More GP100 problems!

[cb1rocket]

Hi all

Finally got engine rebuilt - new piston and a rebore at +1.00 oversize. Went great for the first 20 miles then all of a sudden its running eratic and the throttle just becomes unreponsive, basically the bike just jerks all over the place with constant right hand wrist action.

It was great and was taking it easy as its been rebored for the first 20 miles now all of a sudden the bike just wants to piss me off!

What effect is water in the fuel tank likely to cause? we have had a lot of rain of lately.....

Timing was way off when i got the bike, now I have reset that and got new points. And just to check, I did check the timing again to see if it went off its original mark but nope its ok.

I#m stumped! the first 20 miles was a great grin and smile and now everything after that is steam out of my ears!

[N cee thirty]

drain the tank and the carb and see what happens then

maybe change your plug and air filter aswell
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[pits]

[cb1rocket]

Well my petrol tank has a massive leak so i imagine water has got inside after this horrendous weather.

Is that the effect i would expect to have if water is in the tank?

Anyway another update (same fuel and possible water contamination) the bike did a massive backfire and then died completely - have I wrecked the engine again? Loads of compression so i'm hoping the spark plug has gone duff.

Can't check now as i'm at work and i basically just abandoned the bike for a lift to work!

[pits]

Water and engines don't mix, you could have water contaminated fuel which it will not run on.

Drain the tank, put a new tank on and then try again

[cb1rocket]

[chris-red]

[mr rip]

have a close look at your points & if they look a bit burnt, change your condenser,

a dodgy condenser causes erratic running, back firing, & then a complete stop as they pack up, & that sounds pretty much what's happened to yours

they're only cheap so it's no real loss if it turns out to be something else

the crank oil seal behind the stator plate is worth a look too

another thing to check but not too easy to get to is the woodruff key that times the disk valve mounting

I had mine shear off leaving the disk valve to float freely on the shaft, have a guess at how well that ran,

oh, & yes JB weld works well on tanks, I fixed a leaky steel jerry can with it & it never leaked again
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never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes

[cb1rocket]

[mr rip]

water in the carb would be the easiest to check & fix

normaly what happens on a little single is the bike runs fine at low revs & up to half throttle but as soon as you get past half throttle the bike cuts out but revs again as soon as you close the throttle off a bit, kind of like having an on/off switch at the half throttle point, a quick blast from an air line should fix it

the condenser sends a jolt in the opposite direction when the points open, stopping the current from arking across the points

an easy way to check the condenser is to switch the ignition on & open the points manually & look for a big fat spark across the points as you open them if that happens then it's duff
____________________
never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes

[cb1rocket]

well water in the tank and carb it was then.

So cheers for help there, bike runs as it should.

The tank is still the biggest problem, i'm using epoxy steel and the putty type that goes rock hard can be filed etc but the tank still leaks! Its ok at first and sets hard but as soon as you mount it to the frame back on the bike, it starts leaking again. Problem is its leaking from the edges of the welded on mounting plate that attaches the tank to the frame. So when i tighten it, it distorts the plate and therefore the repair putty so it all leaks again

I think i'm going to have to do something drastic about it.

Can i solder the edges of the bloody tiny gaps?! I would love to weld it but i'm not having it blow up in my face!

[Blau Zedong]

[cb1rocket]

[mr rip]

I've used fast glass resin to line tanks befor & that can work well

but the tank must be drained & vented for at least a fortnight before you try lining it or the stuff doesn't stick properly

my armstrong had a leak down by the mounting bracket & no matter what I tried it just kept breaking open again after a week or so, I think you'd probably be as well to find another tank
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never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes

[nisp]

my ts had a leaky fuel tank when i got it,

theirs stuff called leak fix, it is designed for rad's, petrol tanks that sort of thing. try it 5 quid at halfords
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Suzuki TS 50 1999 Honda CB 125 t2 1981 Yamaha XJ 600 s Diversion Honda cx 500 MZ ETZ 250 1985 Yamaha FZR 400 1981 Suzuki TS 185 1984 Triumph bonneville 790 2001 MZ TS250 1979 Suzuki sv 650 1999 KTM exc RFS 450 2007 Hercules mx 125 1976

[truslack]

[mr rip]

hi Truslak,

thanks for the offer but I sold the outfit a few months back (with a spare tank)
____________________
never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes

[truslack]

[mr rip]

650 quid

I know it was probably worth more than that with the exras I'd put on it but it had got to the point where I couldn't kick it over any more & I just wanted it gone
____________________
never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes

[Robby]

I have tried to replace a leaking (rusted) tank before now. It didn't work.

To weld it you need to sand back to bright clean metal. In doing this I found another 20 pinholes in the area. Tried MIG welding, just blew holes. Tried brazing which worked to an extent, but not well enough - every time I brazed up the holes I just found more little ones.

Just get a decent tank. May seem expensive, but you'll spend more (and also a lot of time and effort) trying to weld and then repaint the existing tank.

[cb1rocket]