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Bike does not drive/pull

Posted: Thu Mar 20, 2008 12:54 pm
Author: HarrisTZ
Gents
I have been scratching my head on this one. :| Basically, I have rebuilt my 1170 engine started the bike but when I tried riding it it would not pull off in first with the usual umph as expected. The clutch does not fell that it is dragging. It has norris cams which have been dialed to std cam timing. I have put a CR gearbox in with 18/42 final drive gearing. Ignition is Boyer set to static timing ie rotor set just below left pole at with engine at TDC
Any thought seriously appriciated.
D.

Posted: Thu Mar 20, 2008 1:09 pm
Author: Surfdeneige
I presume you have checked to ensure it is firing on all 4?

Posted: Thu Mar 20, 2008 1:20 pm
Author: HarrisTZ
Yep.
Got all 4 cylinders now as I fitting Denso plugs after following a thread about how crap NGK spark plugs are.

Posted: Thu Mar 20, 2008 2:06 pm
Author: RALPHARAMA
You don't say if you have had the bike running nicely before with all the trick bits.

Does it sound as though the engine is missing as you increase the load? I'm not a big fan of static timing. Normally static timing uses the 'F' mark as the fully retarded mark and there is another mark to the right of that for fully advanced. I would be inclined to used a timing light on it when it's running.

What about carburation? Big loud pipe? S&B's/K&N's? Have you jetted the carbs to suit the larger swept capacity, hungrier cams freeer flowing zorst/air filters. Does the main jet need want to go up a mark?

HT leads in good shape? Healthy coils? Sparks that look OK at the plug can breakdown under compression.

Posted: Thu Mar 20, 2008 2:48 pm
Author: HarrisTZ
The engine is a fresh build from an aquired engine, I never had it running. It now has .425 lift cams, oversize exhuast valves, ported head, open swept exhuast 4-1 system, wiseco 10.25 cr 1170 kit, CR carbs. All good stuff. That is way I am I little disapointed at the mo. It is a bugger initially to start then after that no problem. Will try to strobe later.

Posted: Thu Mar 20, 2008 3:12 pm
Author: RALPHARAMA
At least once you have performed the dynamic timing, that rules that out as a problem or if you're very lucky will cure the problem!

The problem with sticking a whole load of parts together from various sources, is that you will invariably need the help of a skilled tuner such as Steve Debben with a dyno. I know the pitfalls of tuning but I'm not a tuner myself. Steve is a member of this club/forum. He is very helpful with advice. I am sure that he would be happy to help. He gave me some very usefull advice when I was building my engine. His web site is http://www.debben.co.uk/

I suspect that even if you get it running smothly you will benefit from a dyno session to get the best out of your investment.

Sounds like your bike will go like split shit when it is set up!

Make sure you post some pics!

Good luck

Posted: Thu Mar 20, 2008 3:14 pm
Author: Steve R
Best Money in terms of pounds per horses is to now get it set up by someone good on a dyno, doesnt matter how many good bits are on it if it is not set up properly at best it will be down on power, at worst you will end up damaging the engine.

Will be very interesting to see what it puts out?
:twisted:

Posted: Thu Mar 20, 2008 3:15 pm
Author: Steve R
Ralph you beat me to that reply by 2 mins you must type quicker than me, havent you got work to do?? :lol: :lol:

Posted: Thu Mar 20, 2008 3:45 pm
Author: HarrisTZ
Thanks to date.
I welcome any other comments.
We'll see how she performs this week end then ship her to reliable Dynoman. Any recommendations in the Midlands area. Thought about Strightline over in Kings Lynn.
By the way Ralph, Love the Graphic. Tried to copy and set but she does not move. Story of my life.

Posted: Thu Mar 20, 2008 6:39 pm
Author: Pigford
STRAIGHLINE ARE VERY GOOD :wink:

Who modified the head, for the .425 cams.... and hope ur running under-bucket shims :shock:

Posted: Thu Mar 20, 2008 6:46 pm
Author: Rich
Sams Dyno Hilton/Hatton. Check the pilot system on the carbs.

Posted: Thu Mar 20, 2008 10:29 pm
Author: big green bus
what filters are you running ? the cr's are funny to setup. do you have the plastic bellmouths for the cr's? they put the slow running jets outside the bellmouth air flow.

Posted: Thu Mar 20, 2008 10:48 pm
Author: HarrisTZ
I answer to the latest questions
I have knocked the pilot jets down to std 58's. No bell mouths fitted yet. Not sure what size to fit. Does anyone have any spare.
It has a GPz head so underbucket shims std. SEP finished the head off.
D.

Posted: Fri Mar 21, 2008 5:51 am
Author: london calling
With fitting the close ratio box,1st gear will be much higher.
Have you calculated that you'll need an 18 tooth front sprocket ??

Posted: Fri Mar 21, 2008 8:59 am
Author: big green bus
go onto the sudco web site they have a chart on the cr's it may help.