my front tyre clean, if ya get me. lol


Fitting it isn't a problem as Im a mechanic and had my first ped (yamaha MA50 ) at 10 years old so im looking forward to tinkering with them again. lol

I was just completing the order there and turns out they don't accept paypal in their checkout so i'll have to wait for a reply from them and see if they can do anything,

In the meantime I discovered I'll need some new reed valves too since one of the petals is slightly bent and causing bike to rev erratically as a result.

thanks again man, and cool forum, i think i'll hang around a bit more.

 

The polini kit is a great choice! And it "should" come with a set of carbon fibre reeds too, to save you ordering new ones.

 

Cool, that'd make things easier alright,

Im having problems getting through to scooter-attack though, they haven't responded to me emails so im fishing around for other sources at the mo, any reccomended ones? Ive come across pmtuning.co.uk and they have the Polini kit, but are they reputable?

Also, am i right in thinking the 99-04ish was a "Morini" engine and the later 05 etc were an Apprilia Di-Tech (with fuel injection, restricted ECU etc) Im fairly sure im right but wouldnt mind a bit if reassurance before o place an order.

thanks,

 

Thanks again man,
I thought I read that about them but wasn't sure if it was them, I went ahead and ordered it from scooter-centre.com as per links page.

Cheers,

 

as above, both are good kits, the polini is a bit more torquey that the malossi, which gives better bottom end power (acceleration etc.), whereas the malossi's power is a bit higher up, good for mid-range power and top speed. its up to you what you prefer.

both come with gaskets, circlips, everything you need to fit it.

 

Cheers for the info,

i went with the polini kit anyway and so far im quite impressed with the store, ive had plenty of emails from them to keep me up to date with the status of the order, and also from UPS to tell me its already in transit, (ordered yesterday). Im already looking at a load of other bits i wanna order from them like a bigger carb, exhaust etc etc (open to recommendations too. )

On the head kit though, do ya reccomend lubing the cylinder gaskets at all? or fit em straight as is. I'd usually give them a light coating to prevent it sticking to the head or crank case for future repairs/tuning but im talking much larger engines in my case.

 

my katana lc has a malossi 70 cc kit on it, my advice would be to get the carb kit and a yasuni r, and also a gear up kit. mine also has the malossi variator and clutch at the back. no gear up kit yet though, so stops dead at 55mph, but gets there very quickly. hope this helps

 

Thanks for the info,

I was gonna ask about the Yasuni exhausts actually, I think i might have a leo vinci one in the shed somewhere and was gonna stick that on. I'll look into the Yasuni though.


Going by your sig it looks like your bike is gonna be identical to mine, colour and wheels anf all. lol

 

So it all arrived in one piece today, took something like 4 days to land on the doorstep and im very impressed with the customer service from Scooter-Centre.
Oh and they sent me a free lanyard for me keys aswell.

The face of the new Polini Cylinder head wasnt the cleanest ive seen really, theres some poor casting marks on it and lots of excess material left in the edges etc. Im gonna get cracking with smoothening all those down and flatting them for a good seal before i get assembling it,

One question i have actually, Does anyone know what type of spark plug im supposed to use with this? looking from the inside, its a good 8-10mm shy of where it would normally sit in the original suzuki head and i cant imagine it would be a good idea to use the original plug under those conditions. I assume there's a longer plug used in these heads no? Im half tempted to use the original Suzuki head on it, its better made and I already machined it nice and flat. Looks like it'll fit fine too, and i wont a new plug.

 

Don`t use the original head on this kit.Part of the power comes from the fact it`s centre fire, higher compression and the squish band is matched to the piston crown radius.
Use the head supplied.
Plug? put a short reach (br9Hs) in there and if it dosnt reach the end of the threads it takes a long reach plug (br9Es).Most after market kits take a long reach plug anyway because of the better cooling (more contact area with the head).
I use a smear of Hi-temp copper flange sealant (Locktite 5920 ultra copper from Halfords) around the head avoiding getting any in the combustion zone.
Check the squish and on a 50/70 short stroke engine for road use you are looking at 0.7-0.8mm, adjust useing a different base gasket.
Torque head in a diagonal sequence.

 

My kits came without spark plugs because they used the standard plug from the 50 engine which was NGK BR9ES (piaggio engine).

 

Thanks for the tips guys,

I picked up that plug earlier, my original one was much shorter and this one worked a treat.

So the kit itself, I got it all together this afternoon no probs at all, I had the engine out of the bike anyway so it was a lot handier to work on. It starts up and has good compression but ive noticed theres a whrrrrrrr kinda sound going on, this same sound existed with the previous cylinder and seeing how bad that and the piston was, I attributed the sound to that.
I removed the water pump cover from the engine and started it again, looking for anything that might be causing friction in there and it all looks fine.

its running pretty erratic at the moment, when first started it'll rev up plenty and after a minute or so will die down and either run very low in the revs or completely cut out. This could be a carb issue and ive also noticed the mixture screw is all chewed up.

Anyone got any theories on what the "whrrrr'ing" kinda noise is?

 

Where is this sound coming from? And it will run shit untill you set it up. Upjet carb, lighter rollers etc.

 

It sounds me me like a friction kinda sound and its constant, I haven't pinpointed exactly where its coming from, I was up to my neck with babysitting and assembling the head so i left it for the time being.

It sounds very similar to the sound of a seized brake carrier on a car, that sort of constant friction noise if ya get me.

Im gonna pull everything both sides of the crankshaft and see if theres anything obvious going on.

as far as poor running goes though, its exactly the same now as it was before the rebuild. I've never actually ran this engine properly as it was a replacement for the bikes original one after a heavy whack snapped the exhaust mounts off the crank case and then it sat in my shed for about 4 years. Im thinking maybe replace the carb altogether as the adjustment screws are a bit corroded looking and one of them is stripped. (an excuse for a larger carb huh. )

Oh, now that i think about it, I also sealed up the carb and its manifold with gasket sealant just to be sure there was no air seeping in there and causing the erratic revs but its still the same.

I appreciate the help so far, I'll post back with any findings when im finished stripping out the ignition/variator etc.


EDIT: forgot to mention, the sound is happening with the bike stood still, so its not brakes, final drive etc etc.