Bonneville America Forums Forums Technical Forums Exhaust New exhaust -jetting help needed

Hi guys...having a problem. Finally had enough of the stock exhaust after 4 years, so my journey begins. I'm not really too mechanical, but trying to learn. I recently installed pipes from Chevy605. I have done nothing other than pull the top snorkel over the air cleaner...AI is still in. I used the Jetting Calculator but I'm alittle confused here also...are Don's pipes considered 'all baffles removed'? ....I ended up putting 130's in as this seems to be the most popular ones. The bike once warmed up to temp is smoking from the exhausts quite a bit. I haven't ridden too far yet, perhaps this is the cutting oil still burning off?? or is it too rich? I've played with the air/fuel mixture but with the same results. I have a set of 125's I was thinking about installing. I am alittle confused also as there is popping on deceleration which would indicate a lean condition right? I took off the pipes, re-siliconed them, reinstalled & again some popping, trying to eliminate possible exhaust leaks.
Just wanted to get some feedback before trying the 125's as taking the carbs off was troublesome (but should be easier this time) & I couldn't get the triangle connector (throttle position sensor?)) apart.

Thanks

Rich,
Sounds like you got it right, the smoke is probably something in the pipes as you said, but without seeing it, hard to really be sure.
Check the plugs, are they all black and gummy? if so, then you are too rich. The 130s sound right for those open pipes, and yes, that is considered all baffles removed in my calculator.
The throttle sensor has a little push thingamabob to release it. Clean it off and take a close look and you will figure it out.
The decel popping is normal on our bikes, just if it's a lot then you can get rid of most of it. Mine pops still going downhills with no throttle, but a pubimeter of throttle eliminates it.
To adjust your pilots, put both pilots screws all the way in then back them out about 1.5 turns out to start with. Then warm the bike up to operating temp, then increase idle with the idle screw on the left side of the carbs to about 1200 rpm. Shut down bike, remove one of the spark plug wires, start bike - adjust the side that is running pilot screw in and out as you observe motor sound. As the bike starts to stutter at each end of in/out, find the middle position and set it there, repeat for other side. This should give a decent idle once you readjust idle speed back to normal 850-1000 rpms, depends on individual bikes there. If you are more then 4 turns out, replace pilots with the next bigger size, repeat. Make sense?

Chevy605 uses cutting oil and it will burn out of the pipes in short order.

Thanks for the input Pat...I'll give er a go. I took the bike out for a good 30 minute ride yesterday....still smoking abit...I would of thought that oil would have burnt off by now..??

Hi Ian...thanks for the response...the bike is still smoking..although not near as bad after a 30 minute ride yesterday...still the cutting oil being burnt??

I am not 100% on what damages and what doesn't on the new ignitions so I use an old spark tester. It is a sparkplug with a clip soldered to the side so it sparks just like a normal plug and the clip gets clipped to a ground so you are sure it stays that way.

The pipe takes a good long ride to burn it all out, since it gets in the packing behind the mesh and soaks in. If you go out for a day and come back it won't be smoking anymore.

I added Chevy's pipes over the winter, used the calculator with stock gutted. Also added a K&N hi-flo solo filter and pulled top snorkel. I rejetted to 130 mains and new pilot via the dealer set up. She is not runing as good as she should when cold and have had to adjust the idle a bit to keep her running when cold. Haven't been out lately to see if it is still a problem. The oil from Chevy's cutting should burn off after a good ride. Also make sure you have sealed up the connection of the pipes to the headers.

You need to adjust the pilot screws and Chevy pipes are closer to stock pipes with 1 baffle left than gutted.

If memory serves me right, idle speed is to be 850-1150 rpm. The tack on a Speedy doesn't even register below 1100, so I turn it up just until the tack needle starts to bounce, then back off a slight hair. If I try to lower the idle to less than say, 1000, it sometimes stalls when cold or even too hot...or even taking off from a stop. Also, if you ride in various elevations, the idle needs minor adjusting to keep it right. That is most likely why the idle screw is so easily accessible.

I have also noticed that it runs best at idle at 2 1/4 turns out from the stop on the mixture screws, and then a + or - 1/4 turn for smooth quick-snaps of the throttle twist. I have also figured out to stick with the stock 42 pilot jets with an uncut or non-removed airbox. This eliminated most deceleration pops (hot, unburnt fuel igniting when reaching the outside air at tip of the tailpipe = rich condition) It also can't hurt to make sure the carbs are balanced (synchronized) at around 2500rpm.

You really don't need to remove the carbs to remove jets. Just drain the bowls and unscrew them. I put in allen/hex screws to make this a snap. A flexible precision screwdriver really makes it easy... for bowl removal and of the pilot jets too.
like this one I used the largest flat bit for the pilot jet with the slight help of a small socket, 3/16", it think it was.

Don't ever just set pilot screws at a certain number of turns. Adjust them properly to get the right mixture.

Hey all,

Yup, I wasn't all so right in my last post. I was getting the pop, pop, pop on deceleration, and put the stock pilot jets back in...then I would get straight up BACKFIRES...needed the mixture screws opened up a bit (1/4 turn at a time on each side until there was no more pops....sounds and runs really nice now.
D&D furnishes 135 mains and 45 pilots. The latter was a waste of time and petrol. Pat's calculator suggests 132 mains, but it seems to be fine. I will update at a later time.