buying 84 1200 running on 3: Part II

[crowesnest3]

have an earlier post on same thought. Bike is only running on 3. New info for your thoughts: yesterday went over to sellers and A. ran a compression test, all plugs out, bike was cold, outside temp @50, cranking amps seemed a little low, 3 cylinders show @ 120 - 125, one - front right - showing @ 95 - 105. Bike had not been run but a couple times down the road since mid summer. Seller swapped out plugs with new ones to see if would fix problem. It didn't, plugs were "fresh" with only a couple miles on them. 3 showing a little tan and the front right looks clean/dry. Grounded out each plug, all firing, seemed problem cylinder was weak, but have read that spark does not show strong on "wings". So all getting spark. So, am I looking at a plugged carb which is causing no fire? Also, if carb is plugged could that cause a compression difference? Bike has 54000 miles, is very clean under the powder of barn dust, heads were redone a couple of seasons ago cuz seller was doing own wrenching ( not that that is a bad thing ) but messed up with the timing belts and bent a valve, says piston head did not show any fracture damage. It is seller that says, I believe him, that it is front right cylinder not firing cuz when running header is cool.... plug like brand new clean. New Dunlops, brakes, radio and instruments all good .... its an "Interstate", choke cable is busted and noticed some corrosion on steel cable shields where outside coating was worn away. Don't see any fork leaks, shock system seems intact and runs down the road smooth and straight. Working on a swap with a buy value of @$1300 - $1500. Sure sounds like a bad carb so a winter rebuild and all should be good, obviously and also go over all electronic connections, replace hoses, do the diesel and atf oil bath etc. Your opinions are always welcome and respected .....Crowe... :Egyptian:

 

[joedrum]

thats enough copression to run on that cylinder it seems ...i dont hear any complaints about noise from the bottom end ...so im thinking it all in the carbs ...you sould just buy it if it to your liking otherwise ...if your careful you will fix in front them and then you have fixed there bike they dont want to sale anymore for nothing checking it out ...i quit that stuff after geting burned on that

 

[toytender01]

Do a WET/DRY compression on the bad cylender, could be bent/burnt valve or brokde or stuck rings

 

[dan filipi]

Carb not supplying fuel won't cause low compression but if the butterfly isn't opening, that could.
Are you doing compression check with throttle wide open?
Makes a big difference. The readings on all 4 are low is why I ask.
Sounds to me like a clogged carb on 3.

 

[slabghost]

If the slide isn't opening on one carb that cylinder will read low compression. Procedure on compression test is wide open throttle and crank until highest compression is obtained.

 

[dan filipi]

I agree whole heartedly with what Joedrum said, careful you don't fix it for the guy before you buy it.
I had that happen to me looking at a car for sale, $1500 but running good was worth over 3k.
A mechanic told the girl it needed an engine. It was running real bad, barely running actually.
I looked around a bit under the hood and found the pcv valve hose split open. When I wrapped my hand around it it purred like a kitten. Unfortunately her Dad was standing right there and told her no way your selling it that cheap now. I could have made a EASY $1500 by reselling it but I wouldn't have done that to her anyway. I promise, I'm a sucker for the ladies.

 

[Anonymous]

Carb not supplying fuel won't cause low compression but if the butterfly isn't opening, that could.
Are you doing compression check with throttle wide open?
Makes a big difference. The readings on all 4 are low is why I ask.
Sounds to me like a clogged carb on 3.

+1 :music:

 

[crowesnest3]

yes, throttle open, thinking #'s a little low myself, my 1100 runs about 150 - 160 all the way around, hoping that from info gleaned here that, #'s are low due to 50* cold engine that has not been run much at all for many months except for a few miles down the road, my test run and the seller seeing if new plugs helped ...didn't ... once in my hands I will put her thru the diesel fuel and atf gut wash as a revival. Fires right up with some choke, no smoke, no knocking, just missing. I'm going to go for it, assuming seller agrees to swap for goods offered. He's already expressed that its pretty much a go. I'm feeling pretty secure in the carb problem, won't know till she's opened up........ and I'm all over the thought about fixing for seller so I can buy it for more!

 

[Tory]

I am not to concerned about the over all compresion numbers.Between the temp and the fact is has not been riden much lately I suspect they well come up under differant circumstances.
It does sound like the # carb needing a goimg through.That could also effect the compresion number in cylinder 3.

Buy it,pull the carbs and have them cleaned good in an ultra-sonic cleaner.May not even need to buy kits.

 

[joedrum]

if it cranks right up on the enricher circut witch dumps more gas in the system ...its not realy a choke ...that sorta indecates its straving for fuel ...its been sitting a while it could be the plug wire or end on that cylinder also ....worst case senairio seems to be in the story of the valves hit during belt change ...the way the 1200 is set up it could have slighly kissing the pistons and with the 1200 hydro cushion valves slight bent the valves causing the drop in compression ...i mention this as worst case ...meaning head job top end work as worst case ....on oldwings this is not that hard of a job .....but i would play out the fact its probably not that bad ...its running and the thing to do now is check out carbs ...the 1200 carbs are great carbs ...they have rubber diapham slides ...dont use ant seafom or carb cleaner in the carbs with slides in as they will be eatin up by the cleaner ...and turning your carbs into black goo.........

 

[crowesnest3]

....... " not a choke" carbs on 84/12 don't have a choke?, but have an "enricher circuit" ... tell me about that. As to the bent valve issue, seller says upon bending the valve he took bike into a local shop that redid the heads. Shop is now closed, "its the economy stupid". Know I will be at the very least pulling valve covers since perma gasket was used rather than a "gasket", anything I should be looking for? Since they are hydraulic vs the solids on my 80/11 no adjustments, right? Kinda liking the ultrasonic bath suggestion, Harbor Freight was mentioned, is their unit ok? Boy, I could run both the 80's and 84's thru it and then the one barrel of my Allis B and maybe the yard tractor while I'm at it. Be kinda like going nuts once you have the power washer fired up! ..... Crowe .... :Egyptian:

 

[joedrum]

1200 carbs are rather easy to work on ... i knew nothing abou them and had an old rack fixed in one day if i remember right ...that the one thing on the forums thats just not there ...a good 1200 carb thread with pics to go through them
...there not the biggest carbs for the oldwings fours there actualy the smallest ....but they are the best ...there only down side is if the diaphams are eat up by self inflected carb distruction from bad move with carb cleaner and they leak or have a hole in them from soneone taking them out ....the enricher circut dosent rely on choking the air to get more fuel when the cable is pulled it increases ges input through an additional circut ...air stays the same ...great system that usealy fires right up....i here the habor feight sonic cleaner is under powered but have no hands on knowledge so i dont realy know ...ive also heard what a member here said and i thought it was fantaastic caveman tek....get a tub like plastic id say is best or metal might be best ...hard mount a palm sander to a board big enough to straddle tub fix it to tub with bongie cord or screw it right to tub ...then take bowls off carbs unscrew the 1200 jets that realy easy on 1200 racks ...submerge in tub ...turn on plam sander ....most osolate at about 11000 times per minute ...caveman sonic clearer ....peraonaly i have palm sanders around that are just junk broke but motor still runs ....im doing this same thing im typing soon on one of my racks of carbs .....ive also heard if you realy want good sonic cleaner on the markit its 350dollars plus not me cant afford that....if you have a router control box for working that hangs on your belt habor feight sells them ...you could adjust rate of vibration on the sander

no adjusting valves and im thinking you have no problem with that as you have not heard you complained about valve rackit witch can be bad on a 1200 if something is not right in it ...1200s hold the title to the most quiet and the most noiseyest if something is not right in the valve trane

 

[crowesnest3]

... know thats interesting I had been pondering the idea of a sander as a means to vibrate. Sanders I have, woodworker, square ones, round ones, in line and random orbit, big ones n small ones. Will be checking for rpm stats, but, I'm all over " rube goldberg " before spending hundreds on a once in a great while tool! ..... side note when running she's very quiet, like almost too quiet! Might be thinking of using the Jardines in storage, had em on the 80/11, although the exhaust system is really solid and clean, maybe screw with the baffles a little? Never had a music system before, maybe quiet is a good thing? ..... crowe .... :Egyptian: