warby beta Posted June 28, 2011 Report Share Posted June 28, 2011 Hi guys, firstly bear with me, couldnt find anything searching... Been a while, mainly messing with stupid cars (specifically crappy nissans) but its getting close to the manx so the old girl is coming out again for a bit of practice etc beforehand. So my problems, from last year are: Pinking on road / moorland runs, even with choke on, it also starts to slutter / cut out which suggests to me the float bowl is emptying., GGuk didnt have any #38 pilot jets for last years event so i left it alone. I suspect the waterpump is duff, though it never boiled over (i think) is it an easy enough job to change it for peace of mind ? Other than that she seems ok, would like cheap fixes as the nissan is wanting a turbo amongst other things... Bike is a 2008 GG 300 pro, bog standard bar flywheel weight... Many thanks Quote Link to comment Share on other sites More sharing options...
dombush Posted June 28, 2011 Report Share Posted June 28, 2011 Hi Warby Beta Pinking is a funny thing casued by a number of issues. I'm just going to trot out some possible stuff that you can think about:- Pinking caused by:- ---Igintion timing too advanced (has it changed, easy to check) ---Poor grade fuel (ok, unlikely i know.. but if your worried you could use super unleaded) ---change in Squish clearance / compression (have you fitted a new cylinder/base gasket/piston?) ---Overheating-General (is the fan working?, blocked rad / damaged rad / low coolant) ---Overheating-poor pump performance (poor cooling flow causes hotspots on the cylinder head) ---Float height wrong (pilot jet is first to be exposed to air if wrong) ---Poor fuel flow (fuel filter blocked, fuel tap blocked, fuel needle valve blocked) ---Lean mixture (idle mixture screw incorrect, needle clip incorrect, lean jetting) ---air Leak (crank seals, inlet manifold seal, base gasket seal, carb rubber seal) Thats it i'm spent now... need a lie down!! Dom Quote Link to comment Share on other sites More sharing options...
warby beta Posted June 28, 2011 Author Report Share Posted June 28, 2011 Cheers man. Looks like i have a few evenings work to do Simple 2t engines, hmmmmm.... If the car pinks its a million times easier, if it doesnt melt a piston.... Quote Link to comment Share on other sites More sharing options...
laser1 Posted June 28, 2011 Report Share Posted June 28, 2011 if you think your running out of gas, you may need a larger fuel needle valve assembly. I would also check the tank venting. You should get a nice solid stream of fuel from the unplugged line. Quote Link to comment Share on other sites More sharing options...
ham2 Posted June 28, 2011 Report Share Posted June 28, 2011 I think Baldilocks has answered a similar query in the past and knows what size fuel float valve you would need? I can't find the previous topic using the site search? I think Baldilocks will swoop in, he's always hovering in the background...I'll just shine the batman-baldilocks search light up into the clouds. Quote Link to comment Share on other sites More sharing options...
gallunk Posted June 28, 2011 Report Share Posted June 28, 2011 Hi Warby Beta Pinking is a funny thing casued by a number of issues. I'm just going to trot out some possible stuff that you can think about:- Pinking caused by:- ---Igintion timing too advanced (has it changed, easy to check) ---Poor grade fuel (ok, unlikely i know.. but if your worried you could use super unleaded) ---change in Squish clearance / compression (have you fitted a new cylinder/base gasket/piston?) ---Overheating-General (is the fan working?, blocked rad / damaged rad / low coolant) ---Overheating-poor pump performance (poor cooling flow causes hotspots on the cylinder head) ---Float height wrong (pilot jet is first to be exposed to air if wrong) ---Poor fuel flow (fuel filter blocked, fuel tap blocked, fuel needle valve blocked) ---Lean mixture (idle mixture screw incorrect, needle clip incorrect, lean jetting) ---air Leak (crank seals, inlet manifold seal, base gasket seal, carb rubber seal) Thats it i'm spent now... need a lie down!! Dom Quote Link to comment Share on other sites More sharing options...
laser1 Posted June 29, 2011 Report Share Posted June 29, 2011 You want a minimum of a 300 fuel valve to avoid problems (on a Dellorto) Quote Link to comment Share on other sites More sharing options...
copemech Posted June 29, 2011 Report Share Posted June 29, 2011 If at lower throttle openings, you may want to up that pilot jet still. Quote Link to comment Share on other sites More sharing options...
ham2 Posted June 29, 2011 Report Share Posted June 29, 2011 You want a minimum of a 300 fuel valve to avoid problems (on a Dellorto) I think that's the answer I was trawling for? Quote Link to comment Share on other sites More sharing options...
sting32 Posted June 29, 2011 Report Share Posted June 29, 2011 I think that's the answer I was trawling for? just a FYI. I had an 04, that was fitted with the needle on the float, that was spring loaded (which means it was 3 pieces). The needle itself must have wore out, as it would jiggle itself almost apart, but then be stuck (temporarily) at considerably longer lenght (causing the floats to close the fuel inlet, at a much lower level. THis Issue, was found purely by accident, & cost me several hours at a 2 day meet... because I would take carb off assuming a dirt or something issue. at a meet living out of pickup, not all the good tools or places to work you know. after umteenth attempt (dissamble, reinstall, ride, run fine for a few minutes, then have issues...) I dropped the float while removing, which caused the needle to actually pop apart. while trying to put it back to gether, I ended up just crimping it to make it solid as possible to finish that weekend. I had posted this story back when, and barely think it might be related to what happens to you... Quote Link to comment Share on other sites More sharing options...
warby beta Posted June 29, 2011 Author Report Share Posted June 29, 2011 Replies all sound good but im not too clued up on carbs, F/I & management i get fine so.. 300 fuel valve - what is this bit? Fuel needle valve - assume thats the bit the needle in the slider goes into.? If i can find out what i need i shall get it all ordered so i can fit the bits and get on the bike again Cheers Quote Link to comment Share on other sites More sharing options...
laser1 Posted June 29, 2011 Report Share Posted June 29, 2011 Dont feel bad - the nomenclature is confusing for everyone. The fuel valve assembly is a rubber tipped, cone shaped "needle", that is activated by the floats to allow or stop fuel into the carb bowl. There are different sizes to allow for various maximum flow rates. Heres what the assembly looks like. There is a number stamped on the side. If you are running out of gas, and the supply into the carb is OK, check this. You want at least a 300. Maybe higher is your doing alot of road work. My guess is you have a 270 and a 300 will help. A good info source for the dellorto carb is; http://www.thisoldtractor.com/gtbender/mg_manuals/dellorto_manual.pdf Quote Link to comment Share on other sites More sharing options...
warby beta Posted June 29, 2011 Author Report Share Posted June 29, 2011 Dont feel bad - the nomenclature is confusing for everyone. The fuel valve assembly is a rubber tipped, cone shaped "needle", that is activated by the floats to allow or stop fuel into the carb bowl. There are different sizes to allow for various maximum flow rates. Heres what the assembly looks like. There is a number stamped on the side. If you are running out of gas, and the supply into the carb is OK, check this. You want at least a 300. Maybe higher is your doing alot of road work. My guess is you have a 270 and a 300 will help. A good info source for the dellorto carb is; http://www.thisoldtractor.com/gtbender/mg_manuals/dellorto_manual.pdf Ah i see what you mean sir, would a bigger pilot jet in conjunction with the 300 valve be advantageous? Quote Link to comment Share on other sites More sharing options...
laser1 Posted June 29, 2011 Report Share Posted June 29, 2011 Ah i see what you mean sir, would a bigger pilot jet in conjunction with the 300 valve be advantageous? Where is your fuel screw, if its past 4 turns out and you hear knocking/detonation when you chop the throttle, then yes. If your problem is when your wide open on the road, then no. (or probably not as it relates to this problem) I would call your trials dealer or GGUK to get the proper carb jetting recommendations for your area/fuel. They should know EXACTLY what you want. Its a good exercise to go through. Get to know and love your carb and it will treat you right. Quote Link to comment Share on other sites More sharing options...
warby beta Posted June 29, 2011 Author Report Share Posted June 29, 2011 Where is your fuel screw, if its past 4 turns out and you hear knocking/detonation when you chop the throttle, then yes. If your problem is when your wide open on the road, then no. (or probably not as it relates to this problem) I would call your trials dealer or GGUK to get the proper carb jetting recommendations for your area/fuel. They should know EXACTLY what you want. Its a good exercise to go through. Get to know and love your carb and it will treat you right. 4 or 5 turns i think, not 100% right now. Yes it knocks when i chop the throttle, even if i give it a blip whilst stationary. But also knocks when on the road / moorland runs. Also run 97ron + and 85ml oil to 5l if it helps... I think ill ring GGUK and see what they say.. Thanks again guys Quote Link to comment Share on other sites More sharing options...
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