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-   -   B1 rep flat spot (https://www.pocketbikeplanet.com/83-water-cooled-pocketbikes/111711-b1-rep-flat-spot.html)

jak_e_lee 08-31-2018 12:58 PM

B1 rep flat spot
 
My b1 rep, I ain't had much use our of it yet, just not got time at the minute but, I have it well warmed anytime I have used it and sometimes get this dull flat spot when it won't rev out then all of a sudden,,,it kicks in and off it goes,
Have New plug, petrol filter,cleaned carb but still this flat spot low down
Any advice appreciated to rid me of the dull spot on the rev range

MrKitty 08-31-2018 01:23 PM

283 Attachment(s)
Sounds like a tuning issue these bikes are very finicky and have to be tuned according to the humidity barometric pressure and temperature your tune may change from day-to-day depending upon your weather patterns

This is what pocket bikers are talking about when they say their bike ran a such and such speed on a good day. A good day means the weather was perfect for their tune...

On a side note it's not uncommon for Racers to adjust their tune midday or even as much as tuning morning midday and evening...

On another note your tune is going to change as your bike wears and it slowly loses compression...

jak_e_lee 08-31-2018 01:34 PM

It's just a tad slow on the pick up at times then boom....it kicks in full on!
Great bike every other way,solid handling,no leaks from the pump either.
I was thinking of inspecting the reed block gasket and if it's ok...a rejet down a size or also use a good quality 2 t oil as I'm using basically chain saw 2t at the minute.
It really kicks in hard when it does go,hard enough to lift the wheel off the deck

MrKitty 08-31-2018 01:53 PM

Re: B1 rep flat spot
 
sounds like its going lean mid throttle to me try going one jet size bigger

dont run crappy 2 stroke oil on those rep bikes it kills them and fast you might want to do a compression test and see where its at...

mix your oil properly!!!

dont use one shot mixes it will kill it...

CAM2 08-31-2018 03:25 PM

Re: B1 rep flat spot
 
Quote:

Originally Posted by jak_e_lee (Post 893957)
It's just a tad slow on the pick up at times then boom....it kicks in full on!
Great bike every other way,solid handling,no leaks from the pump either.
I was thinking of inspecting the reed block gasket and if it's ok...a rejet down a size or also use a good quality 2 t oil as I'm using basically chain saw 2t at the minute.
It really kicks in hard when it does go,hard enough to lift the wheel off the deck

There's parameters the reps must meet in order to run good and that is if the ports are all in the right places too...

Look at the specs of a real euro engine...if your engine doesn't even come close to the specs then you have some work to do...

Alls I'll say coming from where I use them in 7-8ft long fiberglass r/c boats the reps need the squish tightened up,,crankcase blueprinted aswell as getting the carburetor setup right with correct atomizer tube ,needle,barrel and jetting..

The rpm your clutch engages at matters too....On euro engines the clutch engeges at 8k......

Good Luck

EPR 08-31-2018 11:17 PM

Re: B1 rep flat spot
 
The problem is there Junk. I have a 50cc C1, if it's not one thing its another. Might need a coil. Did some one put a 19mm Clone Dell PHBG carb on it.

jak_e_lee 09-01-2018 02:33 AM

Re: B1 rep flat spot
 
Quote:

Originally Posted by EPR (Post 893985)
The problem is there Junk. I have a 50cc C1, if it's not one thing its another. Might need a coil. Did some one put a 19mm Clone Dell PHBG carb on it.

It all looks totally standard to me around the engine.
At 40-1...im possibly using too much oil is a thought i had,50-1 is whats specified for it.
When it goes...it really hammers on,you gotta hold on tight,lol
Its just something basic im missing somewhere.
Start with basics...will get good silkolene 2t oil and go 50-1 is my first thing to try.
Currently using comma mineral 2t bought from the gas station.
At 40-1 ,could be oiling the plug!
Carby is 15mm dellorto clone
I know the carby is nice and clean as is my fuel filter and air filter and the plugs new so its gonna be something basic that heals it,it is after all a real basic single cylinder engine

Chrisi 09-01-2018 05:07 AM

When there is to much oil on the spark, you should not reduce 2 stroke mix, you should reduce main jet of the carb.
Small help for starting mainjet is, carb dia. X 5 + 5%. That is 15mm x 5 + 5%= 78, so give in 0,78mm mainjet into carb and trie again.

jak_e_lee 09-01-2018 08:07 AM

4 Attachment(s)
I took a look today and tightened the jubilee clip around the carb to manifold and the bikes on the money now and useable over the rev range .
I did notice the rad weeping around the top where the mounting bracket rivets to it so I'm have to get someone to braze that for me but for now, il monitor coolant level during use but bikes going great today. Had it up the street and it's way better

MrKitty 09-01-2018 11:55 AM

Right on man ride em till they blow that's what I always say 🙂

EPR 09-01-2018 01:41 PM

Re: B1 rep flat spot
 
That's a 14mm clone Dell SHA carb, the 5x times bore is a good starting place.

jak_e_lee 09-01-2018 02:44 PM

4 Attachment(s)
Took it out an hour ago and fried the clutch😂
I took of the bell and half a shoe liner dropped out.
I think this bike has laid up unused for a long time but it was going great until the clutch **** itself .
New one ordered so back in action next week.
Sticking with twin shoe clutch

MrKitty 09-01-2018 04:06 PM

best to order three clutches it's a common problem on them 🙂

Chrisi 09-01-2018 05:07 PM

No problem on them, just order one good clutch, like zocchi, cs or somthing else and not 10 of the cheap china clutches.
Then take a time to run in and adjust the clutch and it will work a long time.

MrKitty 09-01-2018 06:37 PM

it's not worth it on a china rep bike because it's just a matter of time before something else breaks then you've wasted a bunch of money on a clutch

EPR 09-01-2018 07:58 PM

Re: B1 rep flat spot
 
Can you post a photo of the 2 shoe clutch your using. I got mine so hot the whole pad came off the arm, I thought I broke the engine at first.

Chrisi 09-02-2018 12:13 AM

Quote:

Originally Posted by MrKitty (Post 894013)
it's not worth it on a china rep bike because it's just a matter of time before something else breaks then you've wasted a bunch of money on a clutch

There is no wasted money on a good clutch, try it and you will see what i mean.

MrKitty 09-02-2018 01:21 AM

I onley use the clutch for take off then once it hits full lock I intend to keep it locked bliping and reving is what kills them lots of begeners like to give the bike a few quick blips before take off or they stop and let the clutch unlock or both and melt the epoxy that holds the pad to the arm

Chrisi 09-02-2018 02:16 AM

Quote:

Originally Posted by MrKitty (Post 894043)
I onley use the clutch for take off then once it hits full lock I intend to keep it locked bliping and reving is what kills them lots of begeners like to give the bike a few quick blips before take off or they stop and let the clutch unlock or both and melt the epoxy that holds the pad to the arm

Thats right.
And the next problem of china clutch is setting the spring. Just change the spring to original blata and it works. Mostly need also a smaller clutchbell, because they dosn't fit on 80mm bell, nearby 78mm bell it works.

jak_e_lee 09-02-2018 02:31 AM

6 Attachment(s)
That's the shoe. It broke in half and then it kept the transmission engaged so I took it off the bike last night. I was blipping the throttle as I'm used to mannua l road bikes. I guess automatics need a different riding technique!
I was in an area i could only use full power for a split second.


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