KTM ATV HQ Forums banner
1 - 20 of 23 Posts

· Registered
Joined
·
134 Posts
Discussion Starter · #1 · (Edited)
I wasn't sure if there was a picture of the stock SX450 total piston weight including wrist, rings and clips... anyway, pretty light assembly for 97mm stock compression...

Feel free to add if you have weights on other KTM pistons....

Scale Postal scale Light Record player Kitchen appliance



Thanks to Bill....
Wiseco 13:5:1 piston with wrist pin and clips 332.2 grams
CP 13:5:1 piston with wrist pin and clips 335.5 grams


Thanks to Nick...
Stock piston - 12.5: Compression 271.39g (piston, rings, circlips) + 68.86g (wrist only) = 340.25g
Baldwin (Wiseco) 14:1 Compression - 285.45g (piston, rings, circlips) + 69.38g (wrist only) = 354.83g
CP Piston (new forging) 13.5:1 Compression - 263.24 (piston, rings, circlips) + 73.72 (wrist only) = 336.96g

Thanks 997TG3...
Stock 505sx Elko piston with rings = 298 grams
Stock 505sx DLC coated wrist pin = 79 grams


Thanks Harry!
505sx Wiseco 12.5:1

-just the piston= 275 grams.
-rings= 15 grams.
-wrist pin= 65 grams.

Pro-x rod with the big end= 740 grams.
 

· Registered
Joined
·
134 Posts
Discussion Starter · #3 · (Edited)
well, great question! I hope to see some participation from others and weight their pistons and provide input in this thread over time....

My design is in progress so hopefully i will be able to compare at least one other option soon... :)
 

· Registered
Joined
·
134 Posts
Discussion Starter · #4 ·
well, getting a bit more interesting....

97mm 12.5:1 stock piston without wrist, clips, and rings weights 257.6 grams...

vs.

97mm 12.5 JE Pro piston without wrist, clips, and rings weights 256 grams.....

Advantage- JE with features and price...

We'll have to look into CP Pistons, Wiseco's, then finally some high compression pistons too ;)
 

· Registered
Joined
·
880 Posts
Wiseco 13:5:1 piston with wrist pin and clips 332.2 grams
CP 13:5:1 piston with wrist pin and clips 335.5 grams
 

· Premium Member
Joined
·
294 Posts
Easiest way to hit a very reliable 60hp without race gas: Swartfagers head, stock piston, ktm bills pipe, vortex cdi, 2010 intake stiffner, remove the screen from the intake. I ran that setup last year and it made more power than any mx racer needs 60hp, 37lbs (my head was decked so I had to run race gas but he can not deck the head and the loss in power would be very little)...I tried web cams but I liked the stock cams over the web cams but I know others that prefer the web cams. I've heard allot of good things about DRG (from very reliable sources) but I've never ran his stuff and I know swartfagers head worked great for me.
 

· Registered
Joined
·
134 Posts
Discussion Starter · #9 · (Edited)
Easiest way to hit a very reliable 60hp without race gas: Swartfagers head, stock piston, ktm bills pipe, vortex cdi, 2010 intake stiffner, remove the screen from the intake. I ran that setup last year and it made more power than any mx racer needs 60hp, 37lbs (my head was decked so I had to run race gas but he can not deck the head and the loss in power would be very little)...I tried web cams but I liked the stock cams over the web cams but I know others that prefer the web cams. I've heard allot of good things about DRG (from very reliable sources) but I've never ran his stuff and I know swartfagers head worked great for me.
Dang man.... i really wish my PISTON thread wasn't trashed about porting and cam preferences... Lets try to keep everything on topic... thx.:confused:

not trying to be a jerk about it, but i was hoping that site members could benefit from this technical information on KTM piston options... anyway, I'm happy that you are pleased with your setup, but were you going to provide thread topic information about pistons (other than stock you have) but forgot in your post?
 

· Administrator
Joined
·
4,264 Posts
chad, it would be worth discussing pistons with Dustin Swartfager, he was getting several specials made by CP to his specs, they went through allot of R&D on getting setups that didn't crack early in there life cycle.

He also found problems with skirt collapse on the aftermarket pistons where as the stocker stayed "true" to size. A related problems was the cylinders going out of round at the bottom. Fix seems to be to resleeve, Thumper Racing has this down

Whats your opinion on ceramic coating of the piston crown ?

I really like the coating KTM put on the stock gudgeon pin, apparently you can shorten the stock pin to fit the wiseco piston ?
 

· Registered
Joined
·
134 Posts
Discussion Starter · #11 · (Edited)
Im a CP/JE dealer and they have not shared any difficulties, issues, or concerns about KTM piston cracking or folding...

Its possible that the issues that you described are not as common as a few believe on this site,...

In fact, I'd bet that the isolated claims described and the false claims of defective products on this site have being investigated and deflected towards some persons custom design approach...


To answer your question: Im not a fan of the crown coating feature in dirt piston applications..


Anyone got any real piston data they wish to add, or is there previous record of information posted in a previous thread someone could share? Thx.
 

· Administrator
Joined
·
4,264 Posts
Chad, Dustin shared allot of data with me, it's not my place to hand that info over. It was during this information exchange that it was found that the KTM cylinders can develop a taper at the very bottom that also allows the piston to rattle at BDC, skirt collapse follows.

Thumper racing has also observed the out of round lower cylinder skirt issue.

What was interesting was that the stock piston retains its shape where as the aftermarket pistons did demonstrate measurable skirt collapse.

there is an informative post over on KTMTalk on this issue, it relates to the varying alloys used in piston construction. the OEM KTM material is very stiff but will crack with time - the dreaded crown crack. 99% of people get good life and no problems, it;s the ideal OEM product

Aftermarket uses a different alloy blend, it is theorized that this is possibly why skirt collapse occurs but the crowns stay good (no cracking). Most serious racers change out pistons at very short hours and don't have "life" problems.

I can tell you that both Wiseco and CP used allot of Dustins design improvements from his early testing in updating their products early on. these guys where racing the SX from day one it came out at a national level and really pushed the engines "limits'.

I'll search out the various threads.
 

· Registered
Joined
·
134 Posts
Discussion Starter · #13 · (Edited)
OK, I'm not suggesting that opinions were not shared, I'm saying the issues are not related to Aftermarket piston designs, but more to another issue....

As for the data, well again.... what kind of data was shared as to the source behind his custom designs? or was the information just speculation....

Is Dustin a CP Dealer? If so under what business name, or did he just pay by credit card.... I recall Dustin calling me a while back asking for me to port a head for him while he was with Baldwin... I declined because I didn't want to share port techniques... real glad I didn't since now Dustin'c customers are promoting his services in a technical piston thread....


its cool. thx. Merry Christmas...
 

· Registered
Joined
·
202 Posts
I posted this in an old thread almost 2 years ago..........


I have 3 pistons in hand so I took them to work and put them on the scale. Here are the findings:

Stock piston - 271.39g (piston, rings, circlips) + 68.86g (wrist only) = 340.25g
Baldwin (Wiseco) 14:1 Compression - 285.45g (piston, rings, circlips) + 69.38g (wrist only) = 354.83g
CP Piston (new forging)
13.5:1 Compression - 263.24 (piston, rings, circlips) + 73.72 (wrist only) = 336.96

The stock piston had about 5 hours of use and the Baldwin piston had about 20 hours use. The CP piston was brand new. The Baldwin piston had some carbon on the dome but even if it was completely clean, I dont think it would make much difference. Clearly the CP has the advantage over the 3.​
 

· Registered
Joined
·
134 Posts
Discussion Starter · #16 · (Edited)
Wow- Thanks a lot Nick!! i really appreciate you and Bill volunteering your information... You both are good eggs!! :)

depending on other variables such as side load pressures at BDC from the associated rod angle, it could cause premature wear and havoc on piston skirts, but typically its magnified when piston features are omitted.
 

· Premium Member
Joined
·
1,399 Posts
Would you like XC piston weights also? I have a CP 13.5:1 laying around.
 

· Registered
Joined
·
134 Posts
Discussion Starter · #18 ·
sure, we can add a category for XC...

or even the admin could easily split threads if they think its best...

thx!
 

· Registered
Joined
·
544 Posts
Stock 505sx Elko piston with rings = 298 grams

Stock 505sx DLC coated wrist pin = 79 grams
 
1 - 20 of 23 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top