Didn't a forum member in Kansas or Oklahoma end up with your 733?

 

The DS was the first quad ever to have aluminum/nikasil cylinder, now everybody is doing it. it was in some dirtbikes before the DS, but DS was first quad and now all the new 450's are sporting it like their dirtbike brothers.

I think HPR's cylinder comparison is refering to some of the bigbore kits available that use steel sleeves, like those offered by sam coe and tvi, and was not meant to mislead about the stock jug.
as far as the reliability comment # 3 about slipping, well the millions of factory sleeves installed in all motors both bike and quad alike prior to the creation of the DS didn't seem to have any problems, although point #7 about strength does try to validate the reliability statement.

 

I have sleeves in my twister 20mill but the billet jugs are designed around them for strength.

 

Hightower,

I'm trying to figure how much to reduce 11.5:1 CR JE piston on Ebay to 10.5:1 with this site:

http://www.csgnetwork.com/compcalc.html

To do it without complex math for the unknown variables, You can just measure water in cylinder head chamber , and put plastic putty on piston dome and measure water that way. I'll shoot for 10.5:1 (1 CR difference) with rounded corners to reduce to 10:1, so anywhere in between those two would be perfect for max reliable performance with pump gas. If I verify piston dome with plastic putty after polished down, it should take rounded corners into account precisely. Flattening the dome with rounded corners seems to be method most wrenches use on customized performance pistons. I'll have to wait until open engine up and get parts to do it though.

--->>>Would you know the thickness or difference between a 1 CR thick base or head gasket for sanity analysis? The piston crown total height lowered should be between one and two 1CR gasket thickness if rigid AL, less if 'crushable' 1 CR gasket (maybe measure % thickness difference of new and my crushed head gasket?).

It took a while to logically figure out how to do it without uneeded complex math, which would not accound for rounded corners precisely.
This isn't rocket science to you, a skilled Journeyman. But its satisfying to for me to obtain OEM reliable systems at better than OEM quality/performance and at a reasonable cost. Its harder than it looks, lol.


Thanks Hightower!!

 

I do not know gasket thicknesses, I have never had one of the thicker ones in hand to measure.
stock compression is 9.7:1, going to a 10:1 seems a bit futile. anything less than 11:1 to me does not seem worth any kind of bother.
you can get aftermarket pistons in stock compression if you want forged instead of cast, maybe not for the ebay price of $160 but they do exist. or you can order a custom piston in whatever compression you want.
if you have the machine tooling and skills to turn the piston yourself in the lathe, and are confident in your math, then I guess there is a money to be saved but if you are gonna have a shop turn it for you, you might as well buy what you need from the getgo.


and seriously yjacket, you need to stop all this nonsense talking like "This isn't rocket science to you, a skilled Journeyman", you throw that stuff out all over the place and its unnecesary, silly, and borderline annoying, spoken with all due respect of course.

 

To reduce the compression on a stock bore/stoke:
11.5 to 10.5 Increase base gasket from .020 to .053
11.5 to 10.0 Increase base gasket from .020 to .073
Since base gaskets come in .020 / .5mm size, you will have to decide on what you want to do.

Like Hightower said, whats wrong with running 11.5?
Or are you living where only 89 octane is available?


OMR .

 

Hightower,

http://cgi.ebay.com/ebaymotors/JE-Hi...QQcmdZViewItem

----updated part link----------

The above is what I was talking about. $160 JE forged AL for 11.5:1 CR that shows up on ebay every week or so (or just send message to JE piston Ebay seller). It is the same CR that new F650's run, but they have lower rpm problems that are compounded by EFI flow properties (for carb designed engine - horizontal intake manifold). So your 11:1 CR may be a much better suggestion, now that you pointed out how yours ran well with 11.5:1 at optimal sea level altitude.

And polishing down dome 1/2 CR makes it a simpler job. In fact, Millennium has CNC tooling, so I could send cylinder and piston to verify cylinder walls are proper surface/film specs, get piston dome reduced, and gap rings proper. Race tolerance system tuning my top end makes me feel more confident.

I appreciate your suggestions. You helped me nail down the CR sensititivity range, without compromising on the 'safe' side with reduced performance and gas mileage. Glad you have a DS650 with JE 11.5:1 CR piston experience, lol.


Thanks!

 

Thanks OMR!

On the road, you never know what's available away from the expressway.
I would just like to have CR notched a little closer to OEM parameters.
11.5:1 has problems with EFI F650 Rotax and ALSO ran good with Hightowers DS650 at sea level.
So it is close but not a proven touring range solution through different altitudes (6600' Max, east US).
The F650 EFI is probably not a 'forged' 11.5:1 CR piston, so it gives me a little more confidence in 11:1 CR forged piston solution.

Could you please post the base gasket calculations for 11.5:1 to 11:1 (1/2 CR reduction)?

11.5 to 11.0 Increase base gasket from .020 to .037 - ???


Thank You


Also, I found out 2004 Dakar F650's started installing Shim under Tapet springs sets for another HD valve spring alternative. I'd need to call BMW parts man to check price availability. I saw on Chain Gang forum, so would need to verify F650 model as well since couldn't find in BMW fische PN's.

 

This motor has been setting in Randall's shop for several months.

If someone tries to machine the dome on a JE 11.5:1 shelf piston you are asking for trouble because they pocket mill the bottom side of the piston to create a hollow dome for weight reduction purposes. You're going to break through or at best have a very thin spot in the dome. Good luck!

Been alot of sleeve talk lately. Sleeves work fine in cylinders that were designed for them. SLEEVES WORK FINE IN CYLINDERS THAT WERE DESIGNED FOR THEM. CAN ANYBODY HEAR WHAT I'M SAYING? The regulars can debate this till the cow's come home...I could care less but for the new guy that cant afford to waste his money I'm here to tell you stay with a stock bore if you cant afford a good big bore. You will make MORE horsepower with a smaller ROUND cylinder than a big egg shaped cylinder. I have had countless "I got a good deal" sleeved cylinders in my shop and they ALL look the same. Just measured one today with a very few hrs of run time on it. The guy said I just cant figure this thing out...it just wont run, it don't make any power. Anybody care to hear the numbers??

 

yjacket2001-You are either the smartest SOB on the planet or the best Bul#%%itter,i cant tell which.