Hi

Iam looking at some red anodised bolts for my engine and they don't seem to have the correct size for the 2 bolts holding on the water pump which are

M5x35. But they have m5 x 30. Would this be ok to use?

They have got the right size for the longer one at the bottom of the pump.

The bikes an 08 pro 125

Thanks

Ben

you just need to check how much thread is catching, the difference between them is only 5mm so providing the threads on the 30 are gripping enough it should be okay

you just need to check how much thread is catching, the difference between them is only 5mm so providing the threads on the 30 are gripping enough it should be okay

Thanks

id be careful doing that.

as canada280i says, make sure there is enough thread is catching, and id maybe use some thread lock on there for good measure.

I agree with neilh & canada280i, sorta.....

In the shop I work at we always try to have our bolts use at least 2 times their diameter worth of thread engagement. Meaning if the bolts are, say, 6mm in diameter, it would be ideal if they engaged for about 12mm of threaded surface. This works out mucho better for torquing the bolts w/o stripping them (or the mating internal threads), and typically for holding whatever it is the bolts are supposed to hold. Now this is in an "Ideal World"..... It isn't aways possible to do that, I realize. But still, you'd like as much thread engagement as you can get.....

Ben, would it be possible to buy longer bolts, and then shorten them to stock length? The part of the bolt that gets cut off wouldn't be exposed after it goes in the hole......

Jimmie

Added in EDIT: The biggest concern I have about shortening bolts/reducing thread engagement is that it can make it really easy to strip the threads right out of the parent holes in the side case. Sorry if I wasn't very clear about that.....

Edited December 20, 201213 yr by mr neutron

I agree with Mr Neutron that longer bolts cut shorter would be be best option in hindsight, but if not available I would ensure that at least 10mm of the 30mm bolts is catching in the threads, no less.

I agree with neilh & canada280i, sorta.....

In the shop I work at we always try to have our bolts use at least 2 times their diameter worth of thread engagement. Meaning if the bolts are, say, 6mm in diameter, it would be ideal if they engaged for about 12mm of threaded surface. This works out mucho better for torquing the bolts w/o stripping them (or the mating internal threads), and typically for holding whatever it is the bolts are supposed to hold. Now this is in an "Ideal World"..... It isn't aways possible to do that, I realize. But still, you'd like as much thread engagement as you can get.....

Ben, would it be possible to buy longer bolts, and then shorten them to stock length? The part of the bolt that gets cut off wouldn't be exposed after it goes in the hole......

Jimmie

Added in EDIT: The biggest concern I have about shortening bolts/reducing thread engagement is that it can make it really easy to strip the threads right out of the parent holes in the side case. Sorry if I wasn't very clear about that.....

thats a great idea! never thought about it before

no... they dont do 35 but they do 40 so ill cut it down.

thanks

ben

thats a great idea! never thought about it before

no... they dont do 35 but they do 40 so ill cut it down.

thanks

ben

When cutting bolts down it is a bit tricky to get it straight and have the threads on the cut end perfect. So sometimes I will take the cut end of the bolt and grind just a bit of an angle on the end to smooth it out and get past the "rough" end.

Yes I know if I was any good at cutting the bolt then I would not feel the need to "dress" up the end a bit.

For what it's worth, when I shorten a bolt, or have to hacksaw anything with external threads, I try to find 2 or 3 nuts with the correct size for the bolt I wanna shorten. I will thread these nuts on the bolt, then clamp everything in a vise. I let the vise jaws tighten on the head of the bolt and one or two of the nuts I threaded on. Don't tighten vise jaws on the threads!

.After you cut the bolt shorter, you can "unthread"/remove the nuts, and those nuts will chase, or clean up that last thread on the end of the bolt for you. Most times, I have to take a file & clean it up a little more, but not much. LSorta like what Zippy said, if you cut it just a hair longer, you then have a little extra material to grind on to square up the end of the bolt. Or, if you can just chuck it in a lathe, your whole life gets easier, hee hee. That's how I do it now, at the shop I work at. But I can still recall a time when I was trying to accomplish this sorta stuff with basically nothing for tools. It makes you become "creative".......

Anyway, the point here is to have a good, clean first thread on the bolt, so as not to mess up the internal threads on the case.

Jimmie

Edited December 20, 201213 yr by mr neutron

oooh good idea on threading nuts on ahead of time, never thought of that.

Minimum thread engagement is 1x the thread diameter, but when its screwed into aluminium add 2 extra thread pitches. eg M5 bolt 7mm.

Never tighten a bolt to the bottom of a hole!

With a nut & bolt the thread must pass through the nut, if you measure the thickness of full nut it shall be equal to the bolt diameter.

I would have thought the 30mm bolts would be fine. If you remove your current bolts, you will find that they actually thread nearly the whole 35mm (minus thickness of pump + crankcase), so with 30mm bolts you'r probably going to have at least 20mm engaged.

One thing however - are there not 3 bolts holding on your water pump? My 07 Raga has 3 bolts (and one is longer than the other 2 - be aware). My 07 Raga should be the same as any 08 PRO and as far as I'm aware the PRO and normal TXT versions share the same water pump?