Topic: STROKER project, keep your children away

[mec]

long ago, i did a ride with a sohc. suddenly the bike stopped. there was something wrong with the engine. i removed the cap tapped hole on cyl 1 and 4. it was a great surprise that i could see the valves working on cyl 1, but not so on cyl 4 when rotating the crankshaft. it was a miracle to me. this made me philosophiing about god and the world, is the world a disk, is there a god anywhere? I rotated the crank again, same miracle. a short visit in the near church did not help either.
bringing the bike home, i started to disassemble the engine. wow, the camshaft was broken in two, one cam bearing heavily destroyed. it seemed that i goofed in rebuilding the engine two days ago. maybe a tiny little piece of dirt remained in the oilpassages up to the camschaft. this dirt plugged the oiljets under the camholders.

i tried to solve the head o-ring problem my way: i fabricated an alu washer 7.2x11.5x1mm, this will hold the o-ring in place.

two gear levers made from 7075.

mec

[mec]

yesterday was time for assembling the upper end.
another strange find and a lot of good luck: mounting the pistons i found that there was no axial play of the piston pin in two pistons. did not bother me, i thought. a last inspection of the seated pin circlips and it seemed to me, that there was approx 4mm distance of the open end of the circlips. but there was one circlip with 3mm open end however. i checked another time all others, one more circlip with 3mm. both in the pistons without axial pin play. i tried to seat the circlips correct...no chance. i removed the circlips, pins and piston and recognized that there must be the pin a nuance too long. i remembered that i measured the pins (during weight control), all had been the same length. this leads to the conclusion that the distance between the circlip groove is a little bit too small. i shortened both piston pins by 0.2mm, and voila, every circlip was easy to position the right way.
why i tell you that? building a race engine you have to control everything, really everything. i have learned that during my "career" as a modeller flying all the electro powered, methanol and/or kerosin powered model airplanes. if you rely on the manufacturers, you will crash. you have to recheck all by yourself, even brandnew items.
all the racing stuff is not proofed as the oem stuff is.

today was time for degreeing in the cams. engine is now ready for break in.

the next days i will make an engine swap and after break in some dyno runs.

mec

[KB02]

Wow. I can't wait for those dyno runs!! I know there will be lots of pics, but post some video if you can, too.

[mec]

it took 1 and a half our to get the carbs on.
two persons worked, we needed a heat gun, 3 belts to achieve the desired force and some drops of oil.

mec

[turboguzzi]

Hei MEC, looks good, we're all looking fwd to those dyno runs

Dont know what are your plans for running in but just wanted to say that many tuners use the dyno itself to do it. 10-15 pulls, starting from 50% throttle/75% rpm up to 100% on both and thats it.

TG

[mystic_1]

Looking good!  The speed and quality of your work puts me to shame

mystic_1

[MRieck]

Mec
 I believe you said you are using 34mm carbs. Those carbs look like Mikuni RS but just a little different. What are they? I'll be using the Mikuni 32mm TMR carbs on my 1000cc engine. Very nice with the roller system for the slides....very easy throttle pull.

[mec]

i am not sure, i bought them from ebay.
but i believe they are called Mikuni RS34 (from a GSXR1100?).

the TMR are awesome. my first choice, in case i build a super bol d´or again.

mec

[mec]

Hei MEC, looks good, we're all looking fwd to those dyno runs

Dont know what are your plans for running in but just wanted to say that many tuners use the dyno itself to do it. 10-15 pulls, starting from 50% throttle/75% rpm up to 100% on both and thats it.

TG

i am not a friend of long run break in periods. knowing that racing engines do have a short lifespan, i want to have fun with the engine, not to waste my time with run ins.
but half an hour or so at variable speeds and afterwards dynoruns, thats my plan.

good and bad news:
the engine runs fine, throttle response is good, vibrations minor, and it sounds different, not what i was used to hear.... but the engine suffers two oilleaks. one that does not bother me, oil is coming out from the crankshaft where the stud is located fixing the ignition advancer. i will have to replace the o-ring by a bigger one.
but the other one is much worse: the PO crashed with this cases and did weld the engine mounts very careless. further runs will show the need to fix that issue. soon the engine will have to be seperated from the frame again to do the obligatory maintainance work. eventually this is a chance to fix this problems.

mec

[Terry in Australia]

Beautiful work mate, very inspiring, I feel like going out to my garage and machining something up, ha ha! Cheers, Terry.

[mec]

update:

engine has run 4x10min fine.

when the bike stands still, engine is running flawless.

however: two times i did a testride for approx half a mile. the streets are dirty and wet now, therefore it makes not much fun and sense to drive a longer period.
one time it was difficult to engage into first gear (engine running, bike standing still). i do not know the cause of this problem till now. i removed the gear cover, but didn´t find any mistake.
but most off all i am concerned with the following circumstance: i accelerated in first gear to approx 4000rpm, shifted into second and closed the throttle to decelerate. this change from acceleration to deceleration made some ugly noise in the engine, for 1 or 2 seconds only. the other time this happened again, i think it was in third gear now, again changing from acceleration to deceleration.
there is one idea that comes to my mind: are there issues with the long and heavy hivo primary chain? i remember, it was a lucky circumstance that the hivo chain fitted more than well onto the shafts concerning the length and tension of the new chain. there was beneath no slack of the chain, fitting the primary shaft very exactly into the cases. chain tensioner is the cb900f bol d´or type, spring activated without hydraulic dampener however.

first of all i removed the oil pan to have a look inside the cases. but found nothing wrong. i was curious to find any metal flake, chips. but none.

next step is to do the dyno runs. just curious if we will encounter the same issues. eventually this problem shows up in a certain rpm range only. before i will have a look in the clutch regio to make sure that there is no hidden problem.

is it possible that the long hivo is running into "self-frequency vibration" problems?

mec

[Terry in Australia]

Yeah, I suppose a low frequency vibration is possible mate, but how much longer is the hyvo chain in your engine than say, a CB1100F? I'm guessing that it's clutch related, you don't have a busted clutch plate, perhaps? Cheers, Terry.

[MRieck]

Extra plate clutch packs will make shifting difficult at a standstill. Are you running an aftermarket clutch pack? HyVo chains are heavy and the acceleration to deceleration puts the most strain on any chain....it wants to "open" up. It may be bottoming the tensioner unit

[voxonda]

Do you use a glider strip in your topcase? Maybe the chain hits the topcase?

[MRieck]

Do you use a glider strip in your topcase? Maybe the chain hits the topcase?

I'm very sure he is Rob

[mec]

Yeah, I suppose a low frequency vibration is possible mate, but how much longer is the hyvo chain in your engine than say, a CB1100F? I'm guessing that it's clutch related, you don't have a busted clutch plate, perhaps? Cheers, Terry.

cb900 (and so do 1100F and R I think) uses 52bolts, my chain is 70bolts.
I will have a look at the clutch soon.

Extra plate clutch packs will make shifting difficult at a standstill. Are you running an aftermarket clutch pack? HyVo chains are heavy and the acceleration to deceleration puts the most strain on any chain....it wants to "open" up. It may be bottoming the tensioner unit

+1
my clutch pack comes from dynoman and has extra plates. but it is the same as I use in my "small" 1000ccm engine. there arent such issues. the only problem is when oil is cold, then the clutch is not willing to disengage completely. but thats I can live with.
I agree with you, the chain may be bottoming the tensioner unit.

there is a question I was not able to answer till now: should I modify my tensioner to be adjusted by hand and be fixed? this means that the chain will be rubbing against the tensioner heavily under deceleration all the time. i do not know if it is a good idea to go this way.

Do you use a glider strip in your topcase? Maybe the chain hits the topcase?

yes, there is a primary chain guide in the upper case.


mec

[j-conn]

awesome read!

good luck mec!

[Flying J]

I obviously am not as well versed in motors as you but i thought id throw this out there. My 550 made a clanking noise when i decelerated as well. It was the drive chain. When I down shifted it put slack in the top of the chain and would hit inside the cover.

[mec]

doing my first test ride, hearing the noise, i had the same thought. the drive chain was loose too.
I set the chain to the proper tension, but again this ugly noise.

a few minutes ago, i inspected the clutch compartment. everything fine, no problems detected.

dyno runs will be done wednesday 9th of dec.

mec

[mec]

hello,

today was the day

for comparison I took my cb1100r with me and put it on the dyno as well. cause the engine stood still several years (exept one test ride done a few weeks ago) the motor had some ugly misfiring the first runs but performed better and better each run. we did only 4 runs, the last run showed a smooth HP curve and ended at 100 rear wheel HP at 9000rpm.

next step was the stroker.
I gave the engine another 15minutes of break in under various rpm conditions, changed the gears and simulated a test ride. suddenly in first and second gear this ugly noise coming from the transmission. at this time I was sure that the row came from the transmission. changing gear immediately to third, fourth and fifth and everthing was fine again. I stopped the engine, removed the exhaust silencer so that the noise was not heard any more.......no, no, no, I removed the silencer because I was preparing the bike for its first performance run.
I decided to do so, because the test runs are done in fourth or fifth gear.

mec

[mec]

I will make it short: the test results had been a little bit disappointing at first. the engine does have approx 5hp more than my 1000ccm over the complete rpm range exept at high rpm. at 7500rpm it does have 107hp as well as the 1000ccm, above it is weaker hitting its max of 110hp at 7600rpm. from 3200rpm to 7200rpm the torque is better with a max 105,5NM at 6988rpm.

intepretation of the dyno chart:
it was a mistake to do the dyno runs with old, used spark plugs. the air/fuel chart shows that the engine is running on the lean side at high rpms. and best of all, back at home, i found "the great mistake": at high rear wheel rpms the rear wheel rubbed against the swing arm what explains the lack of hp at high rpms. it seems that I will do further dyno runs on day. it is not easy to estimate how many HPs got lost due to these errors, but i am confident that the engine will outperform my 1000ccm motor  

at the moment the engine is seperated from the frame, waiting for the crankcase repair, retorquening of the cyl studs and finding out whats wrong in the transmission.

mec

[Sam Green Racing]

I guess the tyre was rubbing at the front due to centafugal spread, good job there seems to be room to pull it back.
Well done Mec, should see the bigger figures next time.

Sam.

[mec]

I guess the tyre was rubbing at the front due to centafugal spread, good job there seems to be room to pull it back.

Sam.

you are right.
I had to mount a big (48t) rear sproket cause of the longer primary gear. this was the cause , the rear wheel was positioned in the max forward position.

mec

[Sam Green Racing]

Just another link in the chain, easy fix.

Sam.

[mec]

I took a look inside the engine, retightened the head. everything seemed fine.
the primary chain is a little bit on the loose side, to my surprise. i can move the chain 1cm up and down by hand. the chain had much more tension when new. I am hoping it will not lengthen much more in the future.

the mystery of the noise in the transmission is solved: there was a washer missing beneath 5th gear. why 

the cylinder does have some oil leaks. I gave devcon F a chance, hope it will help.

the next days I will try to do the repair on the broken case.

mec