ninjette.org - View Single Post - Another ex500 swap into a pregen ninja 250

Mauricemonge · July 9th, 2022, 11:43 PM

Hey all, I killed my ninja 250 sidecar last week after a 3000 mile trip to Colorado from San Francisco (added lots of miles going to national parks).

Anyway, I started my ex500 swap today. I struggled with how exactly to mount it in, it’s offset to the right side of the bike to make the chain line work. Because of this the carbs don’t line up well.

I luckily had another ex250 frame that I ripped every tube out of the head tube (while thrashing on my sidecar..) I measured the offset of where the sprocket was from a point on the frame, then with the bare frame, did the same with the 500 engine. I found that the lower left engine mount on the frame gave me the right chainline with the corresponding mount on the engine, but only when I removed the rubber insert.

I tried to just use that mount, but it made the engine too low (I’m slammed) and when I started measuring things closer, it really did have to have that insert in there to line up properly.

I spent a lot of time just looking at things. But I did eventually pull the trigger and weld the upper rear motor mount in - only to realize it was crooked!! I panicked, but when I put the motor back in to see how bad it was, I realized that mount has a ton of play in it, and it let me align it a bit.

I then made the front mounts. I figured I’d make them symmetrical, and they’d put the engine back in a straighter position. They did kinda, but since the engine is offset, I had to space them out using washers and nuts of larger size. It worked though.

My chain is now too short by about 6 links., I went and separated the chain, and rode it back and forth to see my chainline and to also see if the teeth were binding or grabbing. It actually looks spot on somehow.

I ordered a 41 tooth rear sprocket to go with the 15, and 4 extra chain links (was at 45 tooth while testing)

I wrapped up without actually get much done. I ordered an ex500 cooling system, my 250 was struggling because my fender blocks a lot of wind when lowered 4”+. And I’ll be using a “modified” ex250 exhaust. I plan to route them 2-1 like I had with the 250 engine, and use the same gsxr1000 can I had before.

I’ll post pictures if I can figure it out. I also plan to make a YouTube video

July 9th, 2022, 11:43 PM	#1
Mauricemonge ninjette.org member Name: Maurice Location: San Francisco Join Date: Sep 2018 Motorcycle(s): bastardized ninja 250 (think land speed record with a sidecar) soon to swap a 500 engine Posts: 34	Another ex500 swap into a pregen ninja 250 Hey all, I killed my ninja 250 sidecar last week after a 3000 mile trip to Colorado from San Francisco (added lots of miles going to national parks). Anyway, I started my ex500 swap today. I struggled with how exactly to mount it in, it’s offset to the right side of the bike to make the chain line work. Because of this the carbs don’t line up well. I luckily had another ex250 frame that I ripped every tube out of the head tube (while thrashing on my sidecar..) I measured the offset of where the sprocket was from a point on the frame, then with the bare frame, did the same with the 500 engine. I found that the lower left engine mount on the frame gave me the right chainline with the corresponding mount on the engine, but only when I removed the rubber insert. I tried to just use that mount, but it made the engine too low (I’m slammed) and when I started measuring things closer, it really did have to have that insert in there to line up properly. I spent a lot of time just looking at things. But I did eventually pull the trigger and weld the upper rear motor mount in - only to realize it was crooked!! I panicked, but when I put the motor back in to see how bad it was, I realized that mount has a ton of play in it, and it let me align it a bit. I then made the front mounts. I figured I’d make them symmetrical, and they’d put the engine back in a straighter position. They did kinda, but since the engine is offset, I had to space them out using washers and nuts of larger size. It worked though. My chain is now too short by about 6 links., I went and separated the chain, and rode it back and forth to see my chainline and to also see if the teeth were binding or grabbing. It actually looks spot on somehow. I ordered a 41 tooth rear sprocket to go with the 15, and 4 extra chain links (was at 45 tooth while testing) I wrapped up without actually get much done. I ordered an ex500 cooling system, my 250 was struggling because my fender blocks a lot of wind when lowered 4”+. And I’ll be using a “modified” ex250 exhaust. I plan to route them 2-1 like I had with the 250 engine, and use the same gsxr1000 can I had before. I’ll post pictures if I can figure it out. I also plan to make a YouTube video