Project Linkin's FZX250 Zeal

Another card in the mailbox, auspost still too useless to do deliveries. Thank you Mr. Green, though

 

Put the new front sprocket on and added a few links to the chain as it was slightly too short... now it's slightly too long! I hate drivechains... I'll fix it later



Some Dr. Murdo engineering on the seat, as someone had hacked off the plastic tab.

 

Got the litetek kit through the carbs today, except for the little o-rings for the jets (OR-004), some of the jets have been attacked by a flatheat that was too small and twisted the soft brass, so don't want to risk breaking them. The high idle problem was the #2 butterfly out of sync, so I did a basic bench sync. Idling properly but too dark and wet for a test ride.

I didn't remember to measure that plastic bit and the little spring holding the needle in place... might have to pick up a set of zeal carbs for spares.

 

Very similar but this is what it looks like on the zeal

 

Looking at your pictures, looks like you have 2KR diaphragms/slides. I will have to check Risky's ones downstairs.

My 3LN1 set of carbs only had the large spring going directly onto the plastic stopper under the c-clip of the needle. Obviously it was no good as I had to replace the needles and emulsion tube.

This is what my 3LN6 had. The plastic threaded bit screwed into the slide.

 

Right ok. It's a shame the 2KR/3LN diaphragms are different, otherwise you could put the 2KR ones into the 3LN bodies.

They either made a mistake with the early 3LNs by removing the bits supporting the needle, or it was a cost saving measure. Clearly they realised it was a bad idea after people no doubt discovered the ovalled out tubes and worn away needles. The Zeal was produced from 1991 onwards, so they changed the design with a slide housing seal and smaller spring and plastic stopper for the Zeal, and went back to the 2KR design for the 3LN6/7. It looks to have been enough as my zeal needles and tubes aren't stuffed.

No mate someone has butchered the jets, I don't want to risk breaking the soft brass trying to get them out... I'll replace the jets eventually. I have the OR-004's in a little baggy on my desk as a reminder

 

Got the new air filter in the mail today. Same part as the 3TJ FZR400. But the filter that arrived was slightly taller than the one I pulled out of the airbox. In any case it still fit properly. Old one was wrong? Who knows... it's cactus, over the shoulder it goes.

I'm calling this bike ready for rego!

 

Check your messages

 

Right so I have been thinking about eventually doing an aftermarket exhaust. All of the ones available for the Zeal require cutting and welding of the original pipes. That's no good because a set of original Zeal mufflers are like hen's teeth to find. What we do have is an abundance of FZR250 headers with EXUP in them. The Zeal CDI has the plug for the servo motor, I wonder if it will work?

 

OK guys try and figure this one out... I took the bike out to the test track, running like a dream. Once I filled up the tank (checking fuel consumption, which was fine), the bike was not running well. I get home and start pulling spark plug leads, and I found #2 being unplugged made no difference in the running of the engine... uh oh, whats going on here? Valve clearances maybe?

So I get the tank and airbox off and start it up again. Fuel comes POURING out of the left recess in #1 carby (for the air jet? choke?). What? #1 is firing fine but #2 is not. I leave it running, scratching my head trying to figure out what is going on, and as the bowls drain it eventually starts running on all 4 again. All the slides were lifting even with #2 not firing. The bike stops running. OK, the bowls must be empty now, right?

So, I whip the carbies off and start taking #1 carby bowl off. Totally full to the brim with fuel, which pours out everywhere after I loosen the screws. WTF is going on, I thought. Checked that the jet housing was secure and the 6mm brass bolt wasn't loose... all good there. Checked the float needle and passage. No wear or obstructions. Decided to bend the tang a little to shut off the fuel supply a bit earlier. Could it be flooding because #1 carb is the lowest point in the carbs when the bike is on the stand?

I check #2 bowl. Still some fuel in there. The 6mm bolt on the jet housing was loose! I nip it up and start thinking about how that could happen. I think that with the new slide housing gaskets (the square ones), pushing the housings in doesn't seat them fully. Gently tightening the 6mm bolt on the jet housing should pull the emulsion tube and slide housing up into the correct position. I guess that this one wasn't fully seated, as it had come loose on me.

I double check the throttle body sync again while the carbs are off. Some more fine adjustments between 1&2 and it looks good.

Carbs, airbox, and tank back on... running on all 4 as it should.

I'm still at a loss as to how #1 bowl was totally flooded with fuel and still firing, yet #2 was the one having problems.