I'm looking to build my EX motor up to a 440 sometime soon. Right now, my motor has a Curtis Sparks X-6 full system, Wiseco 11:1 piston, and XR cam. I am looking for the best 440 kit. I want as much reliability, and power as possible from the 440.

Is there an awesome pre-assembled kit out there? Or should I piece one together? Thanks a lot.

 

If I had to do it again I would go with 88mm piston (426) don't bother with the 440 (89mm) The difference in power is not noticable. You might actually have more power cause some of the 440 kits require the head to be machined to be a tru 11:1.

 

Is the IMS stuff a worthwhile buy? Also, should I stay with 11:1, or should I go higher on compression with the bigger bore? Thanks.

 

I've been out of MX racing for about a year. [img]i/expressions/face-icon-small-sad.gif[/img] SO, I'm feeling lost now with all of the new parts and manufacturers out there. I'm badly wanting to return now. I miss the heated competition, the exercise, and I miss the sport itself.

Now, with the IMS big bore parts, what else would be a wise performance choice? Port and polish? I also am thinking about upgrading my TCS shocks. What would be a good idea to do with them? Thanks.

 

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Anyone got any thoughts? Thanks.

 

It dosent really matter who you get the "kit" from. 11:1 compression is realiable but if you want to go faster bump the compression up. A port job and some bigger valves and a carb would help out a lot more.

 

Have LRD or another GOOD machine shop do it. the 400ex cylinder will actually square up when torqued down. LRD uses a jig to prestress the cylinder to round so it is round when you actually bolt in on to your case.