|
|
Post by FrankenMech on Feb 27, 2015 11:32:37 GMT -5
A bad valve seat or misalignment will cause similar problems. Valve seal needs to be checked at assy or by lapping them in.
|
|
|
|
Post by boostnjuice on Feb 27, 2015 15:32:27 GMT -5
Yeah, when I put the valves in they didn't seat real well, I lapped them in as best I could but I expected them not to last. I need to spend the money on a higher quality head. I might try getting a full out valve job if I can find a local machine shop that can do that small of valves.
|
|
|
|
Post by FrankenMech on Feb 27, 2015 16:00:39 GMT -5
Sounds like you are heading in the right direction. bad valve guides will cause bad seating also. I am just waiting on parts to fix the damage from a failed variator. One should be in the mail when it gets here. I could slop something together using old used parts after that but I am waiting on a new replacement variator from AZ Imports Co thru Amazon with proper splines. The first one just had little burrs for splines. It made it three miles before it failed.
EDIT: The mailman is here with the kickstart gear, still waiting on the variator.
|
|
|
|
Post by boostnjuice on Feb 27, 2015 16:42:11 GMT -5
Cool, hope it works out for you.
|
|
|
|
Post by FrankenMech on Feb 27, 2015 21:02:54 GMT -5
One never knows with China parts as you well know.
A valve job would probably run 10x the cost of a new head.
|
|
|
|
Post by boostnjuice on Mar 1, 2015 8:46:29 GMT -5
SO here are some picts as requested:  Here she is!!  The engine out ready to bet bigger.  Big difference no?  The first destroyed belt.  The second damaged belt.  The first burnt valve. More pictures to come... |
|
|
|
Post by FrankenMech on Mar 1, 2015 12:55:30 GMT -5
So THAT is what a center stand is for! So you have something to set the engine on to work on it  I have not had my engine out. I am not sure I even know how to get my scoot up on the center stand. I have used it a couple times but that experience has faded into the mists of time... Not that that takes a long time anymore. I know I pull the center stand forward with a bungee when I remove the cvt cover. That piston is a BIG difference. That second belt looks like my stock Bando belt when I replaced it. Maybe I will put my variator back together today. The replacement came in the mail Saturday and even seems to have splines on the outer steel pulley, a non-blue kickstart clutch, and a non-melted fan. I have to apply some lead tape to my sliders though. I did get another set of rollers with the replacement but I have not weighed them. The original came with 6g rollers. I really need a bigger spare parts box. Not that a few variator parts take up much space. It just needs organizing. I keep taking off parts and dumping them in the box. My FREE trunk box that came with my scoot already has a box of it's own. |
|
|
|
Post by boostnjuice on Mar 1, 2015 19:52:31 GMT -5
Pulling out the engine is easy, first UN bolt intake from head, then unplug starter&stator connectors and spark plug boot, pull the shock bolt, the brake cable, and finally the long mount bolt. Then just lift the scoot frame off said engine.
Lol,I'm sure I oversimplified it.
|
|
|
|
Post by 190mech on Mar 1, 2015 20:45:28 GMT -5
Pulling out the engine is easy, first UN bolt intake from head, then unplug starter&stator connectors and spark plug boot, pull the shock bolt, the brake cable, and finally the long mount bolt. Then just lift the scoot frame off said engine. Lol,I'm sure I oversimplified it. "Reinstall in reverse order"!!  |
|
|
|
Post by FrankenMech on Mar 1, 2015 21:49:16 GMT -5
So when do you deploy the center stand? I took a long nap this afternoon. Damn meds and lunch often put me down. So I did not get my variator fixed  |
|
|
|
Post by boostnjuice on Mar 3, 2015 21:24:55 GMT -5
Pictures, round 2.  This is the burnt valve and seat after repair. Not perfect but it seams to be working for now.  Not quite sure where they came up with 64mm...   Mass for mass. |
|
|
|
Post by boostnjuice on Mar 17, 2015 5:16:22 GMT -5
Well, I torched another belt last night. Seems a regular belt just can't handle the power of a bbk, and a long daily commute. I will have to get a Kevlar one and try that out.
Funny that most people say the crank can't handle 50mm bbk, but I have had issues with everything but that, lol.
|
|
|
|
Post by humanshield on Mar 17, 2015 9:12:17 GMT -5
Well, I torched another belt last night. Seems a regular belt just can't handle the power of a bbk, and a long daily commute. I will have to get a Kevlar one and try that out. Funny that most people say the crank can't handle 50mm bbk, but I have had issues with everything but that, lol. I have a 50mm piston. The extra mass is a real issue. Some will go longer than others but it's more stress on the crank, rod and bearings than the design called for. It could last a long time..... or not. A lot depends on the rider. Have you tried a "real" Bando belt? As far as the belt issues, you need to cool the CVT down. The heat is destroying your belts more so than the power imo. |
|
|
|
Post by humanshield on Mar 17, 2015 9:16:43 GMT -5
Yeah, when I put the valves in they didn't seat real well, I lapped them in as best I could but I expected them not to last. I need to spend the money on a higher quality head. I might try getting a full out valve job if I can find a local machine shop that can do that small of valves. When an exhaust valve gets tight that allows carbon deposits to build up on the seat and valve contact area. That quickly escalates the problem because the carbon acts as insulation, reducing heat transfer more and also increasing the gap. For that reason I gap my exhaust valves slightly on the loose side. Longevity over the small gain. YMMV |
|
|
|
Post by FrankenMech on Mar 17, 2015 10:57:16 GMT -5
Well, I torched another belt last night. Seems a regular belt just can't handle the power of a bbk, and a long daily commute. I will have to get a Kevlar one and try that out. Funny that most people say the crank can't handle 50mm bbk, but I have had issues with everything but that, lol. As a rule of thumb a single belt drive will handle about 5HP continuously. We abuse that figure often when larger displacement is involved. To make matters worse we enclose the belt drive in a box and don't let it cool off. A long commute at high power output is the worst thing you can do to the belt. Kevelar won't help. It is the friction face material that breaks down under heat and starts slipping worse generating more heat, -slip-slide-sssssss-boom-.... The best thing you can do is cut away the cover almost completely but it will still only take about 5HP. Varying speed and power output to let the belt cool will help some. Every time you go for full power that belt is slipping and heating rapidly. Our rubber band CVT drives are built for intermittent use and are a piss poor design. For higher HP designs a drive needs multiple belts. But what do I know, I only engineered belt, chain, etc, drives for machinery for 20 years. I get the creeps when I look at a lot of drives or machinery people come up with that they say 'works'... -Like Hell it does. |
|
