Author Topic: One for the Brains Trust  (Read 6744 times)

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Offline Slow Pete

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One for the Brains Trust
« on: January 23, 2015, 09:24:14 pm »
I have a 81 RM250X and the engine number is RM250 - 10120.   If I'm reading the list of engine numbers correctly this belongs to a 76 RM250A but it is definitely an X  the clutch arm, crank case , cylinder and reed are all X.   I know the X has a problem with the main bearings chewing out the cases and I wonder if someone has done something fancy to get around it.

Or am I a Twat, that's reading the engine number list wrong ?

Any help would be greatly appreciated.
« Last Edit: January 24, 2015, 01:17:56 pm by Slow Pete »
Past owner of.  Bultaco 125,  Suzuki RM250A, RM125C, RM125T, RM400N, RM125X, Maico AW250 1977.   Presently 81 RM250X , 87 RM125H , 86 RM250G & 81 RM125X.   Current projects 80 RM400T & 78 RM125C

Offline pmc57

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Re: One for the Brains Trust
« Reply #1 on: January 24, 2015, 09:41:31 pm »
I'd say someone's slipped a right hand case off an A in at some time.

Are they the same or interchangeable?

oldfart

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Re: One for the Brains Trust
« Reply #2 on: January 24, 2015, 09:47:36 pm »
Not possible at all ...  81 /X  has a completely different reed to  induction barrel set to a  76/A

Offline Doc

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Re: One for the Brains Trust
« Reply #3 on: January 25, 2015, 12:27:33 am »
RM 250 X RM250 1981 RM250-100001 - RM250-102087

Are you sure you didn't miss a number?

Offline SON

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Re: One for the Brains Trust
« Reply #4 on: January 25, 2015, 10:20:22 am »
Work on the fact that Your frame number is the Identifier with SUZUKI,
The X should be a Full Reed Aircooled engine
Back to your bearing potential problem easily fixed with new C3 bearings and the appropriate bearing Loctite, buy the Loctite from a bearing company and ask the oldest / Wisest guy behind the counter for his advice

mainline

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Re: One for the Brains Trust
« Reply #5 on: January 25, 2015, 10:41:41 am »
Back to your bearing potential problem easily fixed with new C3 bearings and the appropriate bearing Loctite, buy the Loctite from a bearing company and ask the oldest / Wisest guy behind the counter for his advice

The guy at my local bearing shop was telling me that the loctite tech videos now recommend machining so that bearings etc drop in (rather than machine for an interference fit) and use their loctite product on everything. Maybe more to do with finding a good tradesmen to do the job in the first place?

Offline Ted

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Re: One for the Brains Trust
« Reply #6 on: January 25, 2015, 06:35:43 pm »
Faaark. Shit. Crikey. You're not recommending farming out work to professionals in their field are you? The stars have aligned and you've finally seen the light.

But then I guess you miss out on the fun ( cathartic) by nou fuc.....king it up yourself ;D ;D ;D
81 YZ 465 H   77 RM 125 B

Offline Tomas

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Re: One for the Brains Trust
« Reply #7 on: January 25, 2015, 06:51:43 pm »
Back to your bearing potential problem easily fixed with new C3 bearings and the appropriate bearing Loctite, buy the Loctite from a bearing company and ask the oldest / Wisest guy behind the counter for his advice

The guy at my local bearing shop was telling me that the loctite tech videos now recommend machining so that bearings etc drop in (rather than machine for an interference fit) and use their loctite product on everything. Maybe more to do with finding a good tradesmen to do the job in the first place?
belive it or not some motors have bearings loctited in by manufacturers these days. it is cheaper than using expensive machines, tools, etc. to produce tight tolerances and there is no need for presses etc. during assembly process.

mainline

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Re: One for the Brains Trust
« Reply #8 on: January 25, 2015, 08:03:22 pm »
Back to your bearing potential problem easily fixed with new C3 bearings and the appropriate bearing Loctite, buy the Loctite from a bearing company and ask the oldest / Wisest guy behind the counter for his advice

The guy at my local bearing shop was telling me that the loctite tech videos now recommend machining so that bearings etc drop in (rather than machine for an interference fit) and use their loctite product on everything. Maybe more to do with finding a good tradesmen to do the job in the first place?
belive it or not some motors have bearings loctited in by manufacturers these days. it is cheaper than using expensive machines, tools, etc. to produce tight tolerances and there is no need for presses etc. during assembly process.

That's pretty much what i was getting at.

mainline

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Re: One for the Brains Trust
« Reply #9 on: January 25, 2015, 08:06:55 pm »
Faaark. Shit. Crikey. You're not recommending farming out work to professionals in their field are you? The stars have aligned and you've finally seen the light.

But then I guess you miss out on the fun ( cathartic) by nou fuc.....king it up yourself ;D ;D ;D

Haven't f*cked anything up yet.

I don't think there's anything wrong with learning new things when you don't need expensive machinery to do the job. Sounds like you're a bit sensitive about paying someone else ro restore your bikes for you.  ;)

Offline Slow Pete

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Re: One for the Brains Trust
« Reply #10 on: January 25, 2015, 08:24:21 pm »
Thanks Guys,
                    Without doubt it is an X.   Not sure what happened with the numbers and It doesn't appear to have a frame number.  these are what Vintage Suzuki have up.


 Model           Frame Number                        Engine Number

1976   TM75A    TM75-27488 to RM80B    TM75-27778 to RM80B
    RM100A   RM100-10001 to 16021    RM100-10001 to 16023
    RM125A   RM125-30001 to 43982    Not Applicable
    RM250A   RM250-10001 to 20994    RM250-10001 to 21012
    RM370A   RM370-10002 to 17938    RM370-10002 to 17945

1981   JR50X   LN1JA11A_B_100001 to LN1JA11A_C_100000    JR50-______
    RM60X    JS1RB11A_B_100001 to JS1RB11A_C_100001    RM60-______
    RM80X    JS1RD11A_B_100001 to JS1RD12A_C_100001    RM80-______
    RM100X    JS1RE11A_B_100001 to N/A (no RM100 built in 1982)    RM100-______
    RM125X   JS1RF11A_B_100001 to JS1RF11A_C_100001    RM125-______
    RM250X   JS1RJ11A_B_100000 to JS1RJ12A_C_100001    RM250-______
    RM465X   JS1RM11A_B_100001 to JS1RM11A_C_100001    RM465-______

  The motor was rebuilt just before I bought it so I have no doubt it was done correctly so no worries there.   Just have to find time to ride it now.


Thanks
Pete
Past owner of.  Bultaco 125,  Suzuki RM250A, RM125C, RM125T, RM400N, RM125X, Maico AW250 1977.   Presently 81 RM250X , 87 RM125H , 86 RM250G & 81 RM125X.   Current projects 80 RM400T & 78 RM125C

Offline Lozza

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Re: One for the Brains Trust
« Reply #11 on: January 26, 2015, 05:24:12 pm »
Correctly balancing the crank will save all the bodges on the cases/bearings
Jesus only loves two strokes

Offline 80-85 husky

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Re: One for the Brains Trust
« Reply #12 on: January 26, 2015, 08:16:07 pm »
who is "balancing the crank" per say???

Offline Slow Pete

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Re: One for the Brains Trust
« Reply #13 on: January 26, 2015, 08:22:15 pm »
Thanks Lozza,
                     Good advise.



Pete
Past owner of.  Bultaco 125,  Suzuki RM250A, RM125C, RM125T, RM400N, RM125X, Maico AW250 1977.   Presently 81 RM250X , 87 RM125H , 86 RM250G & 81 RM125X.   Current projects 80 RM400T & 78 RM125C

Offline Lozza

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Re: One for the Brains Trust
« Reply #14 on: January 26, 2015, 10:15:07 pm »
who is "balancing the crank" per say???

Per say  or per se ? Whom ever you get to do your cranks
Jesus only loves two strokes