Radare's Triumph Bonneville

The general Seca II forum. XJ600 centric but all motorbikes welcome!
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radare
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Tue Sep 01, 2015 11:10 pm

Finally received some more of the parts I was waiting on from Triumph (courtesy of Bike Bandit). So on Friday afternoon, I plan to pull the carbs on the Bonnie, and go through them.

The first time was an attempt to clean out the pilot circuits while I waited on parts. Now that I have parts, I plan to give the carbs the Radare-treatment as follows (and for future note, this work will be done at right around the 7200 mile mark on the odometer):
  • Again soak the carbs in the ultrasonic to remove any traces of fuel and any missed blockages
  • Blow out all parts with compressed air and confirm cleanliness with gauge wire
  • Install a new set of genuine Keihin #42 pilot jets (a size up from stock)
  • Install a new set of genuine Keihin #110 main jets (stock size)
  • Install new Keihin enrichment plungers and hardware on both carbs
  • Install new Keihin float valves and float bowl gaskets on each carb
  • Set the float heights to 17mm above gasket-surface
  • Install new Keihin O-rings on the overflow tubes and main fuel rail
  • Install new Triumph genuine fuel line and spring clamps
  • Set the pilot screws to 2.5 turns from seat (stock setting)
  • Install new Triumph genuine intake manifold rubber boots
  • Install new Triumph genuine intake-manifold O-rings
  • Install new Keihin vacuum port test plugs on the synchronizer ports
  • Balance the carbs as finely as possible
  • Install new NGK DPR8EA-9 spark plugs, gapped to 0.9mm
If this works out, it should complete the maintenance on the bottom-end of the carbs. I'm still waiting on the replacement slides and will install those when they come. Fortunately, that can be done without removing the carbs from the bike. I also ordered a new pickup sensor since they seem to be problematic on these bikes. I will replace it and re-gasket the stator cover when it arrives.

With the previous oil change, air filter change, carb balancing and brake service, I should really only need to perform chain maintenance and the bike will be up-to-par on all necessary maintenance items. That will leave me ready for the modification phase of this project . . . :ponder:
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radare
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Wed Sep 02, 2015 10:29 pm

This thing is becoming my latest money-pit. Tonight I bought a spare set of headers from a 2005 Bonneville and a set of O2 bungs and plugs. When those come, I'll weld the plugs onto the headers, fit the headers and then can use them to tune the Triumph's carbs with the AEM wideband O2 sensor that I've been using on the XJ's. I wasn't thrilled about spending the money on all that garb but it's really the best way to determine where the bike is running and what direction to proceed, tuning wise. So if I keep the Bonnie for, say, the next 20 years, it'll be worthwhile.

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Siper2
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Thu Sep 03, 2015 12:05 pm

Congrats on the Bonnie!
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radare
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Thu Sep 10, 2015 10:53 am

An update.

The carbs have been completely overhauled. I removed them and gave them a through cleaning as follows:
  • Complete disassembly (minus butterfly shaft removal)
  • Soaked in heated ultrasonic bath with detergent for two 480-second cycles
  • All passages blown out with compressed air
  • Passages confirmed clean with gauge wire
  • New Genuine Keihin jets installed (#42 pilots, #110 mains)
  • New float valve installed and valve seat polished
  • Float heights set to 17mm above gasket surface (found at 16mm)
  • New enrichment plungers installed
  • New slides & diaphragms installed w/ 3.0mm bleed (originals showed excess wear on the engine side)
  • New float bowl gaskets installed
  • Pilot screws removed, cleaned and installed with new O-rings
  • Pilot screws set to 2.5 turns from seat
After the carburetor cleaning, I installed new intake rubber boots, new vacuum caps and new intake-to-head O-rings. I also installed new spark plugs, gapped to 0.9mm and a new Triumph air filter. I finished by synchronizing the carbs using a manometer.

After all this work, the bike was started on full-choke and observed: The idle was smooth and consistent for the first 15 to 20 seconds, before dropping and becoming rough. At that time, the right exhaust popped a few times, almost sounding like a backfire or miss. As the bike warmed up, though, the idle smoothed out and remained consistent.

When riding, the revs no longer hang and the bike pulls well all the way from idle to full throttle. The first 10 to 15 minutes of riding, once warm, are great. The bike idles well, pulls well and runs as it should. Then, after 20 to 30 minutes of riding, it still idles well, but develops a stumble/misfire right off idle that causes the bike to chug and lurch before it will smoothing out and running great. If I run the RPM's a bit higher and slip the clutch, the stumble/misfire doesn't happen. The surging noted previously is still present at lower rpm, lower-throttle, constant speed cruising but much reduced.

I suspected that, perhaps I missed something in the carbs, so I pulled them off and re-cleaned them. I found no gunk, no partially clogged passages, nothing. It's clean. I also checked all the boots and caps for an air leak and found none. Since I'm certain the carbs are clean, I've begun to suspect other issues may be causing the problem; perhaps ignition. I've read a multitude of issues caused by a faulty pickup sensor or failing Gill coil, so I've ordered a new pickup sensor from Triumph and Nology coil, hoping this may help.

Last night, I tested the TPS (according to this procedure) and it seems to be set appropriately. I also set the idle speed to 950 rpm using an induction tachometer on the left plug wire. I then went out and performed some troubleshooting.

First run: The bike is warmed up, choke off. It idles well and runs beautifully. This continues for approximately 10 miles. Then, when making a right-hand turn, I downshift to second gear and roll on the throttle. Engine speed is low, say 2000 rpm or so. As I let the clutch out, the bike stumbles and bucks and stumbles. As I continue to turn the throttle, it picks up and runs beautifully again, through the remaining gears.

Second run: Turned the pilot screws in 1/4 turn. Exhaust note sounds less-crisp but the bike feels fine until that low rpm, second-gear roll on and then it bucks and stumbles, just like the first run. During the stumbling, I pulled the choke out a bit to see if it would change the behavior and it did not; the stumbling continued.

Third run: Turned the pilot screws out 1/4 turn. Same story. Bucks and stumbles at low engine RPM in 2nd gear. Noticed that it seems to have a minor misfire in higher gears at low engine-speed cruising (say fourth gear at 30 or fifth gear at 50).

So to recap: Stumbling in second gear at low engine speed throttle roll-on. Only happens at low engine speed and regardless of pilot screw settings or choke position. Happens only when the engine is warm; after approximately 10 miles of riding.

Based on this information, I'm certain this is not a fueling issue but an ignition issue. Given that the bike seems to run better on the left-hand cylinder and given that it pops on cold-startup on the right cylinder, I suspect the coil is faulty on the right lead.

Measuring the resistance of the resistor caps, both are with an acceptable margin of 5kohms. The left is spot-on at 5kohms and the right measures 4.6kohms. The leads have good continuity and very low resistance. They are good. Moving on to the coil and measuring across the two posts yields an open circuit. No continuity. A sure-fire indicator of a failed secondary winding. This morning, I swapped leads between the right and left-hand coils. Upon cold start, the misfire problem follows the right-hand lead. The right-side of the coil isn't functioning properly. So I've ordered a replacement coil from Nology. It should be here tomorrow. We will see if that solves the problem. More to come.
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arnehulstein
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Fri Sep 11, 2015 3:06 am

Congrats on the new bike. Another fellow Triumph rider now. ;) I haven't been in here for a while due to travels, holidays etc. Anyway, that is one good looking Bonneville you have there. I have been reading up and as every you have already taken most of the thing apart. You should think about buying DIY bikes next time. All new parts, flat packed, just need to put them together. You seem to be doing as much work on them anyway. ;)
radare wrote:Triumph recommends changing the oil every 6k miles (10k kilometers) which I think is ridiculous given how hot these engines run. I mean, it's an air-cooled, carbureted engine with a wet clutch and shared lubrication. So I'll be changing the oil at half that. Every 3k miles. And maybe less than that depending on conditions. This service was done at 7k so the next will be due at 10k.
Actually, the factory intervals are fine. You can run the oil much longer if you want to and current oils are well up to the job for the 10K Km that they recommend. We've got lots of them running around here and I haven't heard of anyone having trouble because of keeping the stock intervals. But, I can understand it if you just want to have an excuse to tinker on the bike. :thumbsup:
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cafe_bill
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Fri Sep 11, 2015 5:10 pm

arnehulstein wrote:
radare wrote:Triumph recommends changing the oil every 6k miles (10k kilometers) which I think is ridiculous given how hot these engines run. I mean, it's an air-cooled, carbureted engine with a wet clutch and shared lubrication. So I'll be changing the oil at half that. Every 3k miles. And maybe less than that depending on conditions. This service was done at 7k so the next will be due at 10k.
Actually, the factory intervals are fine. You can run the oil much longer if you want to and current oils are well up to the job for the 10K Km that they recommend. We've got lots of them running around here and I haven't heard of anyone having trouble because of keeping the stock intervals. But, I can understand it if you just want to have an excuse to tinker on the bike. :thumbsup:
I agree 100%. I've run many Harley and Buell engines and never had an issue. One Buell I changed the oil every 10,000 miles. (using full synthetic) Engine ran flawlessly after 50,000 non-easy miles and didn't burn oil. Oil sent in to test was still good.
Bill
'07 FJR 1300
'02 Sportster
'97 Sportster
'96 Buell S2
'89/'95 Sportster
'92 Seca II
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radare
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Sun Sep 27, 2015 11:42 pm

A photo uploaded from my phone to test out the mobility features of the new gallery.

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xjman
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Sat Oct 31, 2015 12:58 pm

So have you got a replacement coil and did it sort the problem? Do you know I feel embarrassed to be British at times like this, two friends have had the new type triumphs built at Hinckley and they have both had a host of issues.
Bender: I support and oppose many things, but not strongly enough to pick up a pen.

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arnehulstein
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Sun Nov 01, 2015 11:42 am

Just to help you out xjman, my older Triumph has not missed a beat. ;)

Awesome pic Radare!
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xjman
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Sun Nov 01, 2015 11:55 am

arnehulstein wrote:Just to help you out xjman, my older Triumph has not missed a beat. ;)

Awesome pic Radare!
That's good Arne


One friend had a bonneville and the other has a street triple, I think the tiger and the daytona have a better track record.
Bender: I support and oppose many things, but not strongly enough to pick up a pen.

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