Session 48: Where there's smoke there's no fire
It lives!:teeth:thumbup
the part that was damaged earlier velocity stack?.. looks repaired?
I gently "massaged" it back to shape buy burnishing it with the domed heel of a screwdriver handle.
I have done that with no ill effects.
:thumbup I'll try not to slip off the stand and wheelie into a tree.
To me it does sound like you have a dead cylinder. If you can reach the header pipes see if one of them is cold. Those V4 motors are really smooth when running right.
Mad
Did exactly this and you're right. I owe you a chicken dinner. Them pipes get hot btw! Tip: spray water onto pipes and watch for evaporation. Wish I learned this earlier. Good thing my finger tips weren't melted smooth. I found cylinder 2 noticeably cooler then the others. Tip 2: don't run the bike for 5 minutes and try this. The dead circuit feels hot anyways from adjacent cylinder's output. This method works within 1 minute from a cold start.
I read that you ran the motor with the vacuum line off cylinder 4. I'll bet that is the dead cylinder. When you run off an separate tank you have to plug that vacuum port.
Mad
Yeah, I thought this too - the unplugged vacuum line open to atmosphere would make for a lean mixture or something weird. Not the case it seems - I ran engine and used my finger to plug unplug, plug, unplug, etc. No noticeable difference in how the engine sounded at least for my limping engine. I clamped the rubber hose closed with a hemostat anyways.
For those who are curious, the RVF400 uses a skinny rubber vacuum line from cylinder 3 to open the fuel cock: no vacuum = no fuel flow.
Check your spark plug gaps. I had that happen (only running on 3 cylinders) after I put in new plugs and assumed the gaps were all ok. Turned out one was not. The plugs on the RVF are very small and easy to mess up.
Will do. I have thus far only checked for spark using one of the old plugs cleaned up. First order test that's easier than removing buried plug from the forward plug from the engine. I see spark on #2 so maybe you're right. I may need to pull the the plug and measure gap and test for spark.
Before that though I bit the bullet and pulled carbs back off. Tore into carb 2: check idle jet, idle mixture screw, float valve, and float height. All looked fine to me. Odd how I used to be all careful and cautious now I just rip stuff apart and not worry about dribbling gasoline all over my work table and breathing fumes :nchantr
Buttoned all back together but ran outta time to reinstall and hook cables back up.
Next session: carbs back on and fire up. If still bad, will inspect spark plug #2.
Also want to consider compression testing. I went to O'Reillys to buy a Bosch one but it only goes down to 10mm threads - the RVF requires a rather dainty 8mm. Will search online for a compression tester set with the appropriate size or buy one of them separate adapters I found.
