Triumphrat

dbcompetition · 08-29-2006

last week I did a 2500 km trip to Italy, It whas the first long trip for the bonneville, it has now 4000 km and I very happy with it. I have the tors and rejetted to 120 mains, But when I whent above 2000 M for ex the Stelvio the bonnie became so slow I could hardly reach 60 km/u, it whas not possible to open the trottle more than one cm. otherwise it stalled ...
So he is too rich, and normaly the 120 goes with the tors ?
Should I remove the restriktor in the airbox ...

merlin · 08-29-2006

Do not remove the restrictor at this time - there is some other problem with the bike. TOR with a 120 sounds reasonable. Whatever other minor jetting is needed, the bike should not be running as badly as you describe (if I understand your post). There is something else wrong. What is wrong should be determined and corrected before you move further and remove the restrictor, which would only complicate the issue.

ohiorider · 08-30-2006

Good advice, Merlin .... that was my thought, too. We ran our Bonnies out West this June .... one jetted using whatever jet came with the TORs for the 790cc in 2002, and my bike (another 790cc) running TORs, no snorkle, free flow air filter with one shim and 125/42 jetting. We rode across the flatlands, cold (low 40s) heat (107f one afternoon) altitudes as high as 7000' across Continental Divide, and neither bike exhibited any of the characteristics described by dbcompetition.

Bob

dbcompetition · 08-30-2006

Quote:

On 2006-08-29 21:04, merlin wrote:
Do not remove the restrictor at this time - there is some other problem with the bike. TOR with a 120 sounds reasonable. Whatever other minor jetting is needed, the bike should not be running as badly as you describe (if I understand your post). There is something else wrong. What is wrong should be determined and corrected before you move further and remove the restrictor, which would only complicate the issue.

thank you for the advice, but what could be wrong ?? When I ride de bike at sea level it runs great , it easely reach te red line in 5 gear... but above 2000 m altide I can just open the trottle 1 cm if more it slalled and begins tho backfire ... when I go down everything goes back to normal..

grt Dirk

badrufus · 08-30-2006

I'm in agreement with merlin--the bike should not have that severe of a response to altitude. I have an 05 T100 with Norman Hyde Classic silencers, rejetted to 120 mains, and K&N air filter. I regularly ride at 1800 feet (550 meters) up to 3500 feet (1050 meters) and notice no change in the bike. It should if anything run more rich, which makes the backfiring quite confusing. In any case, before you do airbox modifications, try replacing the stock filter with a more free-flowing air filter such as the K&N or Uni. If you open up one end (exhaust), it's a good idea to open up the other (intake).

merlin · 08-30-2006

db - 2000 meters - 6000ft - is pretty high, but other bonnies have done it. The CV carbs we have are kind of self adjusting for altitude.
It seems reasonable that your problem is carburation (not electrical) but I can't get any closer than that. Again, I think a further modification will only confuse this issue. Go over the entire air/fuel system carefully - from filter to float height, fuel, choke, carb boots, everything.
Sorry I can't be more specific

ohiorider · 08-31-2006

Here's a wild guess .... is it possible that your carb heaters aren't working ... perhaps unplugged, or the thermal switch isn't turning them on?

My W650 has CV carbs similar to the Bonneville's, but without heaters (on the USA version), and there's been a couple of times when I believe one of the carbs froze. When that happened, I limped home, barely able to give the bike any throttle. When I did, it would practically stop. It was like I had to run on the pilot or idle circuit until things thawed (after I parked the bike for a few moments). Then things worked fine again.

It doesn't have to be below freezing for carbs to freeze, due to the evaporative action of vaporized fuel, which causes fuel to freeze and block the jets. I would guess high humidity would contribute to carb freezing.

Again, this is only another place you might want to check.

Bob

merlin · 09-02-2006

You're 'wild guess' might have some validity. I check the service manual. The carb heaters are operated by a sensor under the right side cover. a flat, wedge shaped item, its there but you need to look to see it, not very obvious. It turns the heaters on at anything below 10 degrees C. The electrical connects to the carbs are quite obvious, just not to be confused with the TPS. There are two connectors per carb. So the check would be quite easy, turn the bike on above 10C, put a voltmeter across the two connectors. Cool the sensor (ice cube in a sock?) and see if there is any voltage across the connectors. I don't know the voltage, (12v system so/) but it doesn't matter. If there is NO v - there's a problem.
Any your're quite right, of course, the ambiant temp can be relativily high, if the humidity is high you can get carb ice.

dbcompetition · 09-03-2006

Quote:

On 2006-09-02 13:04, merlin wrote:
You're 'wild guess' might have some validity. I check the service manual. The carb heaters are operated by a sensor under the right side cover. a flat, wedge shaped item, its there but you need to look to see it, not very obvious. It turns the heaters on at anything below 10 degrees C. The electrical connects to the carbs are quite obvious, just not to be confused with the TPS. There are two connectors per carb. So the check would be quite easy, turn the bike on above 10C, put a voltmeter across the two connectors. Cool the sensor (ice cube in a sock?) and see if there is any voltage across the connectors. I don't know the voltage, (12v system so/) but it doesn't matter. If there is NO v - there's a problem.
Any your're quite right, of course, the ambiant temp can be relativily high, if the humidity is high you can get carb ice.

thanks guys for the good advice I make control off the heaters, but I think the problem is something else, at high altidude the bike become very rich, the outlet of the mufflers are covert with soot ...I think the main jet is too large, so I will test the air/fuel ratio by a gas-analyser and let you know
Dirk

merlin · 09-03-2006

Dirk,
All of my knowledge and resources are available to you. I will gladly consult, in person, on this issue. I am expert, having owed...well... one whole motorcycle as opposed to you haveing.. well... many.
If you would just cover my flight costs to Italy to check the performance of the bike, I'm sure I can assess the exact nature of your problem.. sooner or later. If a brief stopover of oh.. two or three weeks is required in Belgium, I can manage that also, all part of the service! I really do feel though that the bike should be checked in southern Italy too preferably, the Almalfi Coast, to check performance at lean angles.
Flight costs would be from JFK and I come equiped with.. uh, a hex wrench so I can even take the seat off!
Seriously, good luck with your problem and I hope this issue didn't ruin your trip. You'll get to the bottom of it.