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'96-'04 XR250/400 Piggyback Resi Shock on my '05 150F?

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Hey Gang!! You all GOTTA know by now that I LOVE jacking around riding and building 150F's to race in my local pit bike races.... and, you MAY have seen my 230F powered 150F build on here? I love the bike, and it works great on long and fast outdoor tracks-- but it's HEAVY for tighter tracks, and it seems to emit more vibration than a 150F. I also have a kickstart '05 150F sitting here that's my "practice"/every day thrasher/stocker. It has Hlebo modded stock suspension, and it's pretty decent. Problem is that I'm a mad scientist, and I rarely leave well enough alone.

I've been looking to build my OTHER like new '04 150F I have sitting here up with a 230 carb, ported head, cam, high comp piston, (I picked up a set of Mike Coe kickstart gears that I've been sitting on for awhile now) and I have a like new 230 front end sitting here that I was thinking about using on the project due to the thicker tubes and half inch longer travel specs. (I may just use the stock 150F forks as they seem fairly easy to set up and they work fairly well once they are properly set up IMO) I was thinking that I could use my '05 practice thrasher to get a piggyback rezzied shock tested and set up for that future '04 project. I've been looking at viable shock options, and the best and easiest adaptable shock appears to be a '96-'04 XR250 or 400 shock? Looks like the top mount will fit, the res looks like it will sit just right, and the clevice looks like a fit? I THINK the 250 shock may be only 14.75" eye to eye in comparison to the 15" measurement of the stock shock, but I've adjusted ride height on these bikes by swapping out dog bone links between the 150 and 230 parts. I THINK the 230 dog bone link would compensate for the quarter inch deficit in shock length. Anyone try one of these shocks before on a kickstart 150F? How'd it fit?   --L*64

Edited by luckystar64

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Funny you talk about late XR250/400 shocks I have them in my shop. So you say they will fit on Frame 150 so with battery relocated on 230 should fit also. Yes late xr250 shock too short,one big problem the stock spring over 600 pound rate. Xr400 shock is too long,but you can install spacer inside to shorten. From 96 to 04 looks like two spring rates( Dont Quote me )  9.4 and 9.6. I have two of these Xr400 shocks year unknown. The perfect spring rate On one of my 230s with 87 Xr250 shock is 9.1. The good you can get any spring rate from Cannon Spring the bad 120$.  It maybe possible to mod the 87Xr250r spring to fit the Xr4 shock. So the xr4 shock clears the frame rails and spring clears rt side swing arm ?   I will be sending my xr250/400 shock to Friend in Ca to check fitment next month. 

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BTR, from eye of shock to bottom of breather extension on air box is 2".  It looks like the xr400 shock is about an inch and a half from the eye center to where the reservoir starts, so you may need to hack off the breather exteNsion on air box.

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What is the eye to eye length on the shocks you have there? I'm wondering how long the 400 shock is? 15 inches would be ideal. I'm thinking the clevice could be shortened if need be?

Edited by luckystar64

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I don't think the res would interfere with that breather area on the air box boot. The res feed angles downwards even steeper than say a CR85 shock, and I've seen those 85 shocks used many times. I don't think a quarter inch too short would be a huge issue on a 150 because you can compensate by running a 230 dog bone link without changing the leverage ratio of the linkage because you'd still be using the 150 triangle. Wonder if the stock 150/230 spring would fit on the 250/400 shock? Honestly, a custom spring would be fine too if need be. Or if the clevice parts could interchange? I'm just interested in knowing if the shock would fit in the first place?

Edited by luckystar64

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Stock spring 150/230 no go on late Xr250/xr400. It looks like Xr4 shock 1/2in too long. You could not re-drill mount hole,on bottom Xr shock. It would go into Existing hole.Since I have not found anyone making lighter spring for late Xr250 shock That is out(Unless you can find me one)  Getting back to Xr4 shock,if fits frame (230 with battery moved) It will need revalve,new bump stop,spacer in shock to lower Eye to eye travel. We have some Xr4s with spacers lowering them 1 in . The good they work just as good as the non spaced shocks.Again only problem left on Xr4 shock spring may rub rt side swing arm. If we see 87Xr250 spring can be made to fit no problem. Also Xr4 spring could be ground on side that rubs.It would be very slight. If it fits we will ship it out to my Susp guy in Burbank,Ca.As he knows what to do with my crazy requests.Please dont think you can just buy the Xr4 shock and bolt on with spacer. It has to come apart,revalved,rebuilt. My Xr4 shock will go to Ca this coming Friday so soon we know if it even fits.

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2 hours ago, Baja Rambler said:

BTR, from eye of shock to bottom of breather extension on air box is 2".  It looks like the xr400 shock is about an inch and a half from the eye center to where the reservoir starts, so you may need to hack off the breather exteNsion on air box.

Baja Hooter you maybe right. Only way we know for sure. Mikes bike in CA has his motor and shock out,so easy for him try to fit shock. Im not taking apart my bikes again to try to fit. Both my 230s Fox rear shock,other 87xr250r shock work perfect. I want one extra shock that works perfect. Because I no longer service my own shocks.When I ship to Burbank,Ca. That bike is down for over a month,so need one spare shock. If your 200 pounds or more 85 Xr350 shock works well.

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Well.... If the top of the 400 shock fits, then the 250 shock should too. Is the 400 shock longer than the 250 piece? If it clears the swinger, then I'd do the 250 shock. I'd just make up for the quarter inch with the 230 dogbone link. The top fitting, and the clearance on the swinger would be the biggest issue. So these two shocks must be fairly different from each other then?  --L*64

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Late Xr250r shock spring real short is shock much shorter then Xr4. Xr4 shock and spring way longer. 86/87 Xr250r spring same long length as Xr4 but has reduced inside diameter on spring. If I install backwards Small side up will work,but last to coils on bottom need inside ground out to fit locating ring. If its still has enough meat it will also clear swing arm. Or possible mod locating cap.   

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Looks like that XR250 shock could be a go?  It would likely need an internal spacer, custom spring, revalve, 230 dog bone link, and some custom spacers for the top mount. I can't tell from the pics, but is the gap the same on the 150 and 250 shock clevices? Is the 250 spring slimmer than the 400 spring as to clear the swing arm?

Edited by luckystar64

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Dont understand Lucky internal spacer for what? (late Xr250 shock). 150f shock fitment same as Crf230f The shock Clevices should be fine. As far as slimmer springs the Early 86/95 is the slim spring that just clears swing arm. The late Xr250/400 springs way wide compared to CRf150/230 or early xr250 spring. The late xr250 spring very slight more narrow then xr4 spring. I may have late Xr250r shock to unload. You best try to find custom spring price before you buy one try Cannon.

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