Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: chrisf1 on May 20, 2017, 01:30:46 PM
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Hi again everyone the problems have started as some of you may have noticed by my previous posts I have bought a 1971 CB750 K1 chopper and have been out in the garage tinkering getting it ready or so I thought to run anyway changed oil and filter, fitted battery, first problem the bike is a chopper and has no dash panel lights so I do not know if I have any ignition or not and it did not turn over, but the worst is to come I then decided to renew the spark plugs and number 2 just spins round and round so it looks like the head is going to have to come off, if anyone knows another way round the spark plug problem please advise many thanks Chris
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Sorry to say, the only safe option is to take the head off as you do not want any swarf getting into the head! you then have a choice of either helicoil, or weld a plug in and re-thread? other gents (or ladies), may have other suggestions.
John
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Sorry to say, the only safe option is to take the head off as you do not want any swarf getting into the head! you then have a choice of either helicoil, or weld a plug in and re-thread? other gents (or ladies), may have other suggestions.
John
This Lady has no other suggestion ::) ::). Don't forget the engine has to come out to get the head off (unless the top tube of the frame has been adapted previously to allow for this)
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Looks like someone has already hacked away the crossbars either side of the main tube! :o
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If the crossmember of the frame is missing I would contact the seller, I would also state to the seller about the spark thread.
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You can get spark plug inserts and die, whereby you recut the thread and screw in the oversize insert. Same as helicoil. It's strongly advised you have someone who knows what they are doing to do this and hover out all swaft. It's only a temporary fix until you remove and have professionally fixed. You can get them on eBay.
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Its a risk but you can helicoil using a well greased slow drill and well greased tap to collect swarf then leave the plug out and start engine to blow out any residual. Way back when we would offer the customer the option as if it didn't work OK the engine still had to come out. Over 60% time worked OK
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Looks like someone has already hacked away the crossbars either side of the main tube! :o
Hi again if mine are not there I have no idea what they are like or do could you describe position and function or even better a pic many thanks Chris
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Under the fuel tank you have the main spine of the frame. There should also be 2 tubes, one either side of the spine to brace the headstock. Some people cut these out and fit removable tubes, such as the Gordons frame kit, which allows the cylinder head to be removed without taking the engine out of the frame. Personally I would not ride a bike with such a modification, Honda did not put them there just to annoy owners with blown head gaskets, they are there to stop excessive flexing at the headstock, which can cause stresses on the metal and the welds, and dodgy handling. Yours unfortunately looks like someone has completely removed those tubes so they get the look they want under the tank, and I dread to think what any prospective insurer would think about that, I wouldn't attempt to ride it if that is the case! :o :o :o
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Take some pics of the bike with tank removed and any other problem areas, them post them on here that way you can get more precise answers, And solutions to fix them. Did the engine run before you got it? Or seller said it did?. What about electrics and all that, have you hooked up a battery to see what is working and what needs to be changed from us spec to uk.
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Here is a photo of the rail, they are on both sides of bike , or not in your case.[attach=1]
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Looks to me like the frame has been raked as well
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Hi the 2 rails are present and it has not been raked the forks have longer stanchions Chris
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Hi the 2 rails are present and it has not been raked the forks have longer stanchions Chris
Well, I'm off to Specsavers then, cos I cant see them in place in your picture. The bars should be about 15mm from the top of the rocker cover and all I can see above yours is fresh air ;D ;D ;D
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Hi the 2 rails are present and it has not been raked the forks have longer stanchions Chris
Well, I'm off to Specsavers then, cos I cant see them in place in your picture. The bars should be about 15mm from the top of the rocker cover and all I can see above yours is fresh air ;D ;D ;D
it looksas if the front frame tubes have been extended,to raise the steering head.
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Hi the 2 rails are present and it has not been raked the forks have longer stanchions Chris
Well, I'm off to Specsavers then, cos I cant see them in place in your picture. The bars should be about 15mm from the top of the rocker cover and all I can see above yours is fresh air ;D ;D ;D
it looksas if the front frame tubes have been extended,to raise the steering head.
Could well be that John
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I will remove the tank tomorrow and take a pic to post Chris
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Just extending the fork tubes would lift the front of the engine and that bike looks like it is level
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(http://i149.photobucket.com/albums/s74/chrisfen_photos/P5230002_2.jpg) (http://s149.photobucket.com/user/chrisfen_photos/media/P5230002_2.jpg.html)
Not sure if this shows enough but you may be correct about the rails but not the rake I was mistaking the rails for the ones shown in the pic Chris
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Yes, you do have rails. The frame has definitely been extended at the front somewhere to give the extra space between the top of the rocker cover and the bottom of the rails.
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Cant see the image so cant comment