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Discussion Starter #1
When I put the Hagon rear shocks and progressive would front springs on my 2007 Bonnie last year, I replaced the fork oil with 15W Maxima oil at the same time. All of these changes made a huge difference in the stability and riding pleasure of the bike. When I put the Hagon rear shocks and Hagon progressive wound front springs on my 50th Anniversary Bonnie, I didn't have any fork oil at home and the local bike shop was closed. This morning I decided to do what i should have done a month ago, and took the forks off again and replaced the stock fork oil with Maxima Racing 15W fork oil (orange). What a difference the oil made! I rode the bike for an hour this morning before changing the oil, so I had a good comparison of what only an oil swap would do. I think this is almost a "must" for those with stock suspensions; it's cheap and easy to do. It takes just shy of a liter of fork oil to do both legs.
Too bad Triumph didn't fit fork drain plugs at the bottom of the legs like on my 60's Trumpets - it makes it really easy to change the fork oil!

Dick
 

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I've been thinking my '07 needs heavier fork oil...

...can you go into some detail about the specific differences you noticed with the new heavier oil?
 

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Discussion Starter #3
...can you go into some detail about the specific differences you noticed with the new heavier oil?
The bike has much less front end dive in braking, and doesn't "pogo" when accelerating or decelerating. The most noticeable improvement, however, is how the bike rides over rough surfaces or expansion joints in the asphalt. I originally thought my new springs were too stiff, but I now think the bike was underdamped; not over-sprung. Improved jounce control is more noticeable than the slightly improved control. I used "racing" fork oil in the 50th Anniversary forks; std fork oil on the 2007. I have no idea what the difference is other than $2/liter :>)

Dick
 

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I'm going to try it.

I'm trying to eliminate what might be regarded as pogoing or some kind of out-of-round or out-of-balance condition. The dealer has worked on it several times since I took delivery, with some success. The original rear tire was replaced due to a flat spot. The rear shocks were swapped with another new machine. The rims have been checked for trueness and runout. The front forks were disassembled and checked. The front tire was broken down and rotated 180 degrees on the wheel. I feel the dampning is insufficient, so the heavier oil might be just what is needed.
 

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Dick,

I have replaced the front fork springs in my bike, but I used 5 wt Bel_Ray oil. I'm interested in what you said but I have a question ?

I'm 5' 9" and weight 203 lbs, but fully dressed in riding gear its probably closer to 210.

So my question is (if you don't mind) how tall are you, and about what do you weigh in your riding gear ?

Thanks !
 

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I've never been clear, from the various posts, about the benefits and disadvantages of lighter vs heavier fork oil. The opinions seem to be about evenly divided, so I stuck with (replacing) the original 10-weight when I upgraded my springs.
 

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Is there an inexpensive siphon device that can be used for this? I'd really like to change the oil, but removing the forks is out of the question at this time.
60ml medical syringe and vinyl tubing in a size that fits tightly on the syringe hub. Or a bleeder pump. Or a cheap plastic manual pump that I saw in a Harbor Freight advert for about $4.
 

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Discussion Starter #9
Dick,

I have replaced the front fork springs in my bike, but I used 5 wt Bel_Ray oil. I'm interested in what you said but I have a question ?

I'm 5' 9" and weight 203 lbs, but fully dressed in riding gear its probably closer to 210.

So my question is (if you don't mind) how tall are you, and about what do you weigh in your riding gear ?

Thanks !
I'm 6'2" and about 230, probably 240# with gear and helmet. Maybe a pound or two more after turkey....

Dick
 

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Is there an inexpensive siphon device that can be used for this? I'd really like to change the oil, but removing the forks is out of the question at this time.
Jack, just pick up a bulb-siphon hose from HF...I bought one there for less than 5 bucks...
 

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A Mity-Vac pump can be used for a number of tasks on your Triumph. It will do a fair job with your forks with some longer tubing and will still work to do one-handed brake bleeding (a job all of us should do from time to time).
http://www.mityvac.com/pages/products_hvpk.asp
Might wanna shop around for the best deal. When I was working as a mechanic I was tempted by the convenience of the Snap-On truck, but shopped around & saved a bundle.

I've had mine a LONG time but I BELIEVE I got mine from JC Whitney.

Same tool... WAY less $$$!:)

 

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A Mity-Vac pump can be used for a number of tasks on your Triumph. It will do a fair job with your forks with some longer tubing and will still work to do one-handed brake bleeding (a job all of us should do from time to time).
http://www.mityvac.com/pages/products_hvpk.asp
I have a Mighty Vac vacuum pump, the MV7400. One of the big cylinders that can collect all of the fluid you evacuate. I love it. I've used it on my Honda Accord to periodically refresh the transmission fluid. Sucks out 3 liters with no problem right through the dipstick opening. I used it to help change and bleed my T100 brakes. I'm going to use it to remove the fork oil when I insert Intiminators. My 2011 is very low mileage so I see no reason to go through removing the forks.
 

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I have a Mighty Vac vacuum pump, the MV7400. One of the big cylinders that can collect all of the fluid you evacuate. I love it. I've used it on my Honda Accord to periodically refresh the transmission fluid. Sucks out 3 liters with no problem right through the dipstick opening. I used it to help change and bleed my T100 brakes. I'm going to use it to remove the fork oil when I insert Intiminators. My 2011 is very low mileage so I see no reason to go through removing the forks.
Is there any way to remove the Bonneville engine oil using a pump rather than the drain bolt? I have limited work facilities where I live and am prevented from doing oil changes into drain pans etc by property regs.
 

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Is there any way to remove the Bonneville engine oil using a pump rather than the drain bolt? I have limited work facilities where I live and am prevented from doing oil changes into drain pans etc by property regs.
You could probably suction out most of the oil in the reservoir but the bigger issue for you is the oil filter. How are you going to deal with that?
 

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As far as getting the old oil out of the forks, those pumps look like the ticket. But wouldn't you have to still pull the forks to get the oil level correct? When I changed mine, which made a phenomenal improved difference, I went by the amount of oil Triumph said to use. But I was told the air gap was more important and to use a measuring device to set the oil level with the tubes compressed and upright, after pumping them several times to get the air out. I triple checked the info, and found there was too much oil in the tubes, I think I had to syphon out about 20 ml from each tube. It's so much better now than the old oil. Used Belray 10w. I know you can just put in as much oil as you take out, but oil thins over time and may give a false sense reading. Does that make sense?
 

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Does that make sense?
:D

NO.

FWIW, if changing fork oil to a different type or viscosity, the tubes really need to be inverted and pumped and allowed to drain as they hold a fair amount in the bottom. Otherwise, you don't get the full effect and/or a full change.

Agreed, certainly best to check the level with the fork leg vertical after pumping a few times to re-fill the bottom, springs out of course. PITA there is no drain on the bottom as in "the good old days". Some lawyer is probably responsible... :(
 
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