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MXR problems

Posted: Mon Oct 22, 2007 10:05 pm
by Kic
first of all, hi to all! I`m new on the forum.

I bought the MXR in totally messed up state... then restored it.

new paint job, tires, brakes ignition, bearings, gaskets..etc.

The problem i`m having is with the idling...

When i pull the choke it works fine but without the choke it stalls and it`s impossible to drive below 5000rpm.. over that point the bike runs fine.

The carb is cleaned and inspected, new air filter fitted, new spark plug, coil, stator... i don`t know what else to check...

could someone tell me what are the stock sizes of the jets and is the PHBH 28 MD original carburator on the MXR

TNX

Posted: Tue Oct 23, 2007 7:49 am
by hahne
I think; it`s the carburator!! Clean it by Ultrasound!! ... or take a new one. Bye Gottfried

Posted: Tue Oct 23, 2007 8:17 am
by gileraXR1
Hi!
Yes Gottfried have reason, I think could be minimum circuit (idling circuit).
You can take a part carburetor and transport it in a small basin with fuel or acetone... and re-clean it..... :wink:
But you must be very careful! Acetone melts plastics and rubber parts..... :shock:
About stock sizes of the jets in PHBH 28 MD original carburator (for MXR), I'll teel it in the afternoon! *schnarch*

Have a nice day!

Ciao

Marco

Posted: Tue Oct 23, 2007 8:49 am
by hahne
Or take citrid acid, but be carefully! Bye Gottfried

Posted: Tue Oct 23, 2007 2:17 pm
by gileraXR1
Hi Kic!

Here technical data of carburetor, directly from Gilera MX1/MXR 125 workshop manual:

- fuel N.O.= or > 96 (octane numbers)
- carburetor Dell'Orto PHBH 28MD
- diameter 28 mm
- maximum jet 135
- minimum jet 48
- starter jet 65
- conical pin X40/3rd position
- sprayer 264 DG
- throttle valve 50


Good luck! :wink:

Ciao

Marco

Posted: Tue Oct 23, 2007 3:15 pm
by Kic
thank you!

The specs. are ok but there is still no improvement

is like there is low air in the mixture

I tried a different carb... the idle was ok but i`t wont rev properly :roll:

Posted: Tue Oct 23, 2007 3:19 pm
by hahne
Othersides: I have a lot of new 28 mm carbs here on store!! Bye Gottfried

Posted: Tue Oct 23, 2007 4:54 pm
by gileraXR1
Kic wrote:thank you!

The specs. are ok but there is still no improvement

is like there is low air in the mixture

I tried a different carb... the idle was ok but i`t wont rev properly :roll:
Well.... now I tell you what's the problem of my XR1:

- engine suck air from some place or part (and now I know from where).....!:cry:
- at minimum of rpm it'a all ok...... (1500-1600 rpm)
- when you open throttle a little (2000-3000 rpm)... there is this sound: BOOOOOO.... BOOOOO :roll:
- and when engine return to minimum rpm it remain quite accelerated for some seconds....
- after this n° of rpm all it appears ok (4000-7000 rpm)...

If this it's your exact problem.... well... I think that it's possible that you must to take a part all engine and.... change gasket set of crankcase! :shock:

However look at:
- air conduct (from air box to carburetor), if it's well sealed....
- mixture collector (from carburetor to reed petals group), if it's well sealed too.....

Good luck! :wink:

Ciao

Marco

Posted: Tue Oct 23, 2007 5:09 pm
by Kic
believe ti or not i cheked all of those things... :evil:

i fixed the choke to bi opened half way all the time and now it`s ok...


Another problem... anyone has a motoplat black ignition coil :lol:

mine died a few moments ago :evil: :evil: :evil: :evil: :evil:

Posted: Tue Oct 23, 2007 6:17 pm
by gileraXR1
Kic wrote:Another problem... anyone has a motoplat black ignition coil :lol:

mine died a few moments ago :evil: :evil: :evil: :evil: :evil:
Sorry, actually... no one! :cry:

Ciao

Marco

Posted: Tue Oct 23, 2007 6:45 pm
by Kic
those ignitions are very rare aren't they? I spent 3 months tracing the stator and flywheel.

I managed to burn one original black motoplat and one universal ignition coil :cry:

can`t figure out what went wrong :?:

I think i will sell the god dam thing.. i spent a fortune on it trying to make it work

Posted: Wed Oct 24, 2007 10:31 am
by gileraXR1
Kic wrote:those ignitions are very rare aren't they? I spent 3 months tracing the stator and flywheel.

I managed to burn one original black motoplat and one universal ignition coil :cry:

can`t figure out what went wrong :?:

I think i will sell the god dam thing.. i spent a fortune on it trying to make it work
Hi Kic!
If you want I can try to find some things you are looking for, here in Italy.
If you want.... please tell about it!
Have a nice day.

Ciao

Marco

Posted: Wed Oct 24, 2007 10:57 am
by hahne
Othersides; I have a lot on store! Bye Gottfried

Posted: Wed Oct 24, 2007 1:43 pm
by gileraXR1
hahne wrote:Othersides; I have a lot on store! Bye Gottfried
That's right!

Ciao Gothfried!

Marco

Posted: Wed Oct 24, 2007 4:09 pm
by Kic
i`m interested in the price of the origina coil.. because the last one i bought cost 40€, it was an universal coil and it worked well :roll: