Casa 185 kit- new 66mm piston anyone?

[Pompeydave]

Hi all,

I've been running a Casa 185 kit with a BGM big bore exhaust (ceramic coated), PWK 28mm carb and BGM stator with a Kytronic advance/retard box, GP125 gearing and belt drive. It pulls like a train from low down and is so smooth with the belt drive its unreal. Anyway, all was going beautifully until a wrongly supplied gudgeon pin circlip parted company with the piston and wrecked the piston and bore the other week.

I've had it re-bored to 66mm and Langcourt engineering in Weston Super Mare can re-Nikasil the cylinder, but my problem is finding a 66mm piston. Casa don't sem to make them that big, and the only thing I can find that looks similar is a Mahle 2 ring piston for about £40 off eBay. It comes minus the port cut in the piston as per the standard 64mm Casa piston. Does anyone know where I can a piston to go straight in without modification, or is the Mahle 66mm item my only choice with me getting the extra port cut in it?

[ToBoldlyGo]

I've heard that certain motorcycle (wash my mouth out with soap and water) pistons will work. Got a feeling they were Suzuki, not sure.

[Pompeydave]

These look the same but I can't see round the other side to see if it looks the same as the Casa 64mm piston I already have.

http://www.ebay.co.uk/itm/311485198747?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Scooterlam]

Whats the crown hieght etc.

im not familiar with the casa kit but AF do Wossner in 66mm and will add windows, i have one in my ts200

[HxPaul]

The problem you have with boring the cylinder out to 66mm,is that you still have the 64mm cylinder head and setting the correct squish could be a problem.If you had sent the cylinder with new 64mm piston to langcourts they would have repaired the damage and re-nicasiled the cylinder to suit the piston.

[gaz_powell]

I have a Yamaha IT175 piston in a TS1 200 , straight fit but you need a 115/116 rod

[dscscotty]

I have a Yamaha IT175 piston in a TS1 200 , straight fit but you need a 115/116 rod

You'll need to run a reed valve with the IT piston or alternatively have the reed windows welded up ( not an easy task) . you could look at the mugello range which have a 66mm piston in their 198 which are standard 39mm compression height.

Also ensure the profile of the head is opened for the increase in bore size and matches the dome shape/ height of piston.

[gaz_powell]

my mistake I though the casa was a reed valve

what about a Suzuki ts185 - 2.00mm over size is 66mm ?

[HxPaul]

my mistake I though the casa was a reed valve

what about a Suzuki ts185 - 2.00mm over size is 66mm ?

Getting a Casa 185,64mm piston isn't a problem,but the OP has had the cylinder bored to take a 66mm piston.

[swissdean]

Sorry i can't help on the tech/piston side, but out of interest what are you getting as cruising speed wit your set up. I have a similar set up (delly 28mm vs kehin and chain vs belt) and have the BGM big bore but struggled with jetting so have put the ancelotti back on..if the BGM gives more mph I may invest in finding a shop to set it up properly..done all sorts and still struggle to get anywhere above 60 mph/100kph..thanks

[HxPaul]

Sorry i can't help on the tech/piston side, but out of interest what are you getting as cruising speed wit your set up. I have a similar set up (delly 28mm vs kehin and chain vs belt) and have the BGM big bore but struggled with jetting so have put the ancelotti back on..if the BGM gives more mph I may invest in finding a shop to set it up properly..done all sorts and still struggle to get anywhere above 60 mph/100kph..thanks

I have 2 scooters fitted with Casa 185 kits,both fitted with jetex carbs and KBA clubman exhausts.My top speed on either of these is just above 60mph.I dont think that these kits are built for speed but more for low down power and fuel economy (both of mine return in excess of 100mpg)

[Pompeydave]

Sorry i can't help on the tech/piston side, but out of interest what are you getting as cruising speed wit your set up. I have a similar set up (delly 28mm vs kehin and chain vs belt) and have the BGM big bore but struggled with jetting so have put the ancelotti back on..if the BGM gives more mph I may invest in finding a shop to set it up properly..done all sorts and still struggle to get anywhere above 60 mph/100kph..thanks

Pre blowup I was getting around 60 to the gallon, but I'm 18 stone and it was being ragged quite often so 60MPG is pretty reasonable I think. The bike wont do more than 60 flat out with a Casa 185 kit unless you play with it in a serious way- It's the perfect round town/suburbs kit, bas of low down grunt and a decent mpg but it won't win you any speed records.

[Pompeydave]

The problem you have with boring the cylinder out to 66mm,is that you still have the 64mm cylinder head and setting the correct squish could be a problem.If you had sent the cylinder with new 64mm piston to langcourts they would have repaired the damage and re-nicasiled the cylinder to suit the piston.

Yes, I found this out after I'd had it rebored .

[Pompeydave]

Whats the crown hieght etc.

im not familiar with the casa kit but AF do Wossner in 66mm and will add windows, i have one in my ts200

How do I measure the crown height? Is it from top of the top ring to the highest part of the piston dome?

[swissdean]

Thanks chaps for the info on top end/mpg...time for a rethink then

[dscscotty]

Take a look at mugello 66mm from cam Lam and other outlets, profile of head maybe different to CASA, but can be sorted by using a mugello head?

[Pompeydave]

I've sourced a Mahle 66mm piston as it looks very similar to the original. Just needs the additional port cut in it. The crown is slightly different to the stock piston so I'll have to get the head re profiled to match. It's away at Langcourt for re-nikasil plating now. Will post updates/pics as I go...

[Warkton Tornado No.1]

Are Langcourts aiming to achieve a finished size to suit the Mahle piston, as it sounds as if you still have it there with you…

Sorry if that’s a bit trying to teach “Granny how to suck eggs” but I figured you’d sooner be reminded that to achieve a match, the piston should be with them.

[Pompeydave]

No, they have the piston with the cylinder to allow it to be matched.

[Warkton Tornado No.1]

Post by Pompeydave » Fri Jun 17, 2016 10:44 am
No, they have the piston with the cylinder to allow it to be matched.

Good

BTW. I have Ø66 mm pistons that I never mentioned as they are single ring. Either cast or forged. Presumed you'd only want twin ring....