01 R*, rear cylinder backfiring or missing firing.

[EVOLSMITTY]

2001 R*, V&H LS no baffles, BAK, new intake manifold non ported and nipple sealed, 167.5 main, 37.5 pilot, pms 2 1/2 out from all the way in, new fuel filter, carb cleaned,fresh oil change using the method mentioned here, new plugs the ngk recommended here. Performed SVS procedure from tech tips. When I first fired her up after rejetting to the recomendation of the group, she ran great. Best she had ran since I got her. Rode her to work (86 miles to and from), the next day she started running like crap again. Checked pms, it was good. Checked plugs, they indicate slightly lean. Continued to ride to work for a week. Never got any better. Its back to running like it was. Coaster cap is a year old and its the plastic type. Over the week I averaged 40 mpg. Anything im forgetting to add ill hapilly answer. Really need yalls help. That week of riding is the most ive been able to ride this bike since I got it. All the new stuff mentioned was done recently aside from the coaster cap and intake manifold. Thank You all. Yall have been a massive help to this newb. Also it only runs like crap on the low end of the rpms and idle.

[Tcontrol]

You looked at plugs… slightly rich… front cylinder normal??
i have this ocd issue regarding spark plug caps having a weak connection to coil wire… why not cut 1/4 inch off the coil wire and re-assemble to the spark plug caps… freshen up the electrical connection…. Also remove the resistors and check for corrosion… maybe clean it up a little… after all ..the bike is 22 years old…
it may help… it may not make a difference… couldnt hurt if done correctly…

[EVOLSMITTY]

Slightly lean, sorry. Changed it from rich to lean on my post. Not a bad idea for the plug wires. Thank you. Not sure if it being lean and not rich changes your recomendation though.

[Shores]

If lean then it sounds like you have an air leak. If you installed a new intake manifold that might be where you would want to look first.

[EVOLSMITTY]

Thank you, Shores.

[Tcontrol]

Running lean does change the suggestion… possible leak… agree with shores… you can confirm by spraying a “short short” burst of ether around the intake manifold to rear jug connection…. You will hear a difference in engine rpm if it leaks… try not to get it in carb… pretty much negates the test at that point…

[EVOLSMITTY]

Ok, will do. Thank you both so much.

[brianmac]

ok, 1600 and 1700 have different manifolds, u got the right one right? u used yammie orings and applied some greae to hold them in during installation right? your carb is seated properly right? you did not leave any rags or loses any tools during manifold work right? you have all 4 plug wires connected right? you checked the throttle cables where they come slose to R side coil for worn thru insualtion and shorting right? and whats the mileage, and history of bike, was zinc fortified oil use regularly?

[Tcontrol]

Ouch…. Bam…. Take that….!!!

[EVOLSMITTY]

Welp that nipple I thought I sealed was not sealed. Used silicone this time. She is now running like a champ. Should have known with it being the rear cylinder acting up. Thank you everyone.

[roadiemort]

Welp that nipple I thought I sealed was not sealed. Used silicone this time. She is now running like a champ. Should have known with it being the rear cylinder acting up. Thank you everyone.

Permanently sealed nipple.

[davej]

That is how I did mine. Fuel and silicone don't mix all that well.