I am contemplating a few extra sorties on the TY 250 this year , but after many years the bike could do with a rebore.  I recently rode a newly restored 434 and the engine was sooo sweet and the the guy told me as well as a rebuild he had nikaseled the Barrel. He had in fact done the same with the clutch. I just wondered if I could tap into some knowledge as to whether this is worth it,  I would certainly like to replicate the end product of the bike I rode, it really was fantastic, and although it was only ridden in the carpark straight away I could feel the difference from mine having just spent two days on it .

 

Thanks  

In theory on an aircooled engine there will be no difference in performance between a plated and unplated liner as if correctly lubricated there should be no metal to metal contact. The nikasil bore should last longer but plating costs a lot more than just a bore. The big advantage of plating is better heat transfer on all aluminium (no liner) barreled watercooled engines. This enables closer running tolerances, less distortion and less blowby.

Think porting has been modified by the sound of it.

I rode a 434 in 1977 with a works spec engine which I think had been prepared by Lee Bros of sowerby Bridge. It still had the autolube system fitted. It remains to this day the sweetest running bike I have ever ridden. It would trickle along as slow as virtually dead stop in second gear and pick up cleanly and smoothly. I never rode a standard 434 to compare it with but it was noticeably better than good TY175s and a lot smoother than the monoshock engines that followed.

Thanks for the replies, the bike I rode may well have been ported, to be honest I did nt think to ask and the owner never mentioned it. He was an engineer and maybe when he rebuilt it he just did it very well. As to my bike, I had used it on the road during the summer to avoid holiday road  congestion, I hadn t really thought of it to ride seriously. Due to circumstance, this year  I ended up riding it in a two day trial in Spain and it was so easy to ride, soft , great handling and just that bit different it just rattles.....it has only covered 1400 kms since new and I had to replace, I assume,  the original Dunlop  tyres and I did move the footrests.  In the Pre 75 class it takes some beating and its begging to be used again.

 

Cheers again

I don't think that nikasiling the bore would make any difference to how well it ran compared with a fresh rebore.

Doing the clutch basket fingers sounds like something that might be useful though