Issues with acceleration.

[B1R]

Hello all,

I have what I'm led to believe is a Blata B1 Rep (watercooled). I took it out for the first time today and it seems to splutter in the low rev range. After a while the bike picks up speed and then eventually clears up and runs smoothly in the top-end but when I slow down and thottle back up its back to spluttering. It has no problems with starting. I'm using premium unleaded fuel with Motul 800 Off-Road Synthetic oil (25:1).

Any ideas what the problem may be?

[barnsey]

clutch does it come in earlie or late?
they should come in around 8000rpm
all the springs should be the same legnth in the clutch
also after run in run it at 50:1

[Tz Performance]

Try setting your clutch to come in a bit later and try 30:1-40:1 fuel mix!

[Glen]

those blata rep clutches dont like anything above 7500rpm engagement from what ive tested, they just slip like crazy.

but definitely go to 50:1. the difference is very noticable on the old butt dyno. if you use too much oil you are displacing fuel with it = lean!

[mac90]

Make sure your using a good quality sparkplug NGK is the usual choice
but worry about tweaking it after 1-2 tanks of fuel it may just be tight in the run in period so keep the fuel around 32:1 until its had at least 2 tanks through it then switch to the 40:1 ratio

so for now try a new plug & run the engine in at least 2 tanks of fuel first, it may just be rich down low & clear up after run in period

[B1R]

So many replies so firstly thanks for sharing your knowledge. I should have mentioned the bike is second hand so I'm not sure about the history of it. The previous owner did tell me it is past the run-in period and to run it at 30:1. It turns out I overdid the mix and it ended up being around 26:1 mark (190ml to 5 litres of fuel).

Some of you mentioned the clutch settings and when it comes in. I'm new to these things so I have no idea at what revs it engages, the bike just seems to be fuelly and not burning the mix until it gets higher in the rev range and it takes off.. seems to crackle and splutter around slowly until it builds enough speed to clear it out. If I had to guess I'd say it felt too rich down low or too oily??

The spark plug looks to be chinese (S/S SR8ES).

[Glen]

get your hands on a good Denso W27 plug where are you located anyway? maybe your close to someone that can have a look. diagnosing problems is always tricky on the net.

but definitely clean out the carb first of all if its second hand if nothing else but for general maintanence. 90% of my problems so far have been dirty carb related.

[B1R]

I'm in Geelong, Victoria.

[mac90]

yeah start with a new plug first & see if that helps, if not give the carb a clean out as glen suggested