TY250A mod

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Guy53
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Bike: Ty250A
Club: ATAQ

TY250A mod

Postby Guy53 » Tue Nov 09, 2010 4:36 am

It is my first post on this forum, i hope you will excuse my mistakes in english and often in the way I ask my questions.

Sorry but I am a french camadian..

So here is my question I ride a ty250A ( model 434 ) The motor is great I took the flywhell weight off, new bearings, seals, piston, rod kit etc
I am now about to buy new 340mm NJB Expert trial shocks. To get the spring rate right I have to decide weather I want to leave the original shock setup
OR ??? to incline the shock ( as per general advise at 11 3/4 inch from the center of the swingarm pivot ). I wonder if it is realy worth the mod with the new shock? I already installed 8.5mm spacer in the original Ty front fork.

Thank's in advance for your info/experience
Guy



David Lahey
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Re: TY250A mod

Postby David Lahey » Tue Nov 09, 2010 8:38 pm

The standard shock mount location works quite well with Falcon Classic shocks.
I haven't tried NJB expert shockies but if the damping on them works as well as the damping on Falcons, it will be very nice to ride.
Surely you could try the shocks in the standard location and if you then want to try moving the top mounts, just buy another (stiffer) pair of springs later on?


relax, nothing is under control

Guy53
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Posts: 181
Joined: Tue Nov 09, 2010 4:22 am
Bike: Ty250A
Club: ATAQ

Re: TY250A mod

Postby Guy53 » Wed Nov 10, 2010 4:18 am

Of course the cheap person I am does'nt want to buy 2 sets of springs, but the old rider I am is aware that what you are writing make a lot of sence.I think that I wouldn't get more than 3/8 of am inch more in ground clearance by inclining the shock witch sound a lot for an expert but I don't think that 6 more inches of clearance would make me an expert.
Thank you David
Guy :oops:



Joe Henderson
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Bike: Fantic 240
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Re: TY250A mod

Postby Joe Henderson » Wed Nov 10, 2010 8:11 am

Dear Guy53,

Laying your shocks down the amount you specify and retaining the same shocks will increase the wheel travel, and soften the effective spring rate and damping force seen by the wheel. Depending on the distance of the new mounts from the wheel spindle you can adjust the ground clearance, within reason, as you desire.

Assuming you are going to retain the standard lower mount position on the swing arm :- Distance from swing arm pivot varies spring rate and damping force seen by the wheel. Distance from wheel spindle varies ground clearance.

To keep a handle on any more involved changes of mountings, springs, shocks, geometry changes etc, see the work of Tony Foale!

I have had great success with the NJB shocks. Both on my 325 Bultaco and my 240 Fantic.

If you email Norman. J. Blakemore on norman@njbshocks.co.uk and tell him your bike model and the mods you want to do, he will happily build you a pair of shocks to suit, with the correct damping and spring rate.

The pair I bought from him for my Fantic are perfect, have lasted for several hard, rock riding seasons now and have the same damping qualites as when new.

I think they cost 180 pounds sterling per pair and fell through my letter box, (From the UK to Australia!) within a week.

You will not spend better money!

Regards,
Joe.



Guy53
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Bike: Ty250A
Club: ATAQ

Re: TY250A mod

Postby Guy53 » Thu Nov 11, 2010 2:21 am

Well guy's it is done. I ordered a set of new trialexpert NJB shock 340mm for the standard location on the frame and swingarm that Norman will setup with springs for my weight, It will surely be an improvement from the original. I should receve them at the end of the month so I will have all winter to dream about the better rider I will be, and I will wake up at the first practice this spring the same rider but with one less excuse for that 5 I have to mark on the card.
I will give you feedback next spring.

Guy




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