Advice needed, mk3 engine miss

Status
Not open for further replies.
J

jeffmack

Joined
Dec 15, 2011
Messages
89
Country flag
Hey guys. I need some help. My 850 has developed a miss and has just now gone from bad to worse. Out on a 700 mile 3 day trip. Bike started the trip with a miss, it was always around 2600-3200 rom range. If I was maintaining throttle it was very rough in that Rpm range. When I would accelerate out of that range if get rough engine, lurching, and some pops which seemed to be from the left pipe. Once the bike got above 3500rpm seemed well. Now just 30 miles from home while riding at 70-75 mph it's poppin and lurching and riding extremely rough. Just hoping to make it home now. Bike has a mikuni single, a Boyer ignition that is 1 year old, starts and idles just fine. What you guys think??
Thanks for any advice
 
Change out spark plugs. Then pop of the points cover for the Boyer pick-ups plastic plate inspection up close of the 2 wires where they meet at the plate. This is where they can start to break up from vibration. Also check your battery strength with a voltmeter as Boyers love power or they will start to misfire etc. Check H. T. leads for corrosion. Check fuse(s) for corrosion. Can you tell us what the color is of each of the plugs you will be pulling ,left and right side respectively ?
 
thank you and will do. gonna have a long lunch and let the bike cool and will follow your advice. just hope to make it home. also, i forgot to mention that when I operate the bike with the choke on the popping and backfire are 99% eliminated, but the rough, missing and lack of power remain. make any sense??
thanks again,
jeff
 
Vacuum leak, loose carby? You DO carry a shortened 7/32" hex key, yes?
 
Concourse and Toronto,
many thanks. The Norty is as fit as a fiddle now. 1. after inspecting inside the timing cover I found one of the boyer wires very loose from its crimp, could pull it out with zero effort. a short walk to a auto store for 2 new shrink wrapped crimp connectors so i replaced both. Also I found the hex nut on left side of Mikuni very lose, almost 2 full turns. Found some residue under the Mikuni neck into the top end near the seal. Seemed fresh and had accumulated some road grime in it. So after those 2 tasks i hopped on and cautiously hit the road. I immediately knew you guys saved my day. just pulled over after running 10 miles at sppeds of 20-90 mph with smooth engine and the power is back.
thanks guys, cheers
Jeffmack
 
You're welcome. Glad to help ,if you're ever in Toronto you can treat me to a cold Steam Whistle beer under our famous tower. Don't know what concours consumes in Kensington but at least now you can drive there smoothly.
 
jeffmack said:
Concourse and Toronto,
many thanks. The Norty is as fit as a fiddle now. 1. after inspecting inside the timing cover I found one of the boyer wires very loose from its crimp, could pull it out with zero effort. a short walk to a auto store for 2 new shrink wrapped crimp connectors so i replaced both. Also I found the hex nut on left side of Mikuni very lose, almost 2 full turns. Found some residue under the Mikuni neck into the top end near the seal. Seemed fresh and had accumulated some road grime in it. So after those 2 tasks i hopped on and cautiously hit the road. I immediately knew you guys saved my day. just pulled over after running 10 miles at sppeds of 20-90 mph with smooth engine and the power is back.
thanks guys, cheers
Jeffmack
Click to expand...


Glad you solved the puzzle! Do tell, was the crimp connector a poorly (incomplete) crimped example (conductor pulled out of connector)? Or were the conductor strands fatigued and broken, the original bits still snugly secured in the connector? Or not noticed because a fast paced field repair? Just curious...
 
Deal on the brews, as well if you ever come ride the blueridge mountains let me know. The blueridgeparkway parkway, dragon, and cherahola skyway are close to me and I'll bring the brew.

I can't blame the Boyer on this one. It was a very poorly crimped lead. The other was bad as well but still holding. The bad crimp had the wire just laying inside and came out with zero pressure. It's solid now, and the wires seem to be in tact and strong for now. Bike is running great, took it back out today for a short ride to confirm, came home grinning, she's back to running and pulling hard.

Is there any way to fix the Boyer's future wire fatigue issues? I've read a lot about it. Don't want to wait for it to fail if I can help it. Or is it best to just go Pazon now?
 
Is there any way to fix the Boyer's future wire fatigue issues?
Click to expand...

many people put a thick piece of foam right over the wires so that the points cover is pushing on it to stabilize
the wires from moving about, I have seen big wads of silicone over the connections to further do this

I put a packing slug of silicone into both holes of the timing cover where the wires go into and out so they can't bang around inside
 
1up3down said:
Is there any way to fix the Boyer's future wire fatigue issues?
Click to expand...

many people put a thick piece of foam right over the wires so that the points cover is pushing on it to stabilize
the wires from moving about, I have seen big wads of silicone over the connections to further do this

I put a packing slug of silicone into both holes of the timing cover where the wires go into and out so they can't bang around inside
Click to expand...


+1
 
jeffmack said:
Deal on the brews, as well if you ever come ride the blueridge mountains let me know. The blueridgeparkway parkway, dragon, and cherahola skyway are close to me and I'll bring the brew.

I can't blame the Boyer on this one. It was a very poorly crimped lead. The other was bad as well but still holding. The bad crimp had the wire just laying inside and came out with zero pressure. It's solid now, and the wires seem to be in tact and strong for now. Bike is running great, took it back out today for a short ride to confirm, came home grinning, she's back to running and pulling hard.

Is there any way to fix the Boyer's future wire fatigue issues? I've read a lot about it. Don't want to wait for it to fail if I can help it. Or is it best to just go Pazon now?
Click to expand...

Thanks for closing the loop. Don't know what your using for crimpers, but the run-of-the-mill combination stripper/crimper tools are useless. This is the bomb, been using this for 30 years. http://www.amazon.com/Thomas-Betts-WT11 ... ts+crimper
 
Status
Not open for further replies.
Back
Top