1986 XVZ 1300DS Venture POOR running diagnostics

[Mongoman]

To the group, It starts up quickly, and the choke works fine.It does not stall-out. the fuel filter was checked and found to be acceptable. Audibly,it sounds like one cylinder is not contributing to the power.Just a little ruff sounding. Ignition is "great" on all four plug-leads (Strong and blue ,jumping 1/2 inch to ground). Pulled the front plugs (LH and RH),and they were acceptable in wear and color. The two AFT ( LH and RH)wet with fuel,Not good. I placed a vacuum gage onto a manifold access vacuum point and its swing up and down ,in a pulsating- manner,NFG. The front two carb slider piston valves are moving adequately and the two rear-sliding piston are, "still" ,no motion. I applied a small amount of metered propane to the top of each carb-inlet while running at 1200 rpm.The front two responded,with an overrich A/F mixture condition. The rear two carbs showed -no change at all. With the motorcycle warmed up I performed a compression check and all four cylinders with plugs removed,they were at 145-150 PSI,with throttle opened during cranking 7X. At this time compression and Ignition are acceptable. Air-Fuel mixture is too- rich on the rear two cylinders. This Bike sat for 2-3 years in a garage while starving for attention. I believe that,Ethanol has varnished up the air-bleeds in the atomization functions of these mikuni carbs. Moving the slider piston valves ,while idling ,on the rear two carbs had no change. My recommendation is to is to leak check this engine with propane ,to find any induction leaks. If there are no induction leaks-great. Next remove ,disassemble,clean,inspect and rebuild these(4 each) Mikuni carbs. Also replace the diaphragm/ slider piston valves. Ok Guys, who agrees with me ?? Where can I get carb kits that aren't stamped-out crap?? What else can I check or perform prior to Carb repair? It doesn't have to get up and fly!! Thanks for your opinions and advice. Mongoman in Albuquerque

[MiCarl]

It's almost impossible to make an 86 rich. If those two cylinders are getting too much fuel it has to be carburetors, probably float adjustment, float sticking or bad float needle valves.

 

A fuel level check will confirm that the float bowls are over filling. Process to check is in the service manual. There are service manuals on this site, but I don't know if you can access them as a trial member. SERVICE MANUALS HERE

[Patch]

First I see the post/

Where are you with the project?

[Mongoman]

Guys, the carbs are dis-assembled and OEM parts are on order. All the sliding piston diaphragms were leaking.The enrichment diaphragms were not in much better shape. However the original owner actually kept up on the fuel system ,fuel stabilant and the inside was a lot better than I expected. All parts were clean in an ultrasonic parts cleaner with a safety solvent.they came out Great. Fuel hoses are all going to be replaced. the next step to bring this Beauty back to Cruiser status is checking Valve clearances. T1 and T2 is the designated reference point,and I am getting "TOO Tight" results. With the lobe's pointing straight up,the results are still the same,All readings are approximately-Tight by about .002".I don't think that this adjustment has ever been done-ever on this Motorcycle. So it's time to do one shim ,at a time, remove ,measure, reinstall,compute smaller shim sizes and order . Never turn engine without all shims installed.

This is where your guys can help me......I have been reading Tech talk replies and if you have a article or a recommendation, on Techniques,parts or places to get parts from ,I am very gracious to hear words of wisdom. Because its not what I know...its what I don't know !! I will keep everyone updated. My background is 6 years of USAF,(including Vietnam) ,fixing jet engines, 40 years of being an A&P Mechanic on civilian helicopters,and many years of fixing anything that would roll with four tires. But motorcycles don't have to fly and and they are in my bucket list to understand.Thank you,Mongoman in Albuquerque

[Mongoman]

Guys, I'm starting my search for the,YM 33961 J-tool for adjusting the valves on this 1986 XVZ1300 DS ,and a kit for reshimming the disk. Any advice or assistance would be appreciated. thanks Mongoman

[luvmy40]

Talk to skydoc_17. If you buy your head cover gaskets from him, he lends you a shim kit and tool.

Edited August 13, 2020 by luvmy40

[Patch]

Guys,

 

This is where your guys can help me......I have been reading Tech talk replies and if you have a article or a recommendation, on Techniques,parts or places to get parts from ,I am very gracious to hear words of wisdom. Because its not what I know...its what I don't know !! I will keep everyone updated. My background is 6 years of USAF,(including Vietnam) ,fixing jet engines, 40 years of being an A&P Mechanic on civilian helicopters,and many years of fixing anything that would roll with four tires. But motorcycles don't have to fly and and they are in my bucket list to understand.Thank you,Mongoman in Albuquerque

 

Hmm over qualified and, the bike has only 2 wheels,, if you fork this up: you'll never live it down

[Mongoman]

Hmm over qualified and, the bike has only 2 wheels,, if you fork this up: you'll never live it down

Nothing is as Easy as it appears

Things left to themselves ,always go from bad to worse

Everything takes longer than you expect

There are no stupid questions,just stupid mistakes

Don't fix something that's working OK

If it was easy and simple,anyone could do it

And if everything is going well,you've obviously overlooked something

Edited August 13, 2020 by Mongoman
missed one item

[RDawson]

I second 40s idea on Skydoc’s kit. I went through mine one time, measuring and replacing the shims. I only needed a couple not in the kit that another member sent me. Once done I went thru it again just to double check the measurements. Right as rain.

[Mongoman]

Guys, thank you All very much !! I'm in touch with Skydoc_17 and this is going to work out very well.