Post Valve Check/Shim, Running Lean

[Mincehead]

Good tip Mince cheers, good to have a back up as I've got Remus Carbon end cans which suit the bike nicely.

I was going to put it to the collective wisdom (when the new pipes arrive) to see if anyone new of a 2.5in/63mm slip on to 3 bolt adaptor? I've got a Fuel twin port end can for a fireblade with a 3in ID 3 bolt flange which would go nicely I think.

Try these good folk Neil:

http://www.pjengineering.co.uk/

[Overlord Neil]

Cheers Mince, that looks the ticket, I'll report back in due course.

[cobbadiggabuddyblooo]

I'd go with the TDMR's . They atomise the fuel better due to the emulsion tube set up plus a little more velocity due to 40mm bore which is why you should find better torque in the midrange than the FCR's.
I've seen back to back dyno runs between fcr 41's (50mm blue bell mouth) and tdmr 40's (60mm bell mouth)and there was 10nm more torque around 4,000rpm with the TDMR's but a Loss of 1.5hp at 7500rpm.
I'd sacrifice that for more midrange.

As for exhausts.
2-1 exhaust pulse plays havoc with the 270* crank of the trx in the mid range too.
Even the Akra system gives some losses under 6000rpm from my own back to back dyno runs with the Nojima 2-1-2 large bore system all be it not quite as bad due to how Akra manage the pulse and velocity with longer larger diameter tapered headers with a small balance pipe.
But they really come into their own in the higher rpm range.
So look at where you want your power band Neil and tune accordingly with whatever components.

[Overlord Neil]

Its alive...! Got all back together, turned it over and almost immediately fired up and runs, phew.

I didn't have the exhaust on (at all) or the airbox on, it idles fine and under choke it will pick up cleanly to about 2k rpm but if i try and introduce some throttle (with or without choke on) it stalls.

I checked the position and jets in the carbs, all fairly standard though I did opt for the full Factory Pro emulsion tubes and needle jet. Carb set up:

Main jet: 142.5
Air Jet: 75
Needle position: centre
Mixture screw: 3 turns out

All the other jets are standard

Only thing I didn't record was the float position, though I know I set them in accordance with the Factory Pro set-up guide.

[Overlord Neil]

Stripped the carbs this morning, noticed a little bit of crap in the bottom of one of the bowls, cleaned out all the jets, checked float levels (15mm from float to bowl sealing face). Put it all back together and it starts really quickly but same issues. It will idle but won't pick up on the throttle, choke pulls the revs up to 2-2,500 which would suggest its running ridiculously lean? But then you can't bring the engine speed up any more even with the choke, it just stalls. I tried to get it running as fast as it would go then open the throttle fully to see if it was only a band of jets that were causing an issue, but it won't pick-up beyond idle. Any suggestions?

[cobbadiggabuddyblooo]

Check the air cut off valve cover Neil to see if any cracks or leaking air.. Vaccum lines too.

[Overlord Neil]

lightbulb moment... Thanks Cobba, I think I might have sussed it. The aircut off valves are brand new... what I haven't done is block off the vacuum lines (I'm using an auxiliary tank so the inlet stubs are just sucking air in after the carb... du'oh. I'll try that and see if theres an improvement.

[Overlord Neil]

Drawing a blank here... One vacuum hose to the pump, other blocked off as the tank is off the bike. Reprogrammed the ignition with the standard ignitech map. The thing refuses to rev.

I pulled the carb apart yesterday and checked all the jets were clear, it just feel like something is stopping it from pulling cleanly. I had the carbs completely stripped down and replaced all the seals with the Litek green ones, could I have over looked something? At anything over 2 - 2,500 rpm the throttle just stalls the engine dead. It must be fuel starved?

[dandywarhol]

From memory there's a tiny filter in the tee piece where the carbs are supplied fuel

[Overlord Neil]

Hi Dandy, Checked the filter, a little bit of muck but nothing to halt the flow of fuel. Fuel pump is working well too, took off the supply hose and turned it over and got showered in fuel.

When I was getting the float levels correct i noticed that the actual valve barely moves at all and the tangs on the float bowls both had to be doctored significantly (about 20 degrees) to get the correct float height.

I'm thinking I'll put the tangs back to near original and run it again, that should at least narrow down if that is the problem.

[dandywarhol]

Float height is critical to air/fuel ratio. too high and less air needed to draw fuel into the venturi and vice versa. it's so critical that it can be used to fine tune the mixure
20 degrees is a huge amount

[cobbadiggabuddyblooo]

Odds on Neil, float level is your gremlin.

[Overlord Neil]

I'll check it out when I get home, I did think it was odd that the float required so much doctoring to get the levels 'right'. I'll get the carbs off and use the pipe method to check the fuel level against the casting marks, as the manual states. Fingers crossed.

[Overlord Neil]

Got the carbs off the bike, set them up on an incline to replicate their natural habitat and checked the float level on cylinder #2 carb with a clear tube... 40mm under the casting mark that would explain the fuel starvation. Well, fingers crossed it explains it or I really am screwed. What I did find whilst fettling the tang on the float bowls was that I had to profile them rather than just bend them a little. Using the method of measuring the float bowl against the gasket sealing face, the float height was 'correct' but the tang wasn't allowing the valve to operate properly.

Hopefully get it back together tomorrow and see how she runs.

[Overlord Neil]

After balancing the float bowls yesterday, I was hopeful this afternoon would generate results... Carbs back on the bike, fires up without an issue, still refuse to pull from idle.

As a sanity check, I did a compression check on both cylinders, 150psi in both; not ideal but losses could be in the equipment atleast they are both the same and within limits.

Rechecked the valve timing, checked all the indicators; lobes out on cylinder 1, cam sprocket marks align inlet and exhaust, cam shaft dots align with cam retainers, so thats all good.

Pulled one of the carbs apart, all the jets are clear, blew through all the passages to check they aren't blocked, will do the same with the other then I'm struggling for ideas.

The inlet boots are showing some crazing but it looks superficial, even if there were some air bypass it wouldn't limit the revs to 2-2,500, would it? On both cylinders?

The only other thought I had was that the spark timing is out. I'm ashamed to admit it, but when I was trying to get it running a few weeks back I drained the battery so jumped it off the car... and got the leads the wrong way around I checked the main fuse, it hadn't blown so figured it was a lucky escape, could I have fried the ignitech box? Its still appears to function properly, the bike starts, my laptop talks to it fine and i can reflash the ignition map etc.

It 'feels' like a fuel issue but I'm struggling. Any thoughts?