Forum

[Mark M]

Started to assemble the bottom end of the Mk2 Interceptor today. However, the lovely new billet rods from our Hosts are binding on the crank webs. The rods are fine, they measure up the same as an original rod, but the crank appears a little tight across the journal which appears to be pinching the rod. So it's a problem with the crank. Don't know why so it's back to the engineers to check the grind. Bum. Meantime I'll rebuild the gearbox. Hope that goes ok!
REgards, Mark

[Andy C]

Mark.

Are you using new bolts on the big ends ?

I had a very similar problem on a Trident that I rebuilt some years ago, crank was reground, new shells fitted but when torqued up correctly they would bind.

Fitting a new set of big end bolts cured the problem - no idea why but it did.

Just a thought.

[Mark M]

Thanks Andy, not a bad idea but these are our Host's rods which have doweled caps and ground tapered bolts, very high tech! I've done a whole heap of checking and measuring including a NOS rod, a spare crank and some spare shells and I think the crankshaft grind is shy by about one and a half thou. I've measured as best I can with my micrometer and after doing the maths from a standard grind the answer keeps coming out the same. Trip to the engineers Monday then!
REgards, Mark

[Andy C]

Mark.

Very frustrating. Knowing our Hosts attention to quality it would be highly unusual if there was a problem with the rods - unless it turns out be a rogue set of rods.

Have you checked the journals by taking measurements at 90 deg to each other - i.e. measure the journal, turn through 90 deg and re measure - this would show any out of round.

Also worth measuring the journals at each end and the middle to see if it is consistent.

Just one other thing - are the shells from our Hosts, or of good reputable quality?

Back in my trident days there were some poor quality shells doing the rounds - Italian in origin I seem to remember these also used to cause problems similar to yours, even if dimensionally the journals were OK.

Hope you get it sorted.

[Mark M]

Andy thanks, I have measured as you suggest and that's the figure I get. The shells are NOS Glacier from our Hosts and the rods measure up the same as a NOS one I have here so I'm pretty confident it's a mistake at the grinders. I'll be posting again once (if!) it's sorted.
REgards, Mark

[Alan R]

Better than a 1.5 thou "slop" though..........You might try this ??? >>>>>>>>>> http://www.youtube.com/watch?v=SJUhlRoBL8M

[Mark M]

Ha ha! My wife sometimes says "why does your hobby make you so unhappy?" when I come in from a real problem in the workshop! However, I'm not letting it get me down, I feel lucky to have the time and disposable dosh to play with old bikes and a Series 2 is the bike I always wanted. Besides, I can always ride the Mk 1 (or one of the others!)for a bit of fun!
REgards, Mark

[Alan R]

------------ and of course there's always THIS >>>>>>>>>>>>>>>>>>>>>>>>>>> http://www.youtube.com/watch?v=sZa26_esLBE