Re-build of my blown engine + upgrades

[slawenm]

thought I'd make a thread show how am going with rebuilding that blown engine, got most the parts through the post today the new parts look alot better than the last ones I bought.

first thing I did was open box and snap shot the shiny new parts
all ready gapped and installed piston rings on this pic.
Edit: was about to chuck box and found an exhaust gasket lurking in the bottom will save me a few pounds


very wet and cold outside so wont be doing much more today.

[slawenm]

Forget that been told to just fill it with oil and tip it out the hole the piston goes into instead.

I can see three larger bits of metal that wont come out of the oil drain so trying to pour them out of where the crank is, however oil drains too slow and with each flush they are barely moving I need to quickly fill and flush it to get them out I reckon.

I know I need something thinner to flush with and.... I know Brent suggested kerosene in another topic but I've heard this stuff can ruin the oil seals and bearings etc how true is this?

[190mech]

Kerosene will not hurt the bearings or seals!I've used a pump up garden sprayer for years to flush engines...

[slawenm]

glad to hear it wont cause damage.
not done much again today bad weather and sundays the family have a getogether.

Browsing Ebay I found a 22mm carburettor quite cheap. I know Fox advised a 20mm one to me but for some reason hard to find in the UK and ones I am coming across are very pricey.
www.ebay.co.uk/itm/Scooter-50cc-CARBURETTOR-22mm-139QMB-Baotian-/160693575764?pt=UK_Motorcycle_Parts&hash=item256a156054#ht_2717wt_1265

Wondering if I'd get any gains over my 18mm standard carburettor which has no accelerator pump. its a big jump up from 18mm to 22mm would it be to much..... and cause poor performance?

[slawenm]

saw this gear up kit www.adrenalin-pedstop.co.uk/p-Top_Racing_primary_gear_kit_3_parts_for_Chinese_4T_scooters__17-3938.aspx
good price non pressing ect and its a different ratio of the Naraku ones that I've read infact rob you of top end speed.

[reveeen]

1) when the hole in your head (where the intake mounts) is only 18mm a 22mm carb is not going to end up doing much.

2) An up-gear kit is a good idea, but only if you have no troubles pulling the stock gears.

Both items you have linked to are, well, not quite as cheap as they should be..... SHOP AROUND!

[zedooo]

Yeah little carbs have much better airflow...
Maybe it would be a good idea to get a small-diametered GOOD flatslide carb? (like Mikuni)?

[reveeen]

"Being one to talk", I have a 24mm on mine, but in my case it was a matter of using what I had hanging around, if I was to "buy one in" it would be smaller.

[slawenm]

the prices are from the UK only places I can find cheaper gear ups or larger carbs are from USA and the price in postage makes up the difference + is the risk of having to pay the taxes and duties on the items too.

but thanks for info I'll buy a better 18mm carb with an accelerator pump on most likely.
my engine will be 72cc again when I last had it 72cc it had more than enough power to pull taller gears at least it felt that way.

[slawenm]

Okay shes once again alive I've down jetted the carb because it was bogging running way too rich. I bought a brand new Iridum NGK spark plug but it seems to be faulty bike wont fire off it but if I take it out of head and put it on my HT boot and to the frame it shows a spark. very odd... not happy anyway cost 3x as much as a normal NGK plug.

fitted this new varitor today with the 5.8g weights gave a gps confirmed 5 mph increase so well worth the money for me


my back wheel seems to be spinning freely no matter how high or low I set my idle, the only thing I can come up with is clutch related and most of all springs, time for a set of tougher springs in there or maybe lighten it?

[90GTVert]

Springs or lightening the shoes should help with the tire spin assuming the idle is set to the proper speed. Something like 1900RPM. If you have a scoot with a parking brake, you can set that to stop it.

[slawenm]

my tach is completely shot so not sure on the speed but I set it by ear as I always have just seems with this new kit + varatior it wont stop spinning until the idle is so low the bike is spluttering with very dim lights.

[90GTVert]

That kit should come with a spacer that fits on the drive boss. You could try using that. Might free the belt up at idle instead of squeezing it in the vari.

[slawenm]

aye it has a like 1mm spacer with it, I didnt know what it was for so left it off, will that tiny thing knock my top speed down?

[Deleted]

WHAT SIZE BORE IS THAT ANd where did you get the variator?