roninbuffalo
Member
I got a set of nikasil jugs I want to to put them on a 77 r100 short block is there anything needed to be done before I do this?
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nikasil cylinders on a 1977 r100
- Thread starter roninbuffalo
- Start date
I have a 77 R100RS. I replaced the cylinders, pistons, and rings with the nikasil-coated cylinder set sold by Ted Porter. These were made by Siebenrock. Ted suggested that I add the base gasket to the cylinders unless I planned to make the heads dual plugged.
I had dual plugged heads on a /6 and timing was somewhat altered from stock (a bit more advanced with a different advance curve). I did not want to go through that again so I opted for the base gasket and slightly lower compression.
The bike runs very well, no oil consumption. Installation was very straightforward. [I had Ted Porter work on the heads - new exhaust seats, valves, valve springs, and valve guides. The heads looked new on return!]
At Ted's suggestion I used a 3-Bond sealant (e.g., Hondabond, Yamabond, etc.) about the base of the cylinder rather than the old Hylomar sealant. No leaks or weaps about the cylinder base. Use sealant sparingly!!! Use new push-rod seals and top push-rod guide tube o-rings. Keep sealant away from the o-rings and nearby area!!
I used 25 ft-lbs as the torque setting for the head bolts. Head bolts were re-torqued after 500 miles. Very little, if any, change in valve clearances at subsequent service intervals. I use silicone, re-usable valve cover gaskets. No leaks.
I had dual plugged heads on a /6 and timing was somewhat altered from stock (a bit more advanced with a different advance curve). I did not want to go through that again so I opted for the base gasket and slightly lower compression.
The bike runs very well, no oil consumption. Installation was very straightforward. [I had Ted Porter work on the heads - new exhaust seats, valves, valve springs, and valve guides. The heads looked new on return!]
At Ted's suggestion I used a 3-Bond sealant (e.g., Hondabond, Yamabond, etc.) about the base of the cylinder rather than the old Hylomar sealant. No leaks or weaps about the cylinder base. Use sealant sparingly!!! Use new push-rod seals and top push-rod guide tube o-rings. Keep sealant away from the o-rings and nearby area!!
I used 25 ft-lbs as the torque setting for the head bolts. Head bolts were re-torqued after 500 miles. Very little, if any, change in valve clearances at subsequent service intervals. I use silicone, re-usable valve cover gaskets. No leaks.
roninbuffalo
Member
John or anyone else know where I can find a picture, link, or video to find of the "step" that needs to be ground down? Thanks for all the input.
Nickasil cylinders on 77 R100
That step on the later cylinders positively centers the cylinder in the cases. Without it the cylinder can be mover around slightly against the 77 case. I know this because I bought a Seidelbock 1070 CC kit which cannot be used on my 77 cases.
That step on the later cylinders positively centers the cylinder in the cases. Without it the cylinder can be mover around slightly against the 77 case. I know this because I bought a Seidelbock 1070 CC kit which cannot be used on my 77 cases.
Snowbum writes about this in red font about 1/3 the way down this page:
https://bmwmotorcycletech.info/cylinders.htm
https://bmwmotorcycletech.info/cylinders.htm
I bought the siebenrock 1070cc kit from a vendor in Germany. They did not have the caution about these being for 1980 and later bikes. The entire engine was already reassembled except for the cylinders & heads when I ordered the 1070 cc kit so it would have required pulling it apart again to do the case machining necessary to properly fit the 1070 cylinders. I just ordered the Seibenrock 1000cc cylinder kit. I now have a very expensive kit with longer rods, pistons & cylinders sitting on my workbench. Decided to just keep them for a possible 1980's bike since I got a really good price on them.
Source for cylinder step removal
Sorry it's taken me a while to get back to this. Ted Porters lists the cylinder base machine work to fit 81 on Nikasil cylinders to a 76-80 BMW on their 'cylinder head repair' page. I just reviewed the page. Mail in service: "Remove step on cylinder base to fit 81 on Nikasil cylinders to 76-80 engine blocks" $60.00 per pair plus postage. The page is dated 2021.
Sorry it's taken me a while to get back to this. Ted Porters lists the cylinder base machine work to fit 81 on Nikasil cylinders to a 76-80 BMW on their 'cylinder head repair' page. I just reviewed the page. Mail in service: "Remove step on cylinder base to fit 81 on Nikasil cylinders to 76-80 engine blocks" $60.00 per pair plus postage. The page is dated 2021.
lkchris
Active member
Assume you have the corresponding pistons.
lkchris
Active member
Pistons? I thought the issue would be rings.
The combination. Don't think those A, B, and C nikasil cylinder sizes correspond to iron cylinder piston sizes. Have you seen a chart?
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