Excellent video. Fixing buy a bbr big bore myself for my childhood dirtbike. Got it new in 1992 figured it was time for a refresh. Starts first kick still but smokes like a freight train
There's only 2 ways oil can get into the combustion chamber, rings or valve guide seals. So be sure to replace the seals and check the ring fit in the new cylinder before tearing down your motor. Cheers.
What year was this bike? I'm doing one and having a difficult time getting the cam gear on the camshaft. I have an 88 link timming chain. And someone said the cylinder head was taller on a certain year. Your head is same number as mine. This bike Year could help me out alot in my situation.
This was a 2001 Honda XR100. I ran across that same issue myself on an XR80 a couple years ago. I don't know what year it was, and I don't recall how I remedied the problem. My spreadsheet indicates the part number for the XR100 head is 12200-KA8-010 on engines built in 1981-1982, then the part number changes to 12200-KA9-680 on 1983-1984 engines then back to 12200-KA8-010 from '88-'91 and from 1993-2000. The part number changed again to 12200-KN4-A61 for the head on engines built from 2001-2003. In 2004 the CRF100F took over and is listed as 12200-KN4-A61. So basically, I'm seeing three different part numbers for the head but I honestly can't tell you what the differences are.
@ronporteous1411 Very interesting. What i have is a 1998 frame. I got the bike at an estate sale. So will never know the whole story. But the engine looks like top end was either in the process of being put back together or taken apart. I seen a oem honda box with used piston rings. But I decided to disassemble to make sure everything was done correctly. Which glad I did. Found the lower chain tensioner stud threads stripped. So helicoiled it correctly. But upon the assembly I couldn't get the gear to set on the camshaft. Like I'm a link or 2 too short. I counted the links and I keep counting 88 links. When everything online and in parts diagrams shows a chain with 90 links. Seriously weird. I have a cam gear with 30 teeth. And a crankshaft sprocket with 15 teeth. But where does a 88 link come from, I see nothing anywhere online of a 88 link cam chain. Now if you look at a xr80 the link count is indeed 88links. But an xr80 has 17 tooth crankshaft sprocket. It's not likely I have an xr80 case with the crank sprocket of the xr100 because they are not supposed to be interchangeable. Also the case has never been split. No rounded bolts and no signs anyone has split the case. Also the stator/flywheel has never been removed. Same thing. No signs of rounded corners on nut. Even a good quality snapon will still leave a mark I'm sure. So nobody could of done any kind of swap. Only way to get the chain out, is split case and remove, or pulled stator and the seal cap behind it and drop chain thru hole. I'm positive nobody been in there. But an 88 link chain? Even says Japan and 25 on links. I'm really puzzled. Definately love a challenge, dang, this one has me good. I ran an AI search, for what it's worth. It had told me there was a height difference in heads, so first thought was someone has a different year head. AI search tells me the piston cylinders were all the same thru all years. I'm short approx 1-2 links. Or equivalent to say 1/4" more height to get the cam gear on camshaft. That would be a snug fit probably. Before the tensioner eve factor in. But I'm going to try a 90 link chain and see if the 2 links allow me to get the gear onto camshaft. At this point there had to of been a 1/4"-ish difference in head height where cam carrier sets. Odd because you can look on partzilla parts diagram, and I check most years from 1995-2001 and they are all 90links and 30 tooth cam gear. And the crank gears were also all 15 tooth. Maybe there were a few protype engines out there or something. Would love to share this issue with other. And perhaps educate one another and learn. I'm well versed in all kinds of engines. At first I really thought maybe I was doing something wrong, because it is an odd and unique tension system compared to many other machines. But removing it completely I was like, hmmm. Problem is not a guide or tensioner. Let me know if anything comes to your mind please. And I will gladly let you know once I figure out what's up and get it fired up and share the knowledge. Knowledge is power. It's always hard finding the right people with tribal knowledge. At this point I suspect the head has been changed. But the other kicker is the head and entire engine assembly match perfect really. Patina" and corrosion ect ect. If that makes sense. I'm one to pay attention to the littlest details. So much is unexplainable at this point. And I can't build a story with it. Atleast not yet. I ran numbers on the case and they seem to come back as an xr100 case year. Anybody else has some solid knowledge, more than happy to listen. Thanks
@@justinz4250 I think your mystery was solved in your second sentence "the engine looks like top end was either in the process of being put back together or taken apart". The Facebook pages dedicated to the XR80-XR100 bikes have produced discussions about mounting an 80 head onto a 100 motor. I personally don't see the benefit in that, but it would make sense to install a shorter chain to accommodate the 80 head. Also, it's always a fun challenge to take on someone else's project to completion. Thanks for watching, Justin and a great conversation.
Best XR motor top end video on RUclips, thanks!
Thank you!
Best how to vid i have seen yet! Excellent work!
Thank you, I hope it was helpful.
@@ronporteous1411 Rebuilding one at the moment, stay tuned!
Looking forward to hear how it went.
Jeans, belt buckle, speed wrench, thats right up my alley. Love the work, thanks for posting.
Stay gold.
Thank you! That means a lot to me.
Absolutely great video. I wish you could build mine for me!
Thank you, Michael.
Ron you have no idea how helpful this was thank you so much!
I'm glad I could help.
Excellent video. Fixing buy a bbr big bore myself for my childhood dirtbike. Got it new in 1992 figured it was time for a refresh. Starts first kick still but smokes like a freight train
There's only 2 ways oil can get into the combustion chamber, rings or valve guide seals. So be sure to replace the seals and check the ring fit in the new cylinder before tearing down your motor. Cheers.
Nice job Ron.
Thank you very much . I hope this helps.
Where can I find the tool you used to spin the valves to create the proper valve seat?
I made it. It's a piece of 3/8" round stock. I drilled a hole down the middle using a mini lathe and added a set screw to hold the valve in place.
@@ronporteous1411 thank you sir!
@@ronporteous1411 that is brilliant and simple 👍🏽🇺🇸
What year was this bike? I'm doing one and having a difficult time getting the cam gear on the camshaft. I have an 88 link timming chain. And someone said the cylinder head was taller on a certain year. Your head is same number as mine. This bike Year could help me out alot in my situation.
This was a 2001 Honda XR100. I ran across that same issue myself on an XR80 a couple years ago. I don't know what year it was, and I don't recall how I remedied the problem. My spreadsheet indicates the part number for the XR100 head is 12200-KA8-010 on engines built in 1981-1982, then the part number changes to 12200-KA9-680 on 1983-1984 engines then back to 12200-KA8-010 from '88-'91 and from 1993-2000. The part number changed again to 12200-KN4-A61 for the head on engines built from 2001-2003. In 2004 the CRF100F took over and is listed as 12200-KN4-A61. So basically, I'm seeing three different part numbers for the head but I honestly can't tell you what the differences are.
@ronporteous1411
Very interesting. What i have is a 1998 frame. I got the bike at an estate sale. So will never know the whole story. But the engine looks like top end was either in the process of being put back together or taken apart. I seen a oem honda box with used piston rings. But I decided to disassemble to make sure everything was done correctly. Which glad I did. Found the lower chain tensioner stud threads stripped. So helicoiled it correctly. But upon the assembly I couldn't get the gear to set on the camshaft. Like I'm a link or 2 too short. I counted the links and I keep counting 88 links. When everything online and in parts diagrams shows a chain with 90 links. Seriously weird. I have a cam gear with 30 teeth. And a crankshaft sprocket with 15 teeth. But where does a 88 link come from, I see nothing anywhere online of a 88 link cam chain. Now if you look at a xr80 the link count is indeed 88links. But an xr80 has 17 tooth crankshaft sprocket. It's not likely I have an xr80 case with the crank sprocket of the xr100 because they are not supposed to be interchangeable. Also the case has never been split. No rounded bolts and no signs anyone has split the case. Also the stator/flywheel has never been removed. Same thing. No signs of rounded corners on nut. Even a good quality snapon will still leave a mark I'm sure. So nobody could of done any kind of swap. Only way to get the chain out, is split case and remove, or pulled stator and the seal cap behind it and drop chain thru hole. I'm positive nobody been in there. But an 88 link chain? Even says Japan and 25 on links. I'm really puzzled. Definately love a challenge, dang, this one has me good. I ran an AI search, for what it's worth. It had told me there was a height difference in heads, so first thought was someone has a different year head. AI search tells me the piston cylinders were all the same thru all years. I'm short approx 1-2 links. Or equivalent to say 1/4" more height to get the cam gear on camshaft. That would be a snug fit probably. Before the tensioner eve factor in. But I'm going to try a 90 link chain and see if the 2 links allow me to get the gear onto camshaft. At this point there had to of been a 1/4"-ish difference in head height where cam carrier sets. Odd because you can look on partzilla parts diagram, and I check most years from 1995-2001 and they are all 90links and 30 tooth cam gear. And the crank gears were also all 15 tooth. Maybe there were a few protype engines out there or something. Would love to share this issue with other. And perhaps educate one another and learn. I'm well versed in all kinds of engines. At first I really thought maybe I was doing something wrong, because it is an odd and unique tension system compared to many other machines. But removing it completely I was like, hmmm. Problem is not a guide or tensioner. Let me know if anything comes to your mind please. And I will gladly let you know once I figure out what's up and get it fired up and share the knowledge. Knowledge is power. It's always hard finding the right people with tribal knowledge. At this point I suspect the head has been changed. But the other kicker is the head and entire engine assembly match perfect really. Patina" and corrosion ect ect. If that makes sense. I'm one to pay attention to the littlest details. So much is unexplainable at this point. And I can't build a story with it. Atleast not yet. I ran numbers on the case and they seem to come back as an xr100 case year. Anybody else has some solid knowledge, more than happy to listen. Thanks
@@justinz4250 I think your mystery was solved in your second sentence "the engine looks like top end was either in the process of being put back together or taken apart". The Facebook pages dedicated to the XR80-XR100 bikes have produced discussions about mounting an 80 head onto a 100 motor. I personally don't see the benefit in that, but it would make sense to install a shorter chain to accommodate the 80 head. Also, it's always a fun challenge to take on someone else's project to completion. Thanks for watching, Justin and a great conversation.
I need to slap a 100 motor in my 80