B2 rep water pump issues

[Ray LeCheminant]

Hey guys, just finished putting new top end together for my B2 rep. However, the water pump is giving me grief. AS suggested, I have replaced all crank bearings and seals, and decided to replace the water pump bearings and seal also, as apparently the seals are normally shot.

Here however is my problem. Before I bolt on the pulley the impeller free wheels nicely, but as soon as I try to tighten the pulley onto the shaft with the nut, the impeller feels restricted. In order of assembly here is how it is assembled.

Impeller ->Seal (spring towards impeller) -> bearing -> spacer -> bearing -> cir-clip -> spacer -> pulley -> nut

What I am slightly confused about however, is the spacer under the pulley, looks pitted, but is stainless.

Any suggestions appreciated.

Ray

[DELLORTO]

ask this guy! he noes everything about minimoto's, call him on his website, www.pocketdyno.co.nz he lives in auckland,

[Ray LeCheminant]

Cheers - will do...a little more research suggests there should be a thrust washer that goes between the seal and the first bearing....I think...but will contact him. Cheers

[racefactory]

hey mate,

the problem is not actually the water pump o ring seal that is shot from the factory... its that in china they assemble that o ring the wrong way around...

Can you explain the problem again possibly?

[Ray LeCheminant]

I solved the problem - what was missing from my setup was a thin spacer that sat between the case , under the seal and before the first bearing - found a 7/16 copper washer at Repco , put it all back together - PERFECTION!!!

IN essence, without the "thrust" washer the doing up of the water pump pully nut was PINCHING the bearings together in the housing , and inhibiting the movement....one of lifes B1 lessions!

)

[BigAl]

Good stuff Ray, so does this mean the assembly order is;

Impeller ->Seal (spring towards impeller) -> Washer -> bearing -> spacer -> bearing -> cir-clip -> spacer -> pulley -> nut

cheers.

[mr_penguin]

Hey guys, just finished putting new top end together for my B2 rep. However, the water pump is giving me grief. AS suggested, I have replaced all crank bearings and seals, and decided to replace the water pump bearings and seal also, as apparently the seals are normally shot.

Here however is my problem. Before I bolt on the pulley the impeller free wheels nicely, but as soon as I try to tighten the pulley onto the shaft with the nut, the impeller feels restricted. In order of assembly here is how it is assembled.

Impeller ->Seal (spring towards impeller) -> bearing -> spacer -> bearing -> cir-clip -> spacer -> pulley -> nut

What I am slightly confused about however, is the spacer under the pulley, looks pitted, but is stainless.

Any suggestions appreciated.

Ray

Hi Ray

My bike just had a water pump bearing fail due to the seal being in the wrong way...

Where did you get the new seal ? I think the bearing would be from SKF ?

My bike had 627rs bearings....

The crank has quite a bit of side to side play on the big end... was yours like that ?.

Regards
Ian

[Ray LeCheminant]

Hi Ian, make sure you get the 10 x 18 x 4 seals, the 4mm is CRUCIAL, most places will tell you that only a 5 (mm) is available - CRAP - the 5 mm one will bind on the impeller. I got mine from FRANKLIN BEARINGS in Pukekohe, ask for Wes. Re: the bearing, get the 627 ZR spec, better internal seals. Also, note Al's interpretation of my installation:

Impeller ->Seal (spring towards impeller) -> Washer -> bearing -> spacer -> bearing -> cir-clip -> spacer -> pulley -> nut

No kit comes with the "washer" - I used a 7/16 copper washer from one of those packs you find at Repco and the like, went together perfect in theend, and ran freely.

Hopefully firing it up tomorrow night, just having issues with radiator hoses currently.

Any issues, drop me an email (ray@speedshotz.co.nz)

Ray

[Ray LeCheminant]

Hey Al, yep, reading the exploded diagram written in Chinglish can be frustrating at times - but I think I nailed it. The washer just threw me....spins just awesome now - count-down to fire up will be starting soon.

Also, put a nice carb and pipe onto son's D2 tonight - WOW - what a remarkable difference.....7 tooth on the front next and we are flying - well, that is as much as I am going to do to this one until he is ready for the B2

Cheers

Ray

[Ray LeCheminant]

Ian, sorry missed the crank part. I am not sure if you are talking about the mains or the big end rollers? There was a little bit of play on my big end needle rollers, but not excessive - however there was no free play on the main bearings. Back in my karting days, we used to shim the crank if free play was excessive on the crank bearings - I dunno if that is a normal practice with these engines.

Cheers

Ray

[racefactory]

yeah Ian big ends certainly have a bit of play in them on these C1's/C2's... but seriously don't worry man.. that is jsut the TIP of the ice berg on these... port timing is SHOCKING and don't forget to replace the wrist pin/gudgeon roller bearing as they are all very shoddy from the factory and are extremely prone to top end failures! What i did was order the original Blata italian made roller bearing and there was no worries. Also worth doing is drilling an extra 1.5mm hole in the piston to relieve pressure and provide extra lubrication to the wrist pin bearing as the exhaust port often melts to the piston as the current one is inadequate.

[kermet]

Ray,
Good to see you got it sorted, For you or anyone thats interested here are
some Schematics of different bikes and there motors

Elite 13 Water Cooled is the clearest picture and shows details probably close to
your setup

you have to logon to view

http://www.pocketbikeplanet.com/f133/

Cheers
Brett

[mr_penguin]

yeah Ian big ends certainly have a bit of play in them on these C1's/C2's... but seriously don't worry man.. that is jsut the TIP of the ice berg on these... port timing is SHOCKING and don't forget to replace the wrist pin/gudgeon roller bearing as they are all very shoddy from the factory and are extremely prone to top end failures! What i did was order the original Blata italian made roller bearing and there was no worries. Also worth doing is drilling an extra 1.5mm hole in the piston to relieve pressure and provide extra lubrication to the wrist pin bearing as the exhaust port often melts to the piston as the current one is inadequate.

I was picking that about the bottom end they are no honda nsr that for real.....

I have to get get a new top end as well...... stuffed cylinder and piston....

Has anyone tried the 45/46cc top end kit ?..

Regards
Ian

[Ray LeCheminant]

Well guys - I am well pleased with myself - got the beast fired up tonight (with a little help from ether)....BUT ...and there is always a but...keeping it running is proving to be a challenge, almost feels like fuel starvation, bowl is full, but just dies. Plug not getting wet, so not too rich.

There appears to be an airlock in the fuel line occasionally, just below the fuel filter, so will try bypassing that tomorrow.....

Any ideas?

Ray

P.S Water pump appears to be working, as radiator getting warm after multiple start attempts with ether....

[Ray LeCheminant]

I was picking that about the bottom end they are no honda nsr that for real.....

I have to get get a new top end as well...... stuffed cylinder and piston....

Has anyone tried the 45/46cc top end kit ?..

Regards
Ian

Hi Ian, yes, I have just rebuilt the engine with the 47cc TOP END kit....nice kit and reasonable price. Greg sells these, and can supply full instructions. There is a bit of grinding required however, required to the cases, to allow the bigger piston to travel to BDC. Not too hard, but requires patience. Just fired it up tonight, sounds awesome......got a much nice growl to it.

When you do this, replace the main bearings, seals and do the bearings and seal on the water pump.

Ray