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Post by dubloman on Oct 31, 2017 8:44:35 GMT -5
We do have working brake lights on both levers and the kick stand is working but will double check the cables again.
This scooter does not have a kill switch on the handlebars but does have the side stand switch
Any other ideas are appreciated
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Post by dubloman on Oct 30, 2017 17:42:42 GMT -5
Hi everyone
Try this one for size
I am scratching my head on one
This scooter did start by the button and for no reason stopped
I have checked the continuity of the switch and we have good tone with very low resistance
I have changed the solenoid, starter and the loom (not the switch yet) tried the starter and solenoid on another scooter and they work fine so it's not them
Any thoughts would be helpful, the switch is working so it can't be that
Thanks
Dave
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Post by dubloman on Oct 29, 2017 8:41:51 GMT -5
Problem fixed
Removed the air filter (sponge type) and she runs and revs up well.....................
Who'd a thought that..................
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Post by dubloman on Oct 29, 2017 8:12:27 GMT -5
Another one that's giving me headaches
The scooter was presented with revving issues, it ticks over but when revs applied it increases then settles back down to tick over, increase throttle revs go just above tick over then settles, this goes on until full throttle, but engine will rev up for a few seconds then settle then rev up then settle, if I throttle back it will cut out. The bike did run fine before this issue
First thing I checked was the carb, stripped and cleaned with ultrasonic cleaner and carb cleaner checked jets cleaned them and up jetted the idle jet but not the main. I rebuilt the carb and put back together (tried without oil first problem remains) then putting a bit of oil (GT85) on the slide mech with the needle to help it move and still the same.
Compression is good as if it was not I believe it would not start, the plug was dirty and had carbon build up from it, it has a good spark, but it could be as simple as the plug.
It has been suggested that the stator could be the issues but as this is a young lads scooter he doesn't have much money to spend
It does have an aftermarket exhaust and during the carb clean I removed the brass airflow restriction to improve the air flow.
What do you think could be the problem as the carb is clean and the scooter starts but won't rev?
I have added some redx to the fuel
Any help is appreciated as this lad needs the scooter asap
Cheers
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Post by dubloman on Sept 13, 2017 7:04:52 GMT -5
No, it was not a typo
TDC is where the piston is at it's highest point BDC is where the piston is at it's lowest point
With respect, I do appreciate the feedback, but.... I do know what I am talking about as I have years of experience in car engines as well as MBT's, I was attached to the REME when in the military.
I agree that the top end is fouling but need to know if it is the rocker assembly or the cam, or if there is something that I have missed. With the 125cc engine it turns over perfectly but put the big bore kit on the cam or rotating stops when the piston turns half of a rotation at BDC. Even with the tappets fully slackened off it still locks up
I hope this clears up the misunderstanding and I appreciate your reply but the problem is a weird one and I have never come across this issue and even speaking to racing supply tech's they agree it is weird. I am trying to find the answer.................I know all gy6's are not the same
Cheers
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Post by dubloman on Sept 12, 2017 14:34:39 GMT -5
Hi
I have experience of the GY6 engine and have used big bore kits in the past and will continue to do so moving forward.
The problem I have is this
The above engine we have put a Liyen 150cc block, piston, rings and gudgeon pin (with new clips) on the case.
She fits like a glove and she will turn over (by hand) through a complete rotation without the head and cam (I don't recommend this unless you are experienced) I get no fouling of the piston and she returns back to TDC and the timing mark lines up again
If I put the head on with the cam and bolt everything down, then rotate the engine, I get to BDC and she locks up. If I slacken off the tappets and rotate she still locks up. Do the same again without the rocker assembly on she will rotate no problem.
I am using the head, cam and rocker assembly from the 125 engine and I feel it is either the rocker assembly or the cam that is fouling and causing the lock up
Has anyone got experience with this issue and do I need to change
1. the head 2. the cam 3. the rocker assembly 4. all the above
It's the first time I have come across this problem and it's got me stumped
It looks like the cam won't rotate with the rocker assembly in place so it might need any one of the above but might need them all.
If you have experience of this can you guide me and put me out of my misery and tell me what parts I need (part numbers would be good)
Thanks Dave
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Post by dubloman on Jul 28, 2017 16:13:38 GMT -5
Hi
As we are working outside, we are slaves to the weather
We have cleaned another carb and blown out the jets, it has come off a working scooter so we should get it running
I have ordered some copper gasket and will try this when the weather improves.
We do have everything for putting the big bore kit on but want to know this engine runs (even for a few moments)
I appreciate the offer Geoff and will take you up on the offer if we get to that point after all the new things
If we need your help (I am sure we will....lol) we can bring it to you as that is only fair
I will keep everyone posted on the progress
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Post by dubloman on Jul 26, 2017 13:31:11 GMT -5
Hi Bruno
These guys are very helpful but if you read all the posts on the thread I started it will help as the scooter you have has the same engine near as possible to the one I am trying to get started
Sym Jet 2 stroke 50cc won't start
Hope this helps
Dave
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Post by dubloman on Jul 25, 2017 16:23:03 GMT -5
We have a big bore kit to put on the scooter but want to get it running first before putting it on.
If I spend money on a carb (where do you buy new carbs for $15 to $20) as I am in the UK. Plus if we were to buy a good carb for the 70cc big bore kit would it be usable on the 50cc first and then be good for the bigger bore?
I am sure you understand that we have to see if the engine is a runner before putting the big bore kit on but spending money on something that may only be used for a short time (even if it is the best option) and if I have too then I will)
If you can give me the best advice and if you can guide on the sym jet sport x carbs I would be grateful again
On a personal note diesel and petrol cars and HGV engines are mush easier than this and I am on a very steep learning curve. Give me a 56 ton MBT tank any day as I can fix them, this is a pain in the arse......lol
If anyone is in my local area Preston, Lancs, and you can give some help please shout up as I need the help.....clearly
Cheers
Dave
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Post by dubloman on Jul 25, 2017 15:36:02 GMT -5
I used another method to block the exhaust but keep seeing these freeze plugs, but they are engine core plugs.............what are they called in the UK rubber compression bungs??
I could do with using them instead of the way we have been using
Thanks
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Post by dubloman on Jul 25, 2017 15:31:33 GMT -5
That is an amazing animation of the 2 stroke cycle, I was unaware (I am being honest) most won't) that the crank case is the mixing zone before it goes into the pot. This is why we have fluids in the crankcase....makes sense now....lol
We have as I mentioned in the previous post we have used thinner gaskets and we almost had her start.
With your help we are getting into the right place.
We are going to try again tomorrow so will see if we need to reduce the gasket thickness and I will go and buy some copper gasket to see if we can get better compression and do the leakdown test, compression test, squish test and make sure the mixture screw and tickover screw are in the right place and finally make sure the inlet and exhaust are sorted before we try again.............Oh and a full charge in the battery
If I have missed anything please let me know, so I can get it sorted before the next attempt
Thanks for everything and I will continue to feed back to this group as if I can help others with the process then I am very happy to do so
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Post by dubloman on Jul 25, 2017 13:15:21 GMT -5
Reporting back
Put a thinner head gasket on and picked a head that has a smaller gap in the combusion chamber, done the squish test with 1.2mm solder but it is still not squishing the solder so the gap is greater than the 1.2mm. If the ideal gap for 2 stroke (as per the video) is between 0.6 & 0.9 mm then this could be the reason for low compression.
We have changed the compression from 75 psi to just below 90 psi with the improvements above, we have done a leakdown test and the block that had the hole has been put back on but we have repaired the hole by welding and then metal putty, we have no leak on the head.
One thing we did do was the crankcase did have a lot of fuel in it, we removed it(we are looking to do this after every change) but we are still having lots of fuel getting into the air box through the carb, the mixture has been turned almost all the way down
How do I increase the psi in the chamber (remove the head gasket) or reduce the thickness of the head
Any help is appeciated
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Post by dubloman on Jul 25, 2017 11:32:36 GMT -5
We have done the squish test and I used 1.2mm solder, it did not even touch it.......so I am changing the head gasket as well as the head for a smaller one and see if she starts. I will alway do a leakdown test and check the case to check for fluid before trying to start it
I will report back to help others......hopefully
Cheers
Dave
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Post by dubloman on Jul 24, 2017 17:49:37 GMT -5
Interesting video I will have to check the clearance tomorrow and see what we have.
I do have a kit to put on this engine but need to know it will run before putting it on.
I assume that if the test is higher than the recommended then this could explain the reason for low compression?
Other than the rings not sealing or leaking block or head (I should do another leak test on the replacement block as it might have issues as well
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Post by dubloman on Jul 24, 2017 15:45:06 GMT -5
I felt it was a bit low, I was looking for 115 psi but it looks like I will have to try another block and see what the compression is on that.
I will have try and see what we get with the other, I will have to change the rings as well
Thanks
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