Wow, thats just AWESOME. :hammer:

 

Incredible bit of kit there nOfea4r :bow I can't even imagine why driving something like that would be fun! :lol

I can't really offer you much in the way of advice on actual cam timing numbers because I'm not crazily experienced with early carb R1's runnign std. cams but I will ask if there's any possibility of you replacing the std. cams with aftermarket performance ones as you'll gain a lot of power up top there with the right choice.

Are you not allowed to do that under your racing rules?

 

Thanks for your answers!
1 year ago was the first time we saw this kind of 4-stroke bike-engines from the inside because we ran 2-stroke engines before.
Due to that we only did the obvious things to the head, smoothing the ports (not polished), sharpen the edges between the channels and fitting the port size to the carb and exhaust diameters. After that the valves were grinded.

We did not change anything to the combustion chamber and compression due to lack of experience. We wanted to stay on the safe side and didn't want to change too many things without having run the engine. :scared
During the season there is no time for changing much. This winter we want to try new things and do the next step.

There is not that much money, we built the complete boat by ourselves and have 3 ~600$ engines from ebay, one was built last year, 2 are completely stock yet. So you get the idea of our budget :hammer:

I did a small video some time ago (only amateur filming):
http://www.youtube.com/watch?v=8YdwJoXHOdE



The rules allow to run aftermarked cams. But I thought most of them will only give more power at very high revs. But most of the time is won during acceleration. At high speeds the boat is flying (very few drag) so even with a slightly "falling" power-curve it will rev further.
Maybe there are cams with higher lift and only slighly longer duration? How should a cam be to gain power from 8000+?
What would you say would be a good option from your experience?

I know very little about cam timing but I do know that if you go higher lobe centers in general it'll make more power on top.
I think your Idea about 109/100 is a great place to try & see what happens.

another thought, has your squish been adjusted properly?

The squish isn't changed. From my understanding it won't be changed by milling the head 0.35mm as we plan (Thats not so much but p-v should be on the safe side, too)?
Would it be the better option mill the head a bit less and remove one leaf from the std. head gasket?

Im afraid of having too few p-h clearance since the enginge will rev 12500+ for 75% of the time and will rev 13000+ when the propeller leaves the water.

Am I right that one leaf of the gasket is 0.25mm? Well I don't know if that will work out because we have absolutely no experience with this.

Regards

 

subscribe

 

I know very little about cam timing but I do know that if you go higher lobe centers in general it'll make more power on top.
I think your Idea about 109/100 is a great place to try & see what happens.

another thought, has your squish been adjusted properly?

 

you are asking for trouble reving that high with a std valve spring:fact the redline is 11,800 with std valve springs. there is a reason they dont rev to 12,000+ on our bikes. and the same would be true in a boat.your best bet is to bump compression or you will have to spend money on aftermarket valve train components. changing cam timing or ignition timing or velocity stack length for that matter changes the 'characteristics' of the engine without really adding horsepower. the really get 'more' power you need cams or physically changing compression.

 

I think the std. valvetrain has no problem reving higher than 12000rpm.
There are many posts in this forum telling the same.

I would say a whole season reving nearly 13000 with many impacts due to propeller verntilation that will never happen as though in a bike backs that up a bit. Everything looks like new after that season, no indication of wear.
To be honest we are really impressed by the quality and the durability of this engine.

The question is not whether raising CR or not, the question is how (mill head only / mill head and remove gasket leaf etc.) and how crucial p-h and p-v will become at high rpm like this.

Since we want much torque in a wide range at mid to high rpm and don't bother about low rpm changing the engine characteristic is exactly what we did and want to do further and what these questions are all about.

We already got massive amount of power-gain with the actions taken. But more important than gaining max. hp values is where the power is in the power band and how surface area under the power curve from 8000-13000.

We can't change to a lower gear to be in the range where the power is, we have to get the power where we need it.

Regards

 

well a combination of angle milling ( needed with 5 valve heads) and thinner gasket is the ticket, depending on final cam specs and measured p-v and desired p-h. have you played around with ignition timing? maybe playing around with advancing and retarding might help?

 

for info on milling etc, try here. it's got plenty of reading/info.
http://borg20012.tripod.com/service_section_index.htm

 

We tried very much with the ignition timing and went with a few degrees more advance between 5000 and 9000rpm. This helped a bit but it doesn't nearly change things as much as on a 2-stroke engine.
Top end is still a bit on the safe side.
I guess there will be some work to do after raising the compression.

We can't do angle milling by ourselves so I should find someone I guess. What price-range I have to calculate for a good job?

Thank you for the link this is very helpful!

 

I think your Idea of milling .35mm is probably on the safe side but without measuring I can't say for sure.
I would also remove a leaf from the gasket to adjust the squish.

do you know how to measure p to v & p to H?

 

The engine is completely apart at the moment and we did not measure the clearances before.
We want to make 2 engines race-ready. So what squish and which p to v would you recommend for reving up to 13000 with std rods and - for the time being - std cams / valvetrain?

I would just use some solder to measure p to h and a soft spring and a gauge to measure p to v? Is there a better method esp. for measuring p to h?

why arent u using a 2 stroke engine?

We used a 2 stroke engine from 2003 to 2006. The main problem is that there is a 1000cm? limit. So either you put smaller sleeves and pistons on a 1100 or 1200 engine or you go with a 750 / 900 engine and bore it up.

We used a 900cm? Kawasaki 3 cylinder engine before. There is a lot of power, but the power band is just too narrow. We spend so much time in tuning this 2 stroke engine, even with 3 pipes adjustable during driving, water injection etc.

But with the R1 engine with the gearing we have very much torque at the propeller over a very wide range -> good acceleration with bigger prop with same max-rpm at the propeller -> more topspeed.

There are a lot disadvantages with the 4 stroke engine like its complexity, weight etc. but our first try with the r1 engine gave us 2 seconds per lap over our high-end tuned 2-stroke engine. Cost of 2 stroke engine: min 3500? + tuning. Cost of R1 engine so far: ~1400?. The decision is easy then. :epimp

The top 5 in our class are using 4-stroke bike engines (CBR SC44 and R1 RN01/RN04).

If we had rules like the american hydroplane 1l mod class where 1.2l 2-strokes can be used it could be different.

 

why arent u using a 2 stroke engine?

 

Hello,
...

OK Here are some answers on the issues you raised. Yes, with std cams you will be fine milling the head 0.35mm aka ~15 thou. No problems there, you have plenty of P/V clearence. Try a bit more wide valve clearences though ok? You can also, with this spec, (aka std cams, 0.35mm off the head), remove the center leaf from the std head gasket and impove your squish to 27 thou. And also raise even more the compression. You will still be fine as to P/V safety issues. I know cause I have measured this engine extensively.
Std valves and std valve springs are ok until 13000rpm. Also the std con rods. You need though to remove somehow the rev limiter from the ECU.
Time your cams at 106/104, and play with the needles on the carbs. You want to back off maybe one circlip position to get rid the flat spot at 8000-9000rpm. Its definitely needle related issue. And ask Ivan what float height recommends! It definitely needs to be set correctly if he says so.
There are aftermarket cams with higher lift and almost same duration or both aka more duration and higher lift. Look at kent cams website. Their power band will start at 8000rpm which is not that far away from the min 7500rpm you have set. These are not cheep at all though as they made as billet!
Finally when you've done all the above use a 4 degree ignition advancer if you can afford it in your badget. Its not that important but if you can get it, use it.

Regards,

PS: If your motor is std you dont need to measure the squish P/V etc. Just mill the head and remove the center leaf that will give you more CR and 27-28 thou squish with no extra cost of machining the deck. 23 thou squish is way too close, it will definitely touch with std rods and compromise the reliability of the motor in the long term. 25.5-26 thou is much better. Squish effect takes place at about 27 thou so 25 thou is not really that great improvement as it is, say, from 30+ thou down to about 27 thou.

 

advancing the ignition will lose total horsepower. even ivan says so. and besides he has programmable ignition.:fact and he must have something already that has removed the rev limiter?

 

Could be the YEC box you were seeking answers to?

EDIT Perhaps not with '02-'03 coils.

 

Thanks for the tips BSR and boxter!

We have all 3 engines apart now and have to do lots of work on the 2 new ones (Clutch removal, gearing etc.) before tuning. It will take some time at least one month since we change many things on the boat, too.

On the ignition:

We are using a fully programmable ignition from http://www.ignitech.cz/
It is called TCI4P. There is a newer Version out (Racing3), but the TCI4P is everything we need. Unbelieveable how economically priced it is.

The program used is here

We already used this on the 2-stroke engine and have never had problems. There is really good support, also. You can use it for every engine max. 6 cylinder.

Maybe you guys are interested in this one...

 

On the ignition:

We are using a fully programmable ignition from http://www.ignitech.cz/
It is called TCI4P. There is a newer Version out (Racing3), but the TCI4P is everything we need. Unbelieveable how economically priced it is.

what language is used on that website? I can't seem to translate it.

 

There is a Union Jack on the left hand side of the linked webpage, Click on that and it magically translates it into English.:boobies

Otherwise:

http://www.ignitech.cz/english/aindex.htm

 

There is a union Jack on the left hand side, click on that. Magically translates it into English.:boobies

http://www.ignitech.cz/english/aindex.htm

Spoilsport... :2bitchsla

God I feel like a fool.

 

If it hasn't been mentioned, why not run a Yamaha Apex snowmobile engine?
No gear box, and the PTO is gear reduced by 1.2333. Thus multiplying the torque output by 1.2333!!!