MAP verses Morgo 750 kit
This is my first post in the classic portion of this club. Since I have purchased and used both a 750 Morgo and a 750 MAP kit, I decided to post some feedback.
My son and I are restoring my 1968 Bonneville. He wants it to look original, but have a lot of giddy-up to the motor. I had previously built a couple of nice 750 short rod motors for my son. Since one of the 750's was being cannibalized, I told my son to give me that motor and let me transfer as many parts to the 650 that I can.
I won't go into the details, but the biggest portion was the upgraded oil pump and matching cover, the 5-speed, primary assy, and the 750 cams. And, a ton more smaller parts.
By January this year, we were ready for the pistons. The 650 barrels I had were already .060" overbore. After checking on new barrels, pistons, etc, we opted for a 750 kit. But, which one???
We decided on the Morgo 750. Cost and delivery time were better. I had run Morgo's in the past. I had over 100,000 on the one I had. When I took it apart, it still had some of the honing marks. So, we ordered a new Morgo from England.
The kit arrived in less than a month. Around $500 total. I noticed two things immediately. One was how long the wrist pins were. And, there was no recess "cut" in the side of the piston where the circlips go.
As I checked the clearances, I found the rings butted together in the bore. To me, this was fine. But, suicide if you put the kit together "assuming" the ring gaps were OK. This allowed me to hand file the end gap to perfection. I then checked the piston clearance. At the bottom of the skirt. It measured around .005". Everything seemed fine.
In the first 10 miles, the motor seized. I was riding at 55 Mph up a very small incline in the road. I opened the throttle just a little. Then, instant seizure.
I read this is very typical for Morgo kits. CRAP!!!!
After taking the motor apart, I was expecting the seizure in the piston skirt area. Nope. It was across the wrist pin area. I then knew these pistons were not properly made. I had not measured, but I suspected the widest or fattest part of the piston was across the wrist pin. Not at the bottom of the skirt like ALL normal pistons.
In conclusion, I was able to ride the Morgo about 50 more miles after the seizure. It did have a lot of power.
For those buying Morgo kits, I would recommend opening up the bore at least .002" more. This would be around .007" on the piston skirt. This is not big enough to cause rattling as Morgos did in the past. But, it will allow for the extra clearance of the wrist pin area.
Also, I would recommend hand filing a recess on the piston where the clip goes. Like any normal Triumph piston. This part of the piston is NOT supposed to touch the wall anyway. Just hand file about a .015" deep flat area. This will prevent the seizing on the wrist pin area.
Then, set the piston ring end gaps. Don't build any motor ever without checking ring gaps to perfection. In the end, all the extra work on the Morgo will pay off. A normal shop might charge up to $200 to open the bore a little. The rest, you can do yourself
My son ordered the MAP 750 kit the end of May. Rather than fix the Morgo (which I knew I could accomplish) he wanted the MAP kit. He was told around $1800 and 5-6 weeks lead time.
One thing we did not like about dealing with MAP is MAP was not contacting us with any updates. Ever. We always had to call them. You would think if you invested that much money, someone could call you with updates. Or drop a simple email. How hard is that??????
All summer my son called MAP. All summer, MAP said a couple more weeks. Then, the entire the fall months as well. Each time, my son was told just a couple of weeks more. 20 times??????
On Dec 4th, almost 6 1/2 months later, the MAP kit arrived. The quality is mind blowing. I have worked with every past 750 kit ever on the market and built hundreds of Triumph motors, but never seen this type of high quality.
My son opted for the black painted barrels and the nikasil. The kit comes with copper O-rings for the head gasket. It comes with special pushrod tubes. The piston clearance was as specified. The ring gaps were already set. All I had to do was bolt the kit on and ride.
The only poor quality part in the entire MAP kit was the rocker box gaskets. No wire reinforcement. I had plenty here already. I would never consider rocker box gaskets without the wire.
All in all, the MAP kit is better quality. The power increase over the 650 is about the same on either 750 kit. However, the lead time and extreme cost of the MAP may be out of reach for most people. If you follow what I said about the Morgo kit, this will make just as nice of a kit as the MAP.
Hope this helps
Seizures which mark the piston at around gudgeon pin height are typical of engines that have been detonating, usually caused by bad mixture tuning and/or bad riding (low rpm slogging).
Many designs of piston have no "flat sides" at the gudgeon pin ends. An example is the in-house Triumph piston, used before they switched to Hepolite.
Morgo piston with 0.0065" clearance
My kit seized in 2006
Now .008" clearance with my .020" oversized Morgo piston since 15,000 kilo and no problem ;)
Nice write up.
$500 vs $1800 wouldn't leave me much of a choice. Dangerously close to what I paid for my bike. The Morgo kit used to be aluminum cylinder with fins shaped like the head, is that still the case ? MAP used to be cast iron cylinder that looked like stock. I assume it's solid gold now with a nikasil liner so you don't end up with a oil filter clogged with gold dust.
I've heard of cast iron Morgo barrels, but not aluminium.
Very good info, thanks!
I remember magazine ads from years ago, but I saw one close up at a swap meet a few years ago. I dont remember much about it other than it was aluminum , shaped like the head fins, it had broken fins , and the owner was asking a lot.
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