Slow turn over on starter

[Svsam]

Did have a search before and have tried all advise so far, so dont shoot just yet...

As title says, the starter is real sluggish turning over, ive tried bypassing all wiring putting the live straight on top of starter. Also swapper the starter off my other B12 engine. Always cranks at about 1/3 the speed it usually does. I've tried a 1200 bike battery, and sprinter battery and the battery off my l200 andit still cranks the same speed.

The engine is a B12 bottom end with dot head fitted, the whole point of the head swap is raising compression, is the compression to high to turn over now? 

If i remember right @dupersunchas a motor with dot head.. any starter troubles?

Any advice or tips much appreciated 

 

[Captain Chaos]

ground cable between engine and Battery - ?

[Svsam]

14 minutes ago, Captain Chaos said:

ground cable between engine and Battery - ?

Checked and now using negative to a good contact on the block. 
cheers though. 
starting to question whether the jump leads are restricting cause they get warm. 

[Gixer1460]

1 hour ago, Svsam said:

Checked and now using negative to a good contact on the block. 
cheers though. 
starting to question whether the jump leads are restricting cause they get warm. 

If it's turning slow and the leads are getting warm and its a DOT head i'd suspect compression maybe a culprit ! Assume you are using decent size jump cables - not those pissy 'hardly fit for purpose' 10mm cables - ideally min. 25mm sq welding type cables for least resistance!

[dupersunc]

Mine turns over fine. No issue at all. 

[clivegto]

I have a 1052 with a flowed dot head on, it starts with no problems. 

Bought a 1340cc motor a few years ago which turned over slowly when trying to start it. After a bit of investigation it turned out one of the starter motor brushes was missing.

Try another starter motor if you have a spare or can borrowed one. 

[Wagola]

1 hour ago, Gixer1460 said:

If it's turning slow and the leads are getting warm and its a DOT head i'd suspect compression maybe a culprit ! Assume you are using decent size jump cables - not those pissy 'hardly fit for purpose' 10mm cables - ideally min. 25mm sq welding type cables for least resistance!

I may be looking at this a bit simplistically but...……. if its a compression problem then take the spark plugs out and see how it spins over then ?? If it spins freely then it points towards a compression problem ?

[Dezza]

Why not go through the standard procedure for this (common) problem? Personally, I would start with a battery check, then move on to checking all of the wiring for anything obvious. Then it's the old connect a good battery + ve to the starter terminal, then quickly earth to the engine. If the starter is still slow it's something with the starter. If it cranks OK, then it's probably the solenoid or a poor earth between the engine and frame. Has the frame recently been repainted/coated? If so it may need an earth strap between the engine and frame as suggested by CC.

[Jaydee]

Is it a regular 12Ah battery? Might need a few more cranking amps for the higher compression. If you can get your hands on a 14Ah battery, see if cranks over quicker.