Problem

[TopCatGr58]

Revised Opinion!

Hey Firehawk,

I agree, I think it looks fine!! Now, I ran 4-1 headers with stock airbox for 7 years WITHOUT rejetting, and never had a meltdown or problems with the pistons. With your good colored plugs, you probably don't need to rejet, but are these NEW plugs that you have checked, or were they in there before the pipe swap?!

As to your symptoms, with it dropping rpm, I'm now more in agreement with Danny in that it sounds like the PU coil wires now, like Danny said, due to the increased rotation of the assembly while in second gear causing an intermittent break in the wires which cuts out the signal to the TCI until the engine either changes rpm, or vacuum changes, both changing the rotation of the PU coil plate and causing the wires to reconnect.

The 81 doesn't have "mechanical" centrifugal advance...it's incorporated in the TCI, but it does have vacuum. FIREHAWK, pull and plug the hose from the #2 carb that goes to the vacuum advance, and then try riding the bike and see if you notice the symptoms in the same rpm range as before. IF it doesn't do it, then reconnect the hose, and IF the symptoms recur, then you've pretty much proved that it's the PU coil wires. The 81 isn't as likely to develop this problem but it's not immune since the plate and wires still flex with the vacuum advance.

Sorry Ken and Danny, but I don't drink beer never acquired a taste for it....too strong of a sweet tooth! However I have straight shot J.D. .. go figure!?
T.C.

[Firehawk]

Well, I figure I need to rejet since it has some backfiring during deceleration. I was just gonna go with getting bigger pilot jets though. But the pipes have decolored or anything. The spark plugs have been checked since I changed the pipes.

Alright. I'll check it out next time I'm around it. I'm at college currently and it is sitting in my parents garage until there's no chance of it sitting out in a snowstorm. So it might be a week or two before I get to it. I posted now cause I didn't know how fast you guys would pounce on it.

[TopCatGr58]

Firehawk,

When you put the new pipes on, did you use NEW Exhaust gaskets? I didn't back in '84 when I put my 4-1's on....in my very ignorant youthful years, and mine popped on decel, but I kinda liked it!!

This last year I finally put in some new gaskets, and most of the popping has stopped, but not completely. I've also gone up in MAIN jet size, but I had the larger jets on there for several years, and STILL had prominent popping, but the new gaskets has really cut down on the amount and volume of popping, but it's still there. 4-1 pipes do cause some decel popping.

Before you invest in new pilot jets, try turning the pilot screws out a turn or so first, which will richen the pilot circuit and may also help in reducing the leaning during decel when you close the throttle!?

You again say that the plugs were checked after the new pipes, BUT were they NEW plugs that you had put in AFTER putting on the pipes, otherwise you may be seeing old coloring that was there BEFORE you changed the pipes!?
T.C.

[Firehawk]

Alright, I guess I'll try and organize all the answers as well as lay out a few other problems I've had:

I did use new exhaust gaskets. When I torqued them, the #2 pipe seemed slightly not pushed into the head when it was at its torque. But there isn't a noticeable leak (I don't feel any moving air around the pipe if I put my hand as close as I can without touching).

As a sort of disclaimer, I was the one to rebuild my carbuertors. The first time I had ever done so. I did everything by the book (a textbook I still have from the classes I took for auto mechanics). Though there were a lot of differences in the carbs from the carbs in the book, mainly that these are much more simple.

With that said, I have a problem (since the pipes) with starting the bike easily, if it hasn't run in the past day or so. It just doesn't seem to get enough fuel, even choked. A couple times, I've had to remove the #4 spark plug and put some gas directly in the cylinder to start it. When it starts, it runs fine with a smooth idle and a nice steady climb in revs (other than the cutting out in 2nd gear). And I have that popping in decel.

Also, it only gets about 30-35mpg around town and about the same on the highway. Though I've gotten as low as 25mpg (city). I've had problems with leaking gaslines, petcocks and the like. In addition, I'm not exactly putting around on it either. But I think if I can somehow tighten the lines on there, I'll have better luck with it.

I do have to say, that this bike has broken my stigma of getting a high-ish mileage bike.

I don't expect you guys to know instantly whats wrong and whatnot, but a nudge in the right direction would be greatly appreciated.

[Dragonrider]

(snip)
if it hasn't run in the past day or so. It just doesn't seem to get enough fuel, even choked.
(endsnip)

Did you try the "prime" position on the petcocks?

[Ken Talbot]

Also do a quick search on enricher circuit to read about the orifice at the bottom of the float bowl. This is where any sediment and cr@p will settle over time, and it is critical to delivering a supply of fuel to the choke. IIRC, there's a decent picture howing the location of this orifice..

[Yamaniac]

IIRC, there's a decent picture howing the location of this orifice.

Ken (or anyone else),

(I know I'm slow), but what does IIRC stand for??

Gracias

[Ken Talbot]

If I remember correctly, it means something like........

[prometheus578]

"Put THAT in your pipes(s) and smoke it"

Pipes doesn't explain the probs startin'. I say carbs. Firehawk... do me a flavor... Fire the bike up, let it run for a minute or two and idle, and then spray some water on the headers. (I use a spray bottle of 409 cleaner) See if they all sizzle the same. Choke/enrichener circuit is suspect, which this test won't verify, but it will tell you if you're not really runnin' on all four. Is the battery crankin' it over at a good clip?

[Ken Talbot]

Yamaniac, here's a link to one of the posts dealing with the enricher circuit, in case you haven't found it already.

[xj11john]

Well its obvious its not getting enough fuel, and a lean condition will make you gas mileage suffer.

On my xj I was only getting about 25 miles to a gallon, rejetted using the jet recomandations, but just the mains i left the pilots alone since it idles fine just by turning the adj. screws out.

Now I'm getting about 38-40ish, and very happy with the way it runs.

good luck.

[trbig]

Ahhhhhhh.... I told TC that his beer was on me if we ever met in person for all the help he's done for me... sounds like it's gonna be a cheap date for me!!

[Firehawk]

Originally posted by Dragonrider
Did you try the "prime" position on the petcocks?

That's a whole different story in of itself. I got the tank off eBay because the original (standard) tank was rusted through. But this was the first tank I came accross and was from a 79 or 80 Special. The petcocks it came with didn't have a vacuum shutoff, just two outlets, which both are on in the prime position and I had no room to run a hose that 'T's into another hose to use both and I didn't really have the money to buy new petcocks (and the other ones didn't fit). So I plugged up the one that wasn't on when its on 'primary,' and run it off of the 'reserve' switch and then turn it to off when its not running (as I had a problem with prominent leaks when I just left it on).

Originally posted by xj11john
...rejetted using the jet recomandations...

And those are?

Originally posted by
prometheus578
Pipes doesn't explain the probs startin'. I say carbs. Firehawk... do me a flavor... Fire the bike up, let it run for a minute or two and idle, and then spray some water on the headers. (I use a spray bottle of 409 cleaner) See if they all sizzle the same. Choke/enrichener circuit is suspect, which this test won't verify, but it will tell you if you're not really runnin' on all four. Is the battery crankin' it over at a good clip?

I believe it to be running on all four. The battery and starter are just fine. I'll do this none-the-less when I get home next.

[prometheus578]

"What a tangled web we weave, when first we practice to deceive" (ourselves)

I believe it to be running on all four.

As I qouted the great Holmes in an earlier post... to paraphrase: If you use your beliefs to go searching for facts, your facts will then conform to your beliefs.

[trbig]

I'm not playing against Pro in a Trivial Persuit game of TV and movies.