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post #41 of 113 Old 11-20-2012, 12:54 AM
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Quote:
Originally Posted by BBRMotosports View Post
Got all the parts I need today. Got the new rings on and piston and cylinder installed. Now I just need time to do the head work.

go on bbr,
i really enjoy this thread. but please more info!
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post #42 of 113 Old 11-24-2012, 04:55 PM Thread Starter
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What kind of info do you want? I havent had time to start working on the head. Hopefully next week.

2011 CBR250R, Modded 84 honda spree, 2013 CBR500R 2014 Grom

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post #43 of 113 Old 11-25-2012, 08:23 PM
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Thanks for documenting you mods! I am thinking about doing some similar ones this winter. Had you considered doing a Bore up to 297cc with a JE Piston? HONDA - 2011-2012 CBR 250R - JE Pistons

Keep up the good work!
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post #44 of 113 Old 11-25-2012, 08:50 PM Thread Starter
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I don't want to change the bore but If I knew JE made a higher compression piston I would have went that route. I emailed them a while back and they told me they wernt going to do anything with the 250. I wonder how much the piston kit is.

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post #45 of 113 Old 11-26-2012, 01:15 PM
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Not sure the price for the std bore piston with a slightly higher ratio but the 297cc Piston, 11.0:1 ratio is $205.52 (Piston, rings, piston pin and lock ring).
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post #46 of 113 Old 11-27-2012, 09:26 PM
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I think it's cool and trying to improve performance on the model. I know sometimes alot of motorcycle manufactures don't release the FULL amount of performance of the engine. They don't want an alot none mechanical people in there. But it seems you have tapped in and I want to see the end results as well! Please keep us posted of what you're doing! I'M very very interested!!
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post #47 of 113 Old 11-27-2012, 10:01 PM Thread Starter
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I will keep you guys posted. I might have time tomorrow to deck the head and cut the seats.

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post #48 of 113 Old 11-27-2012, 11:46 PM
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i have nothing particular to ask but just want to see you get more progress on it.
good work again.
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post #49 of 113 Old 11-28-2012, 09:22 PM Thread Starter
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All right guys and gals. Since everything i have in the shop i'm waiting on parts for I had some time to work on my own bike!.

I started buy cleaning up the head. After I got everything cleaned up I decked the head for some higher compression. Then I cut the valve seats. The reason I had to cut the valve seats was because they were pitted pretty bad. The bike only has 5000 miles on it but this is another good reason to hate ethenol!. So now the valves will seal correctly.
Here are a few pictures. I still have a good 4-5 hours of porting to do on the head. As you can see in the pictures the castings are really rough thus slowing down air flow both into the engine and out. When I am done the exhaust side will look like a mirror. and the intake side will be cleaned up but have a bead blasted texture to help with the air/ fuel mix.










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post #50 of 113 Old 11-28-2012, 10:45 PM
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How much did you take off the head and what compression ratio are you shooting for?
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