Rebuild and Replacing nuts/screws before install?

You shouldn't have to rebuild the engine, but it would be a great idea to inspect it before you start your build. You'll want to clean it of all debris and make sure it's lubricated properly. When it comes to buying upgraded hardware, which is a fantastic - almost essential idea, you should probably do a mock-up of how you'd like to mount your engine first. That way, you'll know exactly what size bolts to use and if you could benefit from any additional mounting hardware. Try to use grade 8 hardware, but at least grade 5 - and pick up some blue loctite. The break in procedure is usually included in the manual and I'm certain there's a thread out there about it.

I disagree with the loctite thing. If you use good fasteners and are willing to take 2 min every so often to be sure things are tight & adjusted, you don't need loctite and you'll never have to struggle to get something apart if you decide to change the layout or need to replace something later.

note this thread: http://motorbicycling.com/showthread.php?t=45607

I think that thread is about the red loctite. It's not hard to remove the blue kind at all - just keeps things a bit snug. I use them on nuts that see the heaviest vibration, like the rear sprocket and the motor mounts.

I have nothing against using it where it will do good, but things that need adjusting a lot and periodic removal/refitting seem to make it more of a chore than a help - bent or broken spokes under the rear sprocket come to mind.

Perhaps adding it in after a bike has been run for quite a while might be good.

jlaw7005 said:

You shouldn't have to rebuild the engine, but it would be a great idea to inspect it before you start your build. You'll want to clean it of all debris and make sure it's lubricated properly. When it comes to buying upgraded hardware, which is a fantastic - almost essential idea, you should probably do a mock-up of how you'd like to mount your engine first. That way, you'll know exactly what size bolts to use and if you could benefit from any additional mounting hardware. Try to use grade 8 hardware, but at least grade 5 - and pick up some blue loctite. The break in procedure is usually included in the manual and I'm certain there's a thread out there about it.

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Grade 8 is too brittle.

Also, the "manual" is pretty bad, and gives a lot of mis information.

Like, don't break in your engine with a 16:1 mix....waaay too much oil!

crassius said:

I have nothing against using it where it will do good, but things that need adjusting a lot and periodic removal/refitting seem to make it more of a chore than a help - bent or broken spokes under the rear sprocket come to mind.

Perhaps adding it in after a bike has been run for quite a while might be good.

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After having built with the kit hardware and spending the first season wrenching nearly every ride on SOMETHING, I bought a hardware kit from SBP and used loctite on the head studs, intake/exhaust studs, and motor mounts. The next season passed and I didn't have to tighten ANYTHING, that was awesome!

Since I was installing a quality set of studs I decided to use the RED loctite on the stud/block and stud/cylinder junctions, and used blue loctite where the nuts go on the studs. I never did use any loctite on the rag joint, haven't needed it, it's not broke so I'm not fixing it! LOL Removing nuts with blue loctite isn't a huge deal, red is another story, you better use some heat. So don't use RED unless you are SURE you don't want that junction to budge! (re: don't use red loctite on any of the original kit hardware or you will regret it)

I second the idea of building up your bike without loctite and riding it a while, cause you may end up wanting to tweak the setup a bit. Once you're comfortable riding it and things are all broken in and tweaked that is the time to pull things apart and loctite them if you plan on doing that.

If you have the acorn nuts on the head studs I would recommend changing to regular open nuts. The acorn nuts look nice but could bottom out and give you a false sense that your head is torqued down properly when it is not.

I also took the plunge and tossed the chain tensioner in the trash, I ride without one. I just had such a hard time with it, always needing tweaking cause I was losing chain tension, and it made so much noise and created tons of drag when I was pedaling I finally decided to be rid of it. My rear frame tubes are a flattened oval shape, so I didn't have to worry about the tensioner twisting into the spokes, but that has happened to so many riders and can have tragic results for you and your bike, so keep your eye on the tensioner if you ride with one. I installed a #41 industrial/farm chain shortened to fit without the tensioner and my bike rides like a dream, I've put well over 1000 happy miles on it without the tensioner and never had a problem. The noise and resistance when pedaling is greatly reduced and best thing is I haven't had to touch the chain since I installed it!

A hd chain is the first upgrade you should make to your bike kit. The stock chinese chains are junk. I use #40 roller chain from a local hardware store. I get enough for two bikes for $20bucks. I grind the inside of the clutch cover to clear the chain and have many thousands of miles with no chain issues at all.

maniac57 said:

A hd chain is the first upgrade you should make to your bike kit. The stock chinese chains are junk. I use #40 roller chain from a local hardware store. I get enough for two bikes for $20bucks. I grind the inside of the clutch cover to clear the chain and have many thousands of miles with no chain issues at all.

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I tried #40 chain but found it to be a bit too large, the #41 chain worked out better for me...

no, install it right away. the stock hardware is crap, and more things will loosen up during break in, so you'll have to tighten things as you go.

better to use real hardware so you don't strip anything out or lose any bolts.

(the stock 6mm, black lockwashers are great though. i dunno why they use those, then put cheesy bolts and nuts on everything else.)

i'm against using loctite on my engines.

i actually use anti-seize compound on every bolt i screw into the engine. if you tighten every bolt correctly, and build a vibration free bike, things rarely come loose.

nightcruiser said:

I tried #40 chain but found it to be a bit too large, the #41 chain worked out better for me...

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This is true, I did have to grind for clearance more than #41, but I went ahead since the #4 is so much thicker (and also because it was cheap)
I"ve done several builds for customers and have had absolutely no issues at all.
Use whatever you can get, as long as it's better than the stock cheese-hardened junk.

maniac57 said:

This is true, I did have to grind for clearance more than #41, but I went ahead since the #4 is so much thicker (and also because it was cheap)
I"ve done several builds for customers and have had absolutely no issues at all.
Use whatever you can get, as long as it's better than the stock cheese-hardened junk.

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I understand, just thought I would note that the #40 was a bit too big to work without some sort of mod, while the #41 swapped right in without a problem. The #40 is an extremely solid chain and is noticeably heavier than the #41, but the #41 is pretty stout as well. I think both of them are more than sufficient for a motorized bicycle....

I just bought a #41 roller chain to replace the stock chain and am worried it may ride far enough to the edges of the engine housing to rub or grind at it do I need a wider sprocket on the engine to keep it centered?

Read the post right before yours.

Thank you ... #41 looked pretty tight to me and post #13 is what spurred the question... it leading me to believe that some grinding is necessary for the #41 to clear but not as much grinding as for the larger #40 chain however I have not have a chance to try it yet.

sometimes when I'm running a half-link that is a bit taller at the roller I'll cut a small square slot in the three-screw cover for extra clearance

That make good sense to me, to file or grind in the cover but anything on the engine itself?

wichita jim said:

That make good sense to me, to file or grind in the cover but anything on the engine itself?

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No. Even #40 doesn't require grinding the actual engine case, just notch the cover.