Topic: cm 400 t 78 timing chain info.

[jeepurz]

hi , crazy pj sent me here and ive got a few questions, bike was a $35.00 special had oil weeps around headgasket, so I poped the top  deciding to replace head base gasket and replace  timing and oilpump drive chain, the  new  chain is solid  no split link so recon I have to split the case , I was told  that it was possable to file pin on time chain remove link install without splitting the bottom end, has anyone done this, I dont really want to split cases but I dont want to ruin motor and chain with bad advice. Im making sort of a minichop streetfighter combo for my wife to ride next summer .
 thanks for any input.

[KB02]

Okay, so I'm going to be no help what so ever on your question, I just wanted to say that that is one sick looking set up you've go there!!! 

That's a 78 400 T (I thought the 78 was still the CB and the CM didn't come around untill 80). What are you using for frame and suspension? That mono shock is killer!!!

[crazypj]

Hi Jeep,
As no one else has jumped in yet I'll reply.
The difficult part with this engine is timing the balance shafts chain correctly (you probably know its got 2 balancer shafts?)
You may need a cam chain breaker to push pins out.
 You'll have to 'cut' the old chain to be able to connect new chain to it.
 K&L Supply company list master link (probably rivet type) part no.12 - 0409
Do you have new chain already? If so, dealer who sold it to you should be able to suppy new master link.
Riveting isnt a big deal, just use a large hammer on one side of chain to support pin and a small ball pein to rivet link up, (or use 650 tool if you have one?)
 In a previous existence I specialised in changing CB750/900 dohc cam chains without splitting cases, that engine is HEAVY
BTW, thats a really neat setup. I wouldnrt have thought of doing something like that to a CB/CM twin ( its why I do engines )
You stretched the swing arm?
all for now,
PJ

[jeepurz]

thanks guys , shock is 250 ninja (if I remember right) joe wiseguy  (wiseguys choppers) streached swing 4 over and once im done maching up it will get additional support top and bottom.  PJ, ive already got the chain locally and owner said the thing about filing the pin but he didnt mention a master link.  I also got an oil pump chain too.  I was kinda surprised  T chain cost. dang. Ive got a complete gasket kit coming it was cheaper than buying the gaskets I needed. Ill check into the part you mentioned , bottom end is fine no leaks and it shifts good. Im hoping to do this for under 500 bucks gezzzz and I really want firestone replica
(brat style) tires,  IF all my measurments are right 22 inch ride height.
pj ill probably sell either this or tracker in spring or summer next year to fund a 750Ftwincam and 750 sohc I wanna do winter of 08 so good to know you them figured out too. Im thinkin ya ought come up here and teach a class!!




 Thanks for the input guys.