Sump Bolt!

[Vin]

I am trying to change the transmission oil on My TZR250 (I wish I hadn't bothered!!) It has two drain bolts both of which I removed and drained the oil. I replaced one no problem but when I replaced the second it refused to tighten properly. When I removed the bolt I noticed it had been stretched to the point of breaking. The case thread looked OK. So I got another bolt (not easy) and washers and set the torque wrench to 10ft/lbs (below the yamaha recommended level) and started to wind the bolt in and bugger me if the same thing didn't happen again. I find this a bit weird does theis mean the case thread is damaged? I can't quite believe how easy it is to ruin the bolt!!
Any thoughts?
Vin

[stinkwheel]

Is the bolt you are trying to put in the correct thread pitch?

Sump plugs are usually a fine-pitch metric thread, which is a pretty specialised size. You might be trying to screw a standard-pitch bolt into a fine pitch hole.

If the thread in the casting is damaged, you would need to find out what the correct size thread for it is then run a greased tap along it to clean it up.

If you can't find a tap, a bolt of the right pitch with a groove dremmeled along its length to just deeper than the thread can be used to 'tidy up' a slightly bent/raggedy thread. Screw it in like you would a tap (ie half turn in, quarter turn out, half in, quarter out).
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Korn]

If you've bollocksed the thread that the sump plug screws into, it's going to need a helicoil or other type of thread repair.

For a short term bodge you can drill a hole through the head of the bolt, screw it in just past hand tight using liberal amounts of instant gasket and lockwire it to something that won't allow it to budge.
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3516 Miles, 11 Countries

[Vin]

I'm pretty sure its the right bolt. The original had always been there and the second was sent to me by Taymar Racing who should know. I guess what ever way I look at it the case thread must be buggered I just can't understand why it knackers the bolt though! Weird.
Anyone want to buy a TZR :-/

[sickpup]

[alains]

i know this problem . you should have clean the thread before trying to refit the bolts . the dust metal exiting has stocked in the thread and then you cannot screw it properly , especially if your bolt is long . what i have done to solve the trick is :
- i've taken a tap at the right size and solder on line an extention at 1mm under diameter size
- solder an other piece in "T" at the end
- then turn the tool inside gently until the thread was clean and the bolt went in easily
cost : a tap and a bit of steel soldering (electric ark) 4 quids may be
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the worst day fishing is better than the best day working

[MarJay]

It isn't a sump bolt in the normal sense... its just a drain plug. This is because the bike doesn't have a sump!

Not heard of bolts stretching or whatever, but I changed the transmission oil on my TZR last week and could only find one drain plug on the right hand side of the bike at the bottom.

I realised that the oil would pool on the left hand side of the bike so I leant the bike over the opposite direction and held it up above my catch container like that until no more oil came out.

The bike is so light that this wasn't an issue. Maybe I should look at the other drain plug though...
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[alains]

on mine (nsr) one bolt is use as a drain , but when the old oil goes out it brings dust metal into the thread , that's what i was thinking on your's and why i made this special tap .
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the worst day fishing is better than the best day working

[Vin]

[simon1221]

Dont use the torque wrench on the sump bolt, theres no point.
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Bomberman]

[Vin]