
Screech on start up
- denisblackvtr
- Posts: 167
- Joined: Sat Dec 04, 2010 4:08 pm
- Location: North Tyneside
Screech on start up
Hello oh wise one's, sorry hav'nt been on for a while but i've been doing cct's, vfr handlebars etc. Anyhoooo i've got a problem. When i start my bike from cold it's no problem, but when it's hot it screeches as if the starter is'nt engageing properaly. and it seems to be pulling the battery down. Has anyone got the answer and solution to this problem? Any help will be greatly appeciated. Thanks Den. 

GAS GRASS OR ASS NOBODY RIDES FREE
Re: Screech on start up
Two possibilities:
1. Manual cct chain tension too tight.
To check try slackening manual tensioner until you can hear a slight rattle on tickover, then back in until the rattle goes quiet, no more.
2. Transfer gear between the starter motor and sprag clutch. the two gears are pressed together, but have been known to slip slightly, giving the sound you describe.
If it's not 1. it will be 2.
If so, buy one from a breaker, you'll need to pull off the flywheel and sprag clutch, not difficult really. You'll need to take the front cct out, and then take the lower mounting bolt out from the tensioner blade; you can then just about slip the gear in.
They don't often go, but I recently bought a bike very cheaply because of this problem, the "mechanic" who was asked to fix it couldn't isolate the fault so I picked it up as a non-runner.
1. Manual cct chain tension too tight.
To check try slackening manual tensioner until you can hear a slight rattle on tickover, then back in until the rattle goes quiet, no more.
2. Transfer gear between the starter motor and sprag clutch. the two gears are pressed together, but have been known to slip slightly, giving the sound you describe.
If it's not 1. it will be 2.
If so, buy one from a breaker, you'll need to pull off the flywheel and sprag clutch, not difficult really. You'll need to take the front cct out, and then take the lower mounting bolt out from the tensioner blade; you can then just about slip the gear in.
They don't often go, but I recently bought a bike very cheaply because of this problem, the "mechanic" who was asked to fix it couldn't isolate the fault so I picked it up as a non-runner.
It's not falling off, it's an upgrade opportunity.
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- Posts: 333
- Joined: Sun Sep 21, 2008 2:34 pm
- Location: Dunstable
Re: Screech on start up
Added to that, I suggest checking out the starter motor for a dry armature end and front gearing - used to get this on stop-start-stop-start courier bikes. While you have this out you can also check the condition of the brushes and the commutator.
Starts with a R. Rrrrrrrr. Motorbike!
- denisblackvtr
- Posts: 167
- Joined: Sat Dec 04, 2010 4:08 pm
- Location: North Tyneside
Re: Screech on start up
Finally got round to loosening of cct's, screech now gone. Thanks Tony and TP. Den 

GAS GRASS OR ASS NOBODY RIDES FREE