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TY250R summary


pat
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Hi,

Have finally fulfilled my for 5y maint/improvement plan..Yes, she is running like a dream. Will increase 2-3t at rear sprocket from 10-35, because of more power per crank turn. Did reflect over a need for 36-37 last year at modern clubman..now its absolute required.

Embarresing when I looked at the none worn piston because of liner, was..

Unfortunatley Ive changed 3 things not tested separatley this winter:

rebore, reedcage from Jons CR125 Boyesen and pipe from Sammys..

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Summary

The only improvement idea of mine is reedcage replacement, rest is sum up of what people has done over the ~27y...

*machined combustion chamber / squish -BJ Racing

*IRI BP6

*stainless pipe .ProMonty

*end can (not perfect) -WES GO

*rebored very worn liner..-Wiseco Yam IT 69.00mm

*nine 30mm cooling/weight red holes thrue fins where accepted

*truend crank to 0.02mm

*removed all added flywheel weight

*reedcage -VF3, set up for trials -MotoTassinari

*carb -Keihin for GG

*airfilter -Twinair (box volume is far from perfect)

chassis

re-pos pegs, removed seat unit, replace by seat only for improved air intake, ext shock length...sealed but need replacement now working with fron end update.., GG front end and now blinged wheels (for std front end + YZ-plate) Thanks to Steve providing new Z-spokes and CentralWheels rims ;)

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engine

http://i633.photobucket.com/albums/uu54/patscabinet/ProMontypipe60.jpg

engine

http://i633.photobucket.com/albums/uu54/patscabinet/KeihinandVF3specialfortrials.jpg

hub

http://i633.photobucket.com/albums/uu54/patscabinet/polishedrearhub60.jpg

wheel

http://i633.photobucket.com/albums/uu54/patscabinet/blingedrearwheel60.jpg

wheel

http://i633.photobucket.com/albums/uu54/patscabinet/notfinalizedfrontwheelrebuild60.jpg

Edited by Pat
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  • 2 weeks later...

 

Hi,

Does removing the flyweheel weight make much difference?

For modern clubman I prefer removing all weight, definatley yes.

Time from 3/4 throttle ->shut throttle to idle rpm is reduced vs std flywheel set up, eg riding up in steep section -"stairs", not using clutch the bike continue moving forward with closed throttle..NOK.

And offcourse much quicker throttle responce.

Honestly..now when my engine perform almost like a modern 250, I will search for a lighter flywheel since idle is still not reached fast enough..probably a new ref adding weight to this.

Have increased rear sprocket 35->36 and now riding sections in 2-3rd gear where ealier ridden in 1st, now at much lower rpm as the engine is more powerful close to idle rpm-> AND offcourse top..

Removed flywheel weight offers more precision as wanted in general, riding modern clubman..as well as exact brakes and front susp compr.

Eg, climbing up at 2nd-3rd gear at rather high rev, at the highest point in the section you must turn tight and go down steep, immediate stop in other words..then is benefishal reaching idle as quick as possible, offcourse freqvent clutch use is default part of riding..

What improvements can be done to the forks?

As I see it Kayaba forks for Yam are the superior classic trials forks per 1984.

(if one has the opinion that manufacturing year is a big thing ere which I do not as long as riding classic sections equal to modern clubman.., 38-40mm works perfect with any TS with no esthestic downsides... :rolleyes: )

If you want to improve your forks I suggest you do ask suspension experts for help, eg Maxton Engineering.

Since the std springs are progressive 80´ish fashion...a compression compromize so to speak.

New linear ones has to be ordered and these springs will require different valve performance which has been developed by engineers during the last ~20y.

My forks has been laying on the shelf for some years and have now done a rebuild + bling and YZ shield conversion with rebuilt shoes.

Now testing W15 Agip for improved compression instead of W7 as before:

*End compression is better, to late in the travel and not exact enough vs modern Paioli

*Compression is slower -worse vs W7

*Rebound ok, slower but no downside

Have tested same sections as ridden with GG front end and except from brake preformance Im surpriced how well it working (unfortunatley went from +5y´old tire to new X-light...)

Ive done a complete GG front end conversion because of required brake precision. Did rode modern clubman with a AP 4P caliper + bracket and std forks with satisfaction for many years, the bracket brooke I did the full conversion..Could not believe that improvement of front end handling/front wheel position control could be that great :thumbup:

Edited by Pat
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I honestly don't think there is a need to do that. The TY Mono forks work really well with very good compression and rebound damping. I doubt you would get any benefit from fitting modern forks.

It's only my opinion but I don't think modern forks work that well on older bikes, or rather, their quick action doesn't feel right on older bikes. The mono forks have pretty linear damping characteristics both ways and the slower action, by comparison to modern, allows you to ride slower with more feel over obstacles such as rock jumbles, either dry or streams. The quicker action of the modern forks are more suited to the point and squirt modern technique and get a bit lively when riding 'old style' and picking your way over obstacles.

I've tried a couple of twinshocks with modern front ends and to be honest, I felt there was no benefit over the original Marzocchi forks. If anything, the feeling was worse with the modern forks (for me)

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