Benelli 750 Sei starting problems: Help!

tucandugu · Sep 23, 2011

Hi,

Just finished my Sei but the beauty doesn´t wants to start.

I changed the plug cups for a new NGK ones and checked the breakers.
When I try to start , only the left hand side cylinder (nr. 1) seams to make some explosion.
It started before the rebuild, then I suspect about some wrong electrical connection.

-The coil wiring numbers are disposed in this order (seen in running sense, from right to left): 153426
The work shop manual seams to indicate that the correct order is 123456. Tried both options, but no start symptoms.

-When I dismatled all the coil system I lost one of the wiring connection references from the green wires which connects the coils. May be the green wires -see attached photo- are connected opposite order that they must. Could this affect?.

-Also I don´t know which is the correct procedure to start up this bike. I open the 2 fuel switch and pull full the carburetor choque.

Any suggestions?.

Thanks in advance!.

Carles

Doc59 · Sep 23, 2011

Carles,

Firing order in my manual is 1-4-2-6-3-5

As for the 2 green wires, if you look at the colour of the wires coming from the points you should be able to work out which is which. By the wiring diagram, you have blue, yellow and red wires from the points. If you look at the cylinder number stamped on the points mounting plate you can work out which coil they go to. Coils share cylinders, ie - 1/6, 4/3 and 2/5.

tucandugu · Sep 25, 2011

Doc59 said:
Carles,

Firing order in my manual is 1-4-2-6-3-5

As for the 2 green wires, if you look at the colour of the wires coming from the points you should be able to work out which is which. By the wiring diagram, you have blue, yellow and red wires from the points. If you look at the cylinder number stamped on the points mounting plate you can work out which coil they go to. Coils share cylinders, ie - 1/6, 4/3 and 2/5.

Hi Doc59,
many thanks for your help. There was a mesh of coil wires and with the correct order the engine finally has started up.

Best regards.

Carles

dobbinuk · Sep 25, 2011

Congrats Carles! Looking forward to the vids/pics

tucandugu · Sep 25, 2011

dobbinuk said:
Congrats Carles! Looking forward to the vids/pics

Thanks Lee

.
Now finishing last tunning works like exhaust adjustment , new tyres, oil, etc.:doh:
Hope to post a dynamic clip next week...audio included.

Cheers.

Carles

*Here finished before running, face to face with the TNT.

dobbinuk · Sep 26, 2011

That's a great pic Carles. Is it a sign of age when you start to appreciate the look of a classic bike more than a modern bike? Looking at the two there, I think the Sei is the prettiest. Maybe it's just chrome that does it

tucandugu · Sep 26, 2011

dobbinuk said:
That's a great pic Carles. Is it a sign of age when you start to appreciate the look of a classic bike more than a modern bike? Looking at the two there, I think the Sei is the prettiest. Maybe it's just chrome that does it

I think so Lee, all the classic bike collectors I know are old (except me :rolling: ). Seriously speaking agree with you, is a sign of age...
the bike on the left is what you dreamed when you were young, the bike of the right is the bike that makes you dream, just now... when you're not so young. The equation is, more or less this: age you had when you dreamed for the Sei plus the years between the Sei data production and the TNT, and you have your real age

For me the beauty of the Sei is explicit, she shows all what she has, and may be more, -chrome and so...- , while the glamor of the TNT is more perverse and hidden -you know...-.
The truth is that they are two completely different beauties, without any coincidence except the brand and its exotism.

Cheers.

Carles

Doc59 · Sep 26, 2011

Glad you got it running Carles, thats a nice pic too. Makes me think I should get mine on the road rather than spending so much time restoring the Kawasaki first.

You're probably right about most classic bike collectors being older. I know with mine that the Benelli and the Mk1 Lemans are bikes I lusted after but couldn't afford when I was a teenager but now have the time and money to have them. Reason for restoring a z650 is that I had one back in the 80s and it was my first decent road bike so always had a soft spot for them.

tucandugu · Sep 27, 2011

Doc59 said:
Glad you got it running Carles, thats a nice pic too. Makes me think I should get mine on the road rather than spending so much time restoring the Kawasaki first.

You're probably right about most classic bike collectors being older. I know with mine that the Benelli and the Mk1 Lemans are bikes I lusted after but couldn't afford when I was a teenager but now have the time and money to have them. Reason for restoring a z650 is that I had one back in the 80s and it was my first decent road bike so always had a soft spot for them.

Thanks Doc59!.
Age besides all of us who are doing this sort of things must have a young spirit.
You have a nice collection and probably a lot of work to do. What happens with your Sei, is still to be rebuild or is ready to run?. Hope to see some pics soon.

Carles

Jedzo · Sep 28, 2011

Carles photo is such a great comparison between the old and the new. It graphically shows why after all these years of riding I've gone away from the modern bikes and back to the classics. Somehow they just look right. All mine shake, rattle and roll and require more maintenance than ever but to me that's part of the attraction. They're like living breathing things - sort of like steam locomotives. Sure they can't cruise at today's high speeds (where you actually can) and they're easily beaten away from the stoplights by the modern bikes but firstly you've got to get to the front row to do that. And a Bonnie or a Spitfire with US spec bars is a lot easier to thread through a line of traffic than a new multi.

I can't see myself ever going back to a new bike now.

tucandugu · Sep 28, 2011

Jedzo said:
Carles photo is such a great comparison between the old and the new. It graphically shows why after all these years of riding I've gone away from the modern bikes and back to the classics. Somehow they just look right. All mine shake, rattle and roll and require more maintenance than ever but to me that's part of the attraction. They're like living breathing things - sort of like steam locomotives. Sure they can't cruise at today's high speeds (where you actually can) and they're easily beaten away from the stoplights by the modern bikes but firstly you've got to get to the front row to do that. And a Bonnie or a Spitfire with US spec bars is a lot easier to thread through a line of traffic than a new multi.

I can't see myself ever going back to a new bike now.

Great bikes in your garage Jedzo, congratulations!.
Agree, classics was made to give feeling and glamor and actual superbikes has been designed to fight upon the chrono, born in the track. Nevertheless some few motorcycles like the modern Benellis, at my point of view are able to achieve both aspects: sensations and performance . May be this is their best quality.
Of course, they never will transmit those so special things of a real classic: is a question of time.
In the real life, enjoyment and feeling are more important than the chrono, probably because of that, marketing departments are launching remakes of their classic icons.
One thing is clear, with such two wheel jewels for sure you don´t need any "modern" bike to enjoy your life.
Cheers.

Carles

Doc59 · Oct 9, 2011

Jedzo, wouldn't mind adding a couple of your bikes to my stable too, nice collection. I've usually got a modern bike in the collection too purely because they are good every day work horses (the Vstrom) and pretty easy to ride quickly. Saying that, my biggest thrill is chasing more modern sports bikes through the twisties on one of my old bangers. The Guzzis actually handle that very well. Biggest difference I think is that new Japanese sports bikes are easy to ride fast, I know with the Guzzi's that you really have to get to know the bike first.

Carles has motivated me to get my 750 on the road, it's actually pretty perfect aside from a leaking oil seal so i'll be sorting that now and posting more here.

Quick pic:

tucandugu · Oct 9, 2011

Nice bikes Doc59!.

It's great that you've decided to tune up your Sei. She looks brand new, ready to run.
Suppose oil leak is a minor problem, may be oil filter joint or oil cap joint?.

As I posted recently, after starting up mine, now is impossible to start again. 2 of the 3 breakers doesn´t bring spark or some times the spark is very weak. Have you experienced similar issue?.

Hope to see the bike running soon (probably earlier than mine...:bawl: ).

Carles

Benelli 750 Sei starting problems: Help!

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