has enny one put one of the r254 cylinder head kits on to there standared zenoah . and is there much power gain by doing this convergine (im only looking at the 120. head kit not the rear exause hole motor kit). just the head converin as thay sayu it increses comp. larger ports etc.......
if there is much power gain? or rpm difrence idd like to know . as idd like to do one up .
or am i wasting my time doing this. all info would be great.......

I am sure the kit will increase performance over a stock cylinder.
But word is that I have read to date, the top end runs like a mid mod zenoah with most modifing them further attempting too better the performance of the Full mod Zenoahs.

But then again for the $120 cost you can invest that in having someone do so some minor mods to the stock cylinder and get equal or greater performance

If you were too race an engine with the r254 top end ? If under NAMBA rules the engine would have to be run with the QD's and other exotics.

Just my feeling on the subject

ok cool thanks scott,

so realy do you think i should just perchase a sikk motor. or a zenoah with some mods don to it . i was looking at one from carlo from cc racin.. or looked into a qd . but the websit had there motors listed for 600 for a 25qd h torque. but then when i emailed them thay told me that price was reong and it was 800 for motor only-(.
i dont mind spending up to 500 600 for realy good motor but not 800 to 1000. its only for going fast and not racing.. do you think the bonzi motors are enny good. for there price. on a mod 2 seems ok.

If your desire is to have a REALLY strong 25CC marine engine without going $$$$ crazy ?
A modified Zenoah is your best bet !! .... Personally tried the SIKK engines and ultimately was disappointed with lousy reliability.

thanks scott,
mate im very hands on person. would it be not to hard to try doing some mods myself. i have been reading as meany articals on mods my self .and was thinking of doing some or buying a stock zenoah. using a r254 head kit . doing some piston mods and copper gaskits . etc. or should i just buy one from a engine builder. its just ive seen what mods can be done and the power incresses that can be acheved. and also ive been told by some guys that have payed good $$$ for mods to be done and then when thay have pulled there motors down the mods are less then what thay have acheved doing it them self.... if i was to get a new 26 and do the mods ive read about on the forums . would i be wasting my time . or would i get much out of doing them compared to a stock motor.... also is a 813 wt a good carb to use on a mod zenoah and should i try a r254 head kit or just do some mods to the stock zenoah head and piston. or try one of the other head kits avalable.( if you know off enny shops that sell good mod head kits that i can buy to do the build up my self idd . like to know as i cant find enny only the r254 head kit . or the sikk head kit.......if i could get some mod info that would be great........

If your mechanical skills are such that you are comfortable doing porting work ?
Then by all means do your own modifications to a stock Zenoah

I absolutely agree that the degree of mods done by most builders falls short of what can be done by yourself. The information that was shared on HOW TOO modify Zenoahs has withstood the test of battle over the past 5 years it has been around.
Engines modified like this run every bit at well as those coming from the top builders. In local and National races these engine have more than held there own running against the BIG guns !!
Engines like shown in link below have too date set 3 National records, 2 National titles and many many wins against those $$$$ builders.

*The SIKK top end is a 2 bolt like the Zen RC series and just are NOT beefy enough to stay together when you get near 6 HP and 17/18K rpm.

The r254 cylinder is just a reworked / redesigned Zenoah cylinder with an integral water jacket and top cap. Port layout, EX and IN ports very close to stock specs, but different enough to find more HP than a stock jug has.

Here are two links that will allow you to do mods that will find MAJOR increases in power for only the cost of your own time

LINK: www.modelgasboats.com/Magazine...ne_Porting.html

ANOTHER:
www.modelgasboats.com/index.ph...68&catid=14





seahawkwa wrote:

Thank you scott, you have realy got me thinking now. and your nolage on these motors is great . and its great that people do shear there nolage . idd like to be able to get as much info on doing some mods and pics.
i was going to buy a moded motor but after people telling me that most people that sell mod motors dont even use the motors them self with the mods thay sell. meaning yes thay do mods to the motors thay sell but the motors thay use them self are modded more or better . and after seeing that some mods thuy do are not much at all. idd prefer to do step by step and try some of the simple mods myeslf . in sted of forking out $600. on a motor that only realy has say $50. worth of mods done to it .

agan thanks scott. for you info.....

LINK: www.modelgasboats.com/Magazine...ne_Porting.html

ANOTHER:
www.modelgasboats.com/index.ph...68&catid=14

scott that last link just takes me back to the home page ... was there more tips on mods in there somwhere ....
dose ennyone sell books on modding this motors or somthing...
i dont have a printer and would like to have some info on paper and pics .... as from what i read if all this things are done nice a steady and slowly the motors chauld gain good power. what base cylder gasgets do you recomend to use...
thanks.

The best cylinder we have tested for the Zenoah is the M&D cast cylinder. It is second in power to the Quickdraw, and the complete engine costs about what a modified Zenoah does.

Lohring Miller

thanks lohring ive just been looking at that site of m&d desine. somone just today sead there great motor builders. so there heads are available singly. ive just purchased my new zenoah Donner motor to use to do some mods . and see how i go . now of looking for a good tac for rpm ... well now the fun begines . enny other build info would be great also . for engine mods