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Pulling dents out of expansion chambers.

Started by quocle603, September 13, 2020, 11:30:07 AM

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quocle603

Just got another set of expansion chambers. It had a slight dent on one of them. Decided to see how people pull dents and came across this, *friendly reminder to clean out your oily pipes before proceeding*. I think I will just leave the dents  :eek:

Do not underestimate the power of a two-stroke.

1975 Yamaha RD350 (modified), 1973 Yamaha RD350 (stock), 1971 Suzuki T500, 1981 Yamaha XS650 HS2, 1982 Honda MB5, 1980 Puch Maxi, 1979 Puch Magnum, 1993 Tomos Bullet, 2003 Malaguti Firefox F15 LC

oxford

I used that method on a 4 stroke dirt bike header.  I had an expansion plug in the one side that apparently wasn't in tight enough.  I don't remember how much psi I had going in but the plug going shooting across the garage was pretty impressive.   :dawg:

rodneya

Dirtbike pipes have a flange on both ends. If you do it properly you use a u bolt or something around the pipe bolted to a plate over the plug.
On an RD pipe I would probably weld something onto the pipe to tie  back to. Or just cut out the damage and weld in a new section.

lawnboy

cobbled these together to fix my pipelines. valve on the end allows some air to escape but still provide enough pressure to expand the the dent. a little nerve racking still but worked like a champ.

quocle603

I've seen plenty of people get decent results with a pressure washers. I'm always weary and nervous when a method involves a extreme high and cold temps.
Do not underestimate the power of a two-stroke.

1975 Yamaha RD350 (modified), 1973 Yamaha RD350 (stock), 1971 Suzuki T500, 1981 Yamaha XS650 HS2, 1982 Honda MB5, 1980 Puch Maxi, 1979 Puch Magnum, 1993 Tomos Bullet, 2003 Malaguti Firefox F15 LC


m in sc

as long as there is just liquid in there its fine. make sure you bleed all the air out...  when you have air in there its an issue. ive done destructive testing on vessels at over 20k psi (for work). trust me, its not exciting.  liquid doesn't compress. = nothing to expand and go boom when its released.

quocle603

I might try things out this winter. I will borrow an electric pressure washer from someone to do this.
Do not underestimate the power of a two-stroke.

1975 Yamaha RD350 (modified), 1973 Yamaha RD350 (stock), 1971 Suzuki T500, 1981 Yamaha XS650 HS2, 1982 Honda MB5, 1980 Puch Maxi, 1979 Puch Magnum, 1993 Tomos Bullet, 2003 Malaguti Firefox F15 LC

rodneya

Be careful with using water. the pressure is applied to the entire pipe and you are often more likely to split the pipe before pushing a dent out.

fyingdg

https://www.hydra-force.co.uk/
I have a hydroforce for my dirt bikes and it works  great. I'm trying to make a new one that will work on older non flange pipes now.

pidjones

I'd go with the manual pump. If you truely fill the entire system, one stroke could either a) bump the dent out or b) split a seam. Don't think the pressure washer can be that closely controlled.
"Love 'em all.... Let GOD sort 'em out!"

m in sc

IF you have a diverter valve inline from the pressure washer to the pipe it can be controlled very easily... but the manual one is the way to go.

quocle603

thanks for the input on the matter. I might just leave it, I've heard that the small dents do not do too much to the performance...but I might be devil's advocate.
Do not underestimate the power of a two-stroke.

1975 Yamaha RD350 (modified), 1973 Yamaha RD350 (stock), 1971 Suzuki T500, 1981 Yamaha XS650 HS2, 1982 Honda MB5, 1980 Puch Maxi, 1979 Puch Magnum, 1993 Tomos Bullet, 2003 Malaguti Firefox F15 LC

m in sc

small dents don't matter. if it really bothers you, drill it from the other side, knock the dent out with a punch, weld the hole back up.

quocle603

Do not underestimate the power of a two-stroke.

1975 Yamaha RD350 (modified), 1973 Yamaha RD350 (stock), 1971 Suzuki T500, 1981 Yamaha XS650 HS2, 1982 Honda MB5, 1980 Puch Maxi, 1979 Puch Magnum, 1993 Tomos Bullet, 2003 Malaguti Firefox F15 LC