Laverda 1200 non start

B

budgie955

New member
Location
sheffield uk
Hi all
I have rebuilt a 1200 (which was running before i stripped it), got to the stage where i am ready to start it but it wont fire up. Take the plugs out and it spins over and sparks great. Put the plugs in and the compression stops it dead, just like having a low battery. So.. i bought a new battery, and it is just the same, tried jump starting from the car battery,  Just the same. I have had the starter motor out and it all looks ok. All that has been done to the engine is a bore deglaze and 3 new sets of rings, and all new cam chain and tensioner blades. 
Any ideas please?

thanks
Dave
 
budgie955 said:
Hi all
I have rebuilt a 1200 (which was running before i stripped it), got to the stage where i am ready to start it but it wont fire up. Take the plugs out and it spins over and sparks great. Put the plugs in and the compression stops it dead, just like having a low battery. So.. i bought a new battery, and it is just the same, tried jump starting from the car battery,  Just the same. I have had the starter motor out and it all looks ok. All that has been done to the engine is a bore deglaze and 3 new sets of rings, and all new cam chain and tensioner blades. 
Any ideas please?

thanks
Dave
Click to expand...

Looking OK doesn't mean it's working OK.  Check the power draw when the starter is fitted to the engine, is typically around 150-200Amps.  Much more than that, and the starter needs a little TLC.  Suspecting the starter managed with the worn engine, but with a bit of compression to work against, it just bogs down.  Assuming of course all the starter-related wiring is in good order and engine/frame connection is fine... :D

With what ring/groove clearance did you end up with the old pistons? ::)

piet
 
I will recite the usual list:

1). Is there an clean/efficient earth path back from the engine to frame and battery?
2). The starter motor might look ok, but are the brushes healthy? Does it need an overhaul?
    Spinning it up without load is not a fantastic test.
3). Have you tried bump-starting her? (I am lucky to live on a slope)
4). Does the starter solenoid have a clean action and good contacts?
 
I always put an earth lead, battery cable sized earth wire from Starter motor bolt to Batt earth.  Try jumper lead from batt Pos + to direct to starter motor + post as a test see if it turns over ok that way. If still no go would suspect you have partially US starter.  Go with suggestion as below

Jugs 

 
Jugs_S said:
Go with suggestion as below
Click to expand...

G'day Will

You're obviously one of the few sensible chaps who has set up their forum profile to show the most recent posts at the top. Most people refer to previous posts as "above".

For those luddites who are viewing the forum in the (default) upside down format, and have to scroll down to find the latest post in a thread - go to Profile, Account settings, Modify profile, Look and layout, then tick the box "show most recent posts at the top"



 
Hi all

The earths are all hefty, new and clean contacts, the brushes in the starter had plenty of life in them, and the commutator was clean, next step is the bump start, but i will get the starter motor overhalled anyway. There is a firm near me that overhalls classic car starters. Unless you guys know an expert in the uk?
i will check the draw from the battery though, good sound advice. Cheers

 
Dellortoman said:
G'day Will

You're obviously one of the few sensible chaps who has set up their forum profile to show the most recent posts at the top. Most people refer to previous posts as "above".

For those luddites who are viewing the forum in the (default) upside down format, and have to scroll down to find the latest post in a thread - go to Profile, Account settings, Modify profile, Look and layout, then tick the box "show most recent posts at the top"
Click to expand...
Then you will be reading everything backwards,it wont make sense.Just click on "unread posts since last visit" and you pick up the conversation where you left off,and follow it to the end.
 
Dellortoman said:
G'day Will

You're obviously one of the few sensible chaps who has set up their forum profile to show the most recent posts at the top. Most people refer to previous posts as "above".

For those luddites who are viewing the forum in the (default) upside down format, and have to scroll down to find the latest post in a thread - go to Profile, Account settings, Modify profile, Look and layout, then tick the box "show most recent posts at the top"
Click to expand...

You caught me, I do just that and big fan of unread post button. I'll go with previous next time. But then again I am Left handed and upside down in Aust. 
 
Starter relay ok?
Cables to earth, battery and starter motor/relay ok?
Weak starter motor? (I have seen a few that would spin up on the bench but didn't have the suds to crank an engine over.
 
The test the very experienced Auto Sparky did to my starter motor was to hold the drive sprocket on the end of the starter motor against a soft piece of timber, he used a 100mm x 100mm column in his workshop and energise the starter motor, this is done with the starter motor off the bike. Use common sense doing this, it will hurt you if you don't take care. If it's working right it will tear a chunk of timber away like a router. If it doesn't spin when in contact with the timber it's in need of work.
 
Vince said:
The test the very experienced Auto Sparky did to my starter motor was to hold the drive sprocket on the end of the starter motor against a soft piece of timber, he used a 100mm x 100mm column in his workshop and energise the starter motor, this is done with the starter motor off the bike. Use common sense doing this, it will hurt you if you don't take care. If it's working right it will tear a chunk of timber away like a router. If it doesn't spin when in contact with the timber it's in need of work.
Click to expand...
:o :o
 
Yep, it got my attention. He had the foreman at Aguss Electric. Started in the 1930s by the Aguss Family, the son and grandson of the bloke who started in finally closed it in the late 80s. Ran into the grandson a few years back. They now own a Battery World Franchise.
The old shop used to rewind alternators, do it all onsite. Real old school. That's how they load tested my starter motor.
 
When my jota showed the same symptoms (good battery and electrics but the starter wouldn't crank over compression) it turned out to be as Grant described. Starter motor didn't have enough grunt. It would spin up OK on the bench but not in the bike. I didn't try using it as a router so can't comment on Vince's test!

Anyway, a new starter motor fixed the problem. Turned out that the stator windings in the old one were shorting out, so the thing pulled a lot of current but didn't make any torque.
 
So when did it run properly and how did this non-starting develop?
 
You must log in or register to reply here.
Back
Top