Suzuki GN250 Bobber starting problem

[nodrog:Me]

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[RichardB]

Hey Tombstone, did you get this bike going in the end? I think I have a similar problem. I am able to push start the bike though. Does anyone here know whether a faulty stator can cause he electric start to fail. All I get is a clicking solanoid.

Yeah I'm curious too. Have a GN250 that push starts and runs fine, but trying starter only get a click and feeble whir occasionally. Now for the interesting stuff - swapped out (one at a time) with a working GN250 : battery, starter motor and solenoid. All of which worked ok in the good GN, none of which made any difference in the dead GN. As it runs fine when push started, then its not a engine mechanical issue. Having isolated out the battery, starter motor and solenoid there's not a lot of electrical left. I've tried a car battery directly to starter motor - in the bike its really feeble. On the bench runs like a champ.

So, I'm down to a mechanical issue in the sprag clutch connecting the starter motor to crank. It all looks legit and can only go together one way (??), or am I wrong?

I haven't gone over the starter button switch - the car battery directly to starter motor failure kinda rules that out. Earth strap on battery and starter motor clean and tight.

Anyone else with grey matter input that could help?

[ellipsis]

...sounds like your grey matter is working just dandy...carry on...

[awayatc]

Did not read every post, but.......
to eliminate electrical wrongs.....hook up jumperlead from good battery to + terminal on starter.
Hook up jumperlead from - battery to starter body.
then use 3rd little jumper lead from + battery to solenoid.

[spanner spinner]

looks like your on the right path and have done most checks that I would do plus a few more BUT!!! check the earth cable connection to the engine. This is a cable bolted to the right rear of the engine and the negative battery terminal and is connected by one of the clutch cover bolts. these get left off all the time and then the starter motor tyres to earth back through the wiring loom earth which is to light for the load. Even if the cable is connected take it off and check the connection for corrosion as there is a mixture of aluminium, copper and steel in the connection. add a little electricity and moisture and you get the perfect conditions for corrosion which will eventually cause a high resistance connection.

[RichardB]

Solution at hand...found a seized GN250 for small change which has started me on a tangential path. Seized one had lunched on an exhaust valve - net result = punched piston & skirt (surprisingly FA damage at all to bore!), only valve stem left in head, seriously F'ed up combustion chamber. Its a newer model with bearing shims for cam shaft, but cam and chain were pretty worn. Other surprising thing is that starter would turn over motor (good boy...don't do that for long with that shit going on inside her) Sooooo.....

New plan - strip both motors. Measure, look, twist, poke, compare...steal the best of for one and part out what's left. Cleaned up required best bits - amazing what a bit of effort with a bronze wire brush can do to engine internals. Gears look polished, things slide against each other real smooth, shiny slick stuff. Sounds like foreplay. Trial assembly of good engine - things turn over real sweet and easy. Gears shift nice and smooth. Strip again with the intention of removing internals and bearings, re-assemble cases, barrel and head to sand/bead/soda blast back to nude metal. Want to do cases in high temp black, but leave barrel and head as is.

Anyone got recommendations for high temp clear coat? I have done regular clear coat on engines in the past but suffers from a bit of yellowing from heat. Seems to stick ok, just dont like the sick colour.

Next question - I intend to cut off the non-essential frame tags. Passenger foot peg loops, rear seat frame behind suspension mounts, extraneous mounting tabs etc. Nothing structural - keeping stock suspension, geometry, seating position (for 1). But before I do that can anyone tell me if that constitutes enough modification to get a LV certifier involved? I've been in contact with a m/c certifier in Wanganui to ask him about my plans. I don't want to build something that can't be legally ridden. I've got bigger, longer term plans for this project (a bare bones leaner sidecar hack) - so his response was "send me your detailed plans for the complete project, otherwise you'll be up for 2x certification costs". I couldn't manage to draw him out on whether a modest frame massage and cosmetics would clear a WOF without a red tape swimming pool.

In summary - mystery of starter motor issue resolved, but underlying cause undetermined. Kind of like saying your STD is cured, but we don't know how you got it. Don't think it was engine earth - had been cleaned and tightened. Plus car battery to starter motor (installed) still got no engine turn over. M/c battery or car battery to starter alone (uninstalled) ran fine. If starter motor clutch was rooted it would either not engage and spin freely, or not release - running motor would be spinning the starter all the time. Neither is the case. Still ??? http://www.kiwibiker.co.nz/forums/im...lies/blink.gif

[ducatilover]

Did you open the starter up? Could have been a cracked magnet or something

Just modify it mine might have a WoF one day

[RichardB]

Hahaha..yeah never much of a fan of bureaucracy interfering with art, science and "damn that looks cool". I've gone other way with mine - bobber vs cafe. Your rear sets look cool. I need to figure out some forward controls. Throw some pics up soon.

Yeah, possibly a cracked magnet that shows up under electrical load. Under no load (out of engine) spins freely, but in engine won't crank, regardless of battery/solenoid/starter switch/earth.