Hi All,

I have taken the carb off of my mark 2, to give it a clean and install shiny new jets and gaskets from lesuire trail ( to solve surging issues on the overrun ), but I have stumbled at the first hurdle. The Float bowl screws are stuck hard and chewed to bits. I went to the local engineer workshop an he suggested 6 hours in coca cola, may help shift them. Which I am trying now. If not he can try drilling them out and helicoil but it will be around £150 quid, with no guarentees !!!! Any suggestions greatly appreciated.

Also I had picked up another carb off of ebay, which all looks fine apart from a bent idle screw. But the two carbs are slightly different, where the main jet pokes out at the bottom of the slide area, the one I bought off of ebay protudes only a couple of mil, but the one I took off of the bike protudes about 10 - 15mm in a semi circle ????? I presume these are differences in Marks 1 / 2 / 3 ??? Can anyone shed any light and are they interchangeble.

Not quite sure what you mean by 'protrudes in a semicircle' but the tube that the needle fits into shouldn't protrude that much ('10-15mm') into the area that the throttle slide controls.

Can you post some photos as attachments (I think you can do that without becoming a dite supporter) .

Hope photo links work. Both taken from the same side

Ebay purchase carb photo

http://i855.photobucket.com/albums/ab11 ... AG0082.jpg

Taken off bike carb photo ( CRM 250 mark 2 )

http://i855.photobucket.com/albums/ab11 ... AG0081.jpg

The 'shroud' that is in the second photo was not in the Mk1, but I think was in the Mk3 .

I have always found that even the most mashed float bowl screws can be removed by gripping the heads very firmly with pliers and turning them with the pliers. I suppose it depends on getting the right size of pliers . Post up a photo. £150 is just silly.

Agree, should easily undo with decent pliers, mine were the same an came out easily. If they still won't budge, try tappin them round with blunt blade of a flat screwdriver an a hammer. If you still can't manage it, send it to me an I'll do it for £145, ha

I'll do them for £100 .

You guys are brilliant !!!! One pair of mole grips and a couple of turns and they came right off :-) Thanks a lot all four screws out.

I will continue the clean and jet change tonight / tommorrow.

Now I just need to get some replacement screws.

knackeredMk1 wrote:The 'shroud' that is in the second photo was not in the Mk1, but I think was in the Mk3 .

Just had a look at my carb (MK3) and it does have the shroud as the second pic

dietcoke wrote: Now I just need to get some replacement screws.

i usually bung in some stainless allens,witha smidge of copaslip or similar on the threads.......never had any probs after doing that ........

+1.