Turbo plumbing for a simpleton

[MeanBean49]

Whats the capacity of the float bowls? Im wondering if they are pretty small your maybe never going to get them to work properly, with the fuel pressure they are maybe just overfillung at the slightest opening of the floats.

But yeah as said above, carbs have to be 100% all the time. I take mine off every month and check them over, float heights have always got higher. If i leave them any longer its starts running too rich and flooding

[El Gringo]

Thanks for the replies guys.

I'll get some rebuild kits ordered up soon.

I re checked the fuel level last night, standard 20mm float heights with about a litre of fuel in my remote tank suspended above the bike

It ran like this on Sunday afternoon and idled nicely

The fuel level is now at the same level or slightly above the 2psi line? I fully drained the outer 2 bowls, then let them re fill and got the same result so i think the original gravity fed readings were way off.

Will drain and re check tonight then i'll recheck with the pump running (and remember to take some more photos)

One of the biggest headaches with this bike is getting repeatable results during testing

[slingy1157]

Ok so to throw another slight spanner in the works here with the gravity test. 

The gravity pressure at the floatvalve is directly proportional to the height of the fuel not the volume.

So an 8mm pipe with the end held 1metre above carbs and then filled with fuel will give the same pressure as a 5 litre fuel tank full of fuel with the fuel level 1metre above the carbs.

 

So the key point here when doing a gravity test is that whatever fuel tank you are using, the fuel level needs to be about where it would be  if it were in the oem tank on the bike. 

So if using a temporary tank, it would be better hung from the bars or similar to better replicate the oem setup.  If you have it hung too high you might get a couple of psi of gravity pressure anyway. Which is not what this test is about. Its about trying to get an oem base line setting so you know what to adjust to compensate for the pressure.

[El Gringo]

I did wonder about that, the remote tank is hanging about 1 m above the bike - the only difference between the 2 gravity tests was the amount of fuel in the bottle, which lends credence to the theory i hadn't let the float bowls fill properly on the first test. 

I'll drop it down and hang it above the carbs where the tank would be then and re test.

I've got some carb rebuild kits on the way, hopefully be here for the weekend

Feels like progress even if it's not really moving forward. Once I've done the tests i'll get a video of it running 

Thanks again for your help @slingy1157 i'd still be blindly stabbing in the petrol soaked dark if not for your insight!

*edit - did a bit 'o' maths - remote tank is approx 1.5m above the floats - that's 15kPa or 2.2ish psi - which would fully explain why the line from the gravity test was everso slightly higher than the 2psi regulator/tank test

Edited June 28, 2017 by El Gringo

[El Gringo]

Seeing as Photofuckit has deemed that 3rd party hosting is now going to cost me $400 a year i'm trying a different hosting service

This was from the other day after the float height drop test on the pump

I re tested the gravity test last night using the fuel tank just above the frame and it was way higher than previous - again almost at the same level as on the pump - in fact probably around the 21.5mm pump test height

Carb rebuild kits should be here today, so i think i'll rebuild them, double check the float heights and re do the gravity test again to triple check before i try it on the pump to see how far it needs adjusting.

On the regulator, i had a look at the return spigot, it was just under a 6mm bore, so i very gently opened it up to 7mm - i daren't go anymore as it's quite thin walled now. The actual hole where the stopper is is about 8-10mm across so that shouldn't be an issue.

Will update over the weekend

*edit - fuck me that pictures a bit big

Edited June 30, 2017 by El Gringo

[El Gringo]

Right another update

Stripped and rebuilt the carbs with new seals and float needles - there was a noticeable difference in the tips, new ones were much wider and less tapered - also the sides of the old ones were definitely worn. 

Rechecked all float heights at 20mm bang on - re tested gravity fed level - bang on the same line as before

Then i plumbed the tank in and re checked the fuel pressure on my gauge, now down to 0.5 to 1 psi ish so i wound it up to 1.5psi to make sure that both ends of the spring were contacting the seats, plug it onto the carbs and retested the fuel level

Bang on the same line as the gravity fed mark.

Only thing i will do is retest it with another couple of litres of fuel in the tank as there was only a drop (circa 1 litre or so) in the bottom so i want to be sure it's the same with a decent amount of fuel.

Other than that i think that's that bit of it sorted (He says with fingers firmly crossed) 

Next job will be to start it up again and try and run it on the tank -  then start re introducing the turbo bits again - plenum and up pipe etc

[slingy1157]

Good work. If the fuel height is about the same as gravity i dont you should lower the float height for the moment.  Just do what your talking about and change one or 2 things at a time.

[El Gringo]

Thanks Slingy, that's my plan, softly softly from here

It all seems a bit too easy though........

[El Gringo]

Retested last night with another litre of fuel in the tank

Level rose above the previous line by approx 1mm - so I backed the regulator off by about half a turn, retested and it dropped back down to the line.

Will fire it up later and hope for the best

[Madb]

waiting with anticipation. fingers crossed.

[El Gringo]

Sorry to disappoint, it got a bit late. I had to have the carbs back off and reattach the float bowl breathers which i took off last time i stripped them.

All bolted back up now and ready to go though. Re checked the fuel level on the pump - still ok 

[Madb]

No dissapointment my end, chap!  just like to see that big smile on your face when it's done.  this has been a great adventure into the unknown. I'm chuffed you have shared it with us. nearly there,eh.

[El Gringo]

Well, i'm not sure if that was a successful weekend or not.

Fired it up and it will idle til the cows come home, let it warm up for a few minutes then flicked the fuel pump on.

Shortly after it started burbling and coughing - so i did the clear pipe fuel level test and lo and behold the fuel level was about 5mm higher than the previous line

I can only assume that the dynamic fuel level is higher than the static as previously measured - kind of as the float is now regulating whilst running it's allowing more fuel in than being closed shut.

As a result it started coughing so i swapped the plugs round again until it started back on 4 cylinders again. 

Before running the pump i had tried it a little richer on the mixture screws which it seemed to prefer.

I also managed to get it to run off choke yesterday which it wouldn't do on Saturday for some reason (which later turned out to be a disctinct lack of fuel in the tank - dozy twat!)

I also tried it full rich and full lean on the needles but due to the fuel pump over richening it all i couldn't really tell which was better - i did manage to get it to rev a bit in both cases but not cleanly.

Not sure where to go from here other than to drop the fuel pressure on the regulator again and try dropping the float heights a couple of mm to try and get the dynamic fuel level closer to the previous mark.

One thing i did wonder was whether the dynamic gravity fed level would be any different?

[El Gringo]

The other thing i found this weekend is that the reg/rec is shot so it's not charging at all - which would explain why it gets worse the longer it runs - presumably it starts loosing spark power as the battery drops

[Blubber]

hang on .... your bad luck has to run out... eventually 

[El Gringo]

2 hours ago, Blubber said:

hang on .... your bad luck has to run out... eventually 

I'm glad someone is being positive, lol 

No, it's getting there now, it was never going to be easy, especially starting from just a frame and an unknown engine.

I think once the fundamentals are sorted things should start getting easier.

Got a few more bits done over the weekend, head light, brake light, mounted the ignition and horn too.

Target was to have it running well and Painted/Powder Coated in time for the Kickback Custom show at the Cheltenham Festival of Bikes in September - this may be a little optimistic

[Madb]

bike won't run very well if yer reg/rect is shot so may be most of the prob. (hopefully)

Do you know what a pessimist is? it's an optimist with experiance! ..... boom boom.

[El Gringo]

Right 1,2,3 i'm back in the room

Had to walk away from it for a bit as it was doing my swede in, but i'm back to it now.

Next step i think is carbs back off, drop the float heights a mm which coupled with running the base pressure at around 0.5psi should prevent it from over fueling I hope.

 

[El Gringo]

Right, potentially some progress albeit maybe not of the good kind

After failing to get it to start again, i stripped all the turbo stuff off, stripped and cleaned the carbs then refitted with just the headers minus the turbo.

I also swapped the ignition cover for the non oil feed one (as i wasn't running the feed to the turbo) which also meant it had the other pulse coil pickup

Pressed the button and it fired up straight away pretty much and, crucially, seemed to rev cleanly, certainly much better than before

I then knocked it off as it was getting on a bit and it was horrendously loud through an open header

This means one of 2 things

1. The pick up in the ignition cover with the oil feed is knackered and the old one is working properly

2. The turbo is what is causing the reluctance to start and rev for whatever reason

Next step is to swap the pulse coil pickup into the oil feed cover, re fit the turbo and try again.

I've also found that at some point some hamfisted gibbon (not me) has used a too long bolt on the no3 exhaust collar and gone through into the head as when i fired it up i had a lovely fountain of oil coming from that exhaust stud hole 

I only fitted the outer 2 exhaust collars for speediness, i'm glad i did now as i'd probably never have found the oil leak otherwise.

Edit* Or are some of the header bolts into a wet area of the head?

Edited October 2, 2017 by El Gringo

[El Gringo]

Finally think i've cracked it.

Oil leak from the exhaust bolt aside, the change of pulse coil seems to have done the trick.

Swapped it over into the ignition cover with the oil feed, retested, fired up fine

Refitted the turbo, oil feed and drain, pressed the button and after a little cough, she fired up and, crucially again, it revved.

Of course this is subject to retesting and refitting of all the other turbo gubbin's but it's a huge step forward from where it was

Colour me happy!

[Gixer1460]

Someone's a happy bunny!

[Brad]

YAY! Cant hear it from my house so it cant be that loud.

[Blubber]

Succes, at last 

[mick-ne]

Well done, about time you had some good luck

[El Gringo]

Thanks guys

I'll just leave this here.... oh and @BradI kept the garage door closed so it definitely wouldn't have made it to yours