Chinesse build

[john monser]

]Hello all. Long story short , have had many many bikes and quads over the years. Couple years ago , couple years before my sons departure to Paris island we picked up a pile of blaster parts and tried to put one together out of what was there. Riding , locked up, tore down, wiseco crank , Chinesse top end, riding, top end bearing let lose, shut down, bought oem bearing. Holding together but couldn’t jet correctly so put snorkel and lid back on and left main at 230 and raised pilot to 35. Friends/neighbors rode as (extra bike). Fast forward couple years and decided to play with. Chinese head, Chinese cylinder, knock off namura piston, wiseco crank , oem cylinder

 

[john monser]

Sorry about posting where and what- not to tech savy. Watched KOR’s videos and others and not sure if exhaust port should be raised when running either a knock off piston or the vitos super stock wich both have the lowered piston exhaust side. Wondering if the combination opens exhaust to soon? Thanks for any help.

 

[john monser]

Sorry about posting where and what- not to tech savy. Watched KOR’s videos and others and not sure if exhaust port should be raised when running either a knock off piston or the vitos super stock wich both have the lowered piston exhaust side. Wondering if the combination opens exhaust to soon? Thanks for any help.

 

[john monser]

Threw the tools in thier just so nobody thought I pried my cases apart with screwdrivers lol. Had a cr250 I rebuilt that I had to use jb weld on for that reason like 25 years ago l

 

[john monser]

Threw the tools in thier just so nobody thought I pried my cases apart with screwdrivers lol. Had a cr250 I rebuilt that I had to use jb weld on for that reason like 25 years ago l

 

[john monser]

Last riding picture before departure

 

[Slydog]

How much did you raise the exhaust 2mm?
I would run a regular piston with the port work.
Like the atc

 

[john monser]

How much did you raise the exhaust 2mm?
I would run a regular piston with the port work.
Like the atc

 

[john monser]

Didn’t raise exhaust, although I did run into it slightly. I’m gonna leave be for now and run the Chinese piston with the relief cut. Just experimenting. The atc is nasty. It’s laid me up several times in the past 20 years. Big boy toy lol

 

[Slydog]

Didn’t raise exhaust, although I did run into it slightly. I’m gonna leave be for now and run the Chinese piston with the relief cut. Just experimenting. The atc is nasty. It’s laid me up several times in the past 20 years. Big boy toy lol

I would be careful running that Chinese piston. It could cost you a set of cases if piston skirt breaks off.
Those atc's are wheelie machines

 

[john monser]

So I put the Chinese piston /rings back into the Chinese cylinder. After reading many hours on this forum I finally realized how little I know about the 200cc Yamaha. So..... after realizing that my original problem was more than likely associated with to little squish from likely to thin a base gasket( correct me if I’m wrong) I ended up not using my supplied base gasket but rather made my own out of my favorite gasket material wich measured .030 uncompressed. Not quite the stock uncompressed measurement but much closer than what I had. Head gasket measured .032 uncompressed at outside edge away from raised section. Unlike Chinese kits this gasket set had the copper washers that go under each head nut. Started with the 35 pilot and 270 main , second clip from bottom, stock Mikuni ( not Chinese carb) and no lid. Ended up at a 290 main and middle position on needle clip. Still kinda abrupt powerband so advanced timing 4 degrees and really all in all gained a massive amount of power. Pro circuit platinum pipi and silencer by the way. I like it but not user friendly as it lacks a lot in the midrange and hits really hard up top. Soo.... I definitely want to find an oem cylinder and head. Once I’ve got a jug I’ll order a piston, redo the port work, raise the exhaust port and feel a lot better about the whole thing in general. Bottom line the Chinese stuff will work, but why bother, I’m not really comfortable with it currently and that’s enough for me to get the right oem stuff

 

[john monser]

Forgot to add- yamalube @ 32 to 1. (4 oz per gallon) also when I did the crank I used yamabond. When I did the top end just know I used permeates aviation cement for base and intake gaskets. Also I read on here that very few applications call for a larger pilot jet, so what happens when oil injection is blocked off and your neighbors riding the blaster, we end up going 1 mile plus down a steep hill and he’s got the throttle closed but the engine is going 6 thousand rpms? No gas no oil. You and I know to blip the throttle but not every one graps the concept?

 

[Slydog]

So I put the Chinese piston /rings back into the Chinese cylinder. After reading many hours on this forum I finally realized how little I know about the 200cc Yamaha. So..... after realizing that my original problem was more than likely associated with to little squish from likely to thin a base gasket( correct me if I’m wrong) I ended up not using my supplied base gasket but rather made my own out of my favorite gasket material wich measured .030 uncompressed. Not quite the stock uncompressed measurement but much closer than what I had. Head gasket measured .032 uncompressed at outside edge away from raised section. Unlike Chinese kits this gasket set had the copper washers that go under each head nut. Started with the 35 pilot and 270 main , second clip from bottom, stock Mikuni ( not Chinese carb) and no lid. Ended up at a 290 main and middle position on needle clip. Still kinda abrupt powerband so advanced timing 4 degrees and really all in all gained a massive amount of power. Pro circuit platinum pipi and silencer by the way. I like it but not user friendly as it lacks a lot in the midrange and hits really hard up top. Soo.... I definitely want to find an oem cylinder and head. Once I’ve got a jug I’ll order a piston, redo the port work, raise the exhaust port and feel a lot better about the whole thing in general. Bottom line the Chinese stuff will work, but why bother, I’m not really comfortable with it currently and that’s enough for me to get the right oem stuff

Just keep an eye on these pistons. Any piston slap and they break. Possibly taking your cases with it .

 

[john monser]

I measured the piston to cylinder wall clearance on this most recent tear down and was appalled by by how much clearance I have compared to what is acceptable. Didn’t even write down as they were so bad, I’m talking .015. Mind you it’s probably had 20 tanks of gas ran through it the last couple years. Anyway it’s running good and sounding good but I’m looking for an oem top end so I can feel good about it. Before the neighbor jumps on it lol

 

[john monser]

So I got my wiseco piston.... however regardless of why I ended up with a 66.00 mm piston. The current Chinese piston said 65 .74 or 76 maybe. My question is- despite my crazy bad current clearances is that roughly.25 mm gonna be enough to hone my cylinder to tighten up the specs? I don’t the correct bore measuring tools to determine. I understand nobody can answer this without parts and tools in hand.... just looking for opinions before I tear down, raise exhaust port and bring to my local machine shop. Any thoughts appreciated. Thanks John

 

[Slydog]

Measure the bore. And piston and see what the clearance is .
General rule on these imo is new bore new piston done deal and no worries. And new wristpin bearing

 

[john monser]

Thanks. Just realized no new wrist bearing. Oh well, still have to take to get measured honed