Project The Second Fizzer

Engine's back together, timed up and re shimmed. Had a club mate come round and help me put it in so that's done too.

Did some temp connections and went to start it up and... whoops left the carby drain screws out! So I was swimming in fuel once I put on the tank and turned the key...

LOL guess it was a bit late in the evening for my brain. Called it a night at that point. Might try again tomorrow!

 

"I'll be out in the shed tomorrow night" he tells the missus.

30 minutes later...



Vroom Vroom.

No real issues starting up, bit of a "jimmy rig" setup as you can see but the motor sounds strong. Now for the general tidy up to prepare her for a run, nostalgia is killing me.

Ups to @kiffsta for the engine, has come together well.

 

@Linkin do you still do oil filters? Could use a couple for the 3LN1 engine

 

Right so I spent a good portion of the day tidying up everything and putting her together. Everything went well, I lost a connector by accident so had to do some soldering and rewiring on the connector that has the oil light and the neutral switch. The other issue I had was the startermotor shorted itself out for some unknown reason, it wouldn't start but the starter coil would just click and nothing else happened. Once I figured it out it was a simple changeout and then it fired right up.

Since that time I've noticed the oil light doesn't turn off once the bike is running. This makes me nervous, any ideas on how to best troubleshoot this? I thought about pulling the whole oil switch out and replacing it with one of my spares, but it could be because something isn't pumping properly...? Don't know.

The bike turns on immediately with no choke so it seems to run OK. I've been using some manky second hand oil while I cut the rings in a bit before I do an oil and filter change (no point wasting two lots of good oil) but I have done that before and not had this issue. True I did not inspect the oil pump/sump area when I rebuilt the engine though, so if it was like that I am unsure. When I started the bike the first time I don't recall it being an issue... wiring is definitely correct though.

 

Thanks - maybe a cleanout and fresh oil will fix it, I can't see how the oil pressure sensor would be a problem but I have a spare that I know works.

True that I did not check what was in the sump/base of the engine before I started it up though - probably should have in hindsight. I drained it and there wasn't much in there (maybe 300 ml) and what came out didn't seem too bad so I didn't bother digging into it.

As for using second hand oil, I suppose you could use cheap new oil or what I did - same grade, just done 5,000 kms in a bike prior to me putting it in this bike. Can't see a major risk, provided it's not lumpy or like vegemite but that's just my opinion. If I'm cutting in rings I want a little wear in the bore area, plus dumping new oil would be expensive so there's my logic. Maybe not everyone's cuppa but each to their own I guess.

 

Thanks, I took it out and had a look... couldn't visibly see anything wrong with it but cleaned it out anyway. Dumped all the oil too, will put some fresh stuff in once I get a replacement oil filter. For some reason the bike shop gave me a HF114, that's what their book said, saw it myself and I just trusted them as I didn't check the original filter first (hindsight is a funny thing). What came out of the bike was a HF145... just another pain in the bum.

Bike is ready to go again once I get the new oil filter.. see what happens I suppose. I wonder, can you retrofit a 3LN3 sump to the base of this engine and use the other oil pressure sensor? Just put the wire on that instead, also allowing me to use an external oil filter? might do that if I keep having issues, will also pop the top of the engine to ensure oil is getting up there.

 

Well new oil and filter, the oil light stays on which Brian indicated is the same with his. Maybe it is meant to stay on...? Seems to be getting oil ok.

Had an issue with the thermostat, up to temp was spewwing water out if the housing. Have to swap it out as I have a spare luckily. After that I'll run it again up to temp and can't see why I couldn't test ride.

Club weekend ahead though so may have to wait another week.

 

Umm... theres a problem with the thermostat johnny... its freakin empty!

What happened to the internal bit?



Out comes a spare... that's better... spot the difference lol

 

Ok so I took her for a ride today after a bit more of a clean up and I seem to have inadvertently gone backwards...

She starts with no choke quite well, idles beautifully - best she has ever been. Rides well down low, but as soon as I hit mid range around 8k RPM there is massive bogging. She won't go above that, but when you back off the bogging she doesn't stall, she just hums back to idle again. Prior to this whole thing if you got bogging in the rev range of this significance she would stall out. So this is a bit new, and it has got me thinking... In another thread I saw this:



Now this engine I have is a 3LN1 bottom end, a 3LN3 bore and a 3LN1 cylinder head. The cylinder head, as far as I can tell is totally identical to the 3LN3, and so is the bore - this is mainly why I'm a bit confused that (what seems to be a fuel/carby issue) exists at all? The above suggests all these differences in jet sizes between the 3LN1 and 3LN3, my tired brain is telling me that unless the stroke of the 3LN1 is different to the 3LN3 (meaning there is a volumetric change in the cylinder) in theory the engine should run fine with the 3LN3 carby settings? Everything is set to 3LN3 stock at the moment.

I'm not against having a play, for sure I can get other jet sizes and try and tune it - I'm leaning towards playing with the needles first as I suspect it is running too rich. Yet my head hurts because that is the opposite to what you would expect when the main jets are SMALLER in the 3LN3?

The fact it runs soooo nice down low and at idle has me hesitant to mess with the pilots... maybe too much thinking for one day...

 

Thanks for the help guys. With this bike literally the only thing I have changed is that I have put in a rebuilt/refurbished engine and that's it. Everything else (carbies, air box, coils, all that other stuff) is completely unchanged from the original 3LN I had which ran fine until the bottom end went that took it out of action. I do admit, I did change the fuel filter though with a spare I had as the one before had cracked but this is prior to the fuel pump so I can't see it being an issue?

I'm trying not to mess with too much at once because of the above otherwise I have a feeling I'll open a can of worms...

The carbies would still have the relatively new Litetek kit in it that I did a couple of years back, I've never played with the fuel levels either as I've never had to. Maybe I just need to play with some needle settings and lean it up... it might just be getting too much fuel with the settings now the compression should be a lot higher with the new rings?

It's relatively cool in melbourne this morning so I started it up with no choke to see what was going on and it wasn't a problem.. fired straight up, idle was a bit lower than normal but holding steady.

I understand the comments with the exup, it's all set up correctly for sure. I believed this is a big part of the Low RPM range though, is that correct? It seems fine (actually really good) up to around 8000 rpm? So would this really be a big part of the issue?

The other thing to note is it seems to rev very well through the rev range when sitting stationary. It is only when moving the bogginess exists.