Maintenance for 66cc Motors

[VTECturbo-Bike89]

Hey dudes! So I have a chinese 66cc Motor on my bike, I was told by the person that sold it to me that these engines pretty much have the same maintenance recommendation.. the motor I have is supposed to be a 80cc or true 66cc or whatever it is.. anyways, I was told to RE-TORQUE the head bolts down like IMMEDIATELY after a long ride while its still REALLY hot, Now is this true? or can I retorque them just regularly? and also am I supposed to pull the bolts out 1 by 1 to put red loctite on them?? and last thing, What is the torque spec for the following......

Headbolts Torque specs-?
Intake Manifold Torque specs-?
Exhaust Manifold Torque specs-?


***EDIT*** - Also is there any other motor/magneto/chain/Whatever type of maintenance that I should do? Last night I hit both of the chains in PB BLASTER chain lube formula. That and also, What is supposed to be the BEST oil for 2 stroke that money can buy.. So far I have tried vavoline from autozone and now I got Lucas Semi Synthethic from oriely (kragen) .. But im looking for some straight up nice thick rae synthethic lube that like extreamly good and even pricey.. lol So all in all let this thread be for any and ALL advice regardless if its on topic of off topic, as long as it has something to do with fixing/modifying/maintenaning the bike ill take any advice! Thanks in advance

Thank you all so much if you have any answers! Cheers!

 

[Davezilla]

I just torque mine to 120in/lb but I'm using copper gaskets... likensolid copper, not those copper sandwiched paper gaskets some new engines come with... if you got that gasket keep the torque closer to 80 in/lb, and if you got the typical aluminum gasket 100 to 120in/lb will work fine.

For oil you're gonna get a lot of opinions but I'm using opti2 at 100:1 with excellent results... ive also used amsoil dominator at 50:1 and liked it. Other good ones are Klotz, Lucas, Echo, and if you want to really get pricy, the VP premixes are it... you can buy premixed VP which is 94 octane mixed to either 40:1 or 50:1 and you buy it by the liter for around $10 per liter ... so it will cost about 20 to fill up with that stuff...

 

[maniac57]

I never retorque a hot engine! I wait until it has cooled again THEN retorque.
When you torque a hot engine stud or bolt, you do NOT get accurate torque since the stud shrinks as it cools making it tighter than your torque setting.

 

[VTECturbo-Bike89]

What do you guys reccomend as far as running race fuel for the bike? like what if I can pick up like some 110 or 111 or something from NAPA?

 

[mapbike]

High octane fuel doesnt add power or anything for that matter to a low compression engine, infact high octane fuel in a low compression engine can lower power some.

I run 87-89 octane pump gas inall of my bike engines and all of them have aftermarket heads that increase compression above what a stock kit head will produce.

The VP fuel and similar fuels that are ethanol free are very good fuels but for these little 2 stroke engines aren't something thats needed for them to run good and make good power.

 

[Davezilla]

Very True.. High octane fuels is probably the most misleading thing in all motorsports because the way it's advertised and all, and high octane is done more out of necessity to prevent pre ignition or detonation, not to make power... the same as retarding ignition timing.. it takes away power but you have to do it on a really high compression or supercharged engine. You will find more power using 87 octane pump gas than you will using the 93 octane premium but if your compression ratio is sky high then you need to increase octane, retard ignition timing, or both in order to prevent detonation which will destroy the engine.

 

[BOYGOFAST]

In understanding an over torqued bolt is potentially half broken the studs in these likely will pull free of the emboss in the cast aluminum housing before the bolt snaps. but that's not my problem. I've got a decent running 66 cc but likely it's the counterweight causing the excessive vibration in that simply too light for the attached weight. I've been thinking of tearing it down but don't have the tools currently to do that and the only option if I had would be to remove most of the piston skirt leave enough to close off the exhaust port to keep it running as rumor has it it won't run unless the exhaust port is blocked by the piston skirt at top dead.That leaves running a single piston ring with most of the skirt cut away and drilling a few holes in the connecting rod every gram removed is one less to account for at 5000 plus rpm or more which is the same same a few of lbs @ 5000 plus rpm to help smooth out the engine that has now vibrated itself free of it two rear fasteners they now must be reset with that I'm thing of picking up the 49 cc likely it's much smoother through the RPM range of operation the larger 66 cc is likely better a low RPM produces better torque but again far too much higher rpm vibration to tolerate I'm talking just completely unreasonable beyond slightly insane.

 

[2door]

Torquing fasteners after every ride is a myth. There should be NO reason to do that.
Torque them once, initially, then CHECK the torque after a few heat/cool cycles. By "check" I mean use a torque wrench and check the tightness. This tightening after every ride theory is responsible for most stripped threads and broken fasteners.

Inexperienced builders will read that advice and try to get a turn on a wrench when it isn't needed. You can only tighten a fastener so many times before something is going to break/fail.

Use a torque wrench and tighten the head bolts to 120 to 140 inch pounds if you have 8mm fasteners.
For the intake and exhaust, 6mm fasteners, don't exceed about 60 inch pounds.

Red LocTite has no place on a motorized bicycle. It is considered a permanent installation and will require heat to remove the fastener. Use the blue, #242 or a comparable product only.

If you have the short chrome acorn nuts on the cylinder head, get rid of them and replace with shouldered or flanged hex nuts. The acorn nuts, though pretty, are notorious for bottoming out before they make contact with the head leaving you with a possible head gasket leak and damaged threads on the top of the stud.

Lapping the cylinder head is also good insurance against a poor gasket seal.

Asking which oil is best is like asking which car is best. Everyone will have an opinion based on their experience. This is something you'll need to experiment with and choose what works best FOR YOU. Oils, break in procedures, fuel/oil ratios, vendors, are all issues that can bring up arguments, and usually do. Most of what you read here is based on the experience of the builder who is giving the advice and few things are carved in stone. Except chain/sprocket alignment. That IS carved in stone

Chain lubes are as varied as the personalities of the members. Everyone has their favorite and all, or most will work well. Just don't rely on WD-40 to lubricate anything. It's a great product with many uses but it isn't a lubricant.

Hope this helps a little and you have a good looking bike. Have fun and ride safe.

Tom

 

[Venice Motor Bikes]

I re-torque all the bolts after the first couple of rides.

 

[Davezilla]

I re-torque all the bolts after the first couple of rides.

Same here... Just make sure everything is torqued down proper before the first run and then wait a few heat cycles and re torque...

I fully agree on the red locktite too... it has no place on one of these engines and studs will snap before this stuff lets go, yeah, you can apply heat to help it release, but when blue will do just fine there's just no reason to use the red. On the 5mm bolts like some intake manifold studs I'll use something even weaker like the green penetrating locktite or the purple low strength... if I even use it at all there... Most the time I just snug the bolts up and leave them alone there.

Also, never torque a hot engine... for the exact reasons Maniac described... If someone was to torque a head stud to the max while the engine was hot it could pull out the threads in the case after several hot/cold cycles or when the studs are removed later on. Just torque to 120 to 140 in/lb and maybe a drop of blue locktite in the stud bosses at the base, but I don't use locktite there either... the only place I use blue locktite is on the mount studs, everything else stays put just fine after re torquing after a few hot/cold cycles.

 

[Venice Motor Bikes]

I have to admit... One of the things I always do to my brand new bikes is re-torque the exhaust bolts while they're still hot!
That seems to really set the manifold into those soft stock exhaust gaskets & keep them from leaking (& it keeps the nuts from ever coming loose).

 

[Davezilla]

I do the same but try not to say that in the open where someone could misinterpret it as doing all the hardware when hot...

For the exhaust hardware, Fred sells some brass exhaust manifold nuts and they tend to stay put really well because the softer metal, These work well enough that I can torque them and forget about it... i've checked them a few times after installing and every time I check them they're exactly where I left them... even after several 10,000+ rpm runs...

 

[Davezilla]

I've also made some 1/8" thick solid copper exhaust gaskets with my CNC router and they work really well since they don't compress much at all when installing and torquing... that's the "other" reason I can torque once and forget it... I really need to perfect CNC cutting these because I can only cut 2 or 3 at a time before the metal work hardens enough to chatter and snap the end mill. Last set I made 3 of them before I had to stop and anneal the copper sheet I'm cutting them out of. I've made a few out of .032" copper and they seal just as well as the 1/8" thick ones but have the same work hardening problem.

 

[maniac57]

There is no loctite on any of my bikes and My Pig is as reliable as any doll I have ever seen.
Once things take a set, they rarely require attention if your engine mounts or pipe hangers or whatever are right. (And I also USED to torque exhaust bolts hot until the first time I pulled out a stud during next ride.)

 

[Davezilla]

So far the only stud I pulled out was a 5mm intake stud but that was my fault for trying to get that last 1/4 turn on it when I knew better and should have left well enough alone... no big deal but had to take the intake back off, drill, tap, and helicoil.... I got a few more jugs over here with the 5mm studs but I'm going to re drill them and tap them to 6mm, the 5mm holes are pretty fragile anyway.

 

[mapbike]

the engines that dont have the extreme vibes seem to do fine without loctite on some of the studs and nuts, I use it on areas Ive had trouble with in the past on even new engines as insurance, better to have it and not need it than to have needed it and not have it and as a result have tp push or pedal the bike for several miles home because a stud vibrated out and the other stud broke as a result.

insurance is something we hope we dont need but are sure as heck glad we have when we do right....?

 

[Davezilla]

I agree there... I don't use the locktite on the engine parts like the head,exhaust, or intake anymore but still use it on the mount hardware.... even if its not needed its cheap insurance.... better safe than sorry.
for the head it stays put when torqued to 120 to 140 in/lb and redone after a few heat cycles, for the exhaust, the copper gasket and brass nuts keep it tight and I hadn't needed to retorque at all, and the intake stays put after retorquing after a few heat cycles as well.
For the mounts, these usually stay put but I still locktite the studs in, then double nut these to keep them in place... on the front mount I welded a bracket to the frame and use longer than needed bolts with double jam nuts to prevent torquing into the aluminum which can wear out the threads if redone too many times so a drop of locktite on the bolt and none on the jam nuts holds it in place very well. The rear mount I use 2 of the aluminum mount blocks instead of the steel strap, long studs locktited in and double self locking nuts. This setup has worked really well for me.

 

[Venice Motor Bikes]

I put blue loctite on the bolts that hold the small gear & engine sprocket on.
& I also use pink loctite in the nine bolts for the rag joint setup.

 

[mapbike]

I put blue loctite on the bolts that hold the small gear & engine sprocket on.
& I also use pink loctite in the nine bolts for the rag joint setup.

Im guessing you do this to take some of the load off those tiny woodruff keys by helping to prevent the small gear and drive sprocket from being able to possibly slip on the shaft.

Good idea, does the little china puller stay pop those parts off the shaft fairly easy?

 

[2door]

"Pink LocTite"......Hmmmmm.

Tom