Superbyke RSR 5th gear is weak, max 50mph, 4th gear goes up to 60 - why?

When I was testing my max speed, And I switched to gear from 4 to 5 with high rev, suddenly the engine started to scream, like too much rev, and then settled, but even with max open throttle, it was staying on 50 mph, for minutes. No crawling up, constant 50. And slow revs.

When I swicthed back to 4th gear, it was rapidly went up to 60, but the rev sounded too much, so I switched to 5th again: rev to the skies, screaming, then settling down, and went back to 50mph max.... again.

Like the 5th gear was a 3th.... (except slow revs even with max throttle)

Any idea what's the cause?

Cleaned the air filter ?

Thats the next thing! :) Im going to do that, as luckily the bike is back at my garage finally...

The mechanic cleared the fuel ways, and carb after the fall- so the bike was started normally.

I was able to make some observations:

top speeds in "very high rev" (rev meter is dead, It's just when the fuel tank itself start to shiver, and the sound is high pitch and loud enough for me to stop experimenting...)



1th gear: 15-17mph, "Normal" sounding speed is 5-7 mph....

2th gear: 25-30mph - "Normal" sounding speed is 15 mph.

3th gear: 40 mph, "normal" sounding speed is 25-28 mph

4th gear: 60-62 mph (old observation) "normal" sounding speed is 45-50mph. quite powerful gear.

5th gear (old observation) 50mph, and only low revs.




I know the 5th gear is a problem, but can you tell me, the OTHER gear "top" speeds are normal?

I dont have access to another bike ^^ to test,

so are these speeds seems to be ok for the Sinnis stealth/Superbyke rsr, (not couunting the 5th gear) or are they too weak? Is each gear's speeds fine?





(also according to digital speed measuring signs, (I always approach them with constant speed) my bike cheats by 4-6 mph... ALways show more on it's speedo with 4-6 mph than the truth. Other Sinnis made bikes Ive ridden are the same)

What's the # of teeth on front / rear sprocket? U can calculate & find 1 combination that suits the Transmission ratio http://en.qingqi.com.cn/tech/18098_f...ngtai_text.htm
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Chinese bike's stock carb are eXtra lean... , u may need a fatter main jet / different needle position ...

I have that mikuni carb one thats the same for rmr - I will find out the number of sprocket
teeth, and let you know!

But as far as I know this bike should easily do 70 mph-especially that it lies about it's speed :D so it should do at least 65 in reality and 70 in his speedo. Seen videos where guys do 75-80- Next step aside counting the teeth is to clean the air filter and it's housing- as mechanic says carb should be ok

I dont want to be sounding as someone who wants to race a 125 :D
I just don't want to be dangerously slow on a 70 max dual carriageway. (With CBT I can't go to motorways, but dual carriageways that's the only detour around, have the same speed limit... Only no hard shoulder, so it makes no sense, as they are more dangerous. Especially that they have random 60's areas that very fast come to 40's areas and normal crossroads, instead of sliproads... I was felt off when slowing down to 40 according to the 40's sign, and someone hit me with still 55-60....)
)

Hi, long time no see- had some problems with the network.

So, I checked, and cleaned the air filter, actually it barely had any dust in it.

What can be the other cause of the weak 5th gear? 4th gear revs wonderfully, and I can reach 60 mph in 4th. But as sooan asI switch to 5th, revs go up for a sec, then drop down to a calm level, and no matter what I do with the throttle, (eg: open it totally, or not) the revs in 5th stays low, nothing happens for minutes, and the bike slows back to 50 mph.

Can you think about what can be the cause? Air filter was ok-

It sounds like the bike does not have enough power and the gearing is too high and the engine can not cope with the large gearing and the clutch slips, untill a certain speed where the engine power and clutch slip match up? I'm just guessing :)

-moved it to new topic-