Project The (Mexican) Fizzer Mk III

Couldn't help myself, was an absolute bargain. Runs terribly but runs so it's already worth it. It has a 3LN1 engine in it but is a 3LN3. I wonder what the carbies are, another 3LN5 set and I'd be cheering.

More to come.

 

Now I have a bit more time, the background on this is that I actually know this bike. It was a club members and was put in reasonably good condition before it was on sold to some naive guy who had little idea on what to do when the weather changes and fizzers become temperamental. So he took it to a mechanic, (surprisingly a good one) - who told him the "Carburetors were held together with silicone and need replacement". Isn't that just the biggest cop out ever? They apparently put it back together and it's never run well since... what a farce. Oh well, his loss is my gain - when you can count the number of yellow bills on one hand that are parted with it truly becomes a "kiffsta" special. The mexican fizzer factory now has 3 complete and running fizzers in it - GreyImport Linkin I'm sure you'll agree that's a miracle in itself!



The bike sounds noisy and ticky plus it seems overfilled with oil and doesn't idle so once I drop the oil and reset the carbies (as well as replacing an indicator) I'm expecting it to run reasonably well again. It even has 2 months rego for test riding! Might need to do some valve clearances as well, but been there before - that's more of a time/availability on my part thing. Updates as we go... rainy weekend ahead and now I don't need to spend all my time on the 400 I may as well resurrect this beauty.

 

You've definitely got a knack for the bargains Chris haha.

I don't know yet. Depends a bit on what I find. Probably a "fix and flip" as I have the 400 as my toy and the other fizzer needs to go as well. Any money I make will be sunk into the 400 and my 650 in accessories (after I throw a few bills the wife's way to keep her at arm's length of course - if I'm going to have fun I actually have to still be alive!)

I'm not much of a track person, more a time and circumstances thing because I'm definitely interested. I'd prefer to use the 400 on the track if I was going to do it anyway, got a bit more kick and honestly the 250 is a bit underwhelming in comparison for a gorilla like me.

 

A few of the club guys came around to give me a hand going over the bike. Unfortunately as the evening went on, things got progressively worse. What went from a strong tick when to this, and I knew for sure one of the valves had dropped. Whether it had dropped prior to me getting it or not I don't know, I did suspect some potential top end issues but didn't think it was quite this serious. I had done no engine work until this point so it's a shame but luckily I have a shed full of spares - and I'm glad this bike was only a couple hundred bucks...



Here were the results of the engine teardown:

1. Put oil in your bloody engine you idiot. There was only 500mls in there when there should have been 2-2.2L.



2. External oil filter, so i't s a 3LN3 engine.



3. This piston is so blessed, it's holy!



4. The cylinder head has seen better days... see the bit of valve bashed off heh.





Lots of metal in the sump where we retrieved the broken valve piece and cleaned it out of all the shaved bits. We checked the bottom end while we were there and it looks good still so luckily we only need to worry about the top end.



5. The bore only had a little nick at the top left there, so we decided to take the risk and re-use it after sanding it back a bit with wet and dry. The stopping position of the rings seems to be just below the nick.



6. Carburetor diaphragm problems. Some idiot tried to use sikaflex to try and repair. Had a couple spares so changed those in.



7. Both these piston lugs (that hold the piston onto the conrod) come from 3LN3 engines. Interesting how one is longer than the other, I had not noticed this before.



So at the end of the evening we had transferred the rings to another spare piston (given the bike still seemed to have good compression), installed that piston and put the bore back on. I need to rebuild my spare cylinder head now, I have one that will do the job I just have to put all the valves back in and shim it. Only thing I'll need is to order a new head gasket.

It's going to take a bit longer than I had hoped but considering the situation it wasn't too bad. 3 hours work last night to get the engine back to requiring the cylinder head, if I had one and a head gasket ready we probably would have had it started and test riding.

 

Well... now we're back on this little machine fast forwarding things a little:

I rebuilt my spare cylinder head several weeks ago and procured a new head gasket. Lapped all the valves and all seems OK. Club guys came round a couple of weeks ago and refitted the head, also cleaned up the sump and reinstalled. The shimming took me a while, I'm not sure why but I ended up changing the same 3 valves around 3 times but all is good now. Plugs are in and she's all timed up ready for a kick over. I'll start with stock on the carby needles and 2.5 turns out and see what happens (gotta start somewhere, right?). Will try to get to it again in the coming couple of weeks.

And no I didn't put goop on the valve cover, there's still a bit of residual stuff left but it's not where I think it will become an issue.

 

Jammed exup motor perhaps... I changed the black box out but does the same thing with the spare so it's not the issue.

 

Battery is fully charged. Hmm I wonder why that would be, everything seems connected properly. The EXUP motor is not going through it's initial alignment when the key is turned, the fuel pump doesn't do the initial charge (new fuel pump that I tested on the other bike so I know it works) but the bike does crank. Checked the fuses too, they seem OK.

I'm going to try and change out the EXUP motor, perhaps the initial alignment signal from the TCI is playing up because the motor has an issue or something. After that I might try another TCI but I tested this one on the other bike when I was troubleshooting so I know it works.

 

Hmm. The battery is on charge but seemed to be OK in voltage. What I found was if the fuel pump was plugged in, it would make that sound. When I put the body of the fuel pump onto the frame, it sparked but no sound and the exup started it's normal reset cycle (albeit REALLY slow). I swapped the EXUP motor for my spare but same issue.

I wonder why this is the case, as far as I recall the fuel pump sits in a rubber housing and the body isn't touching the frame. It must be a bad earth and it's trying to do it through the fuel pump body maybe?

Damn without my reference bike it is harder to remember the setup, anyone got a photo of their battery connections? I vaguely remember two red wires connecting to the positive but I've only got the one on this bike. Maybe I'm imagining things.

 

Yeh I think it was 12.6 exactly. The bike seemed to crank fine even though the EXUP didn't move, the fuel pump didn't prime and the relay was making that clicking noise. There's definitely something amiss but I went through ALL the wiring again and everything is connected (apart from the thermostat and radiator fan connections but these aren't really necessary for the bike to run). I can't seem to find that second red wire though, I only have the one red one to the starter solenoid.

 

Thanks mate thats perfect and matches my memory. I must be missing the cable to the fuse box. Need to dig deeper.

 

SUCCESS!

It was a bad earth at the regulator rectifier. I pulled it off, sanded the connections back and also the underside of the reg/rec body as it sits on the frame (for those at home the reg/rec on these is earthed through the body of the unit and not through the wiring harness) turned her on and she primed correctly/exup working fine. Bit of choke to coax her through what were very dry carbies and fired right up! sounds quite strong and good at idle, but loud as anything without the exhaust. At least the hard part is out of the way!

Video and photos to come.

 

Here she is, a bit dirty but running reasonably well. Just need to finalise a few things and ready for a test ride.

 

So due to the fact the fuel pump takes a larger size diameter hose (probably meant to be 12mm but I managed to get 10mm on there with some heat and some elbow grease) I positioned the fuel filter between the pump and the carby as I could attach the 8mm to one side and 10mm to the other. I could have done it the other way around (between tap and pump) but the fuel filter isn't held in place by anything so I didn't want it flapping around. This was the more stable place for it. the 10mm hose fits OK onto the fuel tap provided a decent hose clamp is used (it's a little big but it will do).

Good old cable ties hold the fuel pump in place as I don't have a piece of fuel pump rubber (went with the other fizzer) so had to do something makeshift. It seems to stay there OK and works fine so will see how it goes.

 

Anyone got a spare gear lever assembly? I really only need the footpeg but can't get the darned thing off (I think it's pressfit). It's like the ONLY thing I don't have in my box of spares...