6 replies to this topic

[supermotolee]

when will i learn i bought a 1380 short block off ebay and have been gathering bits ever since to put on it and assemble it even removed the tired old 998 today but i have a worring problem that i kinda thought would go away with some turning over by hand...

its just too tight so tight that when turning the engine over with my 1/2" ratchet it could almost tip the engine over the only thing i did to it was to have the centre main cap machined for the strap and i marked it so i would know which way round it went i torqued all the crank caps and con rod nuts to the haynes torques and i'm really worried this engine has been put together with the wrong shells or something i'm going to have to pull it appart i guess i cant believe it

any ideas what to look for ?

[The Matt]

when will i learn i bought a 1380 short block off ebay and have been gathering bits ever since to put on it and assemble it even removed the tired old 998 today but i have a worring problem that i kinda thought would go away with some turning over by hand...

its just too tight so tight that when turning the engine over with my 1/2" ratchet it could almost tip the engine over the only thing i did to it was to have the centre main cap machined for the strap and i marked it so i would know which way round it went i torqued all the crank caps and con rod nuts to the haynes torques and i'm really worried this engine has been put together with the wrong shells or something i'm going to have to pull it appart i guess i cant believe it

any ideas what to look for ?

hmmm, I was gonna say about the centre main cap again, but as you had marked it, that kinda rules it out. I would try slacking one cap off at a time, see if one frees it up a little. The big ends are also line honed, so one of the big end caps could be incorrectly fitted too.

[supermotolee]

thanks i slackened off the crank caps going to re torque them and have another go then try swapping them around and see thanks for your advice

oh and i put the centre cap back on the other way round and it locked it solid haha not that then maybe i'l try the others...

[icklemini]

a small note:
The caps should be fitted so that the tangs of the bearings are adjacent to each other - and not on opposite sides.

If the rod caps have been mixed up - you're in trouble!

TTFN,
Dave

[Guess-Works.com]

maybe wrth checking you have the correct sized bigends and mains, as you have inferred, they will have std or -.010 or something similar stamped on the back, then get a micrometer and measure the crank...

[Dan]

After the centre main cap was machined flat and the strap fitted, did you get it line honed with the strap in place? The weakening of the cap and fitting of the strap can cause the housing to close up slightly.

[The Matt]

After the centre main cap was machined flat and the strap fitted, did you get it line honed with the strap in place? The weakening of the cap and fitting of the strap can cause the housing to close up slightly.

I didn't know that could cause an issue Dan, thanks for that tip. I will have to re-assess mine once it has been machined.