33hp restrictor >>> Excessive Carbon build up

[drzsta]

so basically i had my drz restricted to 33hp (pointless, but heh ) that cost over £200!!!, the engine is still new with only 6,000 miles.

i had a bike accident and i smashed the fuck out of the stator and left crankcase so i swapped the engine out with an S model with yoshi intake and exhaust cams, but anyway - after i had my engine out on the table (the oringinal one whcih i ran the restricter) i decided to strip it down and inspect it!

https://i184.photobucket.com/albums/x254/FearThis-AK/IMG_5230-1.jpg
https://i184.photobucket.com/albums/x254/FearThis-AK/IMG_6223.jpg
https://i184.photobucket.com/albums/x254/FearThis-AK/IMG_6217.jpg

I found excessive coke buildup on the piston heads, for what is essentially light use! the milling in the barrel is still obvious which shows its had limited running time.

And i've never sat the bike on choke for longer than necessary.

if i pay over £200, i would expect to have my carb jetted for that money - as you can see no such action was taken. if my engine blew threw compression laps (unlikely i know) it would be me to foot the bill

food for thought.
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Current Bikes - BMW S1000RR ‘17 & KTM 690 SMC-R ‘12

[Kickstart]

Hi

What kind of restrictor was it? What carb does it have?

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[drzsta]

the carb is the oem Mikuni BSR36 with restrictive carb top
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Current Bikes - BMW S1000RR ‘17 & KTM 690 SMC-R ‘12

[Kickstart]

Hi

Think it is a CV carb (looks like it in your pics) so the restrictor in the cap is limiting how rich the mixture gets. Possible that they have changed the needle or shimmed it up a bit at the same time though.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[drzsta]

yea, deffo a CV - so how does it the carb top messing with the upper diaphram? eliminate the fact of running too rich, surely its is only there to limit the venturi and thus air?
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Current Bikes - BMW S1000RR ‘17 & KTM 690 SMC-R ‘12

[Kickstart]

Hi

The actual throttle on a CV carb is after that, with the slide lifting up depending on both throttle and revs (stops the down side of ramming the throttle wide open at low revs), and with the needle connected to that slide controlling the mixture through most rpm / throttle ranges.

Thinking about it I would expect limiting the movement of the slide to result in a leaner mixture. Hence quite possible that they have done something with the needle to compensate.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing