Project 3LN1 Restoration

Not anymore,

I picked up an fzr without a broken front fork and merged the best bits of the two onto one. This one looked newer so I put the carbs that were on that bike in the video you linked onto the new bike and it started and ran nicely. I rode around that time without the airbox and the bike ran ok but it surged. I later realised this was likely a faulty fuel pump as the new one pumps a steady steam and doesn’t splutter struggling to fill the float bowls on time. It revved nicely up to 18k rpm in neutral and 15k while under load otherwise.

Before I went to put on the airbox I synced the carbs using guitar wire and then put them on, I didn’t change anything else. The bike ran horribly. I took apart the carbs and checked everything, cleaned all the components and rebuilt them again to be sure. The bike still won’t run....

This is before when I rode it around with no airbox and it felt good aside from the surging. The smoke from the front is just **** burning off the engine because it hadn’t been started in so long.


This is now where I must rev to stop it from dying. It will barely idle and then die. This is full throttle. Notice the fuel spraying everywhere out of the carbs?? I haven’t done a compression test but have I potentially damaged the engine running it incorrectly at such high rpm with a leaning mixture??? I guess I’ll need to put the carbs on the other engine and test.

 

Keep in mind this engine(different bike does not blow smoke so I assume no valve stem issues. However, there must be another issue. Thanks for that @ruckusman however, ill look into it if I go back to the other engine.

They are brand new plugs @driftwood however I have not measured the resistance. I may do this if I figure the issue isn’t the carbs.

I tried running it with both pumps @maelstrom and the issue is the same. Maybe it isn’t running on 4 cylinders. It does sound rather horrible. Would this be an ignition coil/spark issue or something else?

Stand by while I make the time to put the carbs onto the other engine and isolate the issue. If anyone has any other ideas they would also be appreciated.

Thanks for all your help guys it’s greatly appreciated.

 

Keep in mind this engine(different bike) does not blow smoke so I assume no valve stem issues. However, there must be another issue. Thanks for that @ruckusman however, ill look into it if I go back to the other engine.

They are brand new plugs @driftwood however I have not measured the resistance. I may do this if I figure the issue isn’t the carbs.

I tried running it with both pumps @maelstrom and the issue is the same. Maybe it isn’t running on 4 cylinders. It does sound rather horrible. Would this be an ignition coil/spark issue or something else? It just frustrates me that one day it was working almost perfect and the next day it barely works. Absolutely baffling.

Stand by while I make the time to put the carbs onto the other engine and isolate the issue. If anyone has any other ideas they would also be appreciated.

Thanks for all your help guys it’s greatly appreciated.

 

Ok so I’m still gobsmacked, I swapped the carbies over to the other engine and it starts and runs fine so it’s definitely not the carbies.

I tried putting the ignition coils from that engine on this one and it still has the same issue. I also tried swapping the box at the back and the voltage regulator etc as I noticed the fuse has melted the plastic housing. Still the same issue. What could it be???? I’m so confused right now, is it the wiring somewhere else.

 

This is also really hot. Even with a new voltage regulator.

 

I didn’t change much @ruckusman just the better throttle cable, brakes, brake lines and front master cylinder that you sent me.

I have now swapped the ecu, ignition coils, and voltage regulator as well as I know they work fine on the other bike.

Today, I swapped the plugs over from the other bike and it fired up ok. Weird because they were brand new plugs. Ensured all the plug leads were good and doubled checked it all. Some were loose so I retrimmed them and screwed them in tight.

Idled for a while and it was nice and sounded like it was on 4 cylinders again. Revved up well and responsively.



Then all of a sudden it stopped working again. I have never felt my blood boil so much in a long time nor have I been this close to the brink of a mental breakdown from this bike haha. I just don’t understand what’s going on.

See this video how the idle knob does nothing whereas a few minutes earlier it was fine.



Now it’s in an even worse state where it will barely start nor will it rev at all. How can this thing be so temperamental when I literally haven’t changed anything between those videos. I’m so close to giving up and I really don’t want to because I have spent so many hours on this thing and you guys have helped me so much and I really want to finish it and ride it. It saddens me that I could ride it a week ago and now I can’t even get it to idle. Just so frustrating.

Question: when it says the base mixture screw is 3 turns out, does this mean 3 whole revolutions. I have tried 2.5 and 3 revolutions and none of these work. I can’t even get it to idle so that I can adjust them to the right spot anyway.

I’m at my wits end and none of this makes sense. The last thing I need to do soon is check the fuel levels again as I haven’t set them since working on this thing a long time ago but I doubt they would have changed at all. Regardless, if they were slightly off, they wouldn’t cause it to perform this badly so it’s definitely something else.