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25th March 2008
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Senior Chief Know It All 1st Class
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Join Date: Dec 2006
Posts: 1,174 Sportster/Buell Model: XLCH, restored Sportster/Buell Year: 1962 Sportster/Buell Model #2: XLH, period hotrod basket Sportster/Buell Year #2: 1961 Other Motorcycle Model: FXDXT (T-sport) Other Motorcycle Year: 2002
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Tuning situation/question
So, got the bike running on the centerstand in the shed. Pipes got red hot really quick. Not good. Lucky for me I had the drag pipes and not the high mount on it. So I did a bit of tuning, and it seems to be running very well, best I can tell, with it still on the stand in the shed.
Here is where I'm at.
It can sit and idle for as long as I dare without fouling a plug or heating up a pipe. (I close the door and turn off the light real quick to see if it's glowing)
If I run it for a bout a half a minute at 1/4 throttle with a small fan in the front, it starts to glow the front pipe.
Plugs are a little rich, but I have no clean spares to put in it right now. Sad I know.
DC-10 low speed jet is 2 1/4 turns out, high speed is 3 3/4 turns out. Manual says 1 1/2 and 1 1 3/4 should run but be to rich.
Timing is set, 15 point gap, on the factory timing marks. Magneto body sits out in the back about 15 degrees from straight from the motor.
Start right up, revs strong and sounds good. No spitting, sputtering, backfiring or the like.
No Intake leaks that I can tell. Tried with some propane and some WD-40, but no really noticable change with either.
Did not do exhast leak checks except to hold my hand by the head and feel for hot air. None.
No signs of head gasket leaks.
Front runs richer and hotter then the rear.(That's the wierd one I think)
Questions are, in the collective experience of the group...
Should I expect that front pipe to get red hot in these conditions or should I look for wrong?
Or should I not worry about it till I get it on the road and can really read the plugs to see what is happening?
Thanks
Joe
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25th March 2008
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Rider Of The Iron Steed
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Join Date: Dec 2003
Location: London, ON Canada
Posts: 23,712 Sportster/Buell Model: XLH Sportster/Buell Year: 1978
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I would do the exhaust leak test from the Sticky. An exhaust leak will play real havoc with the tune up. Will run as if way to lean. Could explain some of the red hot pipe symptom.
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27th March 2008
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Senior Master Custom Bike Builder
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Join Date: Dec 2007
Location: Australia
Posts: 7,860 Sportster/Buell Model: XLCH 1000 Sportster/Buell Year: 1977 Sportster/Buell Model #2: 75 motor in Norton frame. Other Motorcycle Model: 42WLA 45, Harton, Narley Other Motorcycle Year: 1942
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I would be checking my ignition timing real careful too.
Glowing pipes should never happen.
I would check the timing staticly first, and then with a strobe light. On both cylinders.
It could be a combination of lean mixture and out of time spark.
So check everything.
If I had another carb lying around with a fixed main jet, I would put that on to start with while I eliminated timing, inlet manifold leaks, exhaust leaks, tight tappets.
Then if you get it running right, and put the carb back on and the problems returns, you know it is the carb causing it.
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27th March 2008
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Senior Bike Builder
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Join Date: Nov 2006
Posts: 1,942 Sportster/Buell Model: KHK Sportster/Buell Year: 1954 Sportster/Buell Model #2: XLC Sportster/Buell Year #2: 1958 Other Motorcycle Model: XLRTT Other Motorcycle Year: 1966
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Hi Joe, Hope you're doing OK...
As Hopper said, if you're running rich, you'll have to retime the mag: not enough advance, gas is burning in the pipes...
If you're running the no-retard mag with the original adaptor plate, it should be dead straight and parallel to the bike axis, main body towards the rear cylinder.
All the best from Patrick
__________________
Flat Head Forever...
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28th March 2008
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Biker
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Join Date: Dec 2007
Posts: 24 Sportster/Buell Model: xlch Sportster/Buell Year: 1974
Reputation: 10

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I had asimilar issue. Front pipe glow rear ok. pulled my cam cover to get a weld done. checked my cams and 3 & 4 were off a tooth advancing the front cyl. Front firing with exhaust valve open. First time checking cams on this bike. Have you checked yours
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28th March 2008
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Biker
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Join Date: Nov 2007
Posts: 85 Sportster/Buell Model: XLH Sportster/Buell Year: 1970
Reputation: 10

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i just saw this same "glowing red front pipe" phenomenon a couple of weeks ago. my bro-in-law rebuilt his carb and incorrectly reassembled the pilot screw mechanism. check the sticky on this. "sequence: pilot screw, spring, washer, o-ring".
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28th March 2008
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Custom Bike Builder
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Join Date: Jun 2006
Posts: 2,464 Sportster/Buell Model: XLCH Sportster/Buell Year: 1972 Other Motorcycle Model: Heritage Softail Other Motorcycle Year: 1999
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As said could be cams out of time but more likely ignition timing. Check with a dial back light, that will tell if ignition is the culprit. If the cams are off by a tooth it will run, but run with little power. It won't cause the pipes to glow. Ask me how I know.
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31st March 2008
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Senior Chief Know It All 1st Class
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Join Date: Dec 2006
Posts: 1,174 Sportster/Buell Model: XLCH, restored Sportster/Buell Year: 1962 Sportster/Buell Model #2: XLH, period hotrod basket Sportster/Buell Year #2: 1961 Other Motorcycle Model: FXDXT (T-sport) Other Motorcycle Year: 2002
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Thanks all, got to work on this a bit today.
I'm really sure my cam timing is good, I double checked it before putting the cover on.
I opened the magneto today, and found I had left myself a little comedy of errors. I had set the timing with the old points I had in there last summer...they looked ok...well today I could not get it to a perfect static time via the instructions I got from thefrenchowl last summer. Then I dropped in my spare new point set and the static time fell right into place. Pitting was preventing a good gap measure with the old set. Also, I was a tooth off with the magneto install.
Now off to get some new plugs so I can try and tune my carb...I'll get her started this week and keep y'all posted.
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