stroking and jetting

[seb4lo]

Hi , i ve stroked my engine , i use no spacer and have machined the head to get a positive deck

 

i ve not yet ported it , only flowed

 

I m using stock RDLC carbs , before stroking i was 220 on main

I ve done a few heating cycles on the engine but the top end seems very strange

 

I d like to know the jets you use before and after stroking an engine without porting it , just to have an idea ...

 

thanks

[seb4lo]

bump

[Ducman]

Most people get port work done when they stroke a motor. The porting alone typically causes them to go to larger main sizes. They also have pipes and many other mods which require larger mains. However, with a longer stroke the motor can more efficiently pull in an intake charge, so with no other changes the main size needed could actually go down. 220 is in the range of the stock main size on banshee carbs with no mods of any kind, bone stock. So you still have a completely stock shee with a 4mm stroker crank? I don't know what you mean by RDLC carbs. Also, what do you mean that the top end seams strange? Elaborate on strange. One more thing, before making major jetting changes, if it starts and runs ok, you should break it in good before making changes because when the rings are fully set, the motor isn't loaded with extra oil in the case, it has reached a steady operating temp and the plugs are able to self clean, it will run a lot different than when you are first breaking it in. To be safe, ride it extra gentle, I'm sure you will since your breaking it in, dont go WOT if you know you have jetting issues unless you are doing it for a plug check. If you are really lean you will melt pistons if you get carried away and do very many WOT blasts.

[seb4lo]

Thanks for the tips

 

In fact , my engine is a 350 RDLC ( 1980-1982 ) engine ( the old brother of the RZ and bashee engines ) , so it doesn't have power valves and it's quite close to a stock banshee engine

 

I ve modified the cases to fit a banshee / RZ 350 crank ( since the cranks are not the same ) , stroked my engine and modified the head , i use WSM log rod pistons on 65 bore and +4 mm and 115 rod

 

I use this engine in a track bike and i run in vintage class , so i have to use the old carbs , i m only allowed to mod the "inside" engine components ....

 

So i ve stroked it , timing is very good in fact only after stroking the engine , i ve not ported it , just flowed it , maybee , some would call this porting but i say porting when i change the timings .

 

Now , it's 188 ex and 126 tr . It s quite compressed about 185 psi , i have to run 100LL avgas , i want a torquy engine so i m pretty close to the set up i want

 

In fact i wanted to know : when you stroke an engine and it s the only mod you do , how goes the jetting .....

 

About the top end , i think i ve got DETO ( not small ping ) when going after half throttle , coming from too lean set up but i thought that going on a stroker , you should lean the main .... so my question ....

 

ps :i ve run it on road 150 milles , nead again some more milles to get the break in finished

 

Thanks for the replly

Edited December 20, 2005 by seb4lo

[seb4lo]

bump again

[demonic shee]

i run a stroker banshee with stock ports and it runs great, from what i have learned is 100oct isnt enough for 185 lbs of compression especially if the timing is advanced, are you running blaster pistons or series 795 pistons, the blaster pistons vs. banshee squish differ 2

[420 RACING]

i run a stroker banshee with stock ports and it runs great, from what i have learned is 100oct isnt enough for 185 lbs of compression especially if the timing is advanced, are you running blaster pistons or series 795 pistons, the blaster pistons vs. banshee squish differ 2