OzVMX Forum
Clubroom => Tech Talk => Topic started by: JohnnyO on October 27, 2013, 04:11:20 pm
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Can anyone tell me the standard shock length for a '77 CR390?
Mine is fitted with 14.25 YSS with 4" shaft travel giving only 7.5" rear wheel travel..
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Hi John. I replied on the other thread, but I'll put it here too. Standard shocks on a '77 CR250/CR390 are Gas Girlings, that are 380mm long with around 140mm shaft travel. I think that I measured the travel on mine with the springs off the shocks and it came to around 9 inches, depending on where the axle position was. I ended up putting a set of 383mm remote reservoir Ohlins, that came off a '79 Husky 390 Auto on my CR390, because the shafts on the standard Girlings had rust pits in them.
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My 125 77 mod has girlings and they are 330mls with 110mls travel,i also put 80 husky Ohlins on it but goes past the 9inches of travel.
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My 125 77 mod has girlings and they are 330mls with 110mls travel,i also put 80 husky Ohlins on it but goes past the 9inches of travel.
The 125 Huskys always seemed to be a year behind compared to the equipment on the 250 and open class bikes, much the same as the WR models were a year behind the CRs. I just went and had a look at my Ohlins twinshock workshop manual and it says that the shaft travel on the 383mm remote reservoir shocks is 140mm.
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Around the 375mm is correct. I'm running 340mm shocks now so I comply and it evens up the shorten front forks and if I was going to have too run 9 inch I wanted to at least be lower to the ground so It corners a little better.
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Thanks for the replies guys, I've got so many pairs of shocks but they're all too long except for a pair of the original Fox spring shocks.
Will probably modify some Ohlins for it later.
The YSS are useless, who builds a pair of piggyback shocks with only 100mm shaft travel?!!
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Just came back from a big surfing trip over in Indonesia where everyone
rides a scooter to work.
Interesting to note that most of these bikes had the YSS shocks fitted up to them but one bike did have
an Ohlins setup out of the 10,000 bikes that went zooming past me everyday.
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I run 385mm shocks on my '77 CR390.
K
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I tried a pair of 385mm works performance bigk and the thing was so tall I could only touch the ground tippy toes and I'm not short..
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Thanks for the replies guys, I've got so many pairs of shocks but they're all too long except for a pair of the original Fox spring shocks.
Will probably modify some Ohlins for it later.
The YSS are useless, who builds a pair of piggyback shocks with only 100mm shaft travel?!!
Steve Cramer. Ohlins piggybacks. 104 mm shaft travel. Spot on 9" travel. 1977 SUZUKI RM 125 B
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The KYB airs I had on the Husky are between 380/385 and I feel there a tad to long and I like front heavy bikes.
Buy some Gazzi's with adjustable ride hieght and get the feel you need. At just over $500.00 there a good deal and I love the drive of the corners with these shocks that I cant get with Ohlins or air shocks.
(http://i1357.photobucket.com/albums/q747/Slakewell1/husky01_zps4ed396c6.jpg)
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The KYB airs I had on the Husky are between 380/385 and I feel there a tad to long and I like front heavy bikes.
Buy some Gazzi's with adjustable ride hieght and get the feel you need. At just over $500.00 there a good deal and I love the drive of the corners with these shocks that I cant get with Ohlins or air shocks.
(http://i1357.photobucket.com/albums/q747/Slakewell1/husky01_zps4ed396c6.jpg)
Looks good Slake.. I've got some Ohlins and Fox Airs the right length, I'll revalve and respring the Ohlins to suit it
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(http://i1134.photobucket.com/albums/m605/Husky500evo/DSC01702_zps8fbd7cef.jpg)
This is my '77 Cr390 when I first put it together, with the standard Gas Girling shocks that have the weird square section small springs on them. I originally picked it up at the Barrabool (CD3 ?) swap meet, as a basket case from the boot of a car, for $250 . It is no beauty queen, but it was built as a race bike and it hauls arse. It has a Paul Rooney ported cylinder and a set of magnesium aftermarket Ceriani 35mm forks. The Ceriani forks have 10 inches of travel, but I put 1 inch travel limiting spacers in them for the Coff's Harbour and Conondale Nats and it adversely affected the handling of the bike, because I didn't lower the back end as well. I think that Slakewell's bike has a '78 pipe on it, which is a better option. Mine has the standard '77 pipe, which is very heavy and burns your leg. I currently have the bike pulled down for a freshen up and will put it back together with the correct colour tank.
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Mark mine has a pipe with a stinger and bolt on alloy muffler, is that a 78 pipe?
I've just bolted 380mm Ohlins to it but it has 12" clearance between the rear tyre and guard like an Evo bike but it only has 9" travel so it's effectively at least 2" too high and much taller than my RM370.
I think it's too tall for a pre 78 bike that's why I'd prefer shocks around 360-370mm
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What is the correct tank colour for a 77 CR? I thought red, mine is black..
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What is the correct tank colour for a 77 CR? I thought red, mine is black..
The correct colour is the purple for the 390, as shown on Slakewell's bike and red for the 250. Are you sure you have the correct frame and not a '76 CR, or even a '77 WR frame ? On the '77 CR250 and 390 frame, the top shock mount plates face upwards to allow for longer shocks. On the '76 CR and '77 WR frames , the top shock mounts face downwards and use shorter shocks. The frame number will also tell you what it is. From memory a '77 CR390 will have a frame number between the range of ML16000 to ML22000, but I'd have to look up my numbers to check that. It does sound like you have a '78 pipe though, which I think is a good thing.
I may have to ask you some questions about KX250 A5 shocks, as I want to replace the standard ones on mine with something better. I may also have another KX A5 project in the wings ;). I measured the standard KX shocks at 420mm eye to eye, with around 150mm shaft travel. I have a set of piggyback Ohlins from an '82 CR Husky, that are about 420mm long with 140mm shaft travel and a set of 420mm long Fox piggybacks somewhere. I just have to find the Fox piggybacks to measure the shaft travel, but I did have those shocks put aside to go on my Can Am MX6 250, when I get around to it. Will the Ohlins off the Husky do the job and will the shim stacks need changing much to suit the KX ? Or am I just better off buying a new set of Ohlins set up for the KX, with the correct shaft travel length? I might also PM you to ask how much the fibreglass tank on your A5 cost from Mr. Holley.
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Mark I think you're on the money with my frame, the top shock mounts angle down. That would explain why I need to use 260mm shocks. I just fitted some Ohlins that were 285mm but I used a 25mm shorter shock eye and fitted softer springs and it feels pretty good now.
(http://i1208.photobucket.com/albums/cc374/JohnnyO31/null_zps999361e6.jpg)
With the A5 KX250 I'm using ohlins from a 82 Husky and have rebuilt and revalved them totally to suit the KX and they work really good..
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Mark I think you're on the money with my frame, the top shock mounts angle down. That would explain why I need to use 260mm shocks. I just fitted some Ohlins that were 285mm but I used a 25mm shorter shock eye and fitted softer springs and it feels pretty good now.
With the A5 KX250 I'm using ohlins from a 82 Husky and have rebuilt and revalved them totally to suit the KX and they work really good..
Yeah, that's not a '77 CR390 frame, but interestingly enough the swingarm is the correct one. The '77 Husky CR250 and CR390 swingarm is a one off item, that only came out for that year. I posted up a pic recently, showing the differences between the '76, '77 and '78 Husky CR swingarms. That pipe looks like it is from a '79 WR390. I have a '79 390 Auto pipe, which would be the same as the WR, that I will go and have a look at to compare.
I may have to get my '82 Husky Ohlins to you , if you are interested, to get them revalved. They have already been rebuilt with new shafts. I don't know if the wheel travel you would lose with the 10mm shorter shaft travel than the KX shocks, would make any noticeable difference.
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Yes I'll gladly revalve the Ohlins for you Mark, are they off a WR or CR? WR have an internal spacer that can be removed for extra travel. My KX came with some other cheapo shocks so I've never compared shaft travel to originals but mine has plenty and work great.
Any more info you can give me on the Husky would be good, I may have to get a 77 frame so I can run longer shocks and bring the travel up to 9" instead of 7.5!
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I believe the correct color is indeed black with gold for '77 CR390. To my knowledge the 360's in '75 '76 were purple, not the 390 in '77. Who knows for sure though?
K
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The Husky brochure says black with gold 1977 CR 390
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No way!!!.. Black with gold line was introduced in 1978.. the correct colour for 1977 is purple...
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Type 1977 Husqvarna CR 390 into Google and hit on images at top of page. Scroll down to Husqvarna brochure.
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The brochure may have , as an example 4/77 date in the bottom.. but it is not the 1977 model bike..it is advertising the 1978 bikes... in 1978 the knee panel is different shape (elongated) and the colour for a 390 , is black.. but certainly.. the colour on Slakewells' bike is correct for 1977
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In about the 12th or so row of those images is a scan of the front page of a Cycle World magazine with a test on the 1977 390.. you can see the colour of the tank..it ain't black.. ;)
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I looked inside the top of the tank today and there is purple overspray that looks like it might be the original colour...
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Here is the short travel version. Finally gave up on the Husky front brake cable and its spongy feel and converted to Yamaha cable today.Its heaps better.Now just a final wash detail and off to the Nats.
(http://i1357.photobucket.com/albums/q747/Slakewell1/husky03_zps79381050.jpg)
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I reckon I need that front brake cable too, my brake is shite and way too spongy..
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Here is the short travel version. Finally gave up on the Husky front brake cable and its spongy feel and converted to Yamaha cable today.Its heaps better.Now just a final wash detail and off to the Nats.
(http://i1357.photobucket.com/albums/q747/Slakewell1/husky03_zps79381050.jpg)
The only thing with that bike now is, apart from the leading axle forks, it looks more like a '76 CR360 rather than a '77 CR390. The only person that would have ridden a CR390 like that back in the day would have been a midget that couldn't touch the ground . I thought that vintage racing was supposed to be about reliving an era, not changing history. Not having a go at you Slakewell, as your bike is still beautiful, just the stupid rules that's all. Its a bit like going to watch the Melbourne Cup and seeing Black Caviar (or whoever the favourite may be) wearing hobbles to make it fairer for the other horses. Sorry about harping on , but I just can't let it go.
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I reckon I need that front brake cable too, my brake is shite and way too spongy..
If you want give me your front brake stay after the Nats and I will weld on the bits you need.
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Sorry about harping on , but I just can't let it go.
Hey thats OK reverse engineering sucks but as this Bike was canned at last years nats after it finished second in stock trim I made sure this year it is well within the rules. I should have got off my arse and tried and change the rules so there is no limits on suspension for pre 78.
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I reckon I need that front brake cable too, my brake is shite and way too spongy..
If you want give me your front brake stay after the Nats and I will weld on the bits you need.
Ok, I'll check yours out and compare
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Not that it makes a great deal of difference.. in 1977...the front engine mounts were double bolts...HVA changed the mounting after breaking cases with the stretchy / flexy frames in 1975/76 with the 360's...see you guys on Friday..I'll let you guys have a spin on my 390 Auto which is on it's way as we speak...
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see you guys on Friday..I'll let you guys have a spin on my 390 Auto which is on it's way as we speak...
I'm keen!
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(http://i1134.photobucket.com/albums/m605/Husky500evo/IMG_0366_zps02e12e7c.jpg)
Here is a picture of my '79 390 Auto pipe, which looks like the pipe on John's bike. The reason that I thought that John's might be a WR/Auto pipe is because of the heatshield welded to the pipe. I am not sure if the CR models had this. I think that the '78 CR390 pipe came with the muffler welded to the stinger. I don't know if would be allowed with follow on rules, but a '78 CR390 frame is exactly the same as a '77 CR390 frame, as far as I am aware, other than the '78 frame uses tapered roller steering head bearings ('77 frame uses plain ball bearings) and a frame number upwards of ML22000 .