Topic: F3 Accelerator Pump Operation

[Wayne Meuir]

Eurban, that may be the answer.  I am doing this on the bench, by hand, so maybe it won't be a problem with the cables hooked up, although I don't see how that will make a difference in the ability of the spring to overcome the pressure in the pump.

I'm going to change the spring first and see if that makes any difference, then hook up the cables and try it again.

Thanks,

Wayne

[Wayne Meuir]

Well, I changed the spring back to the old one and it seems to be working correctly so I guess the new spring was too strong.  I could not feel much difference when compressing them by hand, but the carbs appear to be working right now.  I put them back on the bike and have the cables hooked up but I need to install new spark plugs before I try to start it.  If it will start and run, I will sync the carbs.
I have a Uni-Sys carb tool that I use to sync my two strokes, will it work on an F3 the same way.  All it does is measure the amount of air that is being pulled through each carb at idle..

Wayne

[TwoTired]

Doing cone carb at a time is problematic as changing the slide height on one carb changes vacuum/draw on the others.  I won't say you can't do it.  But, it seems the reiteration adjustments could be quite tedious and prone to frustration.

Cheers,

[Wayne Meuir]

Well, in that case, I may just go ahead and buy a set of guages.  I screw around with carbs a lot, admittedly not EVER any like the ones on ths F3 (personally, I think they suck), mostly VM round slides that are simple.  I really don't like the carb stix type sync tool because they don't work very well on two strokes, the pulses make them jump around so badly its difficult to get them even.  I suppose there might be a way to put a restrictor in each line and slow down the pulses, but I don't know if that would work or not.
Why does changing the slide height on one carb affect the others?  Seems like if that is the case, ever getting them syncd correctly would be near impossible, or at least very time consuming.
Never used the guages before, how well do they work?

Wayne

[TwoTired]

The gauges need damper valves to smooth out the pulses and give you a average reading so the needles don't swing as wildly.  My set (bought in 76 or 75) came with the hoses, dampers, and runner adapters.  But, an aquarium supply outlet should have valves that will perform the task, as well.

With the carbs out of sync, the cylinders fight for speed dominance.  If you change one, the speed changes, which effects the draw/vacuum of the others.  With a four gauge setup you can change the one most aberrant and match it to the others even though they are changing, too, as you adjust the aberrant one.

The gauges make the task much faster and work well.  In your case, #2 isn't adjustable. So, you pick the one farthest reading away from it, and adjust to match.  Pick the third to match the other two, and finally the fourth to match the last three.  If you are a finicky stickler, you make a final pass to make them closer to the same across the bank.
I much prefer to do this at the lowest idle the engine will tolerate when the slides are the most closed and sensitive to changes.
Don't forget the big fan to cool the fins of the stationary engine.  The longer you take preforming the adjustments the stringer the fan should be.

You do know that valve adjustments, in fact the entire rest of the tuneup list should be performed before carb sync.

Cheers,

[eurban]

Yes do the tune up first and it will help if you bench synch the carbs prior to installation.  Glad to hear you got it working!

[Wayne Meuir]

I guess I got ahead of myself, I did not know you could bench sync them so I already installed them.  Exactly how would you bench sync them, by measuring the gap at the cut-out on the slide?

Yea, I know about getting everything else set up correctly before syncing.  I already did a cold adjustment on the timing chain tensioner.  Somewhere back in this bikes history, it has had the points replaced by a Dyna S Ignition and I have not checked the timing yet and I still need to adjust the valves.  I lubed all the cables and adjusted the clutch.  I still need to buy a set of plugs and I am a little concerned that the top end may need some work because #2 & #3 plugs didn't look too good.  By the way, them plugs are a bear to get out.  Fortunately, the bike still has the original tool kit and the Honda plug wrench works great.  Nothing else I have will fit in there.

A guy told me that the F2 & F3 were hard on valve guides, is that fact or fiction.  He said that excessive valve lift caused them to eat the valve guides.

One other question:  is it advisable to put a new cam chain tensioner and/or cam chain on a bike like this where you have no history?  Is that something that normally causes problems?

I'm sure there is some other stuff to do as well that I have not thought of yet.

I appreciate the info you guys gave me because I would still be sitting here scratching my head without it

Wayne

[paulages]

Fortunately, the bike still has the original tool kit and the Honda plug wrench works great.  Nothing else I have will fit in there.

i've never found anything to work as well.

[TwoTired]

I guess I got ahead of myself, I did not know you could bench sync them so I already installed them.  Exactly how would you bench sync them, by measuring the gap at the cut-out on the slide?

Yes, either side, actually.  Or, you can back off the big idle knob so that #2 shuts of the light you can see through the carb bore.  Then adjust the others to be the same.  Then crank open the idle knob a bit so the engine can breathe, for start up.

A guy told me that the F2 & F3 were hard on valve guides, is that fact or fiction.  He said that excessive valve lift caused them to eat the valve guides.

There was certainly an issue when the model was first introduced.  Many (most?) of these were corrected under warranty by Honda with hardened valve guides.  Later models already had these hardened valve guides installed at the factory.  78 models likely already have these.  Still, you cannot expect these valve guides to last as long as the K models, due the valve guide angle change, and the increased side pressures they encounter.  This also leads to damage of the valve stem tips, from what I've been told by other experts.

One other question:  is it advisable to put a new cam chain tensioner and/or cam chain on a bike like this where you have no history?  Is that something that normally causes problems?

The tensioner you can remove and examine the rollers for wear and deterioration.  The chain should last till the head needs to come off for other reasons.  Make the cam chain change decision at that time.

Cheers,

[Wayne Meuir]

I think maybe I got the cart before the horse here.  The first thing I should have done, even before I pulled the carbs off, was check the comrpession.  Well, it ain't good.  #1 was about 150, #4 was 95, so I didn't bother to check the others since it has to come apart to fix it anyway.  I rechecked #4 about 5 times to be sure and it came up the same every time.  I went ahead and adjusted the valves and changed the plugs and fired it up anyway.  Never tried to sync the carbs because I don't have a manometer or guages that will work on a 4 cylinder.  I just wanted to see how the lower end sounded and see if it would run at all.

Good news:  Started up pretty quickly, lower end sounds good and bike will rev up, not all that cleanly but the carbs are not set right, so it ain't too bad.  Have not run it through the gears yet, but will try that sometime today.

Bad news: Its smoking worse than any of my 2 strokes.  I thought maybe it was just collected oil from sitting so long, but since the comrpession is so low, the rings are probably gone.  I guess its possible a ring is just stuck from being parked, but I have no idea how you would ever free it up without tearing it down.

Not sure if I am gonna do the teardown.  I may just cut and run while I don't have much invested in it.  I can probably get my money back out of it even if I have to part it out to do it.  How big a PITA is it usually to get the cylinders off?  I know they will come off with the engine still in the frame, but what are the odds it is stuck so badly that I can't get them off without pulling the engine? (Took me about 2 or 3 weeks to get the cylinders off my H2 and my Waterbuffalo) I might do it if I dont have to remove the engine.

I am right in the middle of restoring a 72 H2 and really don't need to spend the time to do this right now.

Wayne

[TwoTired]

If you have a ring issue adding about a teaspoon of oil to the cylinder will significantly increase the compression due to the temporary seal the oil provides.  Do a dry AND a wet comp test.
If it's valves the wet reading won't make much difference.

If it has been sitting for awhile you may have a stuck ring or some surface rust on the cylinder walls that is preventing a ring seal when dry.  Sometimes, simply running the engine will wear this in and free the rings to seat, sometimes not.  See if the smoking lessens/goes away in a 50 miles use and check compression again.

Carb balance helps too as a cylinder not pulling it's load at idle won't burn off any extra oil in the cylinder until made to work some at higher RPM.

Unless your bike frame rails have been cut/modified, you can't do any top end work without pulling the whole motor out of the frame.

I know you are disappointed right now, but it may be a bit too early to condemn the engine.  Give it a fighting chance to redeem itself.  Don't give up so close to the finish line.

 How many miles on the engine?


Cheers,

[TwoTired]

I am right in the middle of restoring a 72 H2 and really don't need to spend the time to do this right now.

This is probably the most telling remark.  It's certain that the bike isn't going to run well without the proper, focused, attention.

If you are unwilling, then the bike is better off sold in pieces, or in someone else's hand who wants to resurrect it, and likes to work on these old neglected bikes.
Just my opinion.

If your goal was simply to flip the bike and quickly make some money off it, I can certainly understand your disappointment.

Cheers,

[Wayne Meuir]

I was actually going to give it to a friend who would like to have a bike because of the cost of gas but can't afford to buy one. Although he can handle the normal maintainence stuff, he probably does not have the knowledge or the cash to rebuild the engine right now.  His truck gets about 11 MPG and his drive is more than 60 miles per day so the cost of going to work is killing him.
I buy and sell a few bikes every year, mostly two stroke street bikes. Rarely make enough on them to pay for my time, but I am retired and enjoy ressurecting them.  Most of them, I just buy in a non running condition and get them roadworthy and then sell them, I don't do much to the cosmetics, but I usually do one complete frame up restoration each year and the one I am doing right now is about half complete.  I really don't want another one torn completely down at the same time.
I may just push this one over in the corner and wait until I get done with the H2 and then do it the right way.  That doesn't do Gary much good right now, and that's what I was hoping to accomplish.
I got the tank and airbox back on this afternoon, so I am going to ride it a few miles tomorrow and see if anything changes, check out the tranny, clutch, etc. and see what I've actually got.  I know the risks when I buy these bikes in these conditions, and once in a while, I lose, but with two strokes, the repairs are much simplier.

Wayne
 

[Wayne Meuir]

I took the bike out for a ride this morning.  Rode about 10 miles and came back and checked the compression on #1 and #4 again, engine was still hot.  Compression in #1 was 148, #4 was 145, so maybe it had a stuck ring and the heat freed it up.  Don't know.
My compression guage is too big to get to #2 & #3, so I am going to have to get another guage somewhere before I can check those.  Tranny and clutch seem to be working correctly.  I cleaned out the front calipers and bled the brakes, but the front brake is a little sticky, so I guess I will rebuild the master cylinder.  I thought it was working correctly but the return hole may be clogged up because the brakes aren't releasing like they should.

Oh, and Lloyd, there probably are not very many people who enjoy working on these old bikes more than I do.  I have 13 bikes right now, one is a 2002 Concours that is my daily rider, and an 84 RZ350 except for those two, The F3 is the newest bike I have, including 2 1965 Suzuki X6 Hustlers, so its not a matter of whether I want to do it or not, its more a matter of setting the priorities on which ones I work on first.  I was hoping this would be a quick fix,(it still may be, I'm just not sure yet)so that I could get my non riding friend on two wheels.

Wayne

Wayne

[TwoTired]

Sounds like good progress! 

Overcoming, neglect and abuse can take time.  Sometimes it's like the Whack-A-Mole game, knock down one problem and another pops up.

Cheers,