Starting a tear down. To Nikasil or sleeve?
Posted: Fri Jan 15, 2021 10:20 am
Hi guys and gal's
I am commencing a kr1s engine rebuild. In initially tearing down the top end I discovered that at some stage the cylinders have had a steel sleeve pressed in. They measure 56.51mm. One cylinder is still very good condition with a very fresh hone cross hatch. The other seems to have suffered a cold start up seizure or an issue with the intake on that cylinder creating too much heat. I have not spent too much time measuring port timing tho I have noticed quite an excess of sleve windows interfering with the cylinder exhaust port and its much more pronounced on one cylinder than the other. There is also a deposit of piston material on the cylinder walls of one cylinder.
I have the option to use a standard kr1b pair of cylinders on the on b sized pistons.
I believe timing is improved on the s cylinders but I'd hate to go ahead with the sleeves if sleeve/port timing is going to cause issues.
Ideally I'd like to prep both sets and have the sleeves as spares in times of recoating or ordering pistons (will be a daily rider) but could use the funds on other items of repair...
So asking a couple of basic questions...
Pros and cons of steel bore on kr1s?
Am I better off using the kr1b cylinders or the kr1s steel sleeve?
Can a sleeve be coated? Is it worth doing?
Any advice in this area is greatly appreciated.
I am sure I will have more.
Oh and as soon as I figure out the pics I will start a proper resto/custom thread.
Thanks heaps in advance.
Dill.
I am commencing a kr1s engine rebuild. In initially tearing down the top end I discovered that at some stage the cylinders have had a steel sleeve pressed in. They measure 56.51mm. One cylinder is still very good condition with a very fresh hone cross hatch. The other seems to have suffered a cold start up seizure or an issue with the intake on that cylinder creating too much heat. I have not spent too much time measuring port timing tho I have noticed quite an excess of sleve windows interfering with the cylinder exhaust port and its much more pronounced on one cylinder than the other. There is also a deposit of piston material on the cylinder walls of one cylinder.
I have the option to use a standard kr1b pair of cylinders on the on b sized pistons.
I believe timing is improved on the s cylinders but I'd hate to go ahead with the sleeves if sleeve/port timing is going to cause issues.
Ideally I'd like to prep both sets and have the sleeves as spares in times of recoating or ordering pistons (will be a daily rider) but could use the funds on other items of repair...
So asking a couple of basic questions...
Pros and cons of steel bore on kr1s?
Am I better off using the kr1b cylinders or the kr1s steel sleeve?
Can a sleeve be coated? Is it worth doing?
Any advice in this area is greatly appreciated.
I am sure I will have more.
Oh and as soon as I figure out the pics I will start a proper resto/custom thread.
Thanks heaps in advance.
Dill.