Should a CBR900 engine fit into same chassis as CBR600

[Sandy Mayhew]

We have ran CBR600 95-98 models in an Ireson chassis for several years. We want to try a CBR900 98 in the same chassis. We know that the size of the sump might be an issue as will the weight but the chassis has severed us well and we race in Scotland so no F1 and F2 class, just Sidecars. Does anyone know if the engine mountings are the same or are we going to need to alter them on the chassis.

Thanks

[Womble]

i think they will swap over as it is a common swap on a solo. the later pc35 is definitely different as i have just done the reverse swap

[Sandy Mayhew]

Thanks. We had 2 CBR600 engines but got one tuned to 14/1 compression and it blew up both heads in separate meetings so looks like it is too highly tuned. We only have a CBR900 in the garage so it will save us a fair bit of cash if we can put that engine in.

[dags]

Easy swap. Exhaust is different and gear change is opposite way around. You could even get away with running same carbs. Engine sits about an in higher though so seat unit would need to be modified if it fully covers engine area. Did 2 race meetings on it and put the 600 back in. Massive push on the front end. Slower times than the 600.

[alanw]

Sandy I ran a fireblade for 4 or 5 years in my baker, even if the mounts are similar you will have to move the engine further forward cos with the extra grunt it will just push the front, i then put an r6 in and went 2 secs a lap faster at East Fortune. Be carefull get the bathroom scales out.