849cc too big?

[DrewArit]

I heard from some one that you shouldn't bore a sohc 750 over 836cc because the cylinder walls would get too thin and warp. I am having mine bored to 849cc using the cyclex kit. Am I going to run into issues???

[Re-run]

You will be fine. Who ever said that has no idea. The sohc 750 has been bored to 1080. Yes the walls to get thinner but an 850 will not hurt it. Just use good oil and if you are in a hot area, get an oil cooler that mounts on the frame and uses spin on filters.

[DrewArit]

Thanks, that eases my mind. What oil would you recommend?

[DrewArit]

Oh, and what would be a good oil cooler to look at???

[2tires]

do not 4 get to rejet and if you go bigger than 850  you will have to change your exhaust system...836 works fine with a factory  exhaust...also you will not get any where near the performance you are  looking for unless you  install a new cam...that holds the exhaust  valve open a split second  longer..called a  "mild cam" ..cost  of cam is just under $198.00  .. and a 836 kit is about $600.00  to most people..installed..

[Re-run]

Your info is a bit bad there. The stock exhaust will work absolutely fine. the legions of sohc riders that do the 836 and larger up to 1080 have used the stock system fine. Also, jetting is subjective. Every engine is different, in fact, the 77/78 engines do not always need a rejet.
Second, the cam part helps yes but the biggest thing you can do is get head work done. the heads on the sohc are very restrictive. Opening them up will make a bigger improvement than just a cam.
Everything comes down to money though. cause if you are going to do a build like this right, you should get new rods, new valves and springs with titanium keepers.
Then given that, new primary chains should be installed. You see where this is going.
Maybe this is a project that will continue when able, then in that case, the 850 will work fine. He might just have to change how the breather works to prevent oil blowing.