problem with exhaust bolt holes

[dirtjones]

OK, someone has had this before, but I don't see anything.
My rebuild, in progress, is a 1978 GS750. I am re-threading the holes for the exhaust bolts. They are 8X1.25mm. NO. 4 upper bolt and NO. 2 lower bolt are not accessable with the tap that I am using because of the frame. If the tap was about 1/2 the length I think I could get it in there. Does anyone have any suggestions, other than get a shorter tap, I don't think there is one.

[JEEPRUSTY]

remove the engine from the frame.

[Agemax]

remove the frame from the engine

[Nessism]

Remove the engine bolts and jack the engine over to the side so you can get access with the tap. Be very careful to tap straight.

[dr_fosg8]

Or remove the head from the engine.

[1980GS1000E]

While you are doing this, consider changing the bolts for studs. Many have, myself included.

[dirtjones]

OK, guys, thanks, guess I need to remove the engine mounting bolts and shift the thing over. Not an easy assignment, since I have it sitting on blocks with both wheels off. Sorry, no pictures right now, camera thing. Just painted the frame, gloss black. I am old and fashiond that way. To me, looks better than powder coating. I will definately change over to studs, about 40mm in length I think.

[buster]

I tried removing my broken bolts as well and it didn't go well. I successfully removed the broken bolt and when I tried to "re-tap" the threads to clean them up I heard a click sound and the tap didn't come back out. The shop that fixed my mistake said I should have just brought them the head to begin with. Good luck!

[sparki]

am i correct in assuming the bolts are removed and you just want to run a tap through the holes to clean them up?

if thats the case then i used a small socket that fitted the square on the end of the tap.... pop an extention bar on it and use whichever size ratchet goes on the bar

worked for me....

[dirtjones]

Thanks guys, you are correct, sparky, . The bolts are removed, all of them, just trying to re-thread the bolt holes. The bike has been sitting up in a shed for about 25 years without exhaust pipes on it, so the bolt holes are full of muddober stuff and who knows what else. As stated before, I can't get the tap in two of the bolt holes because of the frame. I will have to move the engine over about an inch or so, to get the tap in streight. I may pull the head anyway, who knows what went up the exhaust openings, but the compression feels very good. Will do a compression test before pulling the head, of course. Oh, and one of the things I've been learning, is the studs need to be about 30mm long, for this bike.

[sparki]

well, as i mentioned, i had the same issue and just popped a small socket and ext. bar onto the end of the tap and it held fine to clear out the threads..... if it's just muck in the thread there's very little force needed to turn it anyway.... a lot easier than moving the engine over imo.

[hjfisk]

Thanks guys, you are correct, sparky, . The bolts are removed, all of them, just trying to re-thread the bolt holes. The bike has been sitting up in a shed for about 25 years without exhaust pipes on it, so the bolt holes are full of muddober stuff and who knows what else. As stated before, I can't get the tap in two of the bolt holes because of the frame. I will have to move the engine over about an inch or so, to get the tap in streight. I may pull the head anyway, who knows what went up the exhaust openings, but the compression feels very good. Will do a compression test before pulling the head, of course. Oh, and one of the things I've been learning, is the studs need to be about 30mm long, for this bike.

If that is the case [the bolts are out ] you have 2 other choices, 1 you can get a short thread chaser bolt through Snap-on or 2 you can take an old 8mm bolt and a file or dremel with a cutting wheel and cut some relief flutes into the bolt and use it for a thread chaser. I have done this a few different times on things works pretty well, just keep compressed air handy to keep the hole clear and don't force the bolt to much. A little lube in the hole helps also.

[7981GS]

am i correct in assuming the bolts are removed and you just want to run a tap through the holes to clean them up?

if thats the case then i used a small socket that fitted the square on the end of the tap.... pop an extention bar on it and use whichever size ratchet goes on the bar

worked for me....

I just did this last week. Left the engine mounted. The tap will go in 25mm.

I use these with the taps: http://www.lislecorp.com/divisions/p...s/?product=398


Daniel