Home › Forums › All Things 750 Twin › Technical Garage › How To Fix It › starter motor
- This topic has 3 replies, 3 voices, and was last updated 1 month ago by SquadronLeader.
25th January 2022 at 10:10 am #27887NevTParticipant
Aup,im a new member,my starter is crap on cold starting,ok when warm,ive had it checked out by a motor rewinds guy and he said its good to go,i fitted a new starter clutch ,no better.im looking to replace battery ,any idears on make for max power please ? 1976 B125th January 2022 at 1:55 pm #27888NevTParticipant
I’ve sorted a battery will let you know how I get on 👍28th January 2022 at 11:28 pm #27897KaptainkwakKeymaster
Have you done a full refurb of the starter inc new brushes etc?
I use and swear by Motobatt batteries. A bit more expensive but very durable and reliable.
KK22nd February 2023 at 11:08 am #28053SquadronLeaderParticipant
Hi All, I have posted things on facebook regarding starter motor issues but for those who dont use it here is what I have found.
My starter was very sluggish so over this winter decided to see if I can find out why, I removed the motor and stripped it down to check it according to the manual, firstly I noticed that the motor before strip down was quite stiff to turn with thumb and forefinger which I thought was normal, then I stripped it and checked out all the winding resistance according to the workshop manual, all was as it should be, I cleaned up the comms and the brushes fresh grease ect and reassembled it to find it just as hard to turn, stripped it again and found the 2 pins which the planetary gears mount on can move out and was rubbing on the flat plate (No13) in book so tapped them back down and again reassembled, by the way I did fit a new 6003 bearing, now it was not as tight but still stiff.
I refitted the motor and turned it over without any plugs in and it turned over fine, as soon as the plugs were refitted it was sluggish as usual. As I had nothing to compare it to I bit the bullet and bought a spare from 2 wheel motorcycles (D&K).
On inspection found this one easy to spin with said thumb and forefinger and fitted it straight away, low and behold the engine turned over much better, I tried to start it up and the starter motor would stall if you gave the throttle a twist when trying to start it.
This reminds me of a comment made on FB about the timing and what I did when fitting a new set of points and condenser.
firstly the book says to set the points gap at its widest opening point which should be set at between .3 and .4 mm, so I did this and moved on to setting the timing, the next problem appeared when I was rotating the mounting plate to set the opening point, it did not have enough movement on the plate to do this as if the slots needed to be longer. so I ditched the first part of setting the gap and just set the opening position instead.
As I had stripped the carbs down and cleaned the jets out I was struggling to get her started so let it sit for a night to recharge the battery. Next day it fired up firstly on 1 pot then 2, checked it all out and all now seems fine.
took it for a 50 mile run on Sunday and had no issues.
So to sum up, I think the timing has also got a lot to do with the starter motor issues along with the tightness of the motor. I intend to strip the motor again to try and find out why it is so stiff, might have to change to a C3 bearing I will post any finding in the future.
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