GT550 with a different starter problem to the usual

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jantel
Posts: 10
Joined: Thu Dec 27, 2018 7:51 pm

GT550 with a different starter problem to the usual

Post by jantel »

Well here I am, a new member, based (very) close to Gatwick in Surrey, first a little bit about myself got my first Suzuki a 69 reg K11P in 1974, then a T250J I still have a Triumph T100 I bought new in 75 part ex for my T250J, first restoration was Stinger started three years ago, a complete wreck when found but now almost running apart from the need to rebuild the crank, and now the 76 GT550 B.

I looked long and hard at getting an earlier 550, but after the sheer expense of renovating the Stinger (T125) I decided to go for a better condition later model that at least has chrome in usable condition, the master plan is to finish and paint it in an earlier colour scheme, maybe a Blue "J" style, well after being scammed on Ebay for £1200 and no bike I found what has turned out to be a good condition (with one exception) Canadian import, with a known starter issue which I assumed would be the starter clutch . When received it started first kick and ticks over very smoothly, all three seem to smoke the same amount to the the oil feeds appear to be working.

Time to strip down and figure out what is wrong. All stared to plan, clutch cover off, clutch off and have a look around, I find that the starter armature pinion has the teeth stripped off the end to half depth, I find a circlip and washer in the cover under a layer of crud, Hmm I think I know what has happened here, but no, when I pull off the started idler wheel and inspect everything seems good, no damaged teeth, problem is that when I removed the idler shaft I see that the inner crankcase threaded mount has cracked allowing the gear mesh to open up hence shearing the top of the teeth on the starter armature shaft, see picture for details.http://www.kettleclinic.co.uk/kcforum/d ... w&id=23205

Problem is how do I approach the repair, do I weld up the crack, bore the hole and press in an alloy insert, should I drill a third hole in the unused 3rd support point and the idler mount and tap, that or replace the bottom case if another good one can be found ?, are the case "matched" as supposedly my Triumph is ?, any advice welcome.

Terry
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Starter mount cracks.jpg
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Alan H
Posts: 12104
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Re: GT550 with a different starter problem to the usual

Post by Alan H »

jantel wrote: I looked long and hard at getting an earlier 550, but after the sheer expense of renovating the Stinger (T125) I decided to go for a better condition later model that at least has chrome in usable condition, the master plan is to finish and paint it in an earlier colour scheme, maybe a Blue "J" style, well after being scammed on Ebay for £1200 and no bike I found what has turned out to be a good condition (with one exception) Canadian import, with a known starter issue which I assumed would be the starter clutch . When received it started first kick and ticks over very smoothly, all three seem to smoke the same amount to the the oil feeds appear to be working.

Time to strip down and figure out what is wrong. All stared to plan, clutch cover off, clutch off and have a look around, I find that the starter armature pinion has the teeth stripped off the end to half depth, I find a circlip and washer in the cover under a layer of crud, Hmm I think I know what has happened here, but no, when I pull off the started idler wheel and inspect everything seems good, no damaged teeth, problem is that when I removed the idler shaft I see that the inner crankcase threaded mount has cracked allowing the gear mesh to open up hence shearing the top of the teeth on the starter armature shaft, see picture for details.http://www.kettleclinic.co.uk/kcforum/d ... w&id=23205

Problem is how do I approach the repair, do I weld up the crack, bore the hole and press in an alloy insert, should I drill a third hole in the unused 3rd support point and the idler mount and tap, that or replace the bottom case if another good one can be found ?, are the case "matched" as supposedly my Triumph is ?, any advice welcome.

Terry
Nice intro Terry, at least you've some idea when you ask and we advise - unlike some that ask and haven't a clue. :roll:

Right, the later models are mostly easier to work on, with earlier 'issues' being sorted. The motor can be sent to Baz for a refurb - I'm sure that the pinions are fairly easily replaced.
I would get advice from someone who can weld regards the cracks. There must be people around you that can repair aircraft engines, so it shouldn't be too much of an issue.
Crankcase 'halves' are matched, so you shouldn't just change one, unless you can cut the damaged bits out of yours and replace with bits cut from another one. If you need a bottom half or pair of crankcases, I have 'several'! Never had to do a job like that or even known it be necessary - something has been left incorrectly tightened it seems. Let me know if you need bits.
Baz is very good with spares and refurb bits - carbs too should you need them fettling and don't want to do yours.
He's done a few sets for my 550s and Hippo (750).
For interest, I'm on my 3rd 550 resto - details below if you want a loooong read!!

1st one - the K http://www.kettleclinic.co.uk/kcforum/v ... w+starting
2nd one - the A (Earwig) http://www.kettleclinic.co.uk/kcforum/v ... =16&t=5620
3rd one - the J (Yeti) http://www.kettleclinic.co.uk/kcforum/v ... =16&t=9495
Proof that four strokes are over complicated
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: GT550 with a different starter problem to the usual

Post by barney01 »

Hi Terry great intro and welcome to the forum. If you look on the net there are plenty of people who can weld the crankcase, it is really interesting that damage the normal problem is the two bolts securing the idler gear work loose. It happened to me ,soon fixed with threadlock. If it were me I think I would look for a set of cases they aren't that dear. Good luck!
Having said all that here is another chap same damage!
https://www.ebay.co.uk/itm/1975-Suzuki- ... OSwNphb3zq~
NO SMOKE .......NO POKE
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Alan H
Posts: 12104
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Re: GT550 with a different starter problem to the usual

Post by Alan H »

This is how it should look, so it appears that the clip and washer not being located properly caused the issue. That gear has just been rattling about and not allowing the torque to go from motor to clutch gear.
starter detail.jpg
Anyway, if you need bits, PM me. Have you read those threads yet? :lol:
Proof that four strokes are over complicated
jantel
Posts: 10
Joined: Thu Dec 27, 2018 7:51 pm

Re: GT550 with a different starter problem to the usual

Post by jantel »

Thanks guys for the input and suggestions, Alan, yes I have read most of your other threads hence the reason for joining this group ;)

Dug a little deeper and looked again at the two screws retaining the idler gear shaft, they had both been punched to prevent rotation at time of manufacture, however looking at the screws one of them seems to have either been manufactured bad or was bent when the problem occurred, as the threads seem a little strange to look at I suspect a bad screw not bent, any other opinions :)
http://www.kettleclinic.co.uk/kcforum/d ... w&id=23218
Anyway the engine is due to be removed on Saturday, should I take the barrels off first to reduce weight and provide more clearance ?

Engine out then get the frame stripped and off to Maldon Powder coating

Terry
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Bent screws.jpg
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Alan H
Posts: 12104
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Re: GT550 with a different starter problem to the usual

Post by Alan H »

jantel wrote: should I take the barrels off first to reduce weight and provide more clearance ?
Terry
Definitely. Would you like to carry a 'full' lump? :?
Proof that four strokes are over complicated
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es2GT550

Re: GT550 with a different starter problem to the usual

Post by es2GT550 »

welcome !! interesting problem - hope you manage to get it sorted ok - as mentioned secondhand cases are available at reasonable money ifyou need to. Would defo remove the heads and barrels (quick and easy job)n to make it a bit more manageable when removing. Best of luck :)
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