Gpz1100B1 starter motor

[scott]

Hi, i have a Gpz1100b1 engine with high compression pistons. I can only assume that it has a two brush starter motor due to it struggling to turn the motor over effectively. It will start but it seems to struggle. Does anyone know of any other starter motor that will fit but has much better torque??

[zed1015]

All the non kickstart J type engines use a 4 brush starter.
Best you can do is refresh the starter or buy a new one and then use a battery with higher cranking amps making sure all the wiring and contacts in the starting system are 100%.
Did that on a high comp 1260 motor to cure the same issue.
Failing that you could of course twin plug the head.
Use the new vertical 10mm plugs for running and fit decompressors to the original 14mm holes.

[scott]

Thanks Rob. Any suggestion of what battery would do the job?

[zed1015]

The 1260 i did was a Harris and we used a larger Motobatt which mounted under the single seat tail.
It was bigger than a stock Z battery box though so you would have to find one with the correct dims to fit the Z.

[Robw]

Had a similar problem with my lawson, got an overhaul kit from Electrex World and it worked a treat.
You can also fit a starter motor from a Hodna cb900(I think) , you have to rotate the casing, but it's got more amps.
Rob

[scott]

Rob, I contacted Electrex as a first port of call. They don’t do a starter motor for the Gpz. I didn’t enquire about an overhaul kit though, will do tomorrow. I presume Lawson and Gpz use the same starter motor. I think you have stated that already(1015). I’ll look into an alternate battery too.

[zed1015]

I presume Lawson and Gpz use the same starter motor. I think you have stated that already(1015). I’ll look into an alternate battery too.

Yes! same 4 brush starter on all the J type engines.

[scott]

When you say cb900, do you mean an old cb900 from the eighties or the new cb900 Hornet?

[zed1015]

When you say cb900, do you mean an old cb900 from the eighties or the new cb900 Hornet?

You need a 0.8kw starter from either a cb900f or cb1100f.
If you get one beware that there were two types with the other being 0.7kw which you want to avoid.
You could also buy one of RICKS Z9/1000/1100 starters which are claimed to give 15% to 20% extra power.
https://www.ebay.co.uk/itm/174824745222 ... 28b45de906

[scott]

Thanks Rob