BBK and BB case
 

Well i am sending my head off to Tom today to have him port and polish it, plus shave .025 off of it hopefully. I was thinking while its out, that i may just go with the BBK while im at it, or purchase to install later. What i want to know is what BB kits some of you have bought? I dont want one with the thin sleeve and i would rather buy one made buy a reputable company. I have seen a decent price on the NCY kit, but i am not sure what kind of sleeve it has. I would like to keep the build as cheap as possible, without sacrificing quality.

I also saw that ********* Powersports sells pre-bored cases for $125. I may pick one up, but i have had issues with their shipping lately. How do you know if your case is the long or the short case?What is everyones thoughts? Any other places to pick up a pre-bored case for a good price?

:party:

while i don't have any recommendations on pre-bored cases, i think it's the way to go, likely just as cost effective as having a local machine shop do it. I would however let tom know that you are looking into going BBK, it may affect how he works your cylinder head. A recent thread on here had the belt numbers for short and long case.--nice simple method of telling what you have/need. a quick search should pop it up.

I talked to Tom and hashed it all out. Ended up just buying it all from him as i trust his advice and know his service is top notch compared to others i have done business with in the past.So it will be 62mm BBK and a BB case from Tom. Plus hes going to P&P and shave the head.

You just can't go wrong with Tom!!!

If I were you
 

Just a thought here. But I was thinking that once you get that all together and running the very next and most important thing you could do is sell the whole thing to me for $50. I mean I can't think of any better thing to do with all of that. On a serious note, you will have one mean machine after that. Don't let all that power go to your head. Just remember to match that intake and exhaust.

Well tom is porting and polishing it so i dont think there will be a problem. Im so excited i feel like a virgin student on prom night, hopefully without the dissappointment. :evil:

Slestak... no less that $120

That seems a bit steep. Let me think about it and I'll get back to ya. So you sent your intake and exhaust pipe to Tom too? When I'm talking about intake and exhaust I'm talking about the 90 degree intake between the carb and head, and the flange on the end of the exhaust pipe that attaches to the head. The port and polish will open up the head but these parts will still be the same size. Unless you sent them off to Tom as well; in which case, You will have near perfection and all will be right in the world. I would love to go with the big bore but this will be in my future.

I hear you. I sent the head to him with the gasket and spacer still on, as i forgot to take it off. Im sure he has an intake manifold there he can match it with and an exhaust. I will call and find out for sure. I figured since i sold something on Sunday i may as well put the money to good use. Luckily we have been working pretty good and its not gonna put a dent in my pocket. Just hope work keeps up this good.

Ur not going with the stroked crank??

I want to do a big bore also and with the bigger stroke crank tom has is very tempting let us know how it feels once u get it back

Tom says the stroker wont work in my engine. So i cant get it, or i would be more than happy to.

I been debating on goin bbk too. I can't wait to hear ur results mb!

It may take a couple weeks. Between work and getting help to do it,i have no idea when it will be done.

man im excited for results to! lol, I should be working on my buggy a lot this up coming week, on vacation! :)

I noticed a difference with the 62mm 3mm stoked crank (183cc) only after putting a larger cam in. With the stock cam it had good low end but struggled at top rpm. I put a A12 cam in with ncy 11k springs and it came to life. It does get hot after a while and it runs poorly in hot weather with a 39t sprocket and cruising at 7200 rpms or more.

With the 31t sprocket it cruised at 6200 about 25/28mph and didnt over heat, best combo so far for the Baja dune 183cc.

I was told to put a oil cooler on but didnt want to mess with the chance of a leak or the cost of a oil cooler. I wish I put a oil cooler on because with the new motrio rear pulley I put the 39t back on and thought that it would still run lower rpms with the pulley opening more and make up for the 31t.

We went on a long ride about 30 minuets in the desert at top cruising speed and came to a stop for a break and oil was all over the back of the engine.

The gasket blew out under the starter and oil was all over the rear brake. I was able to take the fan cover off and tighten up the case bolts and limp back to camp about 8 miles
and stop every five minuets to check the oil level. Made it back and cleaned it off and put honda bond silicone on the back of the block and made it the rest of the trip with no leaks. I should of kept the 31t sprocket on but nothing ventured nothing gained.

hm, johnny im curious what size rollers or sliders where u using?, do u mind me also asking how much the weight of the 2 of u where while riding?, what weight oil where u using and where u using synthetic? and how hot was it outside?

I was running 10.5/12.5 rollers, 1500 spring that is a year or more older. My wife is about 140 my son is 175. The trail was hard packed and temp was about 78/82? it was windy and a bit of clouds out. The oil I like is 15/40w shell rotella non synthetic because it has a higher zinc that helps non roller cams. The constant rpms killed it because we were with my brother in-law and kids and they were on motorcycles.

It was really dry in the desert like 20% humidity, also forgot to say that I moved the needle from the second to the third clip to lean the carb because last trip it ran rich so I thought.

I finally did a real jet run before we went home and about 100 yards full throttle turned it off and waited till we got home and pulled the plug. I dont like pulling plugs on hot motors. It was clean on one side and a little color/ light tan on the other side.

I have been doing jets runs wrong and letting it come to idle and shuting it down.
It has a 125 main/34 pilot a/f screw about 2 1/4 turns out .

Also weather is different every trip we go. Ocotillo wells desert park is at or sea level.

Dont get me wrong I love the big bore stroker motor and would not go back, just still getting use to tuning it. I also need a bigger header pipe and muffler to get that heat out faster. Still running a stock modified muffler. Good news did get from 28mph to 35mph with the motorio pulley at like 8600 rpms. It ran great around camp and tight trails just not good at constant high rpm with the 39t gearing.

u ever think of trying a synthetic oil? should help, I to use 15w40 which is what my howhit calls for, i am switching to synthetic.

That's awesome that you got that much more top end from the pulley Johnny. Sound like with a 35t might be a good sweet spot between geared for speed and geared for pull. I might be looking for a 35t. Off topic though. I only have plans for a 59mm BBK one day.

Know where we could get a 35t sprocket?

Maybe e-***. Or Google. Just make sure of distance between screws and size of shaft. Going from a 31t to a 35t will take some top end away but will add some pull to it. But if you get that pulley to open all the way it will add some of that speed back. That's why I say it would be a happy medium. Near same speeds as stock with 31t but with a bit more pull.

might have changed
 

My Howhit calls for 10w-40 oil, 15w-40 is what we run in the diesel engines where I work. zman :swordfight: hahahaa

I scored a 36T sprocket from Tractor Supply for around $30. It's kind of a "blank" sprocket that you would have to machine to fit your specific needs. Drilling for the bolt holes is pretty easy, but boring out the center hole would be a little more difficult, but still not too bad.

http://www.tractorsupply.com/en/stor...x?cm_vc=-10005

Sweet. make sure that sucker is centered. That would be some very undesirable wobble.

Slestak, i have taken your advice while waiting on my parts to come in. I started porting the exhaust pipe, but i am a little cuious here. Should i completely remove that metal insert or just shave it down far? If you reccomend fully taking it out, is there a trick to get it out easily? I have already used a couple dremel grinding stones. Do they make anything else that would work better?

I went to Lowes and got a grind stone that started at 1.5" and tappered to a point to put in my regular drill it worked awesome for this task!

But are you suppose to fully rumove that sleeve or is it needed to make a proper seal for the exhaust? I bought the NCY exhaust gasket on Slestaks advice.

You just want to smooth out the weld inside for a smooth transition into the header pipe.

Exactly. You can't remove it altogether. You just open the hole that the exhaust flows through to match the inside of the pipe. Unless yours is not welded on the outside but the inside. Mine was welded on the outside so I was able to open it up to the same size as the inside of the pipe. I used the stones that fit in my drill like bear did and it took me 3 or 4 to get it done. There may be better solutions but they will cost more too.

When you say " sleeve " mb. What are you referring to?? I am talking about the end of the exhaust pipe that connects to the head. It has a big hole for the exhaust to flow through ( this is what you open up ) and two small holes for the mounting studs. I just want to make sure we are talking about the same thing.

And I want to clarify that I have stock exhaust, not performance or aftermarket.

Pretty sure he means the little bit of head pipe that protrudes through the mounting flange that the stock "O" gasket slips over.

Same here Slestak, stock exhaust, but still made a difference didnt it! worth the time.

You sir are coccect!:biggthumpup: The whole thing looks like a small pipe inserted into the exhaust. So the question is..... Do i need to remove that or just bore it out?

To clarify, i have smaller pipe welded inside of my exhaust which the O-ring slips over. You do not see any welds. So far i have bored it out with a 3/4'' grinding stone all the way through. This has made the inserted tube very thin and i wonder if it will hold up.

HMMMMM. Mine only has a flat flange. No tube inside. But it seems to me that if the stock O gasket fits over it then it is smaller than the exhaust port you have on the head. Compare the hole on the NCY gasket that you have. Do you have a weld on the outside of your header? If not I can not advise you on how far you should take it as I have nothing to compare to. Can you take a close up picture? Or maybe xlint could advise. Is it the actual header pipe that goes through the flange?

@bear. YES. It does make quite a difference. My exhaust thumps after doing this. It only makes sense. If you have a 1 inch exhaust port trying to push through a 3/4 inch exhaust flange. You do the math.

The only weld on the outside of the header is where the flange connects to the header. This is actually narrower pipe (maybe2 1/2'' long) welded inside the header that protrudes out maybe 1/8th of an inch

More Crude Pictures
 

This is what I have. Loosely of coarse. Weld is on the outside of the flange and the flange is a flat 1/4 inch piece of metal. The hole ( solid line ) was smaller than the inside of the header ( dotted line ) I just opened it to match the inside of the header pipe.

I understand. If the flange and header are welded on the outside then it seems you could completely remove the sleeve. But I can't say what that will involve. If the whole sleeve is the same size and it fits inside of the stock O gasket , then the whole sleeve is much smaller than you heads exhaust port. The whole sleeve is restrictive. I ( personally ) would do whatever it took to get that whole sleeve out and open the flange to match the inner diameter of the header pipe. That is me though. You have to determine what you are comfortable with.

You do not want to match the header inlet to the head. Let me clear up my earlier post. On the many exhausts I had seen there was a weld on the inside of header pipe which was very restrictive. This is what I was talking about. Now the perfect header pipe will be slightly smaller then the exhaust port. This is what you want. If you notice the header pipe starts with a smaller tube then opens into a larger tube. This creates scavenging as well as I believe the correct term is exhaust reversion. This slight mismatchwill aid in the removal of the exhaust from the cylinder allowing more room for the fresh mixture. I would not remove the sleeve completely which is used to seal the donut ring. If so you will not get a proper exhaust seal. If some have removed this you will need to go with a flange exhaust gasket which will have to be changed much more frequently. Most do not realise that an improper exhaust can actually hurt performance.

Thanks for the clarification on this Tom. On mine the opening on the flange was " at least " a quarter inch smaller in diameter than the I.D. of the header pipe. I opened it to something more like an eighth to a sixteenth and went with the flange style gasket. It's nice to have the voice of experience and know how on here. It just seems odd to me to open the exhaust port and put a larger valve in, but keep the same restricted header flange. So are you saying opening it up is not necessarily bad just don't take it fully to the I.D. of the header pipe??

Exactly, you do not want to port match the header pipe to exh. port. It should be slightly smaller.

How we looking on the head work Tom?

But not a quarter to 3/8" right??

Mine was like MB's header pipe. It had a small part of the header that the O gasket sealed around. I actually "flared" mine to eliminate the exhaust gasses from "tripping" over any step (widening the opening) but also maintaining the stock pipe diameter. I then used the NCY gasket like Slestak posted.

If all goes well should have it by end of week.

fear!
 

When I did mine I left a good lip on my flange, because I was afraid it would crack over time if I took it to the full diameter of the opening. I also made a flange gasket from a sheet of gasket material from the auto parts store that I already had. With the tappered stone it gave a nice beveled lip for exhaust flow>

Regular gaslet material will not last long, the 1000 degree exhaust will incinerate it.

AMEN to that brother.

Word!!!!

Thanks for the heads up I got a piece of old asbestos & mesh type material, would that work for the exhaust gasket?

Sure will.

But you have to lick the piece of asbestos 4 or 5 times before you put it on.:lol:

Please, with all the carcenagenics that I work with, asbestos is like bubble gum!!! lol

OHHHHHHHHHHHHHHHHHHHHHHHHH SNAP! The goodies have arrived! Hopefully i will get this bad B put together this week.

nice mb what exactly did u get? 62mm bore?

Yessir! i got the 62mm and sent my big valve head in to have it ported and polished and shaved.

Nice cant wait to hear the results r u going with an oil cooler?

I plan on it in the future. Right now i have spent to much on this and some home repairs so im gonna wait. Any suggestions on a decent priced cooler?

One of my customers found one for a little over $100.00 but he found out it did not circulste the oil very well. A good one will run around $200.00. The case you have should have the boss under it and I believe your current engine has them as well but if no cooler they will be blocked off. I'll look up what the cooler assy costs from ASW which is a great cooler since it has the spin on oil filter.

I havent investegated enough nor tried one yet to point u in the right direction but it seems like ckau has a nice setup, either way let us know how tbe bb goes

Sounds good. Let me know what you find Tom

I take it that it is not necessary to have a size matching head for these big bore kits. Is that right??

Thats what I got from Tom. I asked about the other companies selling 62mm heads for he BBK. He said it wasn't necessary. I tell you i am a little worried about the head with the .002 shaved off. I hope i don't run into any problems with the piston hitting the valves. Were the edge of your valves pretty much even with the bottom of the head Slestak?

We have the same head with the same treatment. Your head has the stiffer springs. It will be just fine. I've had mine running at the rpm limiter without an issue. Just got my performance CDI with no rev limit and I'm still not scared. Can't wait to hear your impressions. Are you keeping the DR2 on it and did you get it shifting like you wanted??

Just to clearify the head. The difference between a 58mm and 62mm head is the chamber, the smaller the chamber the higher the compression. I have run the stock chamber head on mine with a 63mm bore untill I went with the domed piston. At this point due to too high of compression I had to go with a 63mm chamber to help bring the compression down from 15:1. In your case the 63mm bore with the 58mm head chamber milled .025 will give you around 11.5:1 compression ratio.

Thanks for the input Tom. That's good to know. Other places of coarse want you to believe you need both bore and head. I personally would rather have the compression. I plan on getting your 59mm bore kit one of these days when I have money again. Until then I'm REALLY happy with the head work. ;-)

**** I have toms head shaved .030 lol still havent installed it yet

Wow. Really? What are you waiting for?? Did you have it ported and polished too? If so you are missing out on a big power increase by leaving it off.

I have a bunch of burrs il probally be porting it myself this weekend, its tuff right now I need more time on weekends between work, wife, and new puppy lol

I hear ya on needing time. I'm not working and I still hardly have any time.

Lol and I have a house

I need to take apart the 183cc motor to replace the gaskets and when I get home from work tomorrow always seems like a better day for it. Time flies the older you get it seems. Just don't hurry on the port job and be careful around the seats, I put small strips of duct tape on them for protection. I used small pieces of 3m red scotch brite pad on my dermal to polish the combustion chamber and the exhaust port. The intake was left rough for fuel atomization. I was very happy with the results on my first gy6 port job, it has better mid and top end and revs a lot higher and smoother.

2 fold!
 

I hear ya guys, I'm a pooor s.o.b. who has to work out of town all the time, so I get little time to work on or ride my babies!!! :crying:

mb any updates on that big bore?

Sorry, i haven't been on in a bit. The engine is about put back together, just waiting on a new chain guide to come in and finding a way to pull the bearings out of the gear case. Anyone know if a slide hammer and a pilot bearing puller will do the job? Dont have the $70 to throw away on a blind bearing puller just for a few bearings.

Other than that, the head looks great and i need to finish cleaning up the intake on the port match. Been tinkering with the Trailmaster Vapor, mounting it and running a couple connections until the engine is put back in. Anyone have any suggestions on what size main jet i should use? i was using a 136 with the large valve head before.

Forgot to mention i also have the American Sportworks oil cooler coming in!!!!! Hopefully all will be installed by this weekend.

I dont have the big bore and I am running a 130 and thinking of going with a 132. Im thinking that you could go with a 28 or 32mm carb with that setup. If staying with stock carb i would stick with the jet you have now and clean the plug really good and do a good warm engine test run and see where you stand. Thats already a big jet for the stock carb. Not saying you wont need a bigger one just test it out and see. Remember to open up full throttle for a bit then hit the kill switch and look at the plug. Dont let the engine come back to idle. After you get her running ill buy it for $120. Or just bring it over and let me ride it for a year. :biggthumpup:

If it were me I would try the slide hammer. Just be easy as the case halves are probably pretty easy to mess up if not careful.

Nice mb can't wait to see it done

You could try to warm the case in the oven at like 250 for a couple minuets because the aluminum will expand faster than the steel bearings and make it easier to remove, just warm it long enough that the steel bearings are not the same temp as the case. I do this when installing bearings, put bearings in the freezer and warm the case in the oven or toaster oven. If your wife gives you any grief let her know that your doing it for her.

It worked for me because I was working on her buggy.

Just make sure to take your time and check check check everything to make sure its tight and installed right. We ALL know you are anxious to get that thing going but take the time and make sure its right before you crank that starter. If you are unsure of ANYTHING. Take the time to ask. No one here wants to see you post about starting it up and watching it explode.

You can also find a local atv or cycle shop and have them pull them. They will have this puller and it should not cost much at all since it will be only a couple minutes of work. Just make sure when installing to have the case supported on backside so as not to crack the case. Best to use a bearing installer or anything else to apply an even pressure so as not to cock the bearing upon install.

Well after much wait and work, i was able to reinstall the engine lastnight. Only thing left to do is rejet, hook up a few cables, tighten down the CVT, and run 2 wires for my Trailtech Vapor.

I can feel the excitement.

Oh **** I want to hear the results

I recommend after you get it running to go easy for the first ride. On the 183cc motor I ran it for ten/twenty minuets at 1/4 to 1/2 and then let it cool down all the way. I did that 2 times and then let it rip but still didn't go wide open for long periods of time until I got about a hour on the motor. Maybe Tom might have more info on motor break in, I would do this on my 68 chevelle every time I put a motor in but would go wot as soon as possible to feel the power.

My motor is on the bench waiting for me to put the head on after replacing the case gaskets that blew out. I also got a 13/43 internal gear set to replace the 13/40 gears to get a little more low end with the 31t sprocket. The 39t has to go, way to much low end for the desert. I just need to go by work and press the gear on but need to wait till 4 or later, if I go by to soon they will put me to work.

Cant wait to hear the results of the deeper sound of the 62mm bore.

Very good advise. Production parts have looser tollerances then custom parts. When a speed shop runs their rebuild on the dyno they run it wide open right from the getgo. This is due to the precise boring, journal cutting, ballancing and just general fitting of the parts which are all ckecked and done to very strict tollerances. Most production made products will not have as strict tollerances for cost reasons. This is one reason a true Taiwonese part is more expensive since the tollerances are much stricter then a Chinese produced part in most all cases. The Taiwonese part will not need as much breakin time but I still recomend it. If one looks at the new automobile engines as compared to engines of the past their cost will be 3-4 times the cost as compared to say a stock 350 eng. This is due to the extra time spent in man hours making certain all specs are held to very tight and consistant tollorances, so now new cars do not need to be broken in. One lesson I have learned is you should never rush a rebuild. Everything must be checked, rechecked and checked again to be absoultly certain everything goes together right for this will save you from 80% of the breakdowns and headaches as compared to one that has been put together quickly. It takes only one little messup to ruin a rebuild, so the extra time spent on the rebuild saves you money in the long term on parts and makes the engine all the more reliable. I have heard many on the forums state that building the GY6 will ruin the reliability. If good parts are used along with good skills and mostly patients you will have a reliable engine.

I just found out that the 43 tooth gear is hitting the back of the case. Time to bust out the dermal and make some room, There is always a cause and effect when modifying it seems.

Better to find out now than to get winding down the trail wondering what that sound is. Im curious to see how the gear change works out.

Oh it is at the back of the case not spinning with the cover on. So with a magic marker I will mark it grind it and make enough room. You are right it is good it hit solid than a little and turned into a molten nasty gear oil smelling disaster.

I will say I love the smell of gear oil........ NOT!!!! It has already given me a head ache.

Im glad you added the NOT. I was starting to wonder there for a minute. Gear oil is bad enough but BURNT!!!! Whew. Thats like the bog of eternal stench.

Well here is the not so good news. The piston seems to be smacking the head and the exhaust valve is also hitting the piston. I guess the timing could be off a hair causing the valve to hit, but that still doesnt explain why the piston is hitting. I also thought the valve may be hitting due to the head being shaved down?

Tom can help with that. Pm or call him. Better to call. I believe some fix this with multiple gaskets.

That doesnt sound like a great fix. Were the edges of your valves dead even with where your head was shaved down? What are your thoughts on why my valves are hitting the piston? Timing advanced or retarded a hair?

Wow really that's not good and I have his head shaved down .030 now I'm scared to install mine

The only way for a valve to come in contact with the piston is if its open when the piston comes up. Most likely this is timing related. Pull your plug and hold a straw into the cylinder. Turn the flywheel until the straw indicates the piston is at the top. Then check the position of the cam. The two smaller marks on the cam should be even with the top edge of the head (let me know if you need me to draw a crude picture). The only other reason the valve would touch is if it is sticking open. Also take the time now to check the valve lash. Ckau explained a good method of this in another thread. Ill post the thread in a second.

It is the "gy6 timing mark" thread. Look for ckau's post on setting the valves.

The timing and everything seemed to fine. I also set the valves to .04. Maybe the timing got a little out of whack when i reapplied the tension to the chain from the chain tensioner. Wither way i will probably have to put the extra gasket between the head and the cylinder.