Jump to content

Vfr 1200 Camms And High Compression Pistons


Lionel

Recommended Posts

Hi has anyone ever had there cams cut to stage 2 and put in high compression pistons as well as gas flowed the head for v.f.r 1200 f.d.

if so please give feedback as well as advice. Thanks

Link to comment
Share on other sites

  • Member Contributer

Your bike's compression ratio is 12:1 (which is already high).

If you're serious about having some even higher compression pistons installed, as well as porting and polishing the heads, and having somebody grind you some hotter cams, you're probably going to need a full exhaust, a reflashed ECU, and intake work done as well. I seriously doubt you'll find someone (especially where you live) that has the ability to do that kind of work on a VFR1200 DCT.

You may want to start looking for another bike.

Link to comment
Share on other sites

  • Member Contributer
Link to comment
Share on other sites

  • Member Contributer

Not heard of anyone doing it, but VFR12 is 81mm bore as STD, if Honda have kept to their tried & true 17mm wrist pin, then CRF250 or CBR250 big bore kits with 82-84mm bore pistons could be used. I will assume if the liner tech is MMR like most others then you should be able to squeeze a 2mm over bore, but beyond that you will need to go up to 86mm to completely remove the MMR & replace the cylinder wall with Nikasil or equivalent. That would only be possible if there was enough wall thickness left !

Link to comment
Share on other sites

  • Member Contributer

No standard bike has a compression ratio of 12:1, that is a static compression which no engine used in bikes ever has, as cam overlap loses compression, so dynamic compression ratio is what you need to worry about, on standard pump gas, the max is around 8:1 dynamic, on super that can be taken to 9:1 ish.

You can read some info here http://www.visordown.com/workshop/understanding-compression-ratios/15453.html

Link to comment
Share on other sites

  • Member Contributer

I'm going by the universally accepted (and published) compression ratio. For the current CBR1000RR, it's 12.3:1. On my bike, it's 11.6:1.

Link to comment
Share on other sites

  • 3 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy.