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Xr400 Help and Advice.

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Hi everyone! I had a crf230 that I learned on for months it was built up by the previous owner and it was an amazing and powerful bike for a 230.

I had someone offer a clean xr400. It's a 1996 I bought and well months later here I am. I absolutely love this bike. I've ridden a drz now a 400 and I honestly love the xr more.

Anyways I'm doing a build on it because after months of searching I found one of the previous owners and got the title and that had a extensive record. So I decided to do a rebuild on it after the top end has been making noises galore. Im pretty sure it was just a failed timing chain tensioner but I figured I'd tear down the motor and learn how it all works.

It's my first time and I'm 17 years old by the way. I don't know what the bikes been through and I want this bike to last me a long time. My goals are to have a good round town dual sport. I'm getting a second bike for longer journeys and highway travels.

I'm stuck currently on the camshaft. I have to loose then Allen bolts on the camshaft gear and they won't break loose. I have the tighest fitting Allen wrench I got but it just keeps wanting to round off now before it does round off what are my options? I have the correct size Allen wrench. And I'm getting a new camshaft with gear and everything but wouldn't like to make a mess. Just need tips ! 

My plans for the future are: 

*Weisco 426 kit with new cylinder, piston, rings, and gaskets just under 11 compression ratio

*Stage 2 hotcams camshaft

*Kibble white valve spring sets

*Xrsonly slip on exhaust and modified pumper carb

*Valve seals

*Crf450 timing chain

*New timing chain tensioner

*Maybe new valves but I doubt it. It always started first kick before the tear down

*Clean up and polish the head

*Tusk lighting Enduro kit

*Upgraded headlight(what do you recommend?) 

*New white plastics 

*Good dual sport tires 60% dirt 40% street somewhere around there

I appreciate all the tips and help I receive! 

 

 

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If you have a pencil torch you could heat the bolts then let cool - the heat cycle usually helps break loose stuck bolts.

Actually I'd aim the heat at the cam threaded part behind the sprocket.

I fine tip flame to concentrate heat in that tiny area works best.

If you can get that part hot before heat spreads to bolt head it may walk right out easily.

Hope that helps, you're smart to stop before rounding off.

 

 

One like this might do the trick:

https://goo.gl/images/v7VNFU

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My trick for stubborn bolts is to heat the entire area gently with a pencil torch then white its still hot (NOT glowing) I spray with penetrating oil and then let it all get back to room temp. This allows the oil to get into the threads and around the bolt while its hot and breaks down any thread lock material. Repeat this 2 times. Now that everything is at room temp heat up only the sprocket while not heating up the bolt. This gets the threads hot but not the bolt - giving more room for it to move. Give it a spray of oil and a quick tap from a small hammer and then try to back out the bolt.

 

If it doesn't come out do this two more times. It will yield. Just be careful not to gall out the head.  

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And if the Allen wrench you have is rounding off its corners, grind it down shorter to get new edges.

Heat is good.

Also, use a hammer and punch to tap the head of the bolt. That shock works well to loosen tight bolts. Don't go crazy and pound the crap out of it tho, as the only thing backing up that bolt is the sprocket mounting ear of the cam.

Personally, for longevity sake, I skipped the Hotcams cam with my 440 and put that money toward something else. The stock is pretty good and I think you lose the auto decomp of the stock cam.

As for valves, you won't know until you get it apart and have a look at them and their seats. Instead of the cam, I opted for a complete Kibblewhite valve job.

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Good on you for trying and learning, that's what I did when I was 16-17 only on 2 strokes, that's how you learn, best of luck, lots on knowledge here willing to help.

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I did buy some metrics tools went at it today with heat and penetrating oil. Still zero luck. I'm wondering why it's this hard 

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IDK why the cam gear hardware would be giving you such trouble. I did mine years ago, '98 xr400, and I don't recall any real issue with it. I'd maybe try the heat approach with a pneumatic impact gun? I swapped out to the stage 1 hot cam but kept the stock displacement/compression and there was a noticeable improvement in power/grunt. I opted not to go up more for sake of reliability. There is no auto-decompressor on the hotcams so you'll have to use the manual lever. I'd removed mine and quickly realized it has to be on without the auto version on the cam. Heat and penetrating oil should get that bolt moving, be careful and patient and you'll get it.

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if the heads gets a bit beaten up, the given that it is metric, select the next nearest imperial hex driver and get it to fit with a hammer and then use an impact driver, either air or battery. the bolt is junk anyway.

 

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I did buy some metrics tools went at it today with heat and penetrating oil. Still zero luck. I'm wondering why it's this hard 


Remember: on those.
Righty - tighty / Lefty - loosey

You may want to enlist that help of another set of eyes (find a mechanic buddy with some grey hair) always helps to get a second opinion
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After fooling around I still can't get it. One of them is rounded off now even from the tightest Allen set I had. Where do I go from here it is literally the only thing holding me back. I'm using metric tools, I have a Manuel, and in also following partzilla on their video tear down of a 400ex which is the same motor and he does it so easy why cant I? 

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that's a high tensile cap head - you'll have a job drilling that

did you try heating them ?

 

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Are you trying to do this with the cam still installed? If so, take it out.

You're better off taking it to a machine shop and having them remove it than trying to drill it. Quit while you're ahead.

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I would try a good pair of vicegrips on the head of the bolt now that the center is rounded out. Get them on the head of the bolt as tight as you can and give it a turn.  Also try putting tension on the vice grip and then hit the vice grip with a hammer to see if that might break it loose. I like to use a rubber mallet and that works to jar it loose especially when your fighting against the hole engine turning on you.  

 If that doesn't work concidering how easy it was to round out the center of the bolt I don't think it will be hard to drill off the head of the bolt. Once it is off the rest of the bolt will probably come right out of the cam gear because I don't remember any threadlock on mine. Use a drill bit that is just a little bigger than the threaded part of the bolt and the head will come right off. It's already partially drilled out for you concidering it's an Allen socket head bolt and the hole is rounded out, it should drill right off no problem. Put a rag around it to keep metal from falling down inside the engine. If you do it right you shouldn't damage anything except the bolt  

By the way I don't think you can get the camshaft out of the head with the gear still bolted on the cam and the chain holding everything in

Edited by Toadster25

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1 hour ago, Toadster25 said:

By the way I don't think you can get the camshaft out of the head with the gear still bolted on the cam and the chain holding everything in

He should be able to if he removed the cam chain tensioner.

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I have tried heat and I can't seem to locate a way to move the chain out of the way when taking it off the sprocket to to pull it all out . I'll keep trying heat. Drilling it was an idea. I'm in no rush right now as I have the rest of winter. Im just following the Manuel and the videos. Remember my bike is 21 years old. Who knows what it's been through and what's been done to it 

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Try the vice grips and hit them with a hammer.  I think you might be surprised to find they might get it loose. 

I guess I'm not 100%sure about getting the camshaft out with the sprocket still on it. I didn't think it would come out with the sprocket still on but maybe it will if you can get the tensioner loosened up and removed first. 

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If the head is galled out inside then get a dremel tool and cut two faces parallel to each other on the bolt head. Then get the closest open ended wrench that will fit and try to break it free. Use another wrench to get better leverage on the bolt - like a cheater bar. 

051.jpg

 

Rounding off happens to everyone. This one was by far the worst for me...

WP_20150809_004.jpg

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