big bore kits

Ok guys, lately i have had the need more power itch, I sold my 77 kz1000, so i got some cash to spend on my bike. I have been looking online and i am thinking about stepping up to a 1197 kit. I seen one with 13.5 to 1 comp. I know its high compression, but i plan on keeping my j head on there so that should drop my compression by two points. i am running the .418 lift cams with a high duration now, and would like to keep them. What do you guys think?? i want everyones opinion. Espically larrys. Right now iam running a 1075 kit. Do you guys think i will need to have my crank welded? iam running a 150 rear tire and dont plan on going any bigger. also do you guys think that will be ok for the street? I have a brand new oil cooler i will run with it. I was just wanting to swap jugs and pistons out on my motor if possible. and new cam chain also.can i run a stock block that has been resleeved without any bottom end boring or other mods? Thanks in advance for any and all help and advice.

in hot climates, I worry about going over 1075. I have seen many kz damaged due to over heating issues. I would get the crank welded. I think you will have to resleeve and clearence the cases, are you top or bottom on cam.

Do you mean am i running shim under buckets? if so yes i am

High power means WELD the crank for sure. Backcut trans so the power doesnt make it pop out of 2nd, Clutch will need work soon too.
I do believe you need to machine the upper crankcase for that big a bore. You buying a real big block or boring original block for bigger sleeves ?
Heat will be your enemy even with cooler.

if you get crank welded, take it somewhere that can ck the crank index properly. My bike ran fine with a number 4 journal .040 out.

i am running a ape clutch with needle bearing pusher. the way wireman talked i wouldnt need to get a undercut trans. and i have a mk11 motor. But figured i would need welded crank i will have one of our site sponsors do the crank work

I was thinking on using stock block but not sure whats best. I know there is people out there running them on the streets. I live in indiana so its not all that hot but if i have to shut it down at lights i will no big deal.

Or go wild and send the crank to Falicon . Build the bike strong for the long term investment, They are listed on this site.

Powerstroke_fan wrote: I was thinking on using stock block but not sure whats best.

Everyone has their own opinion.

(Sorry - I was wrong here - needs sleeves) [Some guys say 1197 is fine]

Worst case, you might need to have the stock block sleeved. You likely won't *need* to weld the crank unless you are drag racing or somehow manage to get much more grip out of the rear tire. An oil cooler wouldn't hurt, but I'd get one with a thermostat if you can. Depends on how you ride as to whether you need it or not. Undercut gears aren't necessary, but nice to have if you have the spare cash.

To run a 1197 kit, you will need to resleeve a stock block. Biggest bore on stock sleeves is 1105. Once you put in bigger sleeves, you will need to bore out the top cases to clear sleeves. I would use stock block cause it will run cooler then a big-block cause of the through holes in the block. The j head would lower compression of the 13:1 pistons but with those .418 cams, I would still check for piston/valve clearance. I have been told a J head has different valve angle then a KZ head but have also been told they are the same...maybe Larry C will know for sure. Not sure about the J valve size and pockets in the new pistons are compatible. Crank welding would be a very good idea even with a street tire, for "insurance". Street tire probably wouldn't hook hard enough to cause a problem but it only takes once. Cutting the trans would be a smart idea also for insurance reasons. Some will say not necessary. A MK11 trans is stronger then standard trans...2nd gear is supposed to be .030 wider then standard and 2nd gear is the weak link. I have been abusing my MK11 trans for many, many years in stock form without any problems but if you have the cash, it wouldn't hurt to have it cut...again...for "insurance". An engine builder that is well-known was told by Pearson that a crank out of line by .040 would be ok in anything but a high power motor but you wouldn't want to be out anymore.

Have the crank welded without a doubt .
The problem with running the 13:1 pistons even with the j-style head is you still have the giant hump on top of your pistons for the flame to climb across.
Unless youve head some work done on that j head I personally would just have a regular kz head done up by the master Larry himself with a 10.25:1 1197 kit youll have more power than your stock chassis will want to handle! :laugh:
As far as blocks i prefer the stock blocks with bigger sleeves on the street because they run so much cooler versus the big block.
Have everything in the bottem end checked for wear and tear and have top case half bored for the bigger sleeves.
As far as the falicon stuff yeah its nice,I ran 1 of their big pinned 900 cranks with knife rods in my 1327 but even then it was overkill in my book anyway.

i would weld the crank.
do everything u can to the bottom end first. weld crank, back cut trany, new cam chain, bore block. then keep running the 1075 untill u have the cash to do the top end.
as for the head.
send the mk11 head to Larry for work and use it with 10.25:1 pistons.
or
Use the J head (its cheaper to do the j head vs KZ, because it already has bigger valves, and port) the savings in the head could be put towards custom J&E pistons.
research the cost to do each head and the piston cost,to help u deside.