Everyone talks about the 720 and how fun they are. They are also concerned about the reliability. What are the reliability issues? From what I've read here is mainly head gasket problems. I see that Pami has a new cylinder for a 720 but I didn't see o-rings for it. Why do you suppose they stopped at 720?
I was thinking about making a Nicasil plated billet cylinder with o-rings. Then I thought, as long as I'm making a new cylinder why not make it even bigger? My first idea was an 800. Then I started looking for a piston and so far only found a 108mm. That would be a 760. I'm not looking to be a king of any hill. I just want to build a nice reliable motor that is fun to ride. I would love to hear any opinions about this idea?

 

What piston were you looking at?I only know of the Pami 108mm?
The Pami 108mm pistons are set up for a stroker crank(830cc kit),meaning the piston pin is higher in the piston!
If you try using it,you will need a longer rod,Pami has longer rods availible,none that will put you exactly right where you need to be(what i found was one size 2mm longer would put me just under,the next 4mm over would put me a little over..Now you could change base gaskets to get the needed result,that would also change the cam timing(then the cams would have to degreed)The 4mm over (with the added base gaskets)would also make the cam chain pretty tight.
The other option woul be to stoke or destroke the crank to the desired amount..Pami has an assortment of different crank pins that might make this happen..I havent looked into this area yet...Destroking a little with a longer rod,might make this a real runner,then you would end up with something smaller then a 760cc though.

Also the 2 Pami 108mm pistons that are availible are 11.5:1 and 14:1...For a stroker.
In my research..the 14:1stroker piston...put with a stock stroke would become close to 11.5:1....

Maybe the easiest thing to do,is order a new piston from JE with you own desired spec?

I think it would also be cheaper to buy a pami cylinder 108mm and make the piston?
Also the pami cylinder has enough added meat,so o-ringing isn't nessasary

Of course I would think with any 108mm bore cylinder...the cases will have to be bored to accept the new cylinder

Just my thoughts....

Jeff

 

I've just thought of this project a little while ago so I don't have much research done yet. I was thinking of a Harley V-Rod piston. I havn't seen one yet so I don't know if it is close. I also considdered a JE custom. I figure if I make my own cylinder, I can make it any length I want. Then I just have to find a chain to fit. That may or may not be too hard. I was unaware of Pami's 108 piston. I wonder why they don't put that in there cylinder. The Pami cylinder costs 1000 euro, right? I think thats around $1100 or so. I'm not saiyng thats a rip but I would rather make my own. Expecially with shipping. Like I said, I'm just kicking it around right now. I'm bored and need a project. I appreciate your input and anyone elses.

 

Halfliter I have been thinking along the same lines lately. Build a billet cylinder and have the nicasil coating put on. But if I go to that much trouble I think I'm going with a 111mm bore. Match that with the 7mm stroker I'm having built would net a cool 871cc's. I think I'm going to run the stroker with a stock bore or maybe a 102 on the stock jug for right now and do the billet project when I have more time.

Nice looking work on the LT pipe! I KNOW that took a while.



MrHorsepower

 

i'd like to see a high reving huge bore motor (not too much stroke) with a big turbo such as a garrett GT20.

 

what's the biggest bore possible, even if cases need to be welded to relocate studs? 114mm to 120mm?

 

for the price of that, couldn't you just put in either a snowmobile or streetbike motor with turbo???[img]i/expressions/face-icon-small-smile.gif[/img]

 

Thanks for the compliment on the pipe. That was the second pipe I made. The next one was for the banshee project. It took about the same time for two as for one. I'm getting better.

As for the billet project, yes Bigslim, for the time and money it would be better to put a sled motor in it. In fact, an 800 single is not going to be the greatest motor anyway. A turbo on a stock 650 would be a better choice. It would be fun to make though.

MrHP, do you know where to get that 111mm piston? That is what I'm looking for. Other than finding a piston, I don't see anything real difficult. Is there some problems you think I might run into? I don't think vibration will be an issue. A cool 111mm piston will probably be lighter than the stocker.

 

[img]i/expressions/face-icon-small-happy.gif[/img]

You have my attention......What would a 7mm on a stock cylinder give me? If I match this up with a super light, stock size piston, would I see a little increase in the 300 foot drags?

Would the case have to be trenched out for a 7mm? What about the counter-balancer, would it be in the way?

What about this 111mm on a de-stroked motor, would my times come down in the 300 foot drags?

Give me some opinions, please

DuneDevil

 

related posts by wickedds:

billet head crank cylinder

Billet head crank cylinder