come june lky2 (Motor spec added)

[Deleted]

a little common sense keeps that from happening too. None of my bikes have a kill switch on the kick stand and i have never had a problem.

[ravensguildassasin]

none of the scooters or motorcycles i have rode or owned have ever had a kickstand kill switch. to be honest never even heard of such a thing till now. i agree common sense will keep that from happening.

[aeroxbud]

Most of the motorcycles i have owned (suzuki and Yamaha) have had this. It is a pain when they get older as all the dirt and water from the road goes straight on to the switch. Then one day it wont start. Most people just bypass them.

[tango]

My neighbour bought one of these recently. It runs very well and has a serious motorcycle feel and sound to it. The exhaust note is more throaty than any 150 I have ever heard. I road it around the neighbourhood but haven't had a chance to stretch it out a bit. I'm in Oklahoma City right now so I can't give any updates. And I won't be back in Jamaica until early June.

[ravensguildassasin]

so i found out it is a bottom mount 157QMJ engine. i found a side pic that was clear and zoomed in to read the engine code.

XD so now i can start planing what parts to buy. I'm thinking a stroker crank, BBK, 32mm carb, new CDI, 115mm variator, race clutch, and new coil/plug wire. opinions?

[90GTVert]

I love to see people mod if that's what they enjoy, but that is an expensive parts list you're planning on. I suggest continuing to look at your options until you are ready to purchase. I know you had mentioned that you enjoy the simplicity of the GY6. What part of that is important to you... the assembly and disassembly of it or the fact that it's a CVT so you don't need to deal with a clutch and shifting or both? Are you set on modding because you will enjoy the project and wish to do major work to anything you choose or because the 150 isn't powerful enough for motorcycle use for you or maybe both?

[ravensguildassasin]

i have always loved taking an engine apart and changing what it is doing and the power it is making. if i do mod the engine on the bike it will be getting a 63mm bbk and a +4mm stroker crank. that will bring it to a 192.65cc engine it will be good for now lol. i can always take it bigger later with a 67mmbbk and a +8.2mm stroke taking the engine to 232.69cc but that will be way way down the line if ever. i want this bike for two main reasons the first is i have never seen one like it in my area. the second is parts are cheap. now the side reason is it is cheap and easy to mod so if it blows up on me i don't feel as bad as when my engine on my car blew. i have built race engines for the ford zx2 escort the last one i did before i stopped working on them put out 283 hp N/A. then i have also done a full swap from the stock engine to a turbo 3sgte engine in a 1988 celica convertible then gave it to my friend for his birthday. i like small engines never been a v8 guy i like to take what most people look down on and show what they can do. so what if i have to save a bit to get it. when I'm done i enjoyed every second of it, (even when bleeding all over the shop cause of a slipped wretch.) i love tinkering and my hobbies, right now its scooters.

[90GTVert]

OK, so no matter what you would want a project. If not, it would make a lot more sense to just buy bigger. A used 250 Ninja would put out way more than most GY6 builds would and for a similar price or less. I'm not one to knock scoots, but I have personally contemplated trying to buy a friend's GY6 150 and the lack of power for something tagged as a motorcycle and forced to keep up with traffic always keeps me from doing it. I've been on it in a headwind and been pushed back below the 50MPH speed limit that most roads I'd be on are.... and traffic on 50MPH roads is hardly ever actually doing 50. Even with a build up I question it's ability to ride on 50MPH roads with head room for wind, hills, and worst of all windy hills. lol It's a troubling thought to me to have a tagged "motorcycle" that I worry about obstructing traffic with. A 250cc scooter on the other hand could keep up with 50MPH out of the crate with ease in any reasonable conditions. Of course I'm heavier than a lot of riders, but I still think those thoughts should apply to anyone considering a 150 because of such low output for what some may expect them to do.


At any rate, I assume you know the case needs to be bored to accept the piston size you want? Also, I'd forfeit the race clutch for an aftermarket cam. From what I've seen, most scoots really don't need a performance clutch till the build gets a little wild. Stiffer clutch springs will usually do it. CDI wouldn't be on the top of my list either unless you find it's rev limit. It seems like with so many CDIs no one really knows what they do. Base timing and curves can vary. At least if you mod the pickup to move it, you know you are changing the base timing... and it's free.

[dr1445]

+1 on verts opinion on registered scoots. i have a vento triton but am currently about to tag a 1974 bultaco 250. i did a ground up refurbishment over the winter. i put in a 12v stator with cdi ignition + a mikuni flatside carb. bike weighs in at 220lbs about the same as the vento! i expect to gear it for around 90 or 100 mph. a simple easy to fix 2 stroke for less than a 250 scoot.

[ravensguildassasin]

that's what i forgot to list above was the a9 cam. unless i ride it and think it needs more in a different range of the rpm. i am only 225 pounds and my 150cc scooter ran stock at 60mph (gps verified) all day long wind no wind but as we all know every scooter is different. as far as the bore up goes i plan to buy the tool to bore it myself. i will take it to the shop and have it blasted and cleaned before i go any further. I'm interested as to what i will have to do to get the crank to work most builds i have read said it is drop and go. but on that note i have also seen that the new piston will have to be milled to make it work. but once i start i will do a full build thread with lots of pics to show my work. i love to build things :-D but hey who doesn't? first thing I'm doing is registering and putting insurance on it. for 80 usd a year why the heck not right. i don't think i will take pics of the PDI unless i come across something that i think really needs to be shared. this is if all goes to plan and i get it in june latest would be july. but hey i have a full month bill free after paying everything in advance this month.

[90GTVert]

We don't really see many stroker builds documented here, unless they're 2Ts, so I'd love to see whatever you would like to share. I think most of the 4T stroker cranks are a drop in fit, at least that's what I've read here and there as well. They usually have more room in the crankcase. The two approaches for strokers that I hear are cutting the piston as you mentioned or a base spacer. With a +4mm stroker you've gotta deal with the piston going 2mm higher in the bore and 2mm lower. Guess it depends which method works best to deal with that.

[ravensguildassasin]

yeah it seems that the +4mm crank when at BDC the piston will hit the counter weight. i will run a squish clearance to see how much room is at TDC. of course until i get the parts this is purely speculation in my opinion. it is worth it to build with a stroke for a few reasons. obviously more displacement and then you have more torque. now on the other side of it in this small of an engine it should be harder to start, also it may need more fuel then the BBK would need otherwise. but i think the advantage out wights the disadvantage. i will also have to look at how big the stock head port is considering it is running a 1.25/1.5" exhaust (i cant remember exactly of the top of my head.) but it may be a good idea to look at how big i can go with a four valve head as well in this case. one build i found for this did say that there is enough room on TDC with out the spacer needed. but any bigger then a +4mm crank will definitely need it. i expect in July/August i will start ordering parts to build with. that should give me enough break in time and driving time to tell a definitive difference on the stock motor vs the new parts. heck when all is said and done i may need to look at the gearing as well.

[90GTVert]

You'll definitely wanna make sure you've got good cables running to the starter and relay. If not, run some good 8AWG. That helped me a bit, but maybe my cables were on the crappy side? You can usually find batteries the same size that have more cranking amps too. The last one I got is a Motobatt from eBay for about $60 and it's got 30CCA more than the stocker and is rated 2Ah higher, same size. Not sure how much of an issue it is with the GY6 150, but on the 50cc version and on the minarelli 2Ts, all starters are not created equal. I found some brand new starters barely wanted to crank over my bigger 2Ts, but then a different stock one had no trouble. Might be worth looking into more just in case. 1FASTQMB has a thread in the 4T area about what starters have been working for him. Different starters, but perhaps the brand or manufacturer makes good starters for the 150 as well?

PFS is good about listing specs for parts so I looked there. They list the stock head as 24mm intake and exhaust ports with a 27.75mm intake valve and 23mm exhaust valve. The Hoca 4V head has a 26mm intake port, 25.75mm exhaust, not sure on valve sizes. They also sell a Hoca 61mm head and say it has a 27.5mm intake port, 26.5mm exhaust port, 22.85mm intake valve and 27.75mm exhaust valve (those numbers seem backwards). There's also an NCY 61mm head out there that lists a 27.5mm intake valve and 23.5mm exhaust valve, not sure on port sizes. Scrappy sells a big valve head as well and it has a 30mm intake valve and 25mm exhaust valve, no port size listings. I have used the 50cc Scrappy big valve before. The first one I got was messed up with a leaky valve, but it was replaced and the next one was a nice piece. HERE are some pics and measurements on my 50cc version that may give you an idea of what to expect from the larger version. They really do stuff the largest valves they can fit in the combustion chamber.

There's some info from A. G. Bell regarding port and valve sizes and their relations at the bottom of THIS POST.

One other thing I've learned from working on the 50cc version of this motor is to check piston to valve clearances. It could be even more important when dealing with different sized valves or 4V setups. It takes a lot less time to check clearance with clay than it does to replace parts.

[Deleted]

Anymore info on this bottom mount 150 motor? like where to get one?

[ravensguildassasin]

no after all the searching i have done it seems to only be on the lky2. once i get the bike i will hopefully have more info on it. I'm also hoping it is a gy6b type which comes with 57mm bolt spacing. so i can go larger then a 63mm bore.