An update and preparation for the Piston Rally
Posted: 15 Sep 2017 16:36
My 1978 Morini 500 has been a work in progress for some months now. When I first re-commissioned it after some 20 years hibernation, I put the carbs in the ultrasonic tank, but I tried to avoid replacing any parts in view of the potential need to change jet sizes, etc. For all I knew the existing ones could be right or wrong. In the event, I had to replace the starter jets which were badly corroded and thoroughly varnished up as well. The bike started and idled very well and ran pretty well, the only issue being hesitation coming off idle or going from the over-run back on the gas. I have to say I was slightly disappointed by the general performance, but I had nothing to compare it with.
The original needles were X1, which agrees with the Blue Book, but stripping it down again, I saw they were quite worn and in fact one was slightly bent. The atomisers were 262T, the BB specifies 264T, not sure what the difference is. The pilot jets were 52, BB specifies 50 and a few people have recommended 45. So, I ordered new needles, 264T atomisers and 45 pilot jets. Going over rich on progression is a common reason for that off-idle hesitation in my experience, so a slightly smaller pilot jet seemed like a good idea. I re-checked carb balance and was slightly disappointed to find it pretty well spot on, that would have been another good reason for hesitation!
Well I have to say that the bike is transformed! I can barely believe how much difference this has made. The hesitation has completely gone and it feels a lot more "gutsy" in the low and mid-range. Of course I've made three changes, so I'm not quite sure which has made all the difference. I'm not arguing though!
I've also given up on the original rear shocks which are basically shot. One minute they have no damping and are bouncing around like a pogo stick, and the next they are rock hard. Add to that the fact that the chrome has gone on the springs so they look bad and it was time for a change. I fitted the Hagons with adjustable damping. I'm pretty skinny and I often find rear shocks are a bit too harsh - backing the damping off a couple of clicks makes an awful lot of difference for me. I'm pleased with the Hagons and the back of the bike is behaving a lot better now.
I am off to Spain for the MC Piston Rally next week and I have been hoping to use the Morini this year for a change. The last couple of years I've been on my 750 Bonneville, which has proved itself to be well suited to the terrain (with the same Hagon shocks) and I'm hoping the Morini will be just as much fun. It has much better brakes than the Bonnie and that will certainly be appreciated up in the mountains! Now with the extra bit of grunt I seem to have found, I feel a bit happier about tackling those very steep hills! I shall report back on how the Morini performs.
Regards to all,
Joe.
The original needles were X1, which agrees with the Blue Book, but stripping it down again, I saw they were quite worn and in fact one was slightly bent. The atomisers were 262T, the BB specifies 264T, not sure what the difference is. The pilot jets were 52, BB specifies 50 and a few people have recommended 45. So, I ordered new needles, 264T atomisers and 45 pilot jets. Going over rich on progression is a common reason for that off-idle hesitation in my experience, so a slightly smaller pilot jet seemed like a good idea. I re-checked carb balance and was slightly disappointed to find it pretty well spot on, that would have been another good reason for hesitation!
Well I have to say that the bike is transformed! I can barely believe how much difference this has made. The hesitation has completely gone and it feels a lot more "gutsy" in the low and mid-range. Of course I've made three changes, so I'm not quite sure which has made all the difference. I'm not arguing though!
I've also given up on the original rear shocks which are basically shot. One minute they have no damping and are bouncing around like a pogo stick, and the next they are rock hard. Add to that the fact that the chrome has gone on the springs so they look bad and it was time for a change. I fitted the Hagons with adjustable damping. I'm pretty skinny and I often find rear shocks are a bit too harsh - backing the damping off a couple of clicks makes an awful lot of difference for me. I'm pleased with the Hagons and the back of the bike is behaving a lot better now.
I am off to Spain for the MC Piston Rally next week and I have been hoping to use the Morini this year for a change. The last couple of years I've been on my 750 Bonneville, which has proved itself to be well suited to the terrain (with the same Hagon shocks) and I'm hoping the Morini will be just as much fun. It has much better brakes than the Bonnie and that will certainly be appreciated up in the mountains! Now with the extra bit of grunt I seem to have found, I feel a bit happier about tackling those very steep hills! I shall report back on how the Morini performs.
Regards to all,
Joe.