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General Engine Building Thread


Well-known member
Mar 28, 2022
Member Number
Palm Coast, Fl
All right guys didnt see any engine building thread so figured this could be a good start (if I missed it feel free to delete or merge!) Figured this could be a good place for general engine questions or build help.

I'll start off, built a Daytona 675 engine earlier in the summer for the little brother and he didnt want it so I put it into a rebuilt Daytona. First couple times I fired it up and ran sounded perfect, rode around the block a few times maybe 4k RPM tops in a few different gears and no issues. Took it out today and gave her maybe 2/3 throttle and now I hear a rattling, somewhere from 3K RPM and up, it matches the rpm. the weird thing is it kind of just stays a constant rattle above maybe 8K RPM. Bike pulls hard all the way to redline even with the rattle so I'm thinking it isnt cam related(maybe cam chain tension) and its not a knocking sound like a loose rod think more like change in a cupholder going down a wash boarded dirt road. While on the bike it sounds like its coming from dead center on the engine, while off the bike sounds like its coming from the back of the case in the transmission area. Im leaning toward its just something loose on the bike just havent found it yet, what do yall think?
The gen3 klr has fooled every owner with the fairing rubbing the tank. Sounds like a squeak and a loud rattle that times with the engine.... On honda horizontals the engine mount bolts need to be cranked pretty tight or everything rattles.
Sweet! I'll check all that in a bit! Im really hoping its someting dumb and not something internal from when I built it :lol3
Palm bump the bike with the engine off. I remember a HD classic that at least 5 techs messed with. Owner was bugging service. I found the fairing speaker had a loose coil. It was loud as heck. I had to shake a new speaker and the bad one because nobody believed it. Found by bumping things with my fist. Anything fairing related can be loud. Ya hope it is not the engine. Maybe check the tensioner to safe.
It always amazes me what causes some of those noises lol had a gsxr600 that had this obnoxious whine, turned out to be a very tight cam chain tensioner lol
Putting work in getting this Sprint ST engine back together, case is looking good:thumb Waiting on the cover gaskets and headgasket at the moment so todays job is to give the heads a little port and polish and then start on getting them back together. Should be ready to go by the time the gaskets all get here.
Balancer shafts Delete ? .
I have never done this but often wondered why they bother to fit them on like twins and especially inline fours and sixes, about the only engine i can think of really needing balancer shafts id the V4 configuration.
Apart from obtaining a little bit of refinement in smoothing out a few buzz y vibes and blurted mirrors etc, WHY? and Above all Why the expense of design build and power sapping just to smooth things up a little.
Anyone ever deleted the ballancer?
I'll be honest I have no idea, for me its still going to be a daily bike so I am not to worried about getting that extra power......yet. but I do have a spare engine that I would like to turbo over the fall/winter, I am down to experiment a bit with that engine and see what works and what doesnt!
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