Having difficulty finding a replacement FJ1200 engine that is confirmed to be running well. Is it possible for me to put a modern sport bike engine in this and turn it into a street fighter? I would prefer to leave the bike as stock but if I can't find a replacement FJ1200 engine my only option is to sell as a project bike, part it out, or try to find an alternative engine.
I saw your bike for sale.
If it has a "blown head" why not just replace the head and, if needed, rebuild the engine?
Assuming motor mounts could be worked out, modern sport bike engines are water cooled.
I would worry that there is no clearance on the FJ frame to fit a radiator without contact from the front tire.
Seems like an exercise in futility to me when a simpler solution is readily available.
Cheers
I too think you are best off working with what you have.
Looks like very nice condition - all plastics, etc.
These engines are easy to work on and parts are readily available. If that is something you do not want to do yourself, crate it up and send it to RPM. They can do anything from the minimal repair to a full blown engine build or anything in between.
Any more details on the assessment of a blown head?
The picture of the "blown head" looks to be a valve cover seals leak to me?
Also, if the engine hasn't been running for a while - it will need the carbs cleaned. This you can also do yourself, but you have to be extremely thorough and diligent about it. The idle passages are very small and can be difficult to get clean.
Personally I think you are a lot closer than you think to having a nice running beautiful FJ
Quote from: Pat Conlon on September 22, 2024, 10:29:43 AMI saw your bike for sale.
If it has a "blown head" why not just replace the head and, if needed, rebuild the engine?
Assuming motor mounts could be worked out, modern sport bike engines are water cooled.
I would worry that there is no clearance on the FJ frame to fit a radiator without contact from the front tire.
Seems like an exercise in futility to me when a simpler solution is readily available.
Cheers
There are two holes through the head between cylinders 2 & 3. I've not opened up the engine but I imagine there must be major internal damage. I would like to keep it with an FJ1200 engine but having difficulty finding a reliable replacement at a decent price, so though maybe an FZ engine might fit. I'm not looking to Frankenstein it just curious what options are. Thanks for reply.
Quote from: fj1289 on September 22, 2024, 10:54:25 AMI too think you are best off working with what you have.
Looks like very nice condition - all plastics, etc.
These engines are easy to work on and parts are readily available. If that is something you do not want to do yourself, crate it up and send it to RPM. They can do anything from the minimal repair to a full blown engine build or anything in between.
Can you send me the RPM info? There are a lot of engine builders with that name so I would like to confirm which one you are referring to. Thanks.
Quote from: fj1289 on September 22, 2024, 11:02:28 AMAny more details on the assessment of a blown head?
The picture of the "blown head" looks to be a valve cover seals leak to me?
Also, if the engine hasn't been running for a while - it will need the carbs cleaned. This you can also do yourself, but you have to be extremely thorough and diligent about it. The idle passages are very small and can be difficult to get clean.
Personally I think you are a lot closer than you think to having a nice running beautiful FJ
I have photos of the blown holes in the head, not sure how to attach them here but I could email them. Yes carb and brakes and clutch would need rebuild kits but I can do that and would be happy to do that if I could get it running first, just wondering what my options are. It's a nice bike so would hate to part it out, really just want to keep it as a Sunday rider.
One of the holes in the head
RPM Racing in California. They run this site, and do a little advertising here too.
www.rpmracingca.com
Quote from: gdfj12 on September 22, 2024, 07:54:05 PMRPM Racing in California. They run this site, and do a little advertising here too.
www.rpmracingca.com
Thanks for the info!
George beat me to the website!
I'm 99% sure those holes are supposed to be there - I think they are cast in drain holes.
Took some pics of the head on my bike project. The first pic shows the hole better, the second trying to point out the location with a test probe.
JPEG image.jpeg
JPEG image.jpeg
Going forward I would suggest:
1. Remove the spark plugs
2. Remove the left engine cover and try to turn the engine over with a wrench (14mm if I remember correctly)
3. If the engine is free - try cranking it over with the starter.
4. Check compression - simply with a finger over the spark plug hole or with a pressure gauge.
5. Get the carbs cleaned and enjoy a nice FJ!
The exhaust side of the head has factory drain holes to drain the water from the center of the head.
Photo is not the best and not sure which side of the head the picture is taken.
If the exhaust side, there is probably nothing wrong with the head.
Randy - RPM
Edit- Chris beat me too it...
Thanks Chris.
Quote from: racerrad8 on September 22, 2024, 08:50:10 PMThe exhaust side of the head has factory drain holes to drain the water from the center of the head.
Photo is not the best and not sure which side of the head the picture is taken.
If the exhaust side, there is probably nothing wrong with the head.
Randy - RPM
Edit- Chris beat me too it...
Thanks Chris.
I will post a few more pictures see below comment. If these are drain holes then I will be so happy you have no idea!
Quote from: racerrad8 on September 22, 2024, 08:50:10 PMThe exhaust side of the head has factory drain holes to drain the water from the center of the head.
Photo is not the best and not sure which side of the head the picture is taken.
If the exhaust side, there is probably nothing wrong with the head.
Randy - RPM
Edit- Chris beat me too it...
Thanks Chris.
yes they are on the exhaust side
two photos of each side
See arrow, this is where the holes are. I assumed they were not supposed to be there, they don't look like perfect little circles they are a little jagged and there is oil all over the heads so I thought it had blown the head. If these are drain holes I will try to think of some way I can thank you guys. Can somebody please confirm these are drain holes?
Yes, those are the drain holes.
That's a good picture for orientation because it shows the plug wire routing and the air scoops.
The holes are somewhat jagged because they are simply left "as cast" vice being machined like other passages.
Oil is likely coming from the valve cover seal and the seals for the cam cover bolts. Both easily replaced with the engine in the frame. ***DO NOT*** over torque the valve cover bolts - they bottom out in cam caps and break if you try to over tighten them
added arrows