180 big bore settings ? By rob63 (Read 1,371 times)

[rob63]

We`ve got a Daelim Delfino 125 gy6 on the fleet at work which has been nothing but trouble. It came in recently having destroyed the top end.
We had a redundant 180 big bore kit sat on the shelves, so rather than spend any more money on the bike than was necessary, I fitted the big bore barrel, head and piston assemblies.
Cranked it over first time today and it was a bit reluctant to start, eventually went after giving it handfuls of throttle. It seems to run fine at maybe quarter to half throttle and over, but won`t idle. If I take the speed down to idle level it sounds like it`s 'chugging' before it cuts out, for want of a better description.
I`m torn between the fact that I may be a tooth out on the valve timing even though it looks good on the markings, or that the carb needs the settings altering because of the big bore. Tried the mix screw to no avail, can`t raise the needle as the clip is fixed.
Question is has anyone fitted a 180 kit without altering the carb/jetting, and had it running reasonably ok, before I try resetting the valve timing ?

[Alleyoop]

Yea you need at least a #38 Pilot jet the 125 probably has a #35 or smaller Pilot jet.
I have a bored out 157QMJ with a 62mm and 60mm stroker crank which brings it up to 182ccs. I have #38 Pilot and a 122.5 Main jet.
Alleyoop

[rob63]

Thanks for that Alley, I`ll have a look at the carb tommorrow

[Gti]

Did the same thing and having the same problems. I made some serious errors with this engine but I think with the parts coming I will be right on track. Make sure you have your valves set to 0.04 on the intake and .004-.005 on the exhaust. Keep us apprised of your progress. I would like to see it work out for you.

[rob63]

Finally got around to doing this bike today. Drilled out the jets but same problem. In an odd moment I popped one of the vacuum tubes off the inlet manifold and the thing ran sweet as a nut. Put my finger over the little tube on the manifold and it`s pumping instead of sucking. Did a comp test and showing low, checked valve gaps and they`re good. I suspect that I have a leaky inlet valve, hopefully have a look at it tomorrow.

[rob63]

This was a leaky inlet valve, ground the valve in and the thing goes like the clappers, lots of low down torque.
Only problem I`m having is intermittent stalling. The thing can be sat idling nicely then die off, it also happens when I come in from a spin around the block and pull up to the workshop.
I tinkered around with the idle screw and it seemed to work for a while but then went back to dying off again. I checked hoses for air leaks to no avail. Adjusted the mixture screw following the normal procedure but oddly the fastest idle using the screw is when the screw is wound right in. The more I wind it out, the worse the idling gets.
Any thoughts gents ?

[Alleyoop]

If you wind the fuel ratio screw closed and it is still idleing stronger then the pilot jet is to big and you need a smaller one so you can cut off more fuel.
Alleyoop

[rob63]

Cheers Alley, it crossed my mind about the pilot, it had a 35 in and I took it out to 40. Just a bit too big I suspect. Thanks very much for your help

[rob63]

Took out the pilot today, soldered it up then re drilled to about 37/38, runs spot on now.