running issue. its got me beaten

[Ansimp]

Luckily we seem to have better fuel than you guys down hear. The major gas stations only have a 91 e10 ( 10% ethanol) 91, 95 and 98 octane. The 98 octane has some slow burn characteristics so really doesn't warrant the extra cost unless being used in a high performance EFI vehicle. I have suggested that Maurice should use ATF but I also beleive that he needs more than 500 miles on his new engine before he starts using it.

 

[slabghost]

Mix screws set right and synch at the trouble rpm and ride the heck out of it. Another 500 miles or more will do wonders for it I bet.

 

[mcgovern61]

Ansimp » Fri Sep 26, 2014 9:34 am[/url]":9a7lbgl5]
I spoke to Maurice tonight and he said the variance on the road is quite pronounced. He cleaned and rode his ltd today and confirmed how the 75 should be running. His last statement is the " 75 is not coming off the lift until it is sorted" so I am sure it is only a matter of time before he gets it sorted :good:

Well, that should be a good comparison between the '75 and the LTD. He will get this sorted out.

 

[aussiegold]

LTD ran beautifully on the weekend. apart from the temp gauge fluctuating a little. had the same prob on the 75 once , turned out to be the temp sender. under the carbs... so i took them off today, repaired the loose and corroded wire on the temp sender.
then, put the LTD carb rack on the 75, and ran it. took out for a spin and it still does it.
i know the video does not show what it does on the road, but at a steady throttle it surges.most noticeable at 50 klms in third gear.
there is some thing amiss.
not the carbs. three racks cant all have the same fault. and the LTD ones run fine.
not the fuel , fuel cap, fuel filter, or pump.
not the ignition , leads , plugs or caps.
not the cams, ( i thought there may have been a possibility of a mix up )
the belt timing and valve lash are spot on.
don't leave much.. :head bang:

 

[slabghost]

Have you checked the advancer springs and weights? Could one or the other timing belts be too loose? I'm thinking it almost has to be the advancer now. Timing advance mechanism.

 

[aussiegold]

belts are good and ignition is C5. fiddled with all stages of advance . still does this weird thing in that rev range. tomorrow , i begin a TOTAL stripdown and start again from scratch. i keep you all posted on what i find. :good:

 

[slabghost]

Sorry forgot it was c5.Just got home from a 10 hour night shift. If it isn't ignition timing or carb issue both of which are pretty much ruled out now. It must have something in the mechanical timing moving. Maybe primary chain or cam pulley? I really have no idea how that could cause the fluctuating rpm. Possibly weak valve springs.

 

[dan filipi]

Does it do it at the same rpm in all gears?
Is it more speed or rpm related?
Possible could be a caliper dragging?

 

[joedrum]

what are the like pieces in all the switch overs ....intake horns? what else

 

[Ansimp]

joedrum » Mon Sep 29, 2014 10:42 pm[/url]":st62lmu1]
what are the like pieces in all the switch overs ....intake horns? what else

Complete racks to heads

 

[joedrum]

sheesh i wish we had a single to throw on this bike ...i believe it wouldnt show this hesitation while cruising .......i am sure it would show that the stock setups window of running right is just to narrow on some motors ... being a full time guy with my single set up ...its obvious to me that most of the oldwings finicky traits are all cv stock carb related not motor ... everytime i get on a stock bike thats runs well ...it feels sickly running to me ...even when they dont miss a lick ...stock carbs just cant make the gas charge ....that the weber can .....i feel that where discribe the problem area ...is in the transition zone of stock carbs just off idle ....if your this determine to get it right id say jetting is going to be in the game for it to run with this motor ......when i tried to use stock carbs on hooch it was no way to get it to run good ....eric hung in there with stock carbs and it was vacuum passages that had to modified to get them to work .....im not sure hes totally satisfied ...maybe he will chime in ....


hmmmmmmm change plugs ... c5 can tax a plug at three fires per stroke and might be a sub par plug even if new

 

[Ansimp]

His ltd is running fine with its stock carbs Joe...

 

[joedrum]

let post this again along with the edit i added might be subpar plug even if new ...c5 muilty spark has to have good plugs ....

 

[aussiegold]

let post this again along with the edit i added might be subpar plug even if new ...c5 muilty spark has to have good plugs ....
[/quote]
plugs are not the issue Joe. started out with IRIdium ( resistor plug ) changed to a full new set of D8EA , changed again to a full new set of DR8EA ( resistor type )
at the moment i am very relaxed about this. i will find the problem. it may be a valve not performing right, causing a compression issue. it may be not. but i will find it. :smilie_happy:
here's a couple of pictures of plugs.

 

[aussiegold]

joedrum » Mon Sep 29, 2014 11:42 pm[/url]":1dpvkh75]
what are the like pieces in all the switch overs ....intake horns? what else

Joe, your a wizard. :music: that's how i have to look at this. must ask " what are the constants here ? "
ps
l leave carb intakes on the carbs. can't be them. i did, at one point replace the new clamps on the 75 with some old ones . i did not think the new ones were a good design. still no difference.
she'll be right, as we say here..... :salute:

 

[AApple]

Second pic of the plugs, plug on far right looks to be running extremely lean. Even the center electrode looks weird, compared to the other 3 plugs. The other 3 all have a dark colored center electrode....far right plug looks like you just took it out of the box and laid it down to take a pic.
Just judging from the look of the plugs, I'd have to say you have a lean condition on at the very least that one cylinder. A vacuum leak on either end of the intake horn would do that, as well as cause a surge at idle and cruise. :headscratch:

 

[dan filipi]

My irridiums looked just like that right plug when running the stock rack.
According to Paul at C5 ignitions it's to be expected when running a C5 ignition.

 

[joedrum]

hmmmm im with joel this is lean ...and these plugs show that when a stock rack it tight and in tip top form ... they were set up lean ....in todays terms the gas being even less btu or less power per gallion ....this exaggerates the lean problem and tells me this all makes sense ...that under light throttle ...witch is what we are talking about here the bike futters ...for the smallest of reasons why ... thin margin here very thin

 

[aussiegold]

i cant say for sure which set of carbs the stock plugs were run on, but, for sure, the iridiums were run on the newer set.
and, i can now report, that all the valves were seating correctly, have been given a light clean up, refitted and tested with some fuel poured into each valve port. no leaks.
also, a mate mentioned to test the charging rate. he seems to think that a higher than normal charge rate would play havoc with any electronic ignition. i tested it yesterday and it was a little high, i thought. 14.9 at 3,000 revs. changed the regulator and achieved a small drop. 14.2 at 3,000 revs. and ran just the same. :roll:
onward i go...... :Egyptian:

 

[slabghost]

Do you notice any noise from the primary chain? Did you find a way to test spring tension? How many pounds needed to move each say 3/8"? Have you tried any of the other curves in the C5? I'm honestly out of ideas at least for now.