Shovel FLH exhaust
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Joined: Apr 2007
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Shovel FLH exhaust
Hello, this is my first post, so..............
I've an early '84 shovel FLH. When I bought it ithad non-baffled drags, stockKehien butterfly carb, and an Andrews "F" grind cam. This combo work ok, but the carb wouldn't tolerate baffles or back pressure in theexhaust system. It would run overly rich between 2500-3000rpm (fuel stand-off/reversion)with 72 intermediate & 165 main jetting, when tried.
I wanted too quiet it down some and have mufflers under the both bags, so I ditched the Kehienanddrags for a S&S superE, and Paucho 1 3/4" dual exhaust w/crossover, and stock type 3 1/4" 28"long turnout mufflers (not straight though type). With these changes I needed to run a 28 intermediate, 66 main, and 58 air bleed to reduce fuel stand off in the mid's to alevel where the bike would run ok, but just ok.
I pulled the Andrews "F" cam out believing it was contributing to my midrange problem, and installed a Andrews "J" grid cam. Using only the seat of my pants Ifeel I lost some power above 4000rpm, but it did improve the low & midrange (and the mid's overly richcondition), but I still need to run a 48 air bleed to hold the main's flow off a few RPM, and a 66 main is as rich as it'll tolerateall the way to atleast 5000rpm.(ashigh as I've run itduring my jetting)
I've double checked the ignition timing andcompression. Itwas 120 psi both w/F grind, and is now 133 & 135 psi w/J grind. The bikenow runs fairly decent, but I don't understand why I need to "up" the air bleed to get it running clean in the mids, or why a 66 is as rich as it'll tolerate on the top. I've run a richer mainthan that in a ironhead with a super b and mufflers??
I guess my next step is too install mufflers that'll flow better in hopes of getting it to breathe easy enough I can get the air bleed back down close to a 40, and get it burning alittle more fuel,clean, inthe mid and top for power.
I'd appreciate anyinput on my thoughts the exhaust flow's still my problem, anything I've possibly overlooked, and maybe some leads on where to locate free flowing mufflers that'll fitthis bike. I'm getting tired of buying parts that don't work as I'd hope, and that can't be returned. Am I just going overboard about the fact it seems I'm running "lean" jet's while it's actually running on the richer side, and I should just go with what has it burn right regardless of the actual jet size? This is my first shovel.
Also, FWIW, I'm not going back to drags if that's my only choice to increase exhaust flow. In that case I can live with it as is.
Thanks for any and all replies!!
Jeff
I've an early '84 shovel FLH. When I bought it ithad non-baffled drags, stockKehien butterfly carb, and an Andrews "F" grind cam. This combo work ok, but the carb wouldn't tolerate baffles or back pressure in theexhaust system. It would run overly rich between 2500-3000rpm (fuel stand-off/reversion)with 72 intermediate & 165 main jetting, when tried.
I wanted too quiet it down some and have mufflers under the both bags, so I ditched the Kehienanddrags for a S&S superE, and Paucho 1 3/4" dual exhaust w/crossover, and stock type 3 1/4" 28"long turnout mufflers (not straight though type). With these changes I needed to run a 28 intermediate, 66 main, and 58 air bleed to reduce fuel stand off in the mid's to alevel where the bike would run ok, but just ok.
I pulled the Andrews "F" cam out believing it was contributing to my midrange problem, and installed a Andrews "J" grid cam. Using only the seat of my pants Ifeel I lost some power above 4000rpm, but it did improve the low & midrange (and the mid's overly richcondition), but I still need to run a 48 air bleed to hold the main's flow off a few RPM, and a 66 main is as rich as it'll tolerateall the way to atleast 5000rpm.(ashigh as I've run itduring my jetting)
I've double checked the ignition timing andcompression. Itwas 120 psi both w/F grind, and is now 133 & 135 psi w/J grind. The bikenow runs fairly decent, but I don't understand why I need to "up" the air bleed to get it running clean in the mids, or why a 66 is as rich as it'll tolerate on the top. I've run a richer mainthan that in a ironhead with a super b and mufflers??
I guess my next step is too install mufflers that'll flow better in hopes of getting it to breathe easy enough I can get the air bleed back down close to a 40, and get it burning alittle more fuel,clean, inthe mid and top for power.
I'd appreciate anyinput on my thoughts the exhaust flow's still my problem, anything I've possibly overlooked, and maybe some leads on where to locate free flowing mufflers that'll fitthis bike. I'm getting tired of buying parts that don't work as I'd hope, and that can't be returned. Am I just going overboard about the fact it seems I'm running "lean" jet's while it's actually running on the richer side, and I should just go with what has it burn right regardless of the actual jet size? This is my first shovel.
Also, FWIW, I'm not going back to drags if that's my only choice to increase exhaust flow. In that case I can live with it as is.
Thanks for any and all replies!!
Jeff
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Intermediate
Joined: Apr 2007
Posts: 40
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RE: Shovel FLH exhaust
I figured I'd post what I found, despite not getting any responses, incase it may help someone else with a similair problem.
The mufflers were too restrictive and were causing my carburation issues. I replaced them with two Paughco 3"x 30" tapered mufflers. I could tell right away, before rejetting, the bike was running much better. I was able to drop the air bleed back to a 40, and raised the main to a 68. May be able to go abit more on the main, but rain has cut the jetting session short.
I've no noticeable"fat spot" in the middle of the powerband now, and theengine pulls smooth all the way up with decent power.
Apparently matching cam and exhaust is important even on mildly tuned engines, just for rideability sake.
The mufflers were too restrictive and were causing my carburation issues. I replaced them with two Paughco 3"x 30" tapered mufflers. I could tell right away, before rejetting, the bike was running much better. I was able to drop the air bleed back to a 40, and raised the main to a 68. May be able to go abit more on the main, but rain has cut the jetting session short.
I've no noticeable"fat spot" in the middle of the powerband now, and theengine pulls smooth all the way up with decent power.
Apparently matching cam and exhaust is important even on mildly tuned engines, just for rideability sake.
Cruiser
Joined: Sep 2007
Posts: 241
Likes: 1
From:
RE: Shovel FLH exhaust
Good info... I ran into a similar situation with a Panhead converted years ago to Shovel and with a Sifton 4-12 cam. The exhaust was not as easily chosen as the other modifications. This bike went back to the stock 'through the frame' 'S' pipe and surprisingly did very well that way...must have been just about the correct back pressure for the mild Sifton cam to work well. The change from Pan Heads was the largest gain! Like waking the engine up.
Look for EVO mufflers. They have similar specs to the Shovel as far as stroke - (piston speed and dwell) so reversion may not be as much of an issue. There is, as you probably know, a fine line between 'free flowing' and a system that beats itself up with reversion. A tuned exhaust for a Shovel has been so long ago to be popular that finding a good matched system will take some searching, but I'm quite sure they are still out there. Wish I could help more...I just ride now. My days of working in the engine are fewer nowadays. Carburators? I'll pass now on them too! Good luck, sounds like you are on the right track and having a good time - that's what counts anyhow!
Look for EVO mufflers. They have similar specs to the Shovel as far as stroke - (piston speed and dwell) so reversion may not be as much of an issue. There is, as you probably know, a fine line between 'free flowing' and a system that beats itself up with reversion. A tuned exhaust for a Shovel has been so long ago to be popular that finding a good matched system will take some searching, but I'm quite sure they are still out there. Wish I could help more...I just ride now. My days of working in the engine are fewer nowadays. Carburators? I'll pass now on them too! Good luck, sounds like you are on the right track and having a good time - that's what counts anyhow!
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