Bonneville America Forums Forums Technical Forums Performance Mods Big Bore Success!! (so far)

Just started my speedy up after completing the big bore (904) and she is back on the road. Well, sort of. I'm now in the break-in period, checking for leaks, making minor adjustments, etc. but the main thing is that she started up on the first try and is running great. Woo hoo! To say that I'm grinning right now is an understatement, especially since I did all the work except for the machine work by myself. I was so nervous when I started her up and I still feel like a novice wrench but this has given me a big feeling of accomplishment so maybe I'm a novice wrench +1 now .

I'd just like to thank Pat for the great instructions, Chy for answering my questions, Moe and Pat for some tools, BikerThug for the clutch pics and instructions from a thread a long time ago, my grandad for my mechanical aptitude, the Academy and countless others

It's been so long since I've been on my speedy (7-8 months) that I can hardly remember what she was like before. My Daytona has certainly given me a different perspective and the two are like night and day. Though I know I'm definitely going to enjoy re-learning to ride my speedy.

Here's what I did:
-Big Bore (904 kit)
-complete Barnett clutch (springs and plates)
-turn signal kit (LEDs make the stock turn signals act as red running/brake lights and yellow signals)
-new rear tire (it was a sight to see if you missed the pics)

So far I have some popping on decel down hills so I'll go from 2.5 to 3 turns on my mixture screws. Carbs were still balanced from the last time I did them. Have to check the plug color to see if I need to up the jets or not (150/42 right now if I remember correctly). The throttle action isn't quite as smooth as I'd like it to be but the cables aren't twisted, maybe they just need to be lubed. I've still got my glass catch-can at the end of my crankcase breather tube for now and I hope that issue goes away. There wasn't much I could do while I was in there to fix it.



Oh, and if anyone hasn't done so they may want to empty their fuel tank and dump the grit out. My bike has 34500 miles on it and is 4.5 years old. I was amazed at the amount of crud in there. During my work I took the tank off and emptied it but still had this sloshy sound when I moved it around even though I knew it was bone dry. So I removed the petcock and was stunned by the amount of grit I was able to shake out of the tank and dump out of the petcock when I took it apart. I couldn't get all of it out of the tank but got as much as I could. It's probably a mix of crud from fuel station tanks and rust in the tank (hopefully none of the latter). It's just something folks may want to do every other year or so even though the screen on the petcock is small enough to block it.

Well done Greg, hope everything runs smooth for ya bro

Nice one Greg. I want to do the same myself one day

i still smile every time i start my bike and it runs. nothing better than doing it yourself

Frank

I want one too

Keep dreamin staffo

I've got plans for a Bearmer GS first and then I can play with my Shiela. We have big country which needs exploring and lots of it is dirt

So far it's running great. The power band is much higher (obviously) and it accelerates faster. It's a bit lean so I need to increase the main jets (plugs are very white burnt). Decel popping is still there at 3 turns but after thinking about it doesn't turning the screws out richen the mixture by adding more fuel? Isn't the popping created by unburnt fuel because there's too much to burn in the chamber so it's getting burned in the pipes therefore you would need to decrease the fuel to eliminate the popping? I've turned the screws down to 2 turns to see what that does.

My money's on upping the pilots to 45s.

Fortunately I have some of those on hand so that's the first thing I'm going to try. I dropped it to 2 for a little bit but it was worse and took them back up to 3 turns and it's better so I'll leave it there for now. I've balanced my carbs but the right plug is always dirtier than the left (has been since new) so I may unbalance them slightly to favor a higher vacuum on the left. The current state of the plugs is black and sooty at the base of the plug but burnt white (I don't know what else to call it) at the electrode and the hook (everything higher than the outside threads).

Sooty at the base would normally indicate too rich. You might want to try going DOWN on the mains and upping the pilots to 45. You didn't mention if your airbox was removed. 150 seems quite high if not. Some decel popping is normal with less restrictive exhausts. You might try turning the screws out to 3.5 and see if it gets better, but if all decel popping goes away, you probably should turn them back in a bit.

I took the airbox off some time ago. My current setup in the order I have done them over the years is:
No AI
Epco pipes (130/45 2 turns out)
Freak kit with K&N filters (150/42 2.5 turns out)
904 BB

Each iteration was dialed in very nicely with tan coloration on the plugs and very smooth running. The soot at the base tells me that one end is rich and the popping makes me think it's the bottom (pilots). It's the white burn on the electrode end that has me bothered. I'd rather have it a little rich than lean.

Here's a pic of the plugs on their respective sides. They're looking better than they did earlier today but from previous experience I still think they look bad.

From the pictures it looks like you need bigger squirters all the way around, pilots and mains. That left plug is lean, way lean...the soot looks like a lengthy idle session with the enrichener engaged.