further to my last posting at high revs my engine pinks(70mph)the engine has a 210 malossi fitted ,std carb,simonini sports exhaust,on the ignition side timing is spot on at 18 degrees. the gearing is a 21 tooth clutch sprocket and a t5 4th gear.have tried everything to cure it but to no avail.10 mths i have been trying ,all i can do is keep the revs down to prevent it happening.note the t5 4th just moved the rev range that this happens[:’(]
I would give taffspeed racing a call and get some advice, ask for Terry Frankland.
01633 840450.
Or you could email via their website
www.taffspeed.co.uk.
It would probably be better to talk to him directly.
I have always found him really knowledgeable and helpful.
Hope this helps
Hitman[
]
Hello there. When you say the ignition timing is spot on 18 degrees, has this been set with a stobe or are you just relying on the 125 timing mark on the stator?
I’ve read up a fair amount on the 210 pinking issue and posted a similar call for help a while back - I’m running a very similar set up to yours but with a Scorpion exhaust and 23 tooth clutch, T5 carb.
My timing was initially set to the 125 timing mark which is supposed to be dead on 18 degrees, but read in various places that to get it set correctly you may need to file out the screw holes on the stator plate in order for the timing to be fully retarded for the 210 kit.
I did this (filed screw slots by about 5mm, moved stator clockwise by about 3mm - don’t know how to use stobe, just did it by trial and error).
The result is that my pinking problems were pretty much gone. Smooth power delivery all through rev range. With the Scorpion I still used to get a little bit of pinking when coming off the throttle (not very often though), have now switched to a sito plus for daily riding to work and have no pinking whatsover and it pulls better all through the rev range (lost a little top end speed but more than made up for it with torque, less guzzly on fuel too).
I’m not saying this will work for you but it’s worth trying and only takes half an hour to do. If it don’t work you can just move stator back.
Good luck.
Tom Whip off the flywheel, loosen stator screws and rotate stator clockwise to the stops. If cures and still power, sorted. If loss of power rotate a degree at a time back anti-clock. Main should be around 122. Adjust compression after by using/adding a thicker head gasket, not base as this will alter your port tmings to make it revvier and possibly worsen the fault. With the polini ditto but main around 125-130 due to porting/ pipe
thanks hitman . part of that info i can look at but the octane rating i have had 99. octane fuel + octane booster and it still did it. i will look at bottom end blockage if you can enlighten me anymore thanks. tom[:dance3:]
The ports were only mentioned to try and minimize the loss of power if you were to lower the compression, for example instead of putting on a thick head gasket, you could raise the barrel instead by a larger base gasket; this would lower the compression as well,hopefully without losing as much power. This is only worthwhile doing if the compression is too high.
If retarding the ignition makes no difference then I would try lowering the compression ratio as pinking is caused by pre-ignition, fuel igniting just with heat not by spark [sounds like a bag of nails rattling]. I have read that the malossi 210 is really bad for pinking and that they really need the head set up correctly to avoid it.
Do you know what the compression ratio is?
If you have used the standard head, has it been modified?[:drink:]
cheers hitman .i have not worked out the comp ratio as yet.the cylinder head is std/modified.the pinking that i get seems to happen in the exhaust manifold also the scoot seems to hold back at the point it starts to happen. thanks for telling me it is a common problem on the malossi as thicker cyl heads ,bigger main jets and ignition alterations make no difference what so ever.thanks TOM.
Original von hitman:
I would give taffspeed racing a call and get some advice, ask for Terry Frankland.
You’ll have a long wait,Turbo died nearly 2 years ago.
I’m having a similar problem with a 207 Polini, cases matches, SIP right hand exhaust, PHB30 Malossi carb kit, Mazzucchelli cut back crankshaft, and modified standard head. Placed thick base gasket, changed many main jets ranging from 116 thru 138, seem to worsenig with larger main jet. Time set at 23 or 18 ( according to stator marks), adjusting screw mixture in or out, but no difference. Right now Desperate.
Original von tom-perry:
further to my last posting at high revs my engine pinks(70mph)the engine has a 210 malossi fitted ,std carb,simonini sports exhaust,on the ignition side timing is spot on at 18 degrees. the gearing is a 21 tooth clutch sprocket and a t5 4th gear.have tried everything to cure it but to no avail.10 mths i have been trying ,all i can do is keep the revs down to prevent it happening.note the t5 4th just moved the rev range that this happens[:'(]
I am no expert but the pinking is likely to be to high a compression ratio.
Using leaded fuel substitute may help, or octane booster. But reducing the compression maybe the only answer, especially if you use unleaded fuel. You may get better results with a thicker base gasket rather than head. Although I am no authority on Malossi 210s I am sure the ports will be partially blocked at bottom dead centre.
Hope this helps.
[:look:]
tom, you might also have an air leak?? if airs getting in it will run leaner/hotter which = pre-ignite… also try a hotter rated spark plug, if you have a cool plug from a standard motor, you might find that it gets too hot = pre-ignition. also, like previous posts said, retard it more, ideally strobe it. basically adding a sports pipe ect improves the quality of the fuel/air charge when running at optimal speeds, the better the quality charge the less time it needs to burn and if it burns too quickly then your piston is trying to compress something that is rapidly expanding, hence overheating/pre-ignition. if your positive everything else is set up ok, then retard some more to give it less time to burn. the only problems you’ll get with abit too much ignition retard is loss of low end power (not enough time to burn), hope that helps,
ozzy
I am running a polini(20[H] at the minute and have found a low comp head is needed to stop the pinking. Get a syringe with ml markings and measure the volume of the bowl with oil or other liquid(obviously fit the spark plug first). My head measures 30ml volume in the bowl and about 34ml including the squish (cant take the credit Jerome at Readspeed did it). A shop is best to do this or a freindly machinist who doesn’t mind making a fixture for is lathe. If you’ve plenty of time it can be done with power tools. The slots have been filed on my stator as well and I’ve found this neccesary with every 210 I’ve built. When setting up TS1 Lambrettas 16 degrees is the norm and I see no reason why 210s should be different. I get no pinking from the Polini now and can hold it at full throttle on the motorway between fuel stops (with gt piston). Malossis do have a tendancy to pink so would recomend checking the head volume as well. We did this on another forum and found most shops use a total volume of 30ml including the squish. Olli who distributes the Gt polini piston reports good results from painting the cylinder and head in black heatproof paint (bbq paint is good).He says this helps to dissipate the heat
Johnnystoned you may never clear that pinking as you roll on and off the throtle but I had it for years on my 172 with no bad consequences.
I have the same problem I have the Polini 207 kit and that plinking sound irrates me, can it cause the bike to seize, I found by up sizing the main jet the plinking gets softer, do you have a solution yet , it would help me out heaps, Thanks Clyde South Africa