Modern Vespa

My 87 PK XL has a shitty fuel tank. OK, its not the worst ive seen, worst ive had but evidence in the carb filter suggests crud. In the SHBL20 carb the circular filter is getting about a quarter of its surface coated in the tank wall crud after a few months. OK, i can take the carb off and clean periodically but its a faff.

So as we know with all after market parts they are never right. I cannot get a NOS PK XL petrol tank. The supposedly exactly the same PK XL tank from beedspeed was a load of crap, the fuel sender hole did not have the locking ring welded on to surface to secure my fuel sender. Second hand XL tanks are all the same as mine, the lining of tank reacting with petrol. Im not going down the route of cleaning the tank in a cement mixer with nuts bolts in, been there, done it, made things worse on my old LD 150. So i want to talk inline filters.

Issues, the distance from tank to carb is a very short run of fuel line on a smally.

I appreciate that having a full tank of fuel dramatically improves the gravity feed of petrol.

Have you tried or can recommend a good inline fuel filter that i could use to solve my cruddy tank issue.

I need something that i can visually inspect, easily remove and clean but will allow a decent flow of fuel to carb. Ive tried a very small inline filter to test the concept but i could clearly see the fuel not getting to carb well for startup. Once the scoot starterd, fuel started sucking through.

Ive had the fuel tap which was shot to a fast flow tap, so thinking about one of the glass types you can visually inspect. I need a 6mm filter fitting whereby the filtering material will allow a decent flow.

Also, where is the best place to position the inline filter? Near the carb, middle of fuel line, top of fuel line. Aware the fuel taps have filters too but from experience they arent great with fine particles.

If you can recommend a gravity feed inline filter id be grateful. Would it also be a good idea with inline filter to remove the carb filter to improve flow?

Thanks all.

i'd do whatever it takes to get rid of the root of the problem, otherwise it's always going to come back and bit you in the butt. This tank from SIP has the fuel lever sender cutout... https://www.sip-scootershop.com/en/product/tank_23449800

Another option is to remove the rust from your existing tank by any means possible...such as cement mixer or your mom's dryer. There is no magic fix, other than just buckling down and fixing the problem.

Yes and that tank is wrong as it does not have the welded ring at top that locks in sender . Already got it and sent back . I hear you ok, but I want to go down route of using an in-line filter and want recommendations as to what's a good one and best position. I can reach down and release the filter to clean. These tanks are unobtainable. Cleaning tanks seems simple concept but it really isn't , you clean with the mixer route but the protective surface comes off, you get more rust than the problem of the tank lining coming off. I've done it before and not doing again hence wanting filter in-line.

Mines a 1989 PK50XL and i found that the fuel sender cutout on the SIP tank was different from the original. SIP do also sell the fuel sender that fits the tank though, it just makes it a bit more expensive. The sender wire was different as well, i think rather than being soldered into the sender, it was a plug.

Yes like most after market stuff claimed to be for the XL they really aren't . The new tank was crap with poor manufacture of the petrol cap hole too meaning it didn't lock correctly and no means of putting sender unit in place .

I cleaned a pkxl2 tank in shyte condition using a flexi drive bendy thing on standard battery drill ,with a cheap arse pack of different size wire wheels.i could reach every surface inside easily.it got it down to bare metal.idont like the liquid liner product as it eventually comes off and behaves like the fckn rust.A full tank of two stroke petrol mix doesnt rust.nor does a regular ride with the bare metal.If you dont ride so often just wobble the scoots when your passing. Did one 20 years back and its still good

All repro tanks are made for the newer, plastic fuel sender. There's also a better made tank but you'll need the new fuel sender to match…

https://www.sip-scootershop.com/en/product/tank_22844000

Found an old post on MV, so going to try out the Briggs/Straton as seems to have had good reviews online for 2 stroker mopeds/bikes etc.

Inline fuel filter recommendation

Thanks for this, the flexi drive bending thing, have you got a link to one online? Thanks.

I've done the same wire wheel on an extender trick as Bluecati on three or four tanks now. Follow it up with some Electrolysis to get anything I missed.

I still run fuel filters, though. I like the NCY ones for both function and ease of inspection. I've tested flow through them and there was zero restriction, so don't believe the haters.

Thanks chandlerman , they wouldn't sell them in their droves if they didn't work. This is all I asked for and you given me a link , appreciate it. I've seen the one you posted , I've also seen cleanable one too exact the same look . It's down to the microns of filter as in the old MV post it was stated nothing higher than 150 microns else gravity flow impacted . What's the best position on the fuel line in your opinion ?

Glad I could help

I've cleaned out my NCY's with zero issues. They unscrew from the center filter and you can blast it all with carb cleaner. Takes no time at all if you're disconnecting the fuel line anyway.

Thanks, what's the best position on the fuel line? I'm on a small frame so fuel line length is short

I'm about to install one on my Smallstate. I'm going to put it an inch or two from the fuel tap. Basically, just enough line to not force the bend from horizontal to vertical. My run is abnormal, I think, because of the (very) non-stock carb.

I use 8mm plastic filters that are about 40mm diameter. At this car type size there is almost no restriction.
Fit as close to the tank as you can. Even if the line loops down a little the flow will be the same as direct.

Just be sure to keep the total fuel line length, filter included, the same as the original fuel line, sans filter. I know it matters in the P style bikes, may also apply in smalls.

Thank you very much , really helpful

Great info , much appreciated. Out of curiosity, have you been tempted to remove the filter in the carb as you have one in the line, increase flow? I've had a fast flow fuel tap installed . Before with the small frame even ensuring the fuel pipe went from tank to carb under the choke bar improved how quick it would start.

I'm sure you're right. On my px 177 the line was two inches too long and if tank was less than half full at 60mph I'd run out of fuel then it would kick back into life 55mph. Two inches too long enough to cause issues . Thank you guys for all helpful info.

In always remove the in carb filter. They are not helping flow when there is an in-line filter.
When it's running again, let's go through the pilot jet set up. Half the time they are too lean and it affects starting.