| Author | Message | ||
     Steveford |
I think I already know the answer but are there any 10 over pistons for the Useless which retain the stock compression ratio? I've seen some 12:1s but that's not going to work for me. | ||
| Hughlysses |
I don't know about other sources, but I think Twin Motorcycles can provide them. | ||
| Steveford |
It looks like they're selling Wiseco. Has anyone tried a plus 10 Wiseco Sportster piston in their XB? | ||
| Phelan |
By the time you hone out the cylinders, buy the pistons, rings,etc, you're not far off from buying a 1250 kit that has thicker, stronger iron liners that actually stay in place in the cylinders, unlike the stock liners, which commonly shift inside the cylinders. The bolt-on NRHS 1250 kits have a 10.5:1 compression ratio, which is easily useable with pump gas. | ||
| Steveford |
That's probably the direction I'm headed. I'll do a compression test before I drop the motor on the old pile. I noticed today that acceleration doesn't seem to have suffered any. It's actually kind of speedy... | ||
| Natexlh1000 |
Tight rings = more friction. My friend used to race a snowmobile on pavement. He always told me that it would absolutely fly just before it popped. Of course it was a liquid cooled two stroke. That thing was terrifying! it would lurch to 85 miles per hour almost instantly and then just go that fast the rest of the quarter. | ||
| Ourdee |
Where would you go for a 1250 kit? | ||
| Ourdee |
Would a remap be required for the extra 25cc per cylinder? | ||
| Phelan |
The cc's aren't a big deal. I wouldn't use an OEM map with a 1250 kit because of the extra compression, but if you have an aftermarket exhaust and ECM tune, the difference shouldn't be enough to worry about the map. I used a standard Buell race map with my stage II heads, 1250 kit, and CAT3 cams in my first Uly build, and it was nearly perfect. I kept that setup for over 2,000 miles without issue, only changing it because I made other changes. (Message edited by phelan on November 29, 2015) | ||
| Falloutnl |
I bought a 1250cc kit from Hammer Performance (for my X1 Lightning) it was then remapped by Twin Motorcycles. Thing is absolutely blisteringly fast right now. | ||
| Phelan |
Both of my 1250 kits came from NRHS as well as other parts and work. My first build had 28 RWHP over stock, planning on more with the current setup once I get it broken in and dialed. | ||
| Portero72 |
Pardon my ignorance, but what's the benefit of the extra 50 CCs? Seems like a minimal jump in displacement. | ||
| Phelan |
The 50cc is more of a by-product. The significance is the complete kit with new cylinders that have thicker iron liners that stay in place better, as well as forged pistons with slightly higher compression, of which the dome shape in the case of XB12 pistons actually pushes the squished air back towards the spark plug for a more efficient burn, new chromoly piston rings, and overall much better ring seal. | ||
| Portero72 |
Better function, I see. Is there a performance advantage? | ||
| Phelan |
Yes, slightly, due mostly to the extra compression. 2-4% (Message edited by phelan on December 01, 2015) |
