Linhai 260 questions: rear brake caliper, fuel pump, exhaust By newbug (Read 410 times)

[newbug]

Hello, I picked up a Linhai 260 classic 2006 scooter. This is the yp250 Yamaha clone.. not running/ "sitting for a year"
Happy to find this forum where there is a lot of discussion of this engine etc.

I put in new oil, gas and plug, installed fuel filter, cleaned carb and was able to get it to run at high throttle for around 20-30 seconds. The muffler was shooting sparks (and in bad shape, possibly partially plugged or full of obviously flamible rusty carboned up stuff) after that amount of time so I shut it off.


Questions:
I have now removed the muffler, while I track down a new/ used one, does this engine need back pressure or is it OK to test run it for short periods of time without/ or after drilling out old muffler that I have now?

The plug was fouled black after this so I am not sure exactly if the issue is with muffler restriction, carb, or missing fuel pump.

I was able to find a parts diagram, and the fuel pump is missing/ bypassed. the tank is mounted above the carb level wise and "apparently" the previous owner drove it so maybe gravity feed is ok? Will it even run (right) as-is? I ordered a replacement on ebay that is on its way.

Finally, the rear brake caliper was loose and missing a bolt/pin. The resivoir was dry so I bled it for a long while with a vacuum bleeder, and what came out wasn't too bad. I hit a dead end trying to find a replacement bolt, although it's possible I could try again to order bolts from a Yamaha yp250 source. so I fabricated a bolt using a m10x1.25 thread bolt x50mm long, and grinding down with a angle grinder to match the existing bolt. The bolt seems to work as in threading in to the threads, and the pin section lines things up well.

The pads are installed correctly, there is one retainer clip per the parts diagram, the pistons do move when handle squeezed & the caliper is detached ..however once installed I have been squeezing the handle and the caliper does not tighten up snugly (or engage the brake) at all. It is still 1/2 or more away and loose. 3 attachment bolts are secure.

I can't tell for sure if some part is missing or if the caliper pistons don't have enough travel, or if the master cylinder handle is not putting out enough pressure.

Another possibility is that the existing bolt that I copied was not the correct bolt and the pins are too long. I feel like if I cut 1/2 to 3/4inch off of the end of the pins, it would snug up and work. Is this a crazy idea or worth a try?

Any help VERY greatly appreciated!


Thank you

[newbug]

And the bolts: note: more grinding was done to the new bolt to match exactly after photo was taken.

[cyborg]

You can run the replacement pin you made till you find a original equipment replacement,,as far as the pressure goes either the pistons are frozen in the caliper bores or the master cylinder seals are bad and either rebuild the master or get a new one and replace it

[newbug]

Well a new master cylinder is on order, the old one seemed like it wasnt putting out much pressure, and then started leaking and stopped pumping completely.

but the dual piston caliper is still suspect. one piston was moving fairly well and the other not as well, i did as suggested but in the middle of the process the master cylinder went out.

I would like to order a new caliper if possible, and spent hours last night trying to track one down online that is identical with no luck.. it does not appear to be identical (as far as where the mounting pins are to either the roketa 250 mc-54 or the yp250 yamaha. i am going to pull the 3 bolts to the mounting bracket and see if the roketa or any other similar ones share the same holes and alighnment for the mounting bracket .

any links or advice appreciated to help me track down a replacement caliper


anyways other than that engine has good compression, muffler trick looks like it may have worked, and i am crossing my fingers that the new fuel pump once installed will allow it to idle down evenly and run less erratically.

thanks again!

[newbug]

here is the closest I have found so far, sold/completed listing on eBay from roketa mc 250 b
(2008)

looks to have similar mounting points for bracket





will get measurements tonight

thanks!

[newbug]

Sorry about the terrible quality of the edited picture, i have never tried to do anything like that before.

these are rough measurements center of hole to center of hole. they could be off by a bit, easily

"A"  ~96mm between caliper pins
"B"  ~60mm
"C"  ~63mm
"D"  ~56mm
"E"  ~30mm