GP3 Replica - Water Pump leak Issue

As another member pointed out to me and I kept an eye on it, the water pump leaks when in use (motor running).

If anyone knows exactly what needs to be done to stop the leak please let me know.

Oh, but holy mother does that bike fly out of the box. Cant wait to get my Dellorto carb and BZM ignition on it.

there are alot of guys on the australian PB forum that have reworked those W/Ps
PBracing.com au or something like that

Thanks. Found an entire write-up of a guy that tore his reverse motor down. As I though, thats what Im going to have to do. haha

i think that was me that did that right up :P i ran it without oil (it had grease on the gears just didnt run submerged) and put standard bearings in there to try make it run a bit smoother.

in the end i sold both motors for $200. i just got sick of them. they are seriously not even worth their weight in metal.

a few other guys have converted them to run a standard motor which is HIGHLY what i would recommend.

check the water isnt dribbling out around the base gasket though on the barrel. sometimes it drips down under the pullstart area and you can be mistaken. sometimes an easy fix.

otherwise yeah youll have to rip the motor down and change the seals in there and most likely the bearings if water has been seeping in. get the proper polini shaft and impeller while your at it too.

if you have to do a full rebuild enjoy that. theres at least 8 bearings and 8 seals you have to change :cry: $$$$

or as i said before put a bzm 620 or polini series 2 in there ;p even polini gave up on those things.

they have tons of bottom end and gearing from the factory though. thats how the motor is setup. they just have nothing up top.

cheers

If I wanted a conventional bike I would have slapped a BZM motor onto my extra GP3 frame. :toung:

If you think about pocket bike racing and the tracks normally used to race on, tight and twisty, youd know bottom end can be more important then top end.

Polini know what they are doing. The one major issue with the reverse motor is parts availability. They wouldnt have put out the motor in the first place if it was crap.

I will do what I can for the last two races of our season, then rebuild the motor during the winter with proper bearings, seals, etc.

well thats subjective imho, considering the GP6 went back to the standard motor id say thats as good as saying "yeah it didnt work" in my eyes. but whatever :cheesy:

it had some good ideas "in theory" but in reality none of it worked. i.e. counter rotating crank to offset some of the gyroscopic force of the wheels. the crank is so light it does nothing for it plus the heavy transfer gear rotating in the opposite direction totally offsets it once again. then you have the transfer gearbox. in theory it was done to make the chain run smoother by running a giant sprocket. but with the 6 seals it uses it doesnt run well at all.

wasnt too bad when i put standard bearings in there and took out the seals. but i never got to race the bike for any length of time so i have no idea if it would have gone in the long run. im suspecting it would just fine.

have you done anything else to the bike yet? definitely get the polini coil if you havent already! it was one of the few things i did that made a great difference. its been a while now but it picked up nearly 1000rpm off it.

best of luck with it!

A BZM coil was the first thing I got for it. I like building in stages to see the difference the upgrades make; the coil will make a big difference in revs plus its loads more reliable.

Running a genuine Dellorto will be the next step then I will get into the head.

Im optimistic, I think I'll be able to make it work like the beast it is.

out of curiosity where did you get a bzm coil to fit the gp3? i didnt know they made one. doesnt mention it on their site either.

These reps are very problematic.